E30 Zone

i have just spent the last two days doing my valve clearances and unfortunately missed the portsmouth memorial meet but i finally finished and all seems ok except the idle its idleing at around 800rpm and fluxuating up to 1000rpm every now and again then back down to 800rpm, what have i done wrong? i measured the valve clearance to 0.25mm on a cold engine as instructed but have i messed up the timing by adjusting the valves? i thought i would be doing some good by adjusting them but i have made things worse it would seem. if anyone can help me i would appreciate it because im unsure what to do next other than taking it to a garage.

Did you disconect the battery ?

If so it will settle down after about 30mins driving time

no i didnt, i had the ignition off but didnt disconnect the battery. the idle is not going high its staying low like its struggling at 800rpm. what do you think i should do? go and disconnect the battery?

hughesythelegend wrote: go and disconnect the battery?

No.

Have you left any thing disconected ?

no nothing. i didnt disconnect anything to start off with, i just took the rocker cover off and adjusted them by instructions, i didnt have to disconnect anything. i was wondering if it were an air leak in a pipe or if i hadnt put the rocker cover down tightly enough but if that were the case then it would be idleing higher than 800rpm because air would be leaking but would be coming in also. thats what i think but im not sure. help!

Who instructed you to measure to 25thou of a mil on cold rockers?

rockers should be done warm..

They can be done cold Dan as stated by the Bently bible - - 12 thou though iirc not 25!

Oh right, I was sure it was a warm process.. Ignore me then

- and you of all ppl should of seen that in the bible - then again, you don't have an M20 - you got a real engine

GOOD POINT!! - 12 thou iirc on the M20b25 but, are we talking a different engine here?

What have you got hughesythelegend?

i saw a site called bimmer diy on the net as tacky as it sounds it was quite good and it stated by bently measuring guides they should be 0.25mm on a cold engine and 0.30mm on a warm engine, but that still doesnt explain the poor idle? can you think of any other reason for that?

Jhonno wrote:rockers should be done warm..

Really?

I thought clearances could be done cold or hot? .012" hot or .010" cold.

If anything, wouldn't doing clearances cold give a "truer" sense of things? Hot metal expands and cools over time. Doing clearances cold would provide a uniform environment for adjustment.

I'm probably wrong here but as a bit of a noob I'm certainly keen to learn. I've just had mine done and they were done cold.

24v > 12v..

Well its gonna be an m20 or m30..

they should be closer on a warm engine surely?!

I'v always done it 11 thou on a very hot engine....

Jhonno wrote:they should be closer on a warm engine surely?!

When I first got my car I had the clearances done hot. .012".

"That's how we do it" I was told. I couldn't figure it out.

The mechanic I go to now has only ever adjusted valve clearances cold.

Just looked it up again 010 thou cold on an M20

Which will close up when warm.. Metal expansion etc

When they are brand new yes I agree.

Jhonno wrote:Which will close up when warm.. Metal expansion etc

Or the hot adjustment will close up when cold. LOL! Six of one, half a dozen of the other, I suppose.

Brand new or used the gap should remain the same - 010 cold ? it's what the bible says peps

Bit of confusion here I think, '10 thou' = '0.25 mm'

Original measurement is correct

Are we back to the "Metrix + Imperial" arguments all over again

Dan - i'm now thinking of your M5 valves

Hot or cold ~ as long as you adjust within BMW spec all should be good,

Nelly wrote:Are we back to the "Metrix + Imperial" arguments all over again

Dan - i'm now thinking of your M5 valves

Dont worry, they adjust themselves

Bad part is when you have to pay someone to re-grind 24 valves and seats

Try recutting and then grinding

Thats what I meant, re-grinding then lapping same thing = expensive

ok ok, i found a link to the guide i used, thanks ppl for your comments i appreciate the support as its really puzzling me. i have an m20 engine nelly. still no answer for the poor idle does anyone know why? or will it sort itself out? i did do an oil change also but that shouldnt affect it.

here is the link that i followed instruction too.let me know what you all think i should do about my problem.
http://www.pelicanparts.com/BMW/techart ... Adjust.htm

Clean the icv just to be safe.

Oil change wont affect it - try running her for a while and see what happens fella.

Dan - ££££££££££££ - i don't envy you atm but i'm sure i will as alot of others here will if you get it sorted.

ok thanks nelly appreciate the comments.i just want to get it sorted as i dont want my e30 f*cked.

Could be one of a multitude of things as well fella ie, icv - afm - tps but run her as see what the verdict is after say 50/100 miles and take it from there

whats the ICV? sorry to be a din. I went to bmw in portsmouth today and the guy said basically everything thats wrong before i said it, like struggling to idle, power lose, car shaking and kangerooing in low revs, high fuel consumption. he said that basically i have done it wrong and to start it and do it again he doesnt think that i have done any serious damage like bent valves because it wouldnt be driving at all, i have to take the rocker off and do it all again. BMW offered to do it for me at a small fee of £120 per hour and it would take them a few hours then it may not be right so they would have to do it again if it wasnt. so i gave that a miss and am in talking to a nice fella called roy from ca automotive he has a supercharged m3 and knows a bit more than i do, so hopefully it will be fixed and not too much damage done. i know next time to leave it alone if it aint f*cked dont fix it. thanks for the comments also ppl.

ICV= idle control valve i now know this lol. if anyone knows how to do valve clearances or any advice on correcting them and lives locally then please get in contact i will sort you out a few beers. thanks guys.