360 timing belt tension question

So is it fair to summarize as follows:

If there is a tensioner gap (on cold engine which has already been running/turning before, and without the pin) it means that the tensioner is working. If there is no gap, it means that the tensioner is collapsed and should be replaced.

Also it seems to me that the gap and the ability to move the pin in/out are two ways to check the same thing, as the shaft between the pin hole and the place where the gap is measured is solid. Is it true?

Also, how far should the timing belt be going up and down during rapid gear changes while hard driving? (Obviously the interior and belt covers should be removed for that test so the driver can see the belts while driving). I observed about +/- half an inch with a suspected tensioner which appears to be too much and also points to a bad tensioner. Does it make sense? Thanks

 

I’m no pro but I disagree. If the engine is spun by hand and allowed to sit for a couple of minutes then yes.

However If you shut off running car, the cams, and possibly entire engine may rotate backward a fraction of degree and compress the hydraulic tensioner. This has been discussed in various threads.

-ray


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Ray, you are right. With tensioner having zero gap after shutting off the engine, I've rotated the engine by hand and the gap has re-appeared.

I directly took the Ferrari Tech statement "Also, when I start the job and get the cover off, I look at the tensioner, if it is collapsed, I'll replace it."
It appears that it is impossible to only "look" at the tensioner to see if it is collapsed. I think what he meant was:

"Also, when I start the job and get the cover off, I rotate the engine by hand, look at the tensioner, if it is collapsed, I'll replace it."

Does it make sense?

 

The tensioner position will depend on how tight the belt is when installed. I think it is safe to say that all 360s at this point have had a belt change.
It is true that as the engine sits, the tensioner can collapse, I do rotate the engine to see what the tensioner does. I have only had a hand full of tensioners that I failed in 15 years of 360 belt work. I find that they are usually working as they should.
Modificator is correct in the statement about rotating the engine by hand. I will rotate the engine into the position I want it and if the tensioner is collapsed I will replace it.

 

For the life of me, I could not figure out how to replace the belts without the cams going out of alignment when I rotated the engine. There was always slack in the wrong spot. I don't know if there's a trick to this. What worked for me was putting the new belt on and then following the Aldous article on degreeing the cams using a depth gauge and wheel. But I was also doing seals, gaskets and spark plug O-rings so the cover was already off. What I really wish I could figure out is how to remove the driver-side cam cover without removing the coolant pipe that's in front of it.

 

The cams will rotate if the pulleys are not held bmo vice grips while removing the belt . Takes a little manoeuvring but the passenger side cover does come off without removing radiator pipe . I’ve just completed the entire excercise. If you need to remove the cam pulleys then you can use a thin piece of paper under the first camshaft cap to stop the camshaft rotating . Be patient and careful


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I'm not an expert, but assuming that the car runs well and does not need any cam degreeing etc, I lock the cams, mark the belt and pulleys carefully, remove the old belt, align the replacement belt with the old one and transfer the marks to the new one (making sure the teeth count is exactly the same between the marks) and put the new one exactly in the same spot. This never changes any slack.

For the coolant pipe - if it's time to change the belts, it's probably time to change coolant so disconnecting the pipe and draining coolant is the right thing to do. Otherwise the best way to move the pipe out of the way is to remove the clamp at the bottom (from under the car).

 

You cannot remove the left side cover without removing the coolant pipe. Unless you do a "slight modification" to the cover..which honestly you do not want to do.