Cambelt change

[Jackle]

I'm probably going to be attempting to change my cambelt tomorrow. I've got a water pump and gasket, cambelt, aand tensioner.
Is there anything else I could/should be changing at the same time?

[Brianmoooore]

Coolant, unless it's nearly new, and you can collect it without getting it contaminated, and distributor cap/rotor should at least be carefully inspected, since they will be removed.

[Jackle]

I'm definitely going to need new coolant, mine is rather murky looking. Got to do a radiator change at the same time anyway.
Distributor cap/rotor will be well inspected, but unless it is really bad will have to wait due to shortage of funds!
Are there any seals that can be done at the same time? I have an oil leak which is leaving a nice patch on my driveway..

[Brianmoooore]

There are four D shaped rubber plugs in the ends of the rocker box (block the holes where the rocker shafts slide in and out) which often become hardened and leak, and there's an O ring seal behind the camshaft retaining plate, plus a conventional oil seal for the camshaft mounted in the retaining plate.
There are plenty of other places that M20s commonly leak oil from though. A completely oil tight one is a rare beast.

[Jackle]

Thanks Brian.
I've done the 4 rocker box ones a while ago, I'll get the other 2 in the morning and have a go at changing them if I can. Would be nice to get it completely sealed up, but I don't think that's going to happen!

[daimlerman]

M20 that fails to leak oil in an M20 with no oil in it....

[Jackle]

I've now got everything off, and discovered that the cause of my occasional squealing was probably the fact that the cambelt has very little tension on it, quite possibly due to there not actually being any tensioner spring present!
Can I tension up my new belt by hand or do I actually need a spring there to get the correct tension?

[Brianmoooore]

Tensioner spring is only needed to tension a new belt. After that it has no further function, and is often removed and left off if a water pump change is performed between belt changes.
The spring, and the rod through the middle of it, are only pennies from BMW, and the fact that you are asking this question in the first place indicates that you don't have the experience to tension a belt by hand.

[Jackle]

You are correct, this is my first cambelt change so previous experience is zero.
So there is no rule of thumb that would allow me to tension by hand? Obviously I don't want to get this wrong, but I do need the car back ASAP..
I will go with whatever you recommend Brian!

[Brianmoooore]

I recommend you get a pin and spring ordered up from BMW ASAP - they might just be able to get it in by tomorrow afternoon. Once the tension is set, the tensioner is bolted rigidly in place, and the spring does nothing more until the next time.

[bilun777]

+1 to what Brian says. I had to buy a new tensioner spring and pin. I also fitted a new fanbelt and steering pump belt while every thing was in bits.

[Jackle]

Spring and pin ordered. They said they couldn't get it before 5th Jan, until I suggested getting from another dealer, then they could get it for tomorrow!
Hopefully they will get it, I need the car to take my lad out for his Birthday on Tues...

[wilz]

hey, What website did you order your parts from?

[Jackle]

Got most of it from the local GSF shop, but had to ring BMW dealer for the tensioner spring and rod. They got them next day for me.

[Brianmoooore]

had to ring BMW dealer for the tensioner spring and rod. They got them next day for me.

Try that at a dealer for any other make for a car that went out of production sixteen years ago!