setting a vernier? UPDATE2 21.04.07

[liam012]

Ok - so have put up with very gentle right foot for a long time as car pinks under heavy acceleration and load and generally sounds a bit tractor/diesel like,

I am hoping, no actually i am praying that all this will go away with the installation of a vernier pulley - If any one has any general tips for setting them up that would be great as i am no expert, I am guessing that my window of safe adjustment is about what 6-10" well in retard anyway i wouldnt have the balls to advance it as i fear the 525e and 2.0 head combo has caused mildly advanced timing which i am hoping is the cause of the problems.

i have found a few degree wheels on line i suppose i will need them as i think my catcam has no degree markings on it which is a shame but i'll know for sure when i get home. here is one looks kind of groovey!


so any advice to avoid piston valve sandwich greatly appreeciated

[Ant]

Difficult one Liam

bottom line is advancing is the way to go, retard will increase the chances of bent valves.

the head/bottom end combo is not one I've built so cannot draw on experience but.... set to TDC and arse dyno, then work up the advance to no more than 6 degrees in increments and see what results you get. anything BTDC is moving away from the valves so no real nightmares there dude.

not much help I know, but a way forward perhaps ?

[daimlerman]

Are you useing a zone chip?

[Ant]

he is indeed

2.7 specific supplied by A-Tech ( me )

Ms to go on later on , no more AFM wrongness

[liam012]

cheers - i think i am more confused lookng at that dial i have gotten into a thought loop!

see i understand outer ring stays fixed with the belt on and therefore the crank stays fixed but i then slacken off inner bots to rotate the inner circle which in turns the cam independant of the crank - i actually want to turn the inner circle CLOCKWISE in 6degree increments ????

wow thats bizzare as i thought the pinging needed to be cured by retarding the timing? not advancing it?

tsuch a shame as i have been studying it so much and to thhinkj i have it all backwards

[liam012]

this sounds like a descriptoin of my car:

Pre-ignition is a different phenomenon from detonation, explained above, and occurs when the air/fuel mixture in the cylinder (or even just entering the cylinder) ignites before the spark plug fires. Pre-ignition is caused by an ignition source other than the spark. Heat or hot spots can buildup in engine intake or cylinder components due to improper design, for example, spark plugs with heat range too hot for the conditions, or due to carbon deposits in the combustion chamber. Spark plugs with a high heat range will run hot enough to burn off deposits that lead to plug fouling in a worn engine, but the electrode of the plug itself can occasionally heat soak, and begin glowing hot enough to become an uncontrolled ignition source on its own. Bits of carbon that build up in a combustion chamber can also heat soak to the point where they also are glowing hot and ignite the air-fuel mixture before the proper time.

Pre-ignition and "dieseling" or "run on" are the same phenomenon, except in the latter case the engine continues to run after the ignition is shut off with a hot spot as an ignition source. Pre-ignition might cause rough running due to the advanced and erratic effective igniton timing and may cause noise if it leads to detonation. It may also cause "rumble" which is fast and premature but not detonating combustion.

This heat buildup can only be prevented by eliminating the overheating (through redesign or cleaning) or the compression effects (by reducing the load on the engine or temperature of intake air). As such, if pre-ignition is allowed to continue for any length of time, power output and fuel economy is reduced and engine damage may result. The engine might be slightly harder to get running at once after pre-ignition.

Pre-ignition may lead to detonation and detonation may lead to pre-ignition or either may exist separately.

but its the last sentance which is a killer!

[liam012]

oh one second i might be beginning to understand this....

the vernier will only adjust when the valves open and close in relation to the piston stroke-

its not (the vernier) really adjusting the timing as such in regards to load sites but just in a linear fashion due to the fact the cam turning triggers the ditributer sparks

This is why you have suggested to ADVANCE the timing Ant? so that the valves begin to open later when the piston is on the down stroke?

Am i on the right track

See i was so stumped when you said to advance it it kind of through a preverbial spanner into my wheel of ahead - but thats because i was thinkiung of ignition timing for the spark which the vernier doesnt strictly adjust its just a knock on effect as a result of the rotation of the trigger in the distributer?

[Ant]

Advancing the cam is the only way to go mate, the ignition timing will be unchanged as the timing is referanced from the CPS, the rotor arm is wide enough to acoomodate the change without any issue.

as for 6 degree increments... NO !!!! move 1 degree- reasess, move another degree, to a max of 6 degrees dude.

the vernier is there to allow the cam and crank timing to be put out of synch from factory TDC,TDC setup to tune the cam for best power, or to correct a decked block where the centres have changed and the cam timing would be retarded as a result.

HTH mate, if I was closer, I'd be there for ya dude

[liam012]

no worries! thanks mate
the penny has dropped about the pulley
i'm safe enough to go ahead with fitting it - hopefuly tomorow afternoon
will report back
sorry for dragging the arse out of this project!!

[reggid]

Ant what effect does advancing the timing have on the power/torque band and what sort of change/difference will around 6 degrees make? Will this cause the valves to close later or earlier than BDC for the compression stroke (i.e. how will the dynmaic compression change?

Also why is advancing the timing the only way to go? Is it just interence or will engine performance suffer?

[liam012]

update
well thought i had scored big time not having to remove any belts coolant pipes or viscous and rad only to be thwarted by the BLOODY MALE TORX BOLT!!!
how did i not remember that? car is laid up on drive now.... till early morrow

point of interest: i left the sparks out to make turning by hand easier and there really is a strong smell of fuel of no. 4 injector? i wonder if this isnt sticking open at WOT and combusting casing the pinking sound? probably not though as plug looks ok? mmmm

[liam012]

well -
I advanced timing 4 degrees and got her started -
she now sounds more like a diesel/tractor than she did before making me think that maybe retarding could be the way to go? running the risk of interefernce though is a tough call, do i have 2-4 degrees to play with retarding i wonder?
Also something to note that also got worse is a rumble like 3 or so cylinders missing in a sequence every 2 or 3 seconds - i noticed this before i advanced the timing but only very mildly; advaning the timing has magnified it.
So all the tools are under neath the car until i set it to stock tomorow or maybe retard a degree or two.
Anyone have any thoughts on all this or is it a case of you really have to be here to see (which i guess it is...

a little out of my depth, but having fun!!

thanks

[liam012]

so retarded the cam timing about 3 degrees, turned by hand first to check for interference
couldnt beleive how well it idled at the turn of the key; the engine now has a considerable more silky nature if that makes any sense - lost a tad of that brute grunt feel to it but made the engine feel a little more supple and eager to move is the best way of explaining it.

i would be tempted to retard it some more but this cam pulley adjusting business takes me about 3 hours for each adjustment.

Changing the cam timing while improving the the engines running and removing some of that diesel/tractor like sound to it has had no effect at al on that rattling/pinking type sound. i pulled the grommet from the gearstick and its upsettingly nasty soundying

i am crossing my fingers for an injector or two partialy stuck open or a gearbox that is just a box of nails (it sounds like somebody grinding marbles in neutral... I would love to think that the load put on the engine could be transfered into the gearbox instantly causing a load of worn syncros/bearings to spin around rattling as that is kinda what it sound likes only the time it takes for me to apply partial throttle i can hear the sound which makes me think its closer to the engine/head.

loosing the faith a little now

must get a good quality sound clip actually will go now and get one had an idea of what to use....

[reggid]

so retarded the cam timing about 3 degrees, turned by hand first to check for interference
couldnt beleive how well it idled at the turn of the key; the engine now has a considerable more silky nature if that makes any sense - lost a tad of that brute grunt feel to it but made the engine feel a little more supple and eager to move is the best way of explaining it.

i would be tempted to retard it some more but this cam pulley adjusting business takes me about 3 hours for each adjustment.

from what i can gather by retarding the timing you lose some compression as the valve closes later after BDC so you start pushing fixture back out the inlet at low air speeds (i.e. low rpms).

Is it possible to set it up so that all you need to do is remove the dizzy and rotor for adjustments i.e remove the viscous fan and cam belt covers (for a short time) until you get it right?

Can you give me a bit of step by step process of:

- What you had to remove to change the pulley
- The process of adjusting the gear?

i am planning on doing this later in the year.

Cheers

[liam012]

Yes there is no doubt it can be adjusted in situe but i like having the pulley in my hand to adjust -

MAKE SURE YOU ARE AT TOP DEAD CENTRE MARKS ON ENGINE BEFORE REMOVING OEM PULLEY

1)remove sparkplug leads of plugs and at dizzy.
2)loosen till free all spark plugs, no need to remove.
3)undo 3 8mm dizzy bolts and pull of dizzy
4)undo two 10m bolts that secure the metal coolant pipe so you can wiggle it around for clearance.
5)undo 3 i think t15 bolts for rotor arm.
6)unplug afm and whip out airbox for room
7) remove the the 12mm nut for the alterantor securing bolt and remove. also undo the 13mm nut securing the alternator bracket to the timing cover and remove bracket.
8)undo 10mm and 13mm bolts holding the timing cover in - slip out top timing cover.
9)if you want loosen the 14mm for the tensioner
10)the timing belt should come of easy enough now you'll need a female torx i think 12 to crack of the pulley securing bolt.

thats it for removal now the catcam pulley - i was not impressed AT ALL. it arrived in record time from belgium, which was good but unfortunately one of the 6 locking bolts were missing and more impoortantly the locating dowel was not cut right - you see the original oem pulley is a cast and has a notch to secure and locate the rotor arm fixing plate so that it cant spin independantly of the pulley - because the vernier is a two piece inner and outer wheel they have to use a small dowel with a cut in it at the top half that sticks out of the vernier and then your rotor plate lock itself on that. Unfortuately my dowel must have been cut by a blind man so didnt do its job properly so i had to bugger around with it and some superglue to get it to do its job.
On top of that the rotor securing plate doesnt sit in the new verniers countersink as well as it does the oem one as the securing bolts of the vernier are pushing the plate away from the vernier so i didnt like that.
Perhaps most annoyingly i noticed upon reomval of the catcam puley the back of it was scored to hell and there wa aluminiium shavings all over the front of the head where the pulley had ground against something.
All in all a pretty poor show.
Superficially it has no degree markings, anyone with half a brain can add hem but you pay over a 100 pounds for an aftermarket pulley a few reliable degree marking would be nice.
if there was a thumbs down smiley i would be using it now.

as for adjusting it basicly you are rotating the the inner part of the pulley (which turns the cam) independantly of the outer wheel with the teeth for the belt, - what i did is set it up so that it fit just like the oem one at TDC and gave it its ) degree marking there same as the oem whell has. i then laid it down on a degree wheel similar to the one at the top of this thread and marked out 15 degrees in 5 degree steps either side of 0 - when you get this far it will all make perfect sense and the adjusting of the pulley is very simple just unlock the 6 securing bolts and rote and lock.

[Simon13]

Alot of 325i gearboxes "chatter" Liam in neutral. Does this noise disapear when you push the clutch pedal down?

if it's this it's just the gearbox and don't worry! Just keep the oil fresh in it and it will soldier on like they do no problem

[maxfield]

Alot of 325i gearboxes "chatter" Liam in neutral. Does this noise disapear when you push the clutch pedal down?

if it's this it's just the gearbox and don't worry! Just keep the oil fresh in it and it will soldier on like they do no problem

Lay shaft?

My dads M3 does this and most other M3s i've been in

[liam012]

chattter is fine i can live that however this i cant live with

which is why i got the vernier in the first place to see if i could fix it.

not looking good though.

[Simon13]

Max most 325's do it aswell, every manual one ive had does it. I think it's one of the layshaft bearings

[maxfield]

Max most 325's do it aswell, every manual one ive had does it. I think it's one of the layshaft bearings

Strange.

Also did it when my dad had a new gearbox

Sorry to go OT BTW

[reggid]

Yes there is no doubt it can be adjusted in situe but i like having the pulley in my hand to adjust -

MAKE SURE YOU ARE AT TOP DEAD CENTRE MARKS ON ENGINE BEFORE REMOVING OEM PULLEY

1)remove sparkplug leads of plugs and at dizzy.
2)loosen till free all spark plugs, no need to remove.
3)undo 3 8mm dizzy bolts and pull of dizzy
4)undo two 10m bolts that secure the metal coolant pipe so you can wiggle it around for clearance.
5)undo 3 i think t15 bolts for rotor arm.
6)unplug afm and whip out airbox for room
7) remove the the 12mm nut for the alterantor securing bolt and remove. also undo the 13mm nut securing the alternator bracket to the timing cover and remove bracket.
8)undo 10mm and 13mm bolts holding the timing cover in - slip out top timing cover.
9)if you want loosen the 14mm for the tensioner
10)the timing belt should come of easy enough now you'll need a female torx i think 12 to crack of the pulley securing bolt.

thats it for removal now the catcam pulley - i was not impressed AT ALL. it arrived in record time from belgium, which was good but unfortunately one of the 6 locking bolts were missing and more impoortantly the locating dowel was not cut right - you see the original oem pulley is a cast and has a notch to secure and locate the rotor arm fixing plate so that it cant spin independantly of the pulley - because the vernier is a two piece inner and outer wheel they have to use a small dowel with a cut in it at the top half that sticks out of the vernier and then your rotor plate lock itself on that. Unfortuately my dowel must have been cut by a blind man so didnt do its job properly so i had to bugger around with it and some superglue to get it to do its job.
On top of that the rotor securing plate doesnt sit in the new verniers countersink as well as it does the oem one as the securing bolts of the vernier are pushing the plate away from the vernier so i didnt like that.
Perhaps most annoyingly i noticed upon reomval of the catcam puley the back of it was scored to hell and there wa aluminiium shavings all over the front of the head where the pulley had ground against something.
All in all a pretty poor show.
Superficially it has no degree markings, anyone with half a brain can add hem but you pay over a 100 pounds for an aftermarket pulley a few reliable degree marking would be nice.
if there was a thumbs down smiley i would be using it now.

as for adjusting it basicly you are rotating the the inner part of the pulley (which turns the cam) independantly of the outer wheel with the teeth for the belt, - what i did is set it up so that it fit just like the oem one at TDC and gave it its ) degree marking there same as the oem whell has. i then laid it down on a degree wheel similar to the one at the top of this thread and marked out 15 degrees in 5 degree steps either side of 0 - when you get this far it will all make perfect sense and the adjusting of the pulley is very simple just unlock the 6 securing bolts and rote and lock.

Thanks for the writeup. I am probably going to wait until i need to do a timing belt change then set it up at 0degrees and assembly only what i need to get to the tuner and make adjustments on the dyno to see where its best located. I have a 286/272 cam and i think my timing is a bit retarded as the torque is down a bit (low dynamic compression) from whats expected (even considering the cam) and when i did the belt last i couldn't adjust to be absolutely perfect it was pretty close though.

[toby]

I've been listening to this audio extract really loud through my stereo (my neighbours must think I'm building an engine in here!). It's bloody hard to tell what it is though.

From the symptoms you describe it sounds for all the world like pre-detonation although you have moved the timing and it had no effect on the sound... curious....

I'm sorry if this is of no help but I'm trying have you thought about the fuel in the tank?

The combination of 731 head and eta bloack and pistons is reported to give 10.1 or 10.2:1 and be prone to detonation using 95 octane fuel. 98 octane fuel is recommended. Would be great if it is as simple as that but I'm guess you have thought about this already.

Be lucky,
Toby

[liam012]

YEEEEEEHAAAAAAAA!!!!!!!!!!!!!!!
i tried a different brand of octane booster on the way home - as i had exhausted all avenues od testing known to me, and you would not beleive it - it actually bloody worked!!!! no more horrible sound - i added enough to raise the octane rating 4 points and that all but cleared it in any gear - unless i am really cruel up a hill in 5th i can barely make out a whisp of it.
THIS IS EXCELLENT NEWS FOR ME!!!!!!
I have been troubleshooting this for so long was begining to give up and it ended up being the fiorst thing i tried just that the silkolene pro boost was crap compared to the clp i got.
SO what does this mean about my engine if i need to add octane booster to avoid that horrible sound?

[Ant]

Static CR is possibly too high dude.

[liam012]

so its not good news? oh
i cant just advance ignition timing via ms when i get it?

[Ant]

Liam, you can advance/retard the timing to whatever you wish dude.

should help with the issue for defo, you'll have full control of everything either way.

worst case you can deliberatly overfuel @ the det point to surpress the pinging.

[liam012]

i see but by your tone thats not what you'd do if it was your motor is it?

i dont mind a thicker head gasket if necessary but i dont want to loose power

i thought the higher the comp the better it was just a case of having a a controlable ecu to map it to suit

obviously not by the sounds of things....

mmmm

[liam012]

bugger
well removed the vernier so cam timing is no longer retarded and the rattling sound has come back a bit - _ not as much as before cos i have the octane booster but a definate increase in noise/detonation from advancing the cam timing back to stock from the 4 degresss retard it was running.
more proof i guess that the comp ratio is just TOO high (as ant stated months ago!)
what are my options - mls gaskets seem to run at about 250 dollars shipped plus import duty.
i dont want to make a big spend getting it right as i would be better of building up a new engine. trying to use as many partsas i have already.

[cplagz]

with the cam pulley is the rotor button set in relation to cam position or where the belt is? As I need my cam advanced but timing to remain as standard.

[liam012]

as far as i have been abke to figure out the pads on the rotor are well wide enough to accomodate a change in cam timing with zero effect on the ignition/spark timing especially as it remains triggered by the crank position sensor.
to answer you question exactly the rotor arm does change position when you advance or retard cam position but the pads should be wide enough for this not to mater at all.

[Andy335Touring]

Liam, which cam are you using, standard ?

One way to reduce the C/R is to fit a more sporty cam as the valves are held open a little longer.

[Andy335Touring]

Bump, how's it going now ?

[liam012]

well, (now that you ask you may be sorry!)
sal was good enough to replace the atrocious quality catcam vernier for a kent one (i was relying on superglue to hold the locating dowel for the rotor arm!) and straight away by the packaging alone i could tell it was good quality - however somewhat embarrassingly i could not fit the rotor arm plate it would not clear the kent pulley adjusting bolts, needless to say with the front half of the engine assunder i decided not to have wasted time so to refit the stock pulley (until i run wasted spark) but fit a whole tooth retarded.; luckily no valve to piston contact.
this with a raise in octane of 4 points eliminates pinking and car runs like silk.
the cam i am running is a regrind to 268/268.
megasquirt arrives soon so hoping to unfold some more of the puzzle then.
i would love to get this mnotor dyno'd as though not without its problems it really is a stinker to go, it completely obliterates any 325 i drive and thats with the lazy tall 3.46 diff.
i am tempted to open up the engine and inspect for damage from the pinking before i started using octane and also to check tdc on both the block and head as both are skimmed but maybe there is no need for a while though the engine is changing shells this month and i have a gasket set handy. mmmmm

[Andy335Touring]

At least you've got a decent adjustable pulley now, combine this with the MS ecu and the pinking should be a thing of the past.

I only get a smidge of pinking with mine as the C/R has gone up but my ecu hasn't been remapped to suit yet.

I was thinking of getting a pulley in the hope i could dail in a bit more top end zest which is a bit lacking even though i have a 284/280 cam in my M30.

If you do open up the engine you will be able to test how far you can safely adjust the pulley by dummy fitting the head and measuring the valve to piston clearance(sp?) with the cam pulley at different angle settings.

I might take my head off to see how my squish clearance is doing, i had to grind out part of the head squish area to allow for my 'pina pistons. I played it safe and used the thicker H/G(+0.3mm) which has given me a squish clearance of about 1.2-1.3mm. Using a normal H/G will give me 0.9-1.0mm which is fine in theory but relies on me grinding the head to give a nice uniform clearance, not much room for error !

I've no idea how much losing 0.3mm will bump up the C/R though ?