Mi16 Cambelt Tension And Alignment

[davemar 16]

After far too many years I've decided to give the car a cambelt change. The old one looked very good considering its been on there 8 years, but don't want to take risks.

 

Anyway, currently trying to fit the new one and am not convinced I've got it on correctly. The cams and crank seem to be lined up correctly using the pins, but the tension of the belt doesn't feel right on the top run between the two camshaft spockets. It feels very loose, but I can't pull it any tighter as it's not quite a whole tooth stretch to do this.

 

I suppose a good way of knowing whether I've got the belt on correctly is counting the teeth on the run between the two cam sockets. Would anyone know how many teeth I would expect to have if counting between the 12 o'clock position on each sprocket (assuming the engine in a vertical, not the normal tilted, position)?

 

 

[welshpug 1,657]

use pins, can't get it wrong then.

[DamirGTI 342]

Feed the belt on the exhaust pulley first , then make it snug as you can on the inlet pulley ie. between the two , then round the front tensioner , crank sprocket , water pump and finally rear tensioner (obviously lock the cam pulley's before doing so) .. the idea is that you route the belt in such way so that the greatest slack on the belt is arranged round the tensioners .. then up the tension on the front one a bit then the rear remove locking pins and spin the engine few revolutions by hand and re-check the timing and adjust the tensioners some more or less as needed .

 

D

[davemar 16]

I'm sure I've done it properly now. I think the problem was the sprockets want to spring away from the right place with the pins in ever so slightly, making it tricky to get the belt on correctly. All seems lined up and tensioned well now.

[davemar 16]

Finally got round to getting the engine started again after the cambelt change. The engine sounds and revs nicely, but there's a high pitched whistle now. It does sound like it's from the cambelt end of things but difficult to pinpoint. I've removed the cover just in case it was a rubbing sound, but it is still there. Anyone else experienced this?

[welshpug 1,657]

belt too tight probably.

[davemar 16]

I've tweaked the tension a couple of times now and there's still the sound. I'm not 100% convinced it is the cambelt area that's making the noise, it's very hard to pinpoint the location of it. Could there be anything else that makes the noise?

 

I've removed the fanbelt to eliminate that from the test.

[jackherer 543]

Does it get worse as the engine warms up?

[davemar 16]

Haven't run long enough to get properly warm. I think I've narrowed it down after bodging together a stethoscope from a hose pipe and funnel. It seems to be coming from where the inlet manifold attaches to the head, so is probably a tiny air leak causing a whistle.

Edited June 28, 2015 by davemar

[davemar 16]

Refitting the inlet manifold after giving the surfaces a wipe down. The sound has now gone, so that fixed it!