E30 Zone

Hello all.

I'm new on this forum so hello from me.

I'm a heating engineer/plumber from Bristol and I love cars.

I have just got an old flame back in my life... the e30.

I bought my car a few months ago from an enthusiast with a supercharged m20 in it.

I have been experiencing some engine issues and would like to share my experience in the hope of getting some sound advice/direction.

History:

The engine is an m20 from an E30 325. It was put together last year by the previous owner from a bottom end and top end built by a chap called Byron in Wales.

The spec is confirmed with receipts and as follows:

Ireland Engineering 135mm H-Beam rods - M20 spec - include ARP bolts
Ireland Engineering MLS Head Gasket - M20
Ireland Engineering Oil Pan Windage Tray - M20
Ireland Engineering/Ross Racing Custom Forged Pistons - M20 (885 head, 85mm bore, 8.5:1 comp for 135mm rods, 84mm stroke)
ARP head bolts
Lightened flywheel

I believe this is somewhere near a 2.9 stroker.
The head is apparently re-worked but I cant confirm or get confirmation on exactly what has been worked.

Rotrex C30 94 Supercharger kit
Stage 3 DriveTorque clutch
S80 Pro ECU and DTA wiring harness
2.5l swirl pot
Red Top lift pump
Bosch 044 pump and twin filters
VR6 coil packs
Magnecore HT leads
Custom CAT Cam 264 Degree- full specs available
Nice 6 branch exhaust manifold
Bosch 42lb / 440cc injectors

436BHP, 360ft/lbs at the flywheel - (data taken from rolling road during my ownership)

Here is the story:

I bought the car knowing that there was going to be a little work to do to get it ready for some track use. The engine had covered 4000 miles running on a ”˜safe’ map that was done when this engine was originally put together. It was long overdue a proper map and had clearly not been given a proper run for its money. I was also told that there was a rev limiter on it, set to 5k which was done at the time of the original map. The original map was clearly quite rich.

I loved the look of the car, I really liked the guy I bought the car from so I had some faith that it should be ok. The car is quite well known and has appeared in a few magazines and has won numerous trophies at custom car shows.

Once I got the car home I had covered 30/40 miles and it was clear I needed to make sure the engine (being the most expensive bit) needed to be tuned properly before driving it again. I have had other issues with the car that I am dealing with (wiring & brakes to name a few) but the issue I want to get to the bottom of most is the engine issue I have recently discovered.

Firstly it may be worth mentioning that the previous owner is not what I would consider a driver, he is a custom car guy but doubt he will ever have driven the car like I drive mine. He makes a car look great, is a brilliant fabricator but my attention to detail performance wise isn’t his priority. This is by no means a diss on him, I’m mearly pointing out that I don’t believe he would have necessarily cared about the little issues I found which have lead me to my discovery, enough to have found them himself for some time, if at all. I like the way a car looks, I love a clean car and i’m very particular but through the years I have seen enough engine trouble to know that a catastrophic failure on track is a terrible experience (engine blew up on the Nurburgring a few years ago to name one) and before a car goes anywhere near a track, the engine needs to be in tip top condition. I probably didn’t look hard enough at it when buying the car in the first place TBH. I say all this so as not to hold him personally responsible in this report, if he should read this - I am not making a public attack. However if he should read this and want to offer some advice or help in some way, he is very welcome”¦ I’m sure he will at least regret verbally guaranteeing the engine once he has read to the bottom.

I arrived home from purchasing it.

I noticed the engine oil level was on the minimum. I called the previous owner and he apologised for not checking and confirmed he was using 5w 30, fully synth.

Personally I think 5w 30 is too thin for this particular spec but the oil debate is too much for now - needless to say, running the engine oil this low isn’t ideal. I topped it up.

I planned an oil change with 10w 50 as its not my daily, when installing an oil cooler as it doesn’t have one.

I also planned on fitting an oil temp sensor/gauge as it doesn’t have one of these either.

I noticed the engine (which has no idle control valve) was very lumpy at idle and missed a little when cruising and the engine cut out when floored.

I thought the rev limiter was the cut out issue, although it was hard to determine exactly if it cut out at the same rpm or not.

I also noticed that the coolant temperature gauge was only running at 60 ish.

I booked the car in for a rolling road tune at Circuit Motors (next to castle Combe) as they knew the car from the previous owner and had set up the original map it was running on when I got it. I’ve never used them before, they were very difficult to get an appointment with but they said they knew the engine builder Byron and that they would regroup with him to check on all specs ready for the final tune. I thought this sounded the best option rather than finding a different tuner, however even 6 weeks later this hadn’t happened so I was beginning to loose faith. I finally managed to get it booked in albeit without the consult from Byron.

Before the tuning date around a month ago I carried out a few checks. I charged the battery, started the car, checked the usual stuff. It was wierdly only firing on 5 cylinders. I checked the plugs - all an even colour. On further inspection one of the porcelain ends was loose! It was from the cylinder closest the front (cylinder 1, I believe)



I did some research on the plugs that were used. They were Bosch Super Plus WR7DC. The gaps were 0.029 to 0.031”a These are ok for a well tuned car but maybe not perfect for a 400 odd hp car with a supercharger.

I put in some NGK BPR8ES plugs gapped to 0.025”a

The engine took a while to fire but was fine once going, still lumpy on idle but not as bad as before.

On the drive over to Circuit Motors, another 20/30 miles, the rev limiter had miraculously gone. I think the spark plugs were not quite as cold as they need to be and the gaps were too big? It was like chalk and cheese. No missing a beast either.

The car was strapped down on the rollers and Layton at Circuit Motors went about his work. As we couldn’t get hold of Byron to find out if the springs were uprated in the head or even exactly what work was done to the head and the previous owner couldn’t remember - rev limit unsure and so was set to 7k after running it for an hour or so.

All seemed well. The result was 436BHP, 360ft/lbs at the flywheel with 19psi boost at 6700rpm. This is quite a bit less than the previous owner thought it would do but I thought this was a sensible good result. The C30 Rotrex supercharger is only rated to circa 440bhp anyway.

The car was unstrapped and Layton went out for his final check drive and was gone for quite a while.

20 minutes later he limped into the forecourt with an overheating car.

The coolant temperature on the laptop from the DTA ECU sensor showed 105 degrees and this was assuming of course that there was water surrounding the sensor. The coolant gauge was still only at 75 so it was clear that this was completely wrong although Layton had been reading his own temperatures from the laptop.

We checked the water level which was low, put water in, bled it etc the temps all dropped and the car seemed to start and run fine. There were no signs of anything else wrong so we assumed that the level had been too low or an air lock or ”¦.. anyway, it was fine now”¦..so test it”¦.

So off he went again for his test.

He limped in pretty quickly and it was clear there was a water leak, the clutch had been slipping and water was gushing through the bell housing and out the bottom from somewhere up high but below the head. It took us ages to find where it was coming from, we had it on the ramps, it was very difficult to see. As soon as the engine was turned off and the steam cleared, the least couldn’t be seen.

Long story short, the car was run far too long without the correct amount of coolant in my opinion but we eventually found the problem as being a cracked freeze plug which only seemed to open up when the engine was running and up to a temperature.

I was gutted and concerned about the whole experience.

The car was trailered home.

Once it was home I was obviously going to worried about the head/head gasket etc.

I set about replacing the freeze plug, which I did in situ and it was the one furthest into the bulkhead!

I checked the spark plugs to find number 5 to be much darker than the rest. I decided to get another set of new plugs, re gapped them then put all the bits back together, put a new coolant sensor in (to match the gauges) bled properly etc and got it running. All seemed good.



The oil had no signs of water and the water had no signs of oil. Also it seemed to pass a hydrocarbon test.

There was some blow by but I had read that this can be normal on forced induction engines.

Road test.

Wow. The car ran like a dream on high output although a touch lumpy down below. Really fast. Nice.

I did notice however that at full chat high revs (I didn’t hit the limiter though) it ran really well but there was a slight pinging or rattling noise.

On my return to home after 15 miles I looked into the engine bay to find oil all around the bottom of the block near the bitch tube. It looked as though the oil was leaking from the top and the bottom of this tube. I thought maybe the rattling noise was down to the spring on this tube being moved erratically as the blow by (which hasn’t been managed properly yet) pushes its way out a bit.

I checked cylinder number 5 and it was dark again.

Research led me to the breathing set ups on forced induction cars where some people just vent to atmosphere and some through other means but it was clear from the open to atmosphere set up that I have that the blow by really needed to be managed as clearly crankcase pressure was high.

I took the inlet manifold off to get the bitch tube out to sort the issue of the leak whilst thinking about the dark plug. I have planned an electric crankcase evac pump to suck the crankcase pressure out. More later.

The inlet manifold gasket had oil between the gasket and the head and it was clear some of the leaking was from here! The manifold didn’t come with its rocker cover bracket which i ordered up. Maybe it was too loose without the brace?

To be honest, oil seemed to be a little everywhere, something I should maybe expect with lots of forced induction and no proper crankcase evac/ventilation. Some will say there shouldn’t be any blow by anyway”¦ maybe they are right..

Compression tests all came out good, 170-180 for all.

As the manifold was out, I sent all the injectors off to get tested and cleaned to see if one was running rich, maybe explaining the dark plug. The results were inconclusive as they were all fairly similar.

I plan to somehow test the VR6 coil pack but haven’t as yet properly researched this..

I also carried out a leak down test and found there was 20% more blow by on cylinder 4, 15% cylinder 5 and 10% cylinder 6. All the others where spot on. The air seemed to be passing the rings rather than the valves etc but I’m not an expert. However this was all enough for me to justify pulling the head which I did.

Good pistons leak down reading:



This is what I found:





Piston no.6



Piston no.5



Piston no.4



There are chunks missing from the 3 pistons nearest the bulkhead. One of the chunks looks as though it has been pulled up which shows it happened on down stroke or from the piston ring moving up or ??

I’ve noticed there really isn’t much meat on the bone between the ring and the cut out for the valve. A design flaw?

The bores on the 3 good pistons look like they have never been used. The bores on the damaged pistons look as shown in the pictures - there are visible vertical markings although I can’t physically feel them.

There are no marks on the valves from hitting the pistons:







I’ve managed to put a very small scratch on the head between a dowel and the cylinder position so I may need to get this sorted but apart from that the head, to me, looks fine. Clearly given the circumstances, it will have to be checked properly.

Should forged pistons do this?

What on earth has happened here?

I am now properly gutted as one can imagine.

I guess I need to do the following:

Take out the block (I assume honing is needed and replacing pistons may be tricky with he block still in the car)
Have it re-honed if its ok enough for that
Get some new pistons and rings of a better quality and get them installed - which pistons?
Plop the extra baffle I have ready into the sump whilst I’m at it
Get the head checked over, pray it doesn’t need machining so the compression ratio stays the same to avoid loads of extra tuning and make sure it has strong springs.
Order up new gaskets and seals - MLS gasket again? Maybe from another source, preferably one with some sealant for a sure fit?
Either get the person checking the head and block to put them together with my ARP bolts and I will drop the engine in and finish off or do it myself
Sort out the crankcase evacuation
Install oil cooler
Put new oil and filter in
Flush coolant passage ways and use nice antifreeze -maybe a drop of water wetter.
Get an accurate coolant gauge and re-position the sensor”¦
Have it all checked over by a reputable tuner ready for me to drive on track.

Another option is do it all myself but I work 70-80 hours a week so learning how to do a head and hone/build a block may be out of the question right now?

Can anyone shed some light on what may have happened here and give me some feedback the events, also maybe recommend someone near Bristol for help.

Thank you for reading.

Dave

detonation or preignition is known to crack ring lands, this is the same area it could be the cause

Detonation caused by a whole host of the above issues I guess.

What about the one crack/chip that looks as though its been pulled upwards? Could that be the ring knocking the hell out of the landing? It looks as though its been yanked rather than blown..

Hi there Dave I have PMed you.

I built some bits of the engine, I am more than happy to offer some help and advice to you.

maggspower wrote:Hi there Dave I have PMed you.

I built some bits of the engine, I am more than happy to offer some help and advice to you.

Great, thanks

rings can heat up too much and butt together but id think the bore walls would be scored pretty bad

This is/was kingcruzers right?

I am only about 15 miles south of you, there are a couple of places that could take this on but it all depends what you are looking for in terms of cost.

Looking at those pistons it looks like there may be a couple of factors in it, they do look very thin between the cutout and the first ring, have you got a piston out or is there any way you can check the thickness there?

As noted by Reggid if the rings had butted then it would have done much more to the bores, to me the markings look more like scuff from the pistons.

Based on that I would suspect a heat issue, supported by this being the back 3 hottest cylinders.

Without looking in person it looks like maybe the back 3 pistons were getting too hot and expanded too much on the crowns, causing them to tighten up on the bores.
If the thin cutout was not there all you would be looking at would be the light marks, looks to me that with the lack of meat there the unlubricated contact with the bore was enough to break that section.
Seen this before on Yank V8 pistons.

Hard to say what the cause is/was, its unlikely to be detonation related, there's no marks in the squishband where M20s seem to show most of their detonation first. Piston tops and head look clear of detonation marks.
Likely no one single cause, more likely a combination of piston clearance, heat/cooling, aggressive timing/lean fueling and a fragile spot on the pistons and no piston oilers in the block. All leading up to more heat than intended and finally contact.
I would err on the side of an unfortunate incident and the price to pay for chasing these kind of power levels.
With that said I have heard a lot of grumbling about ross pistons and cracking, also some of the US lot are quite down on IE products. Take from that what you will.

You look to have got very lucky with that, it seems like the chunks that have come off have managed to exit via the exhaust without smashing everything to bits so it looks saveable without too much work.
The bores are marked but they do not look bad enough to cause sealing issues, you will most likely get away with just a bottle brush hone to clean any edges and refinish the surface, without checking the sides of the pistons and the bores in person it's hard to say though.

Pistons are likely scrap, JE now offer forged pistons with the correct crown shape. http://www.e30tech.com/forum/showthread ... 371&page=3
Edit - Valve cutouts on your current pistons are insanely deep for a 262 cam!

Head need checking, looks ok but valves will need to be checked as will the seats, those bits got out some how.

Whole engine needs tearing down to check for debris or damage I am afraid.

Could be much worse though.

HairyScreech wrote:This is/was kingcruzers right?

I am only about 15 miles south of you, there are a couple of places that could take this on but it all depends what you are looking for in terms of cost.

Looking at those pistons it looks like there may be a couple of factors in it, they do look very thin between the cutout and the first ring, have you got a piston out or is there any way you can check the thickness there?

As noted by Reggid if the rings had butted then it would have done much more to the bores, to me the markings look more like scuff from the pistons.

Based on that I would suspect a heat issue, supported by this being the back 3 hottest cylinders.

Without looking in person it looks like maybe the back 3 pistons were getting too hot and expanded too much on the crowns, causing them to tighten up on the bores.
If the thin cutout was not there all you would be looking at would be the light marks, looks to me that with the lack of meat there the unlubricated contact with the bore was enough to break that section.
Seen this before on Yank V8 pistons.

Hard to say what the cause is/was, its unlikely to be detonation related, there's no marks in the squishband where M20s seem to show most of their detonation first. Piston tops and head look clear of detonation marks.
Likely no one single cause, more likely a combination of piston clearance, heat/cooling, aggressive timing/lean fueling and a fragile spot on the pistons and no piston oilers in the block. All leading up to more heat than intended and finally contact.
I would err on the side of an unfortunate incident and the price to pay for chasing these kind of power levels.
With that said I have heard a lot of grumbling about ross pistons and cracking, also some of the US lot are quite down on IE products. Take from that what you will.

You look to have got very lucky with that, it seems like the chunks that have come off have managed to exit via the exhaust without smashing everything to bits so it looks saveable without too much work.
The bores are marked but they do not look bad enough to cause sealing issues, you will most likely get away with just a bottle brush hone to clean any edges and refinish the surface, without checking the sides of the pistons and the bores in person it's hard to say though.

Pistons are likely scrap, JE now offer forged pistons with the correct crown shape. http://www.e30tech.com/forum/showthread ... 371&page=3
Edit - Valve cutouts on your current pistons are insanely deep for a 262 cam!

Head need checking, looks ok but valves will need to be checked as will the seats, those bits got out some how.

Whole engine needs tearing down to check for debris or damage I am afraid.

Could be much worse though.

I'm not sure what the previous owner used as a forum name but it sounds fitting.

Thank you so much for your detailed response. I think you are hitting the nail on the head with it all.

Looking into JE pistons, I used them on a steel Zetec a few years ago for my Westfield. As far as I'm aware, they are still in one piece!

I will be removing the block at the weekend and examining the pistons closely but they do look a little too weak at that spot. Why would you machine it like that?!

I've had a response from Ireland Engineering asking me to send a piston back to them for Ross Racing to inspect. As I'm not the original purchaser of the pistons and they were bought well over a year ago, it might be tough but hopefully something will come of it. if I was them, I might be finding this little story a touch awkward.

Byron has been in touch and kindly offered to take the engine away, strip the block and examine it. He only put the block together as well as reseating the valves in the head. the rest was done by the previous owner. I genuinely don't hold Byron responsible for any of this as the problems with this engine are almost certainly post build, he would agree but given the bad luck, he's doing me a solid and could have a customer for life if it all works out. We are also talking about stronger springs as the ones that are in there may well be standard.

BTW How can I tell if the springs are standard?

Anyway, back to the mess, it is also quite possible the injectors aren't big enough, 440cc may not be able to cope with 400 odd HP without being way over worked... should this be the case I would have hoped it might have been spotted during the mapping so I will have to check out the duty cycles on the map to see. I can't believe that this would have been missed though.

Blaming is almost pointless but understanding why it happens is crucial, however if everyone involved who might actually have some part to play in the mess created actually helped out, the whole experience would be quite bearable compared to how it could have been....

Fingers crossed the block and head are ok. I'm looking down the barrel of some money here which is a shame but this time, it will be done properly.

It could defo be worse.

Daveaholliday wrote:
Anyway, back to the mess, it is also quite possible the injectors aren't big enough, 440cc may not be able to cope with 400 odd HP without being way over worked... should this be the case I would have hoped it might have been spotted during the mapping so I will have to check out the duty cycles on the map to see.

Just thought i would share my experience on 440cc injectors in a M20,

Im running 376bhp on mine there plenty big enough for that, but i have the same issue as your having with the lumpyness in low revs, its because the duty cycle gets so low that the injector is turned off almost completly.

so if you find your injectors are to small (duty cycles above 80% in your map) might be best using a 3.5bar or 4bar fuel pressure reg, and mapping to suit.

good luck getting it back together, ive just blown my gearbox up so fun has stopped for me to

Big injectors are a tricky one and as you say, often the issue is getting the duty cycle low enough for idle and cruise.

It is why a lot of the older setups use 2 sets of injectors. With that said a 6 cylinder engine at those power levels should not struggle with duty cycle.

42#(440cc) injectors are big injectors but not huge when you consider a 4 pot turbo would need them by ~260hp. Lots of cars out there with that kind of power and no idle/low speed issues.

Are you both using the Stock 3 bar E30 regulator? If so perhaps a regulator with a rising rate may be an idea, as noted above the flow scales with fuel pressure so increasing the pressure with the boost levels will allow you to extend the range of the injectors.
If you start at 3 bar and rise to 5 bar you will be able to use 350cc@3bar injectors and have them flow the same as a 450cc injector at 5 bar.

Rising rate regulators have a bad rep as they get used instead of proper mapping, but in cases like this where you are struggling to get pulse widths low enough for low speed then they can have applications.
The engine would need to be mapped to take account of this fuel pressure change.
A surprising number of standard turbo cars actually have FRPs that increase pressure more than the boost pressure.

Your only other options are to go for 12 injector setup or to seek out some Gen 3 style injectors with lighter internals that can operate better at low pulse widths.

my thoughts would be that 440cc with a super charger at 436bhp are maybe a bit small, my 1000cc 4 cylinder bike idles fine at 1100rpm with 440cc injectors and a megasquirt.

A 3bar FPR, holds the pressure of the fuel at 3bar above manifold pressure. Therefore while running at 1bar boost pressure within the manifold, the fuel will be at 4bar in the fuel rail. otherwise it will only be at 2bar acutually in the manifold.

Indeed but the pressure difference would still be 3 bar across the injector so would only flow as though it was at 3 bar.

If your running 1 bar and the reg uses higher than a 1:1 rate then you will have a greater pressure difference across the injectors at high boost than at low boost.

As I assume this will be mapped using the MAP input the fuelling tables would be scaled against the MAP/boost value, in this case a RRFPR could actually be useful to solve low speed fueling issues.

It would result in a map that is artificially flat, instead of for example 10ms at 1000rp and 800ms at 6000rpm, you would be looking at 200ms@1000rpm and 700ms@6000rpm as the flow would be adjusted by the pressure change.

It is the one case where a RRFPR can actually be used correctly, provided it is mapped based on the MAP sensor.

you only have 20ms at 6000rpm to inject fuel minus the injector opening and closing time. having a non rising rate pressure reg eg a constant pressure above manifold pressure will give you more consistent fueling as fuel flow from an injector does not rise evenly with pressure always.

I was just picking numbers out the air for an example.

So having higher fuel pressure using a fixed pressure regulator and keeping the same injectors may improve any potential overworking on the top end but could further hinder the idle/off idle..

I see the advantage of 12 injectors. It must be easier to get the tuning right without having to do this? No idle control valve though so it might be a lot to ask?

A Malpassi adjustable fuel pressure regulator did come with the car but its unused as of yet. I had heard that they are unreliable.....? looks nice though.

Yes, it seems as though the regulator currently on the car is a standard one although I haven't confirmed the pressure rating yet.

Pretty much, Do you know what your current injectors are? There should be a part number on the plastic bit near the connector.
Its really important to know what pressure the 440cc/min is rated at.

440cc/min should be enough for the power you have, but if that is rated at 3.5bar then your below the rate flow using an e30 3 bar regulator. You will only be seeing ~400cc and likely a poor spray pattern from the injectors. (dropping the pressure reduces the atomisation of the fuel out of the injector, it's why injection pressures have been creping up on new cars, The M20B20 is only 2.5 bar and a lot of the new port injection stuff is 5 bar)
An M50/M52 fuel rail is a 3.5bar regulator and has the same injector spacing if the injectors are rated for 3.5bar.

Raising the pressure does increase flow as stated, Through any orifice the flow is dependant on the pressure difference across the orifice, for example the flow of an injector with atmospheric pressure (1bar absolute) on one side a 3bar (4bar absolute)on the other will be the same as an injector with 1bar of boost (2bar abs) one side and 4bar (5bar abs) on the other.
In both cases the pressure difference is 3bar.
To up the flow you would need to up the pressure difference, which is the point about rising rate vs 1:1 rate, a 1:1 rate regulator will maintain the pressure differential regardless of manifold pressure or vacuum while a rising rate will increase the ratio.

There are a couple of things with that though, the injectors have to be able to handle it, as GromGSXR notes not all injectors still preform correctly with a pressure increase, it is vital that the injectors are rated to operate at this pressure or the fuelling gets inconsistent.
Lowering the pressure at low speed results in less atomisation of the fuel and an increase in emissions.
Some tuners will not map around the fuel pressure change.

Really it should not be needed, the injectors you have should run ok but it all depends what they are and what pressure they are rated at.

edit - for what its worth a 42lb injector should be ok up to ~400hp 80% duty at 6500rpm (15.6ms).

Thinking some more, why no ICV? Your ECU should do run one fine?

Is the ECU set up for sequential or batch injection?

Looking at its specs it is capable of 12 injectors but that quite a hard core solution.

Do you know what the cause of the low speed drivability issues? If its not a low pulse width issue then we are barking up the wrong tree anyway.

Wouldn't bother with a cheap aftermarket regulator, more trouble than they are worth.

Looks like the fuel pressure regulator is a Bosch 02801690263, 3.5bar
The injectors are also Bosch, 42lb 440cc part number 0208150558, from a mustang or something like that...

The rev limit was set to 7k which would probably put the injectors around 85% all reading and behaving correctly?

I've yet to check the map..

I don't know the reason for the idle and low speed drivability yet. I've only managed 70 to 80 odd miles in total since I bought it.

I was guessing at fuel mixture and spark plugs to begin with or even a dirty injector.

I've yet to test the coil pack but as the VR6 coil pack works in pairs and I only had one black plug, Im not sure that could be at fault.

Of course it may have been expanded piston sticking in the bores...ha ha

what is the pulse width at idle? how much timing at idle? what injection strategy? you should not have issues with an injector that size

reggid wrote:you should not have issues with an injector that size

That's my thinking which is why I can only think the injectors have quite a high latency or were under the wrong pressure (which they were not).

Slow opening and closing times will make small pulse widths tricky.

Edit -
Just did some googling, the injectors are ford SVO injectors, Injector specs here: http://www.e30tech.com/forum/showthread.php?t=59360
If nothing else it will help when you come to retune.

Going by that the injectors are not very quick, but they are hardly exceptionally slow either.

Just gone back through your first post as well. Couple of things:

- plug gaps - where has the 0.025" come from? 0.635mm seems a little tight, stock gap with the single coil and distributor in the way is ~0.8mm and reasonable gap for a coil on plug setup is around 1mm.
The SAAB turbo lot gap these same plugs to 1mm with their COP.

Even narrowing the gaps to allow for the boost I would still be expecting around a 0.8mm gap, this wont help things if its too narrow. The extra density in the chamber makes it harder for the spark to jump the gap.
The widest gap that ignites reliably is always preferable from a combustion point of view.

Some of the E30tech lot report spark blowout over 15psi and they are narrowing the gaps as a band aid but that is with the stock dizzy and coil. A better solution is to improve the ignition energy.

what about the mechanical issues causing the rough idle?

gromgsxr wrote:what about the mechanical issues causing the rough idle?

100% unlikely to help but it does not hurt to go over anything that will be contributing to the poor low speed drivability before doing a new/rebuild.

I'm thinking this was also a problem before the damage, he says it was grumpy at low speed when he picked it up, the first plug chop looks fine, the second shows damage on no 5, the last set would likely show damage on all 3 rear cylinders.
That damage would have been sudden if it is over expansion of the crowns/bore contact cracking the crown at the ring land.

HairyScreech wrote:Just gone back through your first post as well. Couple of things:

- plug gaps - where has the 0.025" come from? 0.635mm seems a little tight, stock gap with the single coil and distributor in the way is ~0.8mm and reasonable gap for a coil on plug setup is around 1mm.
The SAAB turbo lot gap these same plugs to 1mm with their COP.

Even narrowing the gaps to allow for the boost I would still be expecting around a 0.8mm gap, this wont help things if its too narrow. The extra density in the chamber makes it harder for the spark to jump the gap.
The widest gap that ignites reliably is always preferable from a combustion point of view.

Some of the E30tech lot report spark blowout over 15psi and they are narrowing the gaps as a band aid but that is with the stock dizzy and coil. A better solution is to improve the ignition energy.

Right. Its been 2 hours!

I've been going over my research on plug gaps and I'm still not entirely sure if 0.025 is that bad.

I've not seen anyone, anywhere recommend 1mm yet, many 0.7-0.8mm, 0.022-0.035" depending on set up and even a few of those lower ones don't have the original spark set up.

I found this quote amongst others:

'The 08-10 N54 factory turbo BMW's come with .0275" plug gap and I have read that its recommended to drop to .022" in high boost applications.
I would start at .025" or so.'

Most of the research seems to go with these figures, I know its a different engine but its a BMW and the higher the boost, the lower the gap needed, no?

Would you imagine a VR6 coil pack can deliver enough spark to withstand 18-20psi at a gap on the top of the given brackets and why has my research not led me to the same conclusion as you? What could I be missing?

reggid wrote:what is the pulse width at idle? how much timing at idle? what injection strategy? you should not have issues with an injector that size

Hmm. Slightly out of my knowledge.

I will try and get some answers

Got the engine out today.

Found the toughest to get to Bellhousing bolts weren't actually tightened so they came out easy.

Loads of bits can be tidied properly once the engine is sorted. Loads is going into the parts washer to get ready for the install.

Loads to do and there's never enough time eh..

Still wondering about the plug gaps though.

Daveaholliday wrote:

HairyScreech wrote:Just gone back through your first post as well. Couple of things:

- plug gaps - where has the 0.025" come from? 0.635mm seems a little tight, stock gap with the single coil and distributor in the way is ~0.8mm and reasonable gap for a coil on plug setup is around 1mm.
The SAAB turbo lot gap these same plugs to 1mm with their COP.

Even narrowing the gaps to allow for the boost I would still be expecting around a 0.8mm gap, this wont help things if its too narrow. The extra density in the chamber makes it harder for the spark to jump the gap.
The widest gap that ignites reliably is always preferable from a combustion point of view.

Some of the E30tech lot report spark blowout over 15psi and they are narrowing the gaps as a band aid but that is with the stock dizzy and coil. A better solution is to improve the ignition energy.

Right. Its been 2 hours!

I've been going over my research on plug gaps and I'm still not entirely sure if 0.025 is that bad.

I've not seen anyone, anywhere recommend 1mm yet, many 0.7-0.8mm, 0.022-0.035" depending on set up and even a few of those lower ones don't have the original spark set up.

I found this quote amongst others:

'The 08-10 N54 factory turbo BMW's come with .0275" plug gap and I have read that its recommended to drop to .022" in high boost applications.
I would start at .025" or so.'

Most of the research seems to go with these figures, I know its a different engine but its a BMW and the higher the boost, the lower the gap needed, no?

Would you imagine a VR6 coil pack can deliver enough spark to withstand 18-20psi at a gap on the top of the given brackets and why has my research not led me to the same conclusion as you? What could I be missing?

Yes you would reduce the gap with higher boost but only if required. The more mixture you can light the quicker the burn and overall the safer/more detonation resistant burn. It's all fractions but power gains are all about a fraction here and a fraction there.

On an NA engine with a good COP set up the spark energy should be enough to jump a 1mm gap no trouble, If you look into the COP conversions the yank V8s do and COP conversions for the MX5s etc then you find they are erring towards .035-.45" gaps (0.9-1.15mm).
That much gap would probably blow out at 18psi though, which is why you run less gap.

The stock single coil and dizzy set up is about average for spark energy, yet 0.8mm gaps are fine NA and with a good setup 0.65mm are ok boosted.
There's no way the VR6 coils are worse than the single coil, 2 air gaps and 6+ feet of HT lead.

I have noticed BMW stuff seems to be either very conservative or 10 years behind what other "scenes" are doing.
To me 0.022" (0.55mm) seems ridiculously conservative for a modern ignition system. That's the gap remote control cars run, really it says the ignition system is not up to the job. (wonder if that is due to making the coils light/cheap on the N54?)

Stepping outside the BMW world:
http://www.saabcentral.com/forums/showt ... p?t=177007 (1-1.1mm)
http://www.fordownersclub.com/forums/to ... -plug-gap/ (1-1.3mm)
http://miataturbo.wikidot.com/spark-plugs (.025" stock coil .035-.050" with toyota COP)
http://www.evolutionm.net/forums/evo-ge ... g-cop.html (.028" in similar condition to yours)
http://forum.miata.net/vb/showthread.php?t=319593 (0.05" gap with 15 PSI )

Rule of thumb - more powerful ignition system = more gap possible
More boost = less gap.

I would be gaping to 0.8mm and only brining them down if there's signs of misfire. If the spark blows out you will go rich, in which case gap down.

in my experience miss fires can read as lean as well due to the un-burnt air leaving the cylinders.

another thing to take in to account is dwell time? the time the coil has to charge that can effect how strong the spark is as well

Very true, I'm sure the ECU has a variable dwell time map. I will take a quick look at the ECU .bin files I have for the M20 and M50 (single coil and 6 coil) when I get home and post the comparative dwell times.

Edit - Just pulled open the M20 and M50 stock maps, I will admit ignorance to the exact units used in the table, but it looks from that that the COP give ~50% greater dwell time than the single coil, quite a big advantage.
(the unit might be degrees or counts of the ECU, not sure.)

my guess would be crank angle degree's for the units of measurement. seems to fit. just out of curiosity what software are you using to open the bin files?? id be interested to poke about a stock m20 file.

I think your most likely right, thinking 112 max for the single coil. That would be 672 of the full 720 engine cycle, no more real room for dwell.

I am using tuner pro, I was going to start writing some things up on my M3.3.1 thread to help others and so others can help me.
Save this going too far OT.

HairyScreech wrote:

Daveaholliday wrote:

HairyScreech wrote:Just gone back through your first post as well. Couple of things:

- plug gaps - where has the 0.025" come from? 0.635mm seems a little tight, stock gap with the single coil and distributor in the way is ~0.8mm and reasonable gap for a coil on plug setup is around 1mm.
The SAAB turbo lot gap these same plugs to 1mm with their COP.

Even narrowing the gaps to allow for the boost I would still be expecting around a 0.8mm gap, this wont help things if its too narrow. The extra density in the chamber makes it harder for the spark to jump the gap.
The widest gap that ignites reliably is always preferable from a combustion point of view.

Some of the E30tech lot report spark blowout over 15psi and they are narrowing the gaps as a band aid but that is with the stock dizzy and coil. A better solution is to improve the ignition energy.

Right. Its been 2 hours!

I've been going over my research on plug gaps and I'm still not entirely sure if 0.025 is that bad.

I've not seen anyone, anywhere recommend 1mm yet, many 0.7-0.8mm, 0.022-0.035" depending on set up and even a few of those lower ones don't have the original spark set up.

I found this quote amongst others:

'The 08-10 N54 factory turbo BMW's come with .0275" plug gap and I have read that its recommended to drop to .022" in high boost applications.
I would start at .025" or so.'

Most of the research seems to go with these figures, I know its a different engine but its a BMW and the higher the boost, the lower the gap needed, no?

Would you imagine a VR6 coil pack can deliver enough spark to withstand 18-20psi at a gap on the top of the given brackets and why has my research not led me to the same conclusion as you? What could I be missing?

Yes you would reduce the gap with higher boost but only if required. The more mixture you can light the quicker the burn and overall the safer/more detonation resistant burn. It's all fractions but power gains are all about a fraction here and a fraction there.

On an NA engine with a good COP set up the spark energy should be enough to jump a 1mm gap no trouble, If you look into the COP conversions the yank V8s do and COP conversions for the MX5s etc then you find they are erring towards .035-.45" gaps (0.9-1.15mm).
That much gap would probably blow out at 18psi though, which is why you run less gap.

The stock single coil and dizzy set up is about average for spark energy, yet 0.8mm gaps are fine NA and with a good setup 0.65mm are ok boosted.
There's no way the VR6 coils are worse than the single coil, 2 air gaps and 6+ feet of HT lead.

I have noticed BMW stuff seems to be either very conservative or 10 years behind what other "scenes" are doing.
To me 0.022" (0.55mm) seems ridiculously conservative for a modern ignition system. That's the gap remote control cars run, really it says the ignition system is not up to the job. (wonder if that is due to making the coils light/cheap on the N54?)

Stepping outside the BMW world:
http://www.saabcentral.com/forums/showt ... p?t=177007 (1-1.1mm)
http://www.fordownersclub.com/forums/to ... -plug-gap/ (1-1.3mm)
http://miataturbo.wikidot.com/spark-plugs (.025" stock coil .035-.050" with toyota COP)
http://www.evolutionm.net/forums/evo-ge ... g-cop.html (.028" in similar condition to yours)
http://forum.miata.net/vb/showthread.php?t=319593 (0.05" gap with 15 PSI )

Rule of thumb - more powerful ignition system = more gap possible
More boost = less gap.

I would be gaping to 0.8mm and only brining them down if there's signs of misfire. If the spark blows out you will go rich, in which case gap down.

Thanks for that.

I think what you are saying makes total sense and is my understanding but I just couldn't find any proof of anyone doing larger gaps on forced induction. I was also reading about symptoms like cutting out and I was experiencing this also so felt a smaller gap was ideal. Quite possibly the gap I have used is taken from someone using the standard sparks.

I'll go up to .8 and try it out - when the engine finally fires back into life

most of the boosted m20 guys use smaller gap in practice, sure in theory a bigger gap is better but ive read about heaps of people with spark blow out needing to tighten it up

Update:

Byron has kindly examined it all and we have both decided that the problems really couldn't have been anything to do with his work.

What impresses me is that Byron drove out, picked up the engine and spent quite sometime with me discussing the potential issues. Then he took it all away, stripped it down and sent me details photos of everything and his explanation of what probably happened.

Because of the service, i wouldn't have hesitated to use Byron for the build of the new engine.

Whatever caused the issues in the engine obviously had a lot to do with temperatures. Byron could elaborate but essentially the cooling system was the e36 system which is temperamental at best. The engine core plug got a hole. The temperature gauges were probably sitting in air rather than water. Bad all round. For all we know, it could have mapped at temperatures being incorrect (no blame on the mapper)

The oil also hadn't been changed for quite some time, it really looked as though maybe it was the second lot after the initial run in. The metal matter collected in the sump was bad.

The head gasket had done very well although was starting to creep with the heat.

Chicken and egg here, did the map cause the heat or really was it the failed cooling system coupled with no anti freeze, poor oil, possibly the wrong grade for the performance and a cracked core plug.

The mapper swears he didn't suspect pinking during the mapping which is the first thing I thought I was hearing after I put it all back together VERY carefully, after the core plug failure.

Difficult to say for sure really as at the time I drove it, I thought I heard pinking where the mapper thinks I was hearing the bits flying off the pistons and rings, which were probably already compromised when it over heated.

Leighton at Circuit Motors, the mapper I used has told me that he would be happy to go through the map with me when the car is back together and show me how it would have been impossible to blame the map for the destruction. It's also on offer to put the car on the rollers, get it all checked out and any adjustments to the map made so long as I don't change the set up too much.

Anyway, the head survived. Amazingly. Just as well as it has had triple edges ground in for the valves. It's now going to have Schrick springs and HD rockers to protect the high revs.

The block is toast.

I have taken delivery of some JE pistons, ceramic coated crown with moly sides and strengthened pins with Sure Seal rings,

The pistons, rods and rotating assembly will be balanced and the flywheel will be further lightened.

There will be a windage tray and a baffle in the sump. I could be wrong but I believe this is wise for any car going on a track.

The engine bay is being stripped and everything cleaned up, painted etc. I have bought a paint curing light and really getting stuck in. Plenty of photos to follow.

Byron, feel free to put any part of the engine build onto the forum and thank you for your help so far.