E30 Zone

Hi there, in the process of putting together my 2.7. I've taken the engine i had sold to me as a 2.5i to bits (some of you may remember the problem i had with ground off engine no.s??? ) and found that it has the 130mm conrods in (so am i right in assuming its definatly not a 325i) , but as for the right crank to use, i'm not too sure. Does anyone know if theres any way of checking to see if it is the 525e crank, or any numbers i could check for? Also, i think i'm going to use my 325i pistons and 885 head because they look like the better option in terms of air flow etc, but any advice would be greatly appreciated.
Cheers, Guy.

hello mate there's 3 m20 engines that used the 130mm con rod they are 2-litre, 2.3 and the 525e.
the 325 con rods are 135mm long.

however if your gonna do the job wright and use your 325 pistons like you say then you will need the 130mm con rods, 525e crank 325 or 525e block as they have the steam holes in and the block will need skimming by about 1.5mm but dummy build first for the exact figure! you also need a vernier cam pulley and remap

the only way i know of recognizing a 525e block is the piston crown and engine code No's will always start with 27 example 27 6E A followed underneath with the engine no.

I'm down in Brighton so prob a bit far but if you need a 525e bottom end i have 2 good ones and good ones are hard to find these days i was gonna hold on to and sell on eBay beginning of next summer but would be open to offers as its a zoner

jay

thanks for the help buddy, one of my friends has a complete 525e engine, which i have heard running and he only wants 100 quid for it, but thanks asking n e way. As for the numbers on the block, some numpty has ran a grinder over the first bit of them. all i have left to read is 6E A (a bit dodgy dont you think? ) so i cant tell from them. The piston crowns are more or less flat, except for 2 small cut outs for the valves (nothing compared to my 325i ones) but didnt they also get used in the early 325i's and 323's too??? theres some numbers on the crank, which read :- H81 and then below that G66 700. Not sure if they mean owt... Cheers, Guy.

i cant say to be fair as Ive always relied on the block code to be sure. you say 2 small cut outs for the valves??? the 2 blocks i have here only have 1 small cut out for valves per piston. will try to put pic on for you latter

Hi again, actually looking at my pistons a bit more closely it seems as though at some stage in this engines slightly jagged history the valves have been hitting the tops of the pistons. So, it looks like the pistons might be the same after all . I've taken a picture just to make sure. The fouling on the piston is quite hard to see, but its at about 2 o'clock


I also took a picture ( not the best quality if i'm honest!) of the engine numbers on the block

yes mate the pistons look the same but that's not to say its an eta what head came of the engine

could the numbers beeing ground off be to do with a engine conversion . and the owner trying to hide the block number to the insurance comps

cubic. when are you in brighton ?

hello psychochild i live in brighton mate

hello, the head that came off was a 731. any ideas? . Bit of a head scratcher aint it lol.

ok mate you got 3 alternatives i can see... 323i, 320i or the 731/eta 2.7 conversion cause like sychochild said it could be an insurance cover up. best bet give bm a ring and see if you can match the crank No's up

thats great, cheers for all the help geeza's, i'll get on the phone in the morning me thinks.

Cheers, GUy.

any joy with BM GUy

nope, not as yet... i've left them with all of the numbers etc that i could see on the crank its self, and they told me that they would ring me as and when. I'll keep you posted, hopefully i'll find out some time this week . Guy.

I think the eta pistons have a larger oil scraper ring

hello again GUy just a thought mate like i said before i can see 3 possibles ie 323i, 320i or 731/eta conversion. have you measured the pistons to ELIMANATE as the 323i and 320i had 80mm bores and the 525e and 325i have 84mm bores and steam hole between each cylinder.

cant believe i didn't think of before

i would say measure the crank as well but i haven't a clue what these measurements should be

hi there, yep, already done that... mines got 84mm bores. I actually thought that it was only the 320 and the 318 which had the 80mm bores, i didnt think about the 323 to be honest.
So, to recap , my block has 84mm bores, steam holes between them, 130mm conrods, a 731 head, flat top pistons, and a dipstick in the block. The thing is, it cant be a 325i coz of the short conrods, so does that mean i'm back with the 525e?? I'm still waiting for the clown at bm to get back to me (proberbly some work experience kid or summin ) ... Yesterday, i bit the bullet and gave my mate 100 quid for his 525e motor, as kind of a back up, just incase mine wasnt. He's droppin that off tonight, so if i get time, i'm gonna strip that one and then compare the two cranks... Fingers crossed!! . I'll keep ya posted

Cheers, Guy.

Hope you dont mind me butting in but could it be an early 325i,did,nt thet have different shaped pistons.
Exscuse my ignorance if totally wrong.

Hi there, yes i think your right, but the thing is the engine only has 130mm conrods, not 135mm. I'm pretty sure that every 325i had 135mm ones... Chances are, that some plank has made a right bodge of putting the bloody thing together before i got my hands on it, and used loads of random bits n bobs...

Thanks for the reply though buddy. Cheers, Guy.

it seems to me the engine you took apart (sold to you as 2.5) is actually a 2.7 mate but get the crank measurements just to be perfectly sure.

318 are 4 pot.

early 325i pistons had same crown but longer skirts

Dont say that!! how gutted would i be!! i'm really not sure bout it being a 2.7 coz it was ridiculously slow. I mean, my missus could keep up with me in her 1.8 escort!!! ! And i got burnt off my some little chav in a e34 4pot (highly embarrassing!) That was the final straw which pushed me to ripping the lump out in the first place.. But then, i thought back, and wondered if actually, i'd been sold a 525e instead of a 325i, and then thought about the 2.7 conversion . you dont think that it was possible that whoever had the engine before me had made a cockup and put 130mm conrods in by mistake do you instead of the 135's??? Or is that a silly idea? .

Thanks for all the help so far though matey! Guy.

Hi again, right, i've got my friends '525e' engine back to my place, and taken it bits. Ive noticed that the pistons look the same as the ones in my picture above, but instead of there being a raised section in the centre, its sunk down. Are the 525e engines you have 'cubic' the same? as you've proberbly guessed i gave in waiting for bm

Cheers, Guy.

hello guy been having me a manic week

right one of the blocks i have has the raised centre and the other has the sunken centre i think this may be on account of the year of manufacture i have a mag that says the early 525e cars built up to sept 1985 had a very high 11:1 compression ratio whilst the latter cars were dropped to 10:1.

however both cranks are the same

what reg is the one you just got from your mate???

Hi, ive done two versions of a 2.7 engine, 1st was 325 block, 525e 1980 pistons and rods. 2nd was the 325 block and 325 pistons and rods, this way the pistons sit above the block by 3 mill so its closer to the head the valves go into the slots in the pistons nicely with no valve slap this way gives you more top end, and the 1st one gives you a quicker 0-60, BUT you must use the pistons from a 1980-1984 525e as the pistons are a higher compression giving you a 11:1 Comp Ratio,as you can tell the middle of the pistons is slighlty raised, and after 1985 onwards the piston is slightly concaved in the middle..which gives you 10:1, now if you have that engine 1986 onwards the head is a casting of 885 (325) you can use that. before the year 1986 you cant cos of oil rails..

A company called Stannard motors years ago gave this info to me as they were the first in the country to carry out this conversion then after that some guys called Tom, Dick and harry started it...

from the pistons i see in the pic, they seem to be the early ones with 11:1 comp ration use them with either its rods or from the 6 cylinder 320 e.t.c. you cant go wrong, i found out using the 325 pistons had power but not as good as flat top pistons, now bear in mind using using the pistons from a 1988 onwards which are concaved (dish type).




jimi

Thanks for the advice jimi, i wouldnt have thought that i could have used the 135mm rods. I was gonna use the 130mm ones and then get the block skimmed to suit. your right about the pistons in the picture, they are the ones which are raised, so you think i should use them, along with my 885 head? To me, the 885 head looks like it is best suited with the 325i pistons. I was thinking about putting an uprated cam in it at the same time, so would that be a problem if i was to use the 2nd method you mentioned?

Thanks mate, Guy.

Bailey

try having a word with Iain temple8e30 when he,s on line next
he,s built a couple of 2.7 using different options so may well be able to help you solve the riddle

Daz

Haven't read all of the posts but why cant you just measure how far down the pistons travel in the block?
'e' crank will be 81mm and i crank will only be 75mm.

As for lack of power if 2.7i conversion has been done poorly it is possible the c/r will be low, or its just a stock e motor which are slow anyway.

Thanks Daz, will do.

I would have thought that someone, somewhere, would have written an indepth article on how to do the 2.7, because it seems like a popular mod.

Cheers, Guy.

you have a pm mate