Scared to change the cam belt...

[samcoombes]

Really want to do it and feel confident enough but there's something inside me saying i'll balls it up!

How easy is it to do exactly?

I't the timing bit that i'm worried about...

[Widge]

Don't worry about it the timing bit is perfectly straight forward.
You align the marks then take off the old betlt and tensioner, ten put the new one on really carefully. The crank won't move because the is a lot of resistance, and you just have to be careful not to knock the cam, although it's got a bit of resisance on it too. It's no where near as bad as changing a twin cam!

[Andy_magic]

Also, if you turn the engine over by hand a good few times before hitting the starter you will know if the timing is out and any valves are going to hit.

A guy I know gets the belt covers off and runs a stanley knife along the belt cutting it in half so the belt is only half as thick as it was. If you know what I mean.

he then slackens the adjuster off and feeds a new belt on, gives it a couple of turns to make sure everything is good then cuts the remaining half of the belt off and slides the new one on fully, tighten the tensioner up and all is well.

[Davenotouring]

How about if you have taken the head off?

Can you use TDC and so on to time it up?

[samcoombes]

A guy I know gets the belt covers off and runs a stanley knife along the belt cutting it in half so the belt is only half as thick as it was. If you know what I mean.

he then slackens the adjuster off and feeds a new belt on, gives it a couple of turns to make sure everything is good then cuts the remaining half of the belt off and slides the new one on fully, tighten the tensioner up and all is well.

Know exactly what you mean and souns an excellent iea. Can the tensioner then me replaced without removing the belt? hmmm...

[Karan]

WOW what an idea!!!!! im less afraid of doing mine now!!!! i was worried id shag the timing too! Dave there are marks on the head and on the block so roatet lump to those marks TDC then put the belt on..... this is how i did it on the m40....

[Brianmoooore]

OP hasn't said what engine he's talking about. Setting the tension is automatic on a M20, but a bit more involved on the M40.

[Widge]

You can probably replace the tensioner with the new belt on, probably easier if you do it when it's only half on. If your going to replace the tensioner then it's probably a wise idea to do the spring too, only 88p from GFS.

I did the stanly knife idea on the first M20 I did, and yeah it helped my nerves co I knew it was still in time, but you don't really need to do it once you have changed one. I'd really suggest doing it the first time though.

[Karan]

OP hasn't said what engine he's talking about. Setting the tension is automatic on a M20, but a bit more involved on the M40.

yeh i did a head rebuild on the m40.....its a right silly engine......talk about overcomplicating things!!!!!

[Brianmoooore]

It's called progress, mate. Try rebuilding an M50 vanos !

[Widge]

I thought Vanos had little pixies who pushed the valves up and down when they got poked Did one of your's get lung cancer from the from the leaking exhaust gas, I heard this was a common fault, those pixies aren't cheap either!!!! Oh wait no thats how the VTech works, the Vanos is MAJIC

[Andy_magic]

I don't use that method myself, as I mark the motor up before doing a change regardless of engine type. If anyone has ever done a rover 214 belt will know why (Not my car - honest)

It is a good way of doing it if your nervous etc. I know another guy who just chucks them on, he usually kills them too, he's a right animal. One car had 3 engines in it as he kept changing belts and getting it wrong. Not a very complicated engine either, the 8 valve Rover 1.1 used in metro's. He paid me to do the head gasket on the 214.

[E30Adam]

I'd like to see a stanley knife cut through an M20 timing belt. They are reinforced with metal and I doubt very much that you'd be able to do it.

[Karan]

I'd like to see a stanley knife cut through an M20 timing belt. They are reinforced with metal and I doubt very much that you'd be able to do it.

hmmm i was thinking that..........

[Widge]

I'd like to see a stanley knife cut through an M20 timing belt. They are reinforced with metal and I doubt very much that you'd be able to do it.

hmmm i was thinking that..........

Tin Snips

[Karan]

yeh i guess u could use those cutter pliers things....

[Adammcf]

Surely if you line up the TDC on the cam and crank markers you can go wrong?

[Widge]

Surely if you line up the TDC on the cam and crank markers you can go wrong?

Yeah you can!
It's just unlikley, but then the concequences are unthinkable.
It's especially neurve wracking when you've never done one before.

[E30Adam]

The best way is to make sure you mark both the cam and the head and also the crank and bottom pulley. If you mark all 4 and make sure they are all lined up then you won't go wrong. Once the belt is off just make sure you don't rotate the cam or crank and if for some reason you do, just rotate it back and line the marks up again.

Hen you've got the new belt on and tensioned up, turn it over a couple of times by hand at the crank. If you feel anything other than compression resistance then you have a problem.

Bottom line is... if you make sure the lines are marked up and don't move then you can't really go wrong. Cutting belts up sounds a bit long winded and unnecessary if you ask me.

Sam, you're in Bournemouth too right? If you need a hand then feel free to PM me and you can come and change it at mine, I have all the tools and plenty of spare E30 bits!

[Andy_magic]

if you turn the engine over by hand a good few times before hitting the starter you will know if the timing is out and any valves are going to hit.

Hen you've got the new belt on and tensioned up, turn it over a couple of times by hand at the crank. If you feel anything other than compression resistance then you have a problem.

I would agree with that

[samcoombes]

Sam, you're in Bournemouth too right? If you need a hand then feel free to PM me and you can come and change it at mine, I have all the tools and plenty of spare E30 bits!

Will do mate - cheers for that