e head to a is head

[gnastydent]

i have a 325es and i want to switch the e head to a IS head i was wondering what needs to be done to do this and a 88 super eta is not a option

[Harls]

So do you have the 2.7 ETA at the moment? If so you have to more than just a head change as the eta has flat top pistons, where's the M20 b25 has dome top pistons.

HM

[kenika65]

Originally Posted by gnastydent

i have a 325es and i want to switch the e head to a IS head i was wondering what needs to be done to do this and a 88 super eta is not a option

The head off of the 325i-is cars is called an "i" head not an "is" head. The i head had domed pistons, there is no difference in the m20's between i models. The 325e-es models had a head called "eta" which had flat top pistons.

If you are going to put an i (2.5l) head on an e (2.7l) block with out putting in 1988 super eta pistons, or other pistons to match the domed shape of the i head, then you will have lower compression, irradic idle, hard start, and trouble tunning (but it will work great)...

so if you do put the i head on the stock e bottom-end it would be and is a great low compression m20 for FI (turbo, super charger)...

So if you are going in the FI route then yes put everything from an "i' car on to your eta... the only thing left should be your 2.7 bottom end with all i addons... might as well buy an i parts car like i did...

this pic is before installing all i parts


I have put everything from a 1989 325i car on to my 1986es except the the i head because i do not plan on FI with this m20 and i prefer to have smooth idle, and higher compression...



((1986 325es stock 2.7 bottom end, and head. All other parts are from my 89 325i, Intake with injectors, 3.0bar fpr, TB, AFM, 1.3 motronic harness and sensors, 173ecu, 90amp alternator, pulleys, single pump fuel tank, 3.73 diff, 7000 tach, duel exhaust w/glass packs, Plans to swap in 89i plastic bumpers, flywheel and transmission


If anyone would like help on their swap let me know i have plenty of pictures and a good write up...

[frost_dxb]

how about "i" Pistons, Head & ECU on an eta block will i need more parts?

[kenika65]

Originally Posted by frost_dxb

how about "i" Pistons, Head & ECU on an eta block will i need more parts?

Can you elaborate please?

i pistons with e rods on the e 2.7 crank will cause the pistons to stick out of the block 3mm too much so you will have to have them shaved,

i pistons with i rods and e crank will b 3mm to short so you have to deck the block and get an adjustable cam gear,

1988 super eta pistons(only year with domed e pistons), e rods, e crank works perfectly but hard to find

custom pistons preferably high compression for NA, i rods for lower rod ratio, e crank is your best build

but as for me I kept the stock 2.7 bottom end, stock e head with i double valve springs. All other parts are from my 89 325i, Intake with injectors, 3.0bar fpr, TB, AFM, 1.3 motronic harness and sensors, 173ecu, 90amp alternator, pulleys, single pump fuel tank, 3.73 diff, 7000 tach, duel exhaust

and yes you need everything from an i motor to get 1.1-1.3 motronic to work in a e car so do like i did and find a i parts car! or you have to locate everything i just explained!!!

[gnastydent]

thankyou great info

[kenika65]

Originally Posted by gnastydent

thankyou great info

so what are your plans?

[gnastydent]

i dont know i just want something different but this will cost alot

[kenika65]

All you need to do is find a 87 but preferably 88-91 i car for super cheap, look at junk yards and peoples houses just go on a hunt. I found a 1989 325i for $100 and have used everything from it except the head because I want the pistons and head to match for better idle and compression... I'm telling you you can find a i car for super cheap and it will have everything you need even if the timing belt is broken all the parts you need will be good well good luck and keep me updated on your plans

[gnastydent]

well finding the i is not a problem i just wanted to switch the heads but what did you do with your car? what did you switch? any horsepower gains?

[austra]

why dont you just mil the I head to raise the compression back up. i just had my race e head shave .017 and the said they could shave .035 safely. if you shaved it to .035 that would raise the compression almost 1.5 points. i did some math to get the 86 E motor to 9.5 with just the shaving of the head thats where i got the .017 from

[E30Hooligan]

if you have a 84-87 eta the only mods you want to do are a chip (markd, dinan, etc.) and 3.25/3.46 lsd. Suspension aswell but I'm refering to power output here. If you have a 1988 325 (super eta) you need a "complete I head" one with 7 oil hole drillings and dual valve springs and an updated camshaft. You'll also need the never mototronic and wiring harness. Of course you'll also need the bigger intake manifold and TB. Then you need to go to BMW....yes the dealer and have them get you a speically tuned DINAN chip for this exact setup. And one final step is to add a 3.73 diff, perferably an LSD. Oh yeah a 7k tack too and if you want the 90amp alternator as aposted the 80amp in there although it's not really nessesary. You now have yourself one badass machine.....I drive this setup around everyday. Some guy with an M50 swap was mighty surprised when he got burnned when we raced up a long steep hill. Remember you now have about 190lbs of TQ. and if you were smart enough to rebuild the head and had it milled down your compression will be even higher. and have around 190HP and 200TQ atleast that's the output from my engine. however by this point you'll need some m50 injectors to mach your heavily increased power from that little m20. Have FUN