Loose timing belt

[m122794]

Well, I've had the head and block skimmed and installed all new bits with a new MLS gasket but now have an issue with the timing belt.

I've installed the belt and checked the tensioner is within spec (10-11mm piston protrusion) but with everything bolted up there's now about 1-2mm gap between the end of the tensioner piston and the tensioner pulley carrier. Have any of you had the same issue? Is this OK? I would have thought that there should have been at least some tension on the belt...

Do you think I can weld a small plate to the idler roller carrier to pad out the slack and introduce some tension?

Thanks for any help,

Graham

[jimi]

Are you sure you have the correct belt for your car, there are differences in the belt depending on the model. There's something wrong if the tensioner isn't tensioning the belt, did you follow the BGB procedure ?

[Voivod]

Well, I've had the head and block skimmed and installed all new bits with a new MLS gasket but now have an issue with the timing belt.

I've installed the belt and checked the tensioner is within spec (10-11mm piston protrusion) but with everything bolted up there's now about 1-2mm gap between the end of the tensioner piston and the tensioner pulley carrier. Have any of you had the same issue? Is this OK? I would have thought that there should have been at least some tension on the belt...

Do you think I can weld a small plate to the idler roller carrier to pad out the slack and introduce some tension?

Thanks for any help,

Graham

Rev1 Rev2 13568-79045 178MY25 178 teeth

Rev3 onwards 13568-79105 177MY25 177 teeth

Rev1 Rev2 and Rev3 tensioners are different too

Rev1 has elongeted holes, Rev2 have round holes and Rev3 completly different from Rev1 and Rev2.

Just get the right belt and tensioner...also would be handy to know what Year and model of MR2 you have.

Rev1 13540-88381 1989 -1991

Rev2 13540-88382 1991 -1993

Rev3 onward 13540-88480 1993-1999

[m122794]

Thanks for the replies. I forgot to say its a 1994 gen3 engine. My guess is the belt is stretched as I'm re-using one but it has only done 5000 miles. I'll get a new one and see if its any better. My worry is that with a skimmed head and block any belt will be a bit too loose.

[Voivod]

Thanks for the replies. I forgot to say its a 1994 gen3 engine. My guess is the belt is stretched as I'm re-using one but it has only done 5000 miles. I'll get a new one and see if its any better. My worry is that with a skimmed head and block any belt will be a bit too loose.

The belt don't stretch even after 40000 miles that would cause any problems unless it's made of cheese or Durex!

[MR2DI4]

The belts don't really stretch but they do wear a little which changes the inside diameter.

Those tensioners dont have much travel, you need to turn the crankshaft the right direction to take out all the slack and while someone is pressing on the tensioner as hard as they can do up the bolts that hold it and then pull the pin out of the tensioner. You cannot simply put it in and bolt it up. Bolt it up so it can still slide and get someone to press sideways on it hard. its in such an awkward place that you really cannot press it to hard.

Unless the tensioner is visibly leaking oil you can reload it carefully and slowly using a vice and put a pin back in it and reuse it. Done my belt twice and reloaded it twice.

[m122794]

Thanks guys... I bought a new belt and it was better but not perfect so I don't think the belt was the main cause. For better or worse I've welded a 2mm thick piece of steel to the 'anvil' of the swing arm on the tensioning pulley and the belt is now perfect with no play and just the right tension.

[jimi]

I've never ever heard of a anyone having to do that on any MR2 engine, something wrong there IMHO.

[MR2DI4]

Yep something not right there.

Pitch of the belt teeth is quite big so if you add an extra tooth in the belt then your going to get to much slack.

My pick is the wrong belt.