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Discussion Starter #1
Hi,
Just changed the cambelt on a 24v 3.0 1996 Alfa 164. Ran fine but, after a couple of days, have just fired it up and it suddenly sounds not good. Suspect a jumped tooth on a cam.

Having gone back over threads on tensioning the 24v am confident can now set the tension correctly but it is now a 'stretched' belt. Does that change anything?

Thanks.
 

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no. reuse the belt. If your pulley marks line up still, that means that the cam/pulley interface has slipped. This is why its important to mark the pulleys AND you can use the end of the cam to see the scribed line. Hopefully the belt just jumped and not the cam/pulley slipped
 

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Discussion Starter #3
no. reuse the belt. If your pulley marks line up still, that means that the cam/pulley interface has slipped. This is why its important to mark the pulleys AND you can use the end of the cam to see the scribed line. Hopefully the belt just jumped and not the cam/pulley slipped
Thanks Goats. Will reset it tomorrow.
 

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Thanks Goats. Will reset it tomorrow.
Hope you understood what Goats really said. You do know the pulleys are not keyed to cams on the 24v engine. They are just tapered fit. So did you loosen any of the pulley retaining bolts and knock a pulley loose from camshaft? If so and a pulley slipped on cam then all bets are off on is cam in correct time even if any painted marks on pulley line up.
 

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Discussion Starter #5
Hope you understood what Goats really said. You do know the pulleys are not keyed to cams on the 24v engine. They are just tapered fit. So did you loosen any of the pulley retaining bolts and knock a pulley loose from camshaft? If so and a pulley slipped on cam then all bets are off on is cam in correct time even if any painted marks on pulley line up.
Hi Steve,

Yes, understood Goats point, thanks.

Didn't loosen any of the cams as the timing was spot on so just expecting a jumped tooth, probably on a rear cam because that is the hardest to get to. Will get on to it tomorrow and post the findings.

Thanks again,
Richard
 

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Hi,
Just changed the cambelt on a 24v 3.0 1996 Alfa 164. Ran fine but, after a couple of days, have just fired it up and it suddenly sounds not good. Suspect a jumped tooth on a cam.

Having gone back over threads on tensioning the 24v am confident can now set the tension correctly but it is now a 'stretched' belt. Does that change anything?

Thanks.
No issues. Go for it.
 

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Discussion Starter #7
Thanks, Steve.

Both rear and rear front pulleys had slipped. Took off tensioner and compressed it in a G-clamp so could put drill bit in to hold it down.

Spent ages getting everything perfectly realigned but while tightening the tensioner pulley, pin taken out, my hand slipped on it and the tensioner piston came out fully. Belt didn't move out of position but question is now do I:

1) Try to slowly recompress the piston while it is mounted on the car?
or
2) Try to keep some manual tension on the belt while removing the tensioner to recompress it in the G-clamp?

Guessing the answer is probably '2' but thought I'd ask anyway.

Cheers.
 

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Richard did the pulley slip on the taper? or did the belt jump teeth?

If the former I would suggest you set the pulley/cam clocking, then sharply strike the pulley onto the camshaft with a suitable steel hammer and socket centered over the bolt. Then tighten the bolt to torque spec with blue Loctite. You could also add green wicking locktite to the pulley/taper interface. Ive seen instances (my own car) where I simply could not get the pulley to stop slipping on the camshaft taper. In that case it we required to install a keyway effectively locking the pulley to the camshaft.

I hope this is not your case. We called Alfa in Italy and every tech advisor I knew. No one had any suggestions to help.
 

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Discussion Starter #9
Richard did the pulley slip on the taper? or did the belt jump teeth?

If the former I would suggest you set the pulley/cam clocking, then sharply strike the pulley onto the camshaft with a suitable steel hammer and socket centered over the bolt. Then tighten the bolt to torque spec with blue Loctite. You could also add green wicking locktite to the pulley/taper interface. Ive seen instances (my own car) where I simply could not get the pulley to stop slipping on the camshaft taper. In that case it we required to install a keyway effectively locking the pulley to the camshaft.

I hope this is not your case. We called Alfa in Italy and every tech advisor I knew. No one had any suggestions to help.
Hi Goats,

Thanks for this. The belt just jumped the teeth as I had misunderstood the tensioning procedure - basically my fault and lucky that I seem to have gotten away with it valve wise.

Didn't realise there could be issues with slipping on the taper. Fortunately I didn't need to undo my cam pulleys as the timing was spot on.

Just got to set the tension now and probably going to take the tensioner off again to recompress the piston in the G-clamp. Unless there are any other options....

Cheers
 

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yep take the tensioner off and reset the plunger it in the c clamp or vise.

Good news on not having to change pulley/taper orientation. Don't ever do that unless absolutely necessary
 

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Discussion Starter #11
yep take the tensioner off and reset the plunger it in the c clamp or vise.

Good news on not having to change pulley/taper orientation. Don't ever do that unless absolutely necessary
Many thanks. Will take tensioner off again tomorrow and look to continue not needing to move the cam pulleys on their taper.
All the best,
Richard
 

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Discussion Starter #12
All done!

Didn't take tensioner off but used long pair of 90 degree thin-nosed pliars to keep load on tensioner piston until it finally retracted enough to get the pin in.

Usual combination of rotate engine, wait for tensioner to stabilise, check gap, adjust, rotate engine.....

Ran the car for 30 seconds and sounded a little rough. Checked again. Air-gap had all but vanished. Rotated engine to alignment points and when looked again it was back at perfect position and still able to insert pin. Considered driving car temporarily with rear cam cover off to keep an eye on things but decided that was inviting trouble with road debris and I was just being paranoid about the tensioner after getting it wrong last time.

Took it for short drive and, after running for a few minutes, it all became smooth and lovely again. Guess it just needed waking up after being parked up for most of the past 2 weeks.

Thank you very much for your help guys! Couldn't have done it without you :)
 

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Hi all, I think this is the right thread to resurrect! I have just changed the cambelt on a 1994 24v AR66301. I'm going round the pin/weight/torque nut/rotate/check gaps rinse and repeat. The problem I am having is that the airgap always closes below the 1/8" spec after rotation and the piston is depressed too far into the tensioner housing to get the pin in. two questions:
1 - does this imply I am over or under tensioning the belt (too much or too little weight on the arm)
2 - What are the correct figures? 24v manual says 224mm from centre of pulley to weight; I have 2.12kg as the weight. Is this correct? I'm using a home-made tool.
Thanks
 

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Discussion Starter #14
Hi,
sorry for delay in replying - have been away from the site for a while. Have you resolved the problem? If not let me know and will try to help.
 

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Thanks Richard, I have managed to get to the right place in the end, as measured by the pin and gap. I've not started the engine yet, but I'm optimistic!
 

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Discussion Starter #16
Sorry again for delay in replying. Not on the site as often as used to be.
If you haven't tried starting the engine yet, suggest manually rotating it and checking the air gap and timing remains good afterwards. I usually leave mine overnight for the tensioner to settle - just to be sure.
All the best with it.
 

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It's been sat for three weeks, and I've turned it over manually and remeasured several times, and it's staying put, so I think it's OK. Thanks richard
 

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Discussion Starter #18
Great news. Really glad to hear that. And well done! Think everyone deserves a medal for getting the cam tension done well on these engines. No other Alfa V6 uses this tensioner. What does that tell you...?
 

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Hello
I share with you a strange problem that I had with my tensioner six years ago.
Cold tension was correct but as the engine warmed up, the tensioner piston went down which caused the belt to relax.
I tested several things without ever solving the problem, I deduced that my tensioner was defective so I modified my tensioner to adjust the tension manually.



 
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