My M20 B28 build, 200+ bhp/tq now bits to deal with it

[StuBeeDoo]

Seriously, I'm guessing it'll be too tight to break the 200 barrier, maybe after it's done 5 figures??

I agree. Anything less than 10k and the engine's likely to be way too tight. Around 20k would probably give the best figure.

Anyway, I'm guessing 200bhp/210lb-ft - but only when it's loosened-up.

[daimlerman]

Seriously, I'm guessing it'll be too tight to break the 200 barrier, maybe after it's done 5 figures??

I agree. Anything less than 10k and the engine's likely to be way too tight. Around 20k would probably give the best figure.

Anyway, I'm guessing 200bhp/210lb-ft - but only when it's loosened-up.

Yes,mine just gets better and better,now run 40,000 miles and still makes me grin like a lunitic when I let it go...
Do'nt think the cam on this one will be aggresive enough for 200 plus,though....

[goosiegander]

201bhp dude, 185lbft thats my bet

[stonesie]

Just got the tank and lines changed, service ect too but no suspension work...



The good... I found out why i always get a burning oil smell

The bad... It's coming out of the number 6 lower exhaust stud, when they drilled out the snapped stud they must have nicked the oil way and its pushing past the helecoil.



A quick re-cap on the spec for the predictions.....
B25 low comp pistons, block and head both skimmed (minimal on the head, 0.5mm on the block to retain standard squish) approx 9.7:1 CR
M52B28 crank
M20B20 rods
CatCams 273/273 with vernier
A Tec 2.8 chip tweaked for LPG
BBTB
Ultrasonicly cleaned B25 injectors
Standard exhaust manifold/down pipes, new genuine middle box and a magnex back box

[StuBeeDoo]

The good... I found out why i always get a burning oil smell

The bad... It's coming out of the number 6 lower exhaust stud, when they drilled out the snapped stud they must have nicked the oil way and its pushing past the helecoil.

I had the same with the 'head on my M20B20. That was on the front top one though.
I took the stud out, wrapped some PTFE tape 'round it, then a dollop of Red Hermetite around the stud before fitting the manifold back on.

[stonesie]

Thanks, i will be trying that next time i work on it.

Some pics from today now i've got the phone talking to the pc...

[stonesie]

Well it has been to the RR, unfortunatly the MG ZS that went on before me managed to brake the RPM sensor so im going to have to re-book it another day, maybe saturday

The graphs will be posted when i get them.

[stonesie]

She's in on monday afternoon, will be a brisk drive straight from work so that should get the gearbox/diff oil's nice and warm... hopefully there wont be any rover things with dodgy plug leads knocking about the place this time

[Morat]

Good luck stonesie, this is going to be a fantastic car

[stonesie]

Well the results are in general chat but the headline figures, calculated at the flywheel are

206 bhp
203 Lb:Ft


http://www.e30zone.net/modules.php?name ... c&t=147072

[Andyboy]

Impressive, young Skywalker. There aren't many C2 2.7's that do that!

I thought it felt quick. Give the bugger another 3-4000 miles and it'll start to really loosen up and the oil consumption will drop.

[Gunni]

Engines don´t loosen up like that.

Few miles in and things are settled.

[Andyboy]

Engines don´t loosen up like that.

Few miles in and things are settled.

I see.

So why do road test cars deliver better performance after 10'000 miles than the original test when it had done 1000 miles? Lighter driver perhaps? I can give some examples if you like.

With brand new pistons and new bores you might stand a small chance. However, with new rings in original honed bores the rings take rather more than 'a few miles' to bed in. Oil consumption drops, blow by is decreased and thus properly sealed rings manage to compress more of the inlet charge. That equals more power...no?

We're not talking 10 bhp - 3 or 4 perhaps.

[Gunni]

I´ve car not have any oil consumption and nilch blow straight from a rebuild.
Driving off from a rebuild into normal usage without a hint of any difference betwee 0mile
-100miles prior or 1000miles after.

[Andyboy]

So you build engines with zero blow by eh? If that was possible from a new engine, why does it have a crankcase breather?

Again:

Why do cars deliver better performance after they've been well run in?

I'll give you an example:

E21 323i: 0-60 mph time when new is 8.8 seconds. After 24'000 miles 8.3 seconds. Why is the same car half a second faster after 24'000 miles?

Why do BMW still give all press cars 1000 miles of 'free revving' use before they are given for road test?



I know you build perfect engines better than anyone else, but can you explain the above to me please?

Ta!

[Gunni]

Cause most of it´s weight has rusted away cause it´s a E21?

Funny how it´s ME saying this.
This is what I have seen from all around me.

Run in hard to wear the piston rings in to the bore.
After that there is nothing more. This surtenly doesn´t take 24,000miles.
This takes a matter of minutes , and this procedure should be done right as the engine is started.

http://www.mototuneusa.com/break_in_secrets.htm

This procedure has been done by so many people that I have no count.

[Andyboy]

You're not going to answer me properly then. Oh well, pity.

10'000 miles of running in...in a matter of minutes eh?

Fine, I'll leave you to it.......

[stonesie]

Thats the link i kinda followed and i think the RR results confirm it works to a point, but the engine also uses a little oil, mainly on over-run (on the RR vid you can see ZERO smoke while its under load then when its running down it starts)

The oil consumption is calming down though, as Andyboy has said my bores are 2nd hand so the piston/bore clearance is above standard so this oil burning is not un-expected by me or the guys at the machine shop who carried out the hone.





It's amasing, i leave this thread alone for a day or 2 and it gets interesting



I have let a mate drive it who used to have a E36 328 coupe, he says mine is faster but dosent feel it because its got a much smoother power delivery...... He also cooked my brakes, smoke from the rear pads anyone? so i have parted with more coin and got a set of EBC reds comeing for the front, I was happy with textar but if its ever going to see a track it needs something better.

I'm impressed with the discs though, all that punishment and no warpage...... Brembo = recomended

[Andyboy]

Upper limit bore clearances won't cause oil consumption if the rings are good. Because your bores are original and honed, the rings will take longer to fully bed in than they would on fresh ones. For example on my old M42 I honed the bores and used the ORIGINAL rings... because it had good compression before the head came off and the bores looked very glazed. Oil consumption in the first 2500 miles was alarming. Now it uses none...because the rings have bedded in. You don't need to thrash the nuts off a new engine to bed the rings in - 2-3000 miles of normal driving will do it just fine. It's not a race to bed the rings in, and the engine needs to last a long time.

A pint of Black Sheep says that your oil consumption will be down to next to nothing in 3-4000 miles.

BTW EBC yellows are what you need.

[stonesie]

Ball's, they're on the way now

Ah well, im changing the front brake pipes at the weekend and flushing the whole system with ATE super blue, Will they be worth a try or flog them on here and re-order yellows?

[Gunni]

You're not going to answer me properly then. Oh well, pity.

10'000 miles of running in...in a matter of minutes eh?

Fine, I'll leave you to it.......

there is no running in.
Once the rings have bedded in thats it.

If you follow the procedure there and do it right.
Then after that there is no more running in. The engine is ready.

To answer your question.
I have only seen cars perform better when run in fast and hard, against slow, So why something has gone better in 24,000miles on some car I have no idea.
The number of variables is just to great to be able to pinpoint it down to slow running in.

[tomislav]

I thrashed a freshly built engine once.. then i had to back and pick bits up off the road that broke

Slow and steady is the way to do it if you ask me

[Andyboy]

Exactly. This engine cost 2 grand to build and he doesn't want to score a bore or break a ring because he was too impatient to do it properly. Matt didn't use this method of bedding the rings in, so it will need 2000 - 3'000 miles of normal driving. As little idling or constant speed driving as possible, use the revs but without caning it.
When I drove it it had done 500 miles (?) but it seemed revvy enough.

[Gunni]

That´s exactly the procedure of how to do it in the link I posted.

I did not say to CANE it. But follow the procedure and it is very similar to what you have said.

[Jhonno]

Ball's, they're on the way now

Ah well, im changing the front brake pipes at the weekend and flushing the whole system with ATE super blue, Will they be worth a try or flog them on here and re-order yellows?

Red's are crap..

Yellows are better, Performance Friction are betterer..

[daimlerman]

Well the results are in general chat but the headline figures, calculated at the flywheel are

206 bhp
203 Lb:Ft


http://www.e30zone.net/modules.php?name ... c&t=147072

Well impressed young man,buy you a beer tonight on the strength of that!
Just shows that all the attention to detail has paid off.
Well done!

[stonesie]

I will see you there

[SteMarsden]

I know that on racing 2-stroke motors that we would rebuild after 8 hours, the running in period was about 45 minutes (or about 10% of its life before being rebuilt again).

The most important thing with these motors (BT82 TKM engines) was 5 short runs, building revs from a max of 8000 rpm on the first run to its max of 15500 on the last runs and loading / unloading of the engine upto the maximum for that session.

Although not competing Nationally or having any real budget to speak of, in 6 years we never siezed a motor and finished in the top 3 of a Club Championship for 3 years in the row.....

....my twopenneth....

[stonesie]

EBC's will be going in today... thats the thing with EBC, theyre always tweaking the compounds so just because you tried some a few years ago dosent mean theyre still the same, with fresh fluid and goodrich flexys it should improve things.

[stonesie]

All thats on and the H&R 60/40 kit too, I had to jack the car back up at the front and lower it onto some bits of wood to get the jack out, it looks much better and will be having a lovley run in a bit to bed those pads in.


The pads are awesom, good when cold and better when hot.

I tortured the old pads till they faded, which suprisingly didn't take very long

After the same abuse the reds are just getting started


Suspension wise, its a bit 'jiggly' but the cornering is much improved and no issues with speed bumps so im happy. (also re-assured that i have 2 spare sump's and brakedown cover to get it towed home if i crack one.)