[KFehr911]

Well I never thought I would own a BMW. Well she is an 84 with original every thing. It has 334000 kms on the original engine but has been very well maintained. There are some little things but I'm not concerned about those right away. It has an idle issues but very slight and possibly a valve adjustment. Will be dealing with those this weekend.
Is there any others issues I should be aware of?
How reliable is the timing chain? When should it be replaced?

 

[1991318i]

chains are the man. so long as you take care of the engine and dont beat the s**t out of the car, i wouldn't worry about it. barring any situations like that, the only thing with the chain that i might consider is the chain tensioner

 

[BMWFatherFigure]

If the PO was GOOD at having services you should have no probs. The rubber will be the first place to check - hoses belts and tubes.

 

[Nick323]

I thought the I6 had a timing belt :dunno:
& I would replace that if there is any doubt as to its history

 

[BMWFatherFigure]

I thought only the 4's have timing belts :dunno:

 

[tim96]

correct me if I am wrong but
earlier e30 318's with m10 engine were chain
all others 318's with m40, 318is with m42, and 320 + 325 with m20 engine are belt

 

[Gold Chariot]

Tim I believe you are correct! My 86 318i has a chain i think and i believe it was the last year for the chain?

 

[KFehr911]

It's has a timing chain. I've been told that was much more reliable then the belt.

Thanks I know that the chain tensioner is accessible on the out side of the block so I will do has the manual says.

 

[hornhospital]

M10s/40-44s (4-cylinders) all have chains. Very little if any maintenance required to the cam drive.

M20s (6 cylinders, 2.5 and 2.7) have belts. Replace the belt on schedule/mileage or risk a major repair job. More M20s have been scrapped due to cam drive belt breakage than all other causes combined. They're like every other BMW engine: do the maintenance on schedule and they'll last an amazingly long time; ignore the maintenance and they'll eventually strand you somewhere.

 

[BMWFatherFigure]

I can feel my neck exposed out here - M10 chain. M40 belt. M41 ?. M42 chain. Never worked on M41 - Isn't that the twin cam? Only worked on 6 cyl with chains.
Must run with 'hornhospital' - service on time everytime - don't get bashful over suplimental oil and filter changes either.

 

[hornhospital]

M42 is twin cam, and you are correct, I was wrong. M40 indeed was a belt drive single cam. I can find nothing about an M41, but I'm very familiar with the M42/M44. AFAIK we didn't get the M43 in the States.

 

[BMWFatherFigure]

I've just done a head on an E36. The gasket set said M42 and it was single cam chain. That's why I thought the M41 was the twin cam. Hve done twin cam Jaguars but not BMW's yet......

 

[hornhospital]

M42 and M44= single chain, two cams.

 

[BMWFatherFigure]

I said my neck was exposed but this is how you learn the thing you don't know. So M40 1 x belt; M41 1 x Chain; M42 2 x chain; M43 ?; M44 2 x chain. Have I got it now?

 

[Prankbuddie]

Agreed mines the belt just had it replaced on time the chains are more reliable. Like the advice says as long as you don't thrash the hell out of it you should be ok. The idling issue could be a few things mine was the ICV idle control valve needed replacing and air flow meter resetting. The air hoses get leaks on them a lot that can cause idling problems also cheap and easy to replace. My advice get them replaced cheap to do get the valves adjusted. She looks lovely

 

[Nick323]

Chain vs belt

Belt is the way to go, as it stretches minimally, so not to upset cam timing.
Replacing a belt on a multicam V engine takes a doctorate & some cussin :tsk:
Replacing a chain on a multicam V engine takes a doctorate, valium & extreme foul language
Both have to be replaced sometime

 

[downhiller]

Belt is the way to go, as it stretches minimally, so not to upset cam timing.
Replacing a belt on a multicam V engine takes a doctorate & some cussin :tsk:
Replacing a chain on a multicam V engine takes a doctorate, valium & extreme foul language
Both have to be replaced sometime

i just help my buddy convert his 300z tt from a belt to chain. dhoc v6. he still cant pay me enough to quit bitchin about that job.

but to the op, all m20s have a t-belt. in fact the 3 series was mainly the only vehicle bmw made with a belt. the 1, 5, 6, 7 series all have t-chain with the exception of the 80s to early 90s 5 series with the m20 motor.