M20 2.7 Conversion Info/advice/help/project ideas please

[Dan318-is]

recently acquired an early m20 engine for college and am rebuilding it, anyone got any ideas of what i could do it in the way of 2.7 conversions, or just bolt on a newer head? experiences or recommendations ??

im not that full of knowledge on the m20s i dont no much about them and any ideas of a good project would be much appreciated

iv got about 40 hours worth during the year to do it at least

and a limited amount of money so no forced induction lol. any ideas lads?

[jay528ise1985]

What capacity M20 is it? 2.0, 2.3, 2.5 or 2.7?

[Dan318-is]

2.5 block fella

[Sjoerd320i]

tell me if you need a diesel crank ( handles high revs beter than eta )

and help the guy out lads, Karan, Jimbob etc

[E30Adam]

Do a search mate, there is plenty to find on the forum about the 2.7 conversion.

[Dan318-is]

cheers adam

[Simon13]

The joys of the 2.7 is u can go a good few ways about it. As u can use all different parts of various M20 engines!

This is what i know so i'll try my best!

one thing u need for all of them is the crank out of an E28 525e (eta engine) which in this country only came as autos. Or if your really lucky a euro only 324d crank which alpina used.

U can use a 2.5 block,eta block, or have a 320 block bored out

conrods the shorter 2.0 or eta rods, 2.5's are too long

2.0 or 2.5 heads, but if u can only use a 2.0 head with an eta block anyone? (Easy 2.7 is eta bottom end with 2.0 head)

325 pistons chrome or facelift ones, 2.0 too small, and eta are wrong for some reason

theres alot more to it but this should help?!

[Dan318-is]

gr8 help

what sorta cash for those parts considering i alreayd have a 325i??

hjow much power at the end?

[Simon13]

as u have the best engine to start with for performance u would need

eta crank
320 rods

in theory this is all to build a basic 2.7

but the block will need to be decked about 1.5mm and a verney pulley fitted to adjust the timing and an appropriate chip


powr depends on what u use, how it's run in, performance mods along the way, how deep are your pockets!!!

[M5pilot]

This topic has been so discussed that everyone on here is an expert now!

Defo try using a TD Steel crank for starters.

Get the compression nice and high. Buying custom pistons for this might prove to be quite expensive so the next best alternative is early 325i pistons.

The last two cars built using this method have both shown to break the 200BHP barrier with ease. Those being Quaser's engine and Jimbob's engine.

[Dan318-is]

pockets not that deep

got early 325i pistons already

how much are pulleys?

deck the block?? WTF?

[Sjoerd320i]

deckin the block is done by a thicker gasget IIRC

[Karan]

deckin the block is done by a thicker gasget IIRC

no.... u have to shave metal off the top of the head

[Dan318-is]

cylinder head?

how much

[Sjoerd320i]

deckin the block is done by a thicker gasget IIRC

no.... u have to shave metal off the top of the head

thought that's called skimming (spell)

[Dan318-is]

:yeahthat:

[Karan]

deckin the block is done by a thicker gasget IIRC

no.... u have to shave metal off the top of the head

thought that's called skimming (spell)

sorry i meant block.....

decking i believe is shaving a layer of the block itself!

Karan

[Widge]

Guys, guys guys.....

DECKING :- (vrb) To shave off material from the top of a cylinder block, commonly used when using 320/eta con rods with 2.5 pistons, as they will be approx 3mm too far down the bores.

SKIMMING :- used to take a tiny amount ie thousanths of an inch off a head to increas compression or straighten a warp.

DECOMPRESSION PLATE :- See HERE

This is the method I am going to use, uncommonly used when using 2.5 rods and pistons.

If I was you mate, I'd just go the normal 320 rods route, you will have to machine the pistons but hopefully you can! And maybe if you feel up to it, the M20 can be bored from 84mm to 86mm giving an extra 100cc, so you could make a 2.8. Alternativly if you could get an M50 crank you could make a 3ltr!!

[Dan318-is]

how hard is that

[Jimbob]

Decking the block is like having it skimmed several times.

Tbh I'm yet to find someone who's done this for under Ԛ£1k. Depending how/IF you do it, the pistons need shaving as well to sit on the crank right. If either of these steps are out by like 0.01mm you'll pink. The measurements the machine shop gave me were down to 3 decimal points! (Hmm, priceless figures in fact!)

[Widge]

Well, you'd need to machine the front of the crank to accept the timing belt pulley, but that could be simple if you have a big enough lathe as it's only a straight shoulder with a woodruff key. You may have to modify the clutch end too. Then you would have the interesting job of finding suitable sized rods!! Adam will know he's got one. Do you realise it will be Ԛ£350+ in parts alone to recondition the engine?

[Dan318-is]

f*ck this its all come at once

il do some research an think about it in bed lol

sounds expensive i mite just do up the m20

any other project ideas then?

[bigdek]

so is most of the money spent on machining ?

[Sjoerd320i]

f*ck this its all come at once

il do some research an think about it in bed lol

sounds expensive i mite just do up the m20

any other project ideas then?

FI

[Widge]

If either of these steps are out by like 0.01mm you'll pink. The measurements the machine shop gave me were down to 3 decimal points! (Hmm, priceless figures in fact!)

That's why I'm completely removing the machining process, and going the decompression plate route - cheaper than machining, just bolts togeather, and only one measurement to get right.

[bigdek]

where do u buy such a plate ?

[Jimbob]

so is most of the money spent on machining ?

Not just machining, my receipts folder quadrupled in about 3 months spanning over Ԛ£2k..

Just over a tenner per 1bhp

[Karan]

2.7 rules thoughԚ¬!!!

i love mine and have become really attached to the way the power delivery is!

Karan

[Moofles]

wait till the gt-r karan...

tbh i heard if you want a 2.7, whichever way you go you're looking at 1k+

[Widge]

where do u buy such a plate ?

HERE

[pacerpete]

Moofles ,ain't you got a chariot yet? you NEED my TrulyRancid7 ragtop then you would be able to savour on the edge open top motoring again. I'll do you a good deal.

[Stevin]

Haha, I'm not even gonna say anything.

Cause I would be repeating myself, but I think this is the best bottom end for a stroker.

http://www.e30zone.co.uk/modules.php?na ... highlight=

The route I'm going, this is after quite a bit of research

[Widge]

Did you use the M3 piston rings in the end then?

[Stevin]

Yes I did... though it was safer, even though it is more expensive.. rather not modify something u don't have to

[Widge]

Yeah, thought it was a bit silly modifying unnessicrily to avoid th cost of rings, the M3 must be up to the job. How much machining did the crank take? And what cc is the engine now?