WTB m30b35 or m30b34 engine

[tcbaurpower 5]

For a 1985 e28 535i.

I am looking for an e34 engine with low/medium k's.

Cheers, Adam.

Edited February 9, 2011 by tcbaurpower

[topcat 11]

For a 1985 e28 535i.

I am looking for an e34 engine with low/medium k's.

Cheers, Adam.

yes have both,an e28 3.5L 240k.

and an e32 engine with 220k.

both ran great and have looms/ecu's for both

[BM WORLD 1283]

e28 engine has more power and torque than the e34 type and will bolt in easier with the mounting holes and manifolds etc

[tcbaurpower 5]

e28 engine has more power and torque than the e34 type and will bolt in easier with the mounting holes and manifolds etc

I have spent some time reading up on the b35 swap and it is possible however like you say the mounting positions are not the same. So I would need a cert for a modified one?

The b35 was the stronger engine and has better cooling passages. As Im using this as a daily driven I thought this might make the E34 a better option. Would you agree?

note: e24 will swap straight in and some early e32's, no e34's will.

Edited February 9, 2011 by tcbaurpower

[BM WORLD 1283]

I have spent some time reading up on the b35 swap and it is possible however like you say the mounting positions are not the same. So I would need a cert for a modified one?

The b35 was the stronger engine and has better cooling passages. As Im using this as a daily driven I thought this might make the E34 a better option. Would you agree?

note: e24 will swap straight in and some early e32's, no e34's will.

no quite true

use a e28 535i or later 1983 onwards e23 735i or e24 635csi engine . these engines are basically the same as the e34 ,e32 engines except for the lower power due to lower compression pistons etc.

(there are other differences in the head like valve size and ports etc )

i think when you talk about the cooling you are refereing to the very ealry 3.5l which has a different bore to stroke ratio and a different head casting which sometimes has problems with over heating etc . commonally called a m90 engine built from about 1978 to 1982 used in early e12 ,e24 and e23 models

if you fit a e34 or e32 engine it will be down on power and torque , fuel ecnomy etc

so just get the correct engine like the on marty mentioned above he has one from 86 535i

i would only use a e34 or e32 engine if a e28 etc if i couldn't find the correct type and desperate to get it going

or you could go for a early block m90 type block fit the later crank to it custom pistons and bore it out and make a 3.65L engine with 11.:1cr if you want a bit more power etc

see pic for some details

Edited February 9, 2011 by Brent HARTGE535i

[tcbaurpower 5]

Cheers for the info... I think reading us specs gave me the wrong idea. An e28 engine will be less hassle to install. So now looking for a m30b34. Will PM marty however being in Auckland I cant check it out for peace of mind.

Edited February 9, 2011 by tcbaurpower

[BM WORLD 1283]

Cheers for the info... I think reading us specs gave me the wrong idea. An e28 engine will be less hassle to install. So now looking for a m30b34. Will PM marty however being in Auckland I cant check it out for peace of mind.

yes you have to be carfull as a lot of the info out there relates to us spec engines etc .

there e28 535i only got 186hp due to been only 8:1cr.

marty's engine is a good one , i heard it run , from a tidy nz new car with low owners etc

was only removed to make way for his big arse turbo engine .

[tcbaurpower 5]

mmm turbo... nope dont temp me with conversions... it must be reliable. haha

[kiwi535 538]

whats the easiest way to bump the compression on a e34 engine?

[BM WORLD 1283]

whats the easiest way to bump the compression on a e34 engine?

you can plane the head a bit

and deck the block a bit

but if you do the block it would have to be removed and stripped down.

or fit some e28 10:1 pistons to the e34 block , but also better to fit the e28 head on top , port and pollish the ports and swap the the valves over to e34 type.

[Silver Fox 43]

Mines an E28 head and block, both have been planed, with E34 valves and regrind on the original cam, and the miller maf conversion, and it's got 153kw and 380 nm of torque at the wheels.

[tcbaurpower 5]

Would the millar maf conversion be a good upgrade to do even if you were not doing any internal mods?

[Silver Fox 43]

I believe so, they say around 10 hp, but mine went from 191hp on a before run to 208hp with the maf conversion, no other mods were made between the 2 runs. Nicer sound too.

[kiwi535 538]

mr e34 did a map_ecu which replaces the old butterfly valve and reported excellent resuslts

[topcat 11]

whats the easiest way to bump the compression on a e34 engine?

no easy way,other then what Brent said,plane the head to minimium and the block.

that should bring it up to 9.5ish.add e28 pistons=9.7

or fit an e28,e23,e24 head=9.8cr

or fit the m90 block with the e34 crank and rods,again skim the head=9.8ish.(3660cc)

bore the m90 to 95mm add custom domed pistons=10.5ish