building a 24v DOHC engine

[lifeiskaos]

People who are serious about such project (and have the technical knowledge to achieve it) don't post questions as the ones you just asked. Lots of wishfull thinking and particularly no clear direction.

Sorry for bringing the bad news. What's your background that makes you think you can build a 500hp motor with 10:1 pistons, with race cam and loppy idle, with MS but not on start-up? Why are you scared of engine management

i am very serious about this project. do you think some people are born with such knowledge? im sorry for trying to learn? no clear direction, shall i quote myself?

my background has been working with cars all my life, building several engines, tuning experience with megasquirt. i said i want lower than 10:1 comp pistons. i asked for specific advice, not your opinion. if you have nothing helpful to share, please gtfo

i love these threads!

hooray!

[mentaleeill]

i meant just to start with a m52, use its crank and get custom rods and pistons. want to keep the bore as small as possible to keep material between the cylinders on boosted engines for headgasket sealing. so look on bfc and there are plenty of people with their rod and piston specs posted.

[dpgrand]

i love these threads!

[Massive Lee]

care to elaborate?

People who are serious about such project (and have the technical knowledge to achieve it) don't post questions as the ones you just asked. Lots of wishfull thinking and particularly no clear direction.

Sorry for bringing the bad news. What's your background that makes you think you can build a 500hp motor with 10:1 pistons, with race cam and loppy idle, with MS but not on start-up? Why are you scared of engine management

[lifeiskaos]

I have the first piece to your puzzle for sale! An s50 crank! Pm me if you want it.

i'll keep it in mind!

your gonna need 2-3 cans of high temp spraypaint for a project like this...

i am not kenika

The initial post is soooo funny. :giggle:

care to elaborate?

i thought this was the funnest post. i dont think he knows r3v yet lol.

good for you?

I've got a m50tu swap to start. I plan on using a z3 2.8 aluminum block and m54b30 crank and rods with custom pistons for 3.0. Should be torquey

Mr Sik

sounds fun! unfortunately i've heard those aluminum blocks+boost=bad... otherwise it'd make some great weight reduction. good luck

[lifeiskaos]

but the engine you are talking about is not from an e30.

you are gonna want the s50 crank if you wanna go 3.0 with just a slight overbore. just get the m52 as it has forged internals and is most likely gonna be easier to find with less miles. look on bfc in the fi section and you will find rod and piston specs very easily.

alright, i was unsure of the compatibility between m and s engines, and obd1 v obd2 etc.. a bigger crank though on an otherwise stock m52 would likely end up in valves kissing pistons, but are you saying i can use s50 crank with m52 rods and aftermarket pistons? thanks for reply

An M54 is for you!

hah, the recent m54 swap thread has drawn me straight away from that. i can build an engine, but im not ready for that much fab work

Grab either M54B30 crank and get some aftermarket rods/pistons with CR of like 9:1 or get an S52 crank and aftermarket rods/pistons (both the same actually). I would HIGHLY recommend starting out with either an M50 or M52 block and only boring out to (at the most) 85mm (+1mm from stock) just to keep cylinder wall strength. That and if you are going for serious power get some 12 or 13 mm head studs and main studs, yada yada. If you go with an S50 crank and a bore of 85mm, you will be right around 2.9L.
Oh, and the M52 has forged rods/crank but not pistons. None of the factory pistons will be forged.

thanks for the highly detailed response! god an idea of what length rods i should be looking for? very good point about the cylinder wall thickness. i will hopefully be pushing ~500bhp, so i'll want them to be strong, plus keeping room for o-rings, unless they're not as necessary as they are on m20's? head studs are already considered a must. thanks again

[sikboy]

I've got a m50tu swap to start. I plan on using a z3 2.8 aluminum block and m54b30 crank and rods with custom pistons for 3.0. Should be torquey


Mr Sik

[e30s52]

or i could post on a site dedicated to e30's with owners who supposedly help each other and ask very basic questions... stop being an asshole

i thought this was the funnest post. i dont think he knows r3v yet lol.

[Massive Lee]

The initial post is soooo funny. :giggle:

[BeirBrennerE30]

your gonna need 2-3 cans of high temp spraypaint for a project like this...

[PiercedE30]

Grab either M54B30 crank and get some aftermarket rods/pistons with CR of like 9:1 or get an S52 crank and aftermarket rods/pistons (both the same actually). I would HIGHLY recommend starting out with either an M50 or M52 block and only boring out to (at the most) 85mm (+1mm from stock) just to keep cylinder wall strength. That and if you are going for serious power get some 12 or 13 mm head studs and main studs, yada yada. If you go with an S50 crank and a bore of 85mm, you will be right around 2.9L.
Oh, and the M52 has forged rods/crank but not pistons. None of the factory pistons will be forged.

[e30_325es]

I have the first piece to your puzzle for sale! An s50 crank! Pm me if you want it.

[hoveringuy]

what's the fun in starting with an s50? :D half the fun to me is building the engine, plus the combo im looking for is slightly different than a regular s50

An M54 is for you!

[mentaleeill]

or i could post on a site dedicated to e30's with owners who supposedly help each other and ask very basic questions... stop being an asshole

but the engine you are talking about is not from an e30.

you are gonna want the s50 crank if you wanna go 3.0 with just a slight overbore. just get the m52 as it has forged internals and is most likely gonna be easier to find with less miles. look on bfc in the fi section and you will find rod and piston specs very easily.

[lifeiskaos]

Well an s50 is merely same block as m50 that has a different crank and rods and a bit wider pistons. So I would either start w/ m50 and get all s50 internals for it, or get an s50 and call it a day.

what's the fun in starting with an s50? :D half the fun to me is building the engine, plus the combo im looking for is slightly different than a regular s50