308/328/Mondial Timing belt replacement tutorial

updated link in original post

 

If you unlock the cam by removing dowel pin then the cam pulley rotates without rotating the camshaft.

 

Yes, but you only have to do that if you want to change the cam timing. If you’re happy with the timing you already have, you leave the pins in and the sprockets bolted to the cams. The new belt goes on with the same spacing as the old one (that’s why you mark the belts and/or lock the cams) and you’ll get the same timing to within the limits of accuracy of the belt.

 

BAD IDEA.

Loosen the Tensioner Bearing and rotate the crank Counter-clockwise a few degress. You'll get all the slack you need.

TRUE.

At a very DESERVED $Price.


I'm a Selective 'Part Collector'

I own more than 4 different sets of Cam Gears: trapizoidal and half-moon toothed, NON and Adjustable, One and Two Piece.

I have every combination and permutation 'Covered.'

 

Thanks for keeping the Cam Gear manufactures in business.

 

Like I say, I collect selective 'Parts.'

Im looking for a 308 GTB/S clock with the 'hollow' numbers ...

 

HI,
I have read almost all the 308 QV timing cam belt threads - (actually studied them) - my question -> what is the best practice to fit the new belts over the new tensioners -- the belts are very tight and it is quite the fight - these belts - don't stretch and can be damaged. I have tried all the methods mentioned -- but I am still about a 1/4 inch short of getting it over the tensioner pulley (all belt teeth are seated in their cogs - belts are tight to the cam pulleys with the binder clips ( thank you Birdman)- I think it shouldn't be this hard and instead of trying all different methods mentioned -- I want to just ask the experienced fellowship here - what is the best - most successful method of getting the new belts on the tensioner pulleys?

I have tried the following - 1) "swinging" or pivoting the tensioner in place with the bearing (2) "locking" the tensioner pulley fully open or slack and fitting the belt over the pulley with the tensioner in place. Is 1 or 2 the better practice? Are there other methods I missed -- these new belts are tight and tough to get over - even a fully slack tensioner pulley - I want to finish this R/R belt job -- again worried about belt damage.

All comments, ideas, experience welcome - I'm in the middle of this job and stumped.

 

Hello Mike,
Fully agree with you.
I always take the cam covers off and check that the timing marks are in place. Despite all the arguments on this subject, the manufacturer knows more than me.
Apart from that, I've replaced the belts without replacing the tensioners many times... so far so good.
these tensioners(bearings) don't suffer at all, they just spin with very little load on them.

Just my experience.

John.

 

Maybe you have not fully compressed the tensioner spring?

The method I use is to free the cams and put on the belt on the tensioner side first. Make sure the belt is tight by rotating the relevant cam counter-clockwise. Do not move the crank, it is not necessary.

Then align the teeth on the belt with the teeth on the other cam pulley. A fixed wrench on the pulley bolt works great to position it.

Of course, you need marks on the pulleys to know you are in alignment. I am also taking the precaution to not change the belt at TDC. The pistons are out of the way by doing so. Some people say we do not need to worry ... but it is easy to make marks anywhere to know the alignment is correct.

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I don't try and get the belt around the tensioner pulley. I install the belts with the pulley/bracket completely removed, then with the belt held in place with clips, I pull the slack to the side and then reinstall the pulley/bracket into place.

In other words, it's easier to slide the pulley around the belt, than the belt around the pulley.

 

THANK YOU Conan and Thorn! It is always good to check in with those that have gone before -- "There is no substitute for knowing what you are doing!" With your help I'm looking to finish off the belt job this rainy Saturday -- Interestingly -- the belts that came off "looked" great -- but I found though that even though new belts are tough that can be brittle especially with lateral force ( twist) and point pressure -- I think it says somewhere "do not kink"

 

UPDATE: I used the Thorn method (1) belt on first - held tight with clips - no tensioner 2) tensioner fully retracted 3) fit tensioner assembly in place under belt.

This proved the most promising but was still unable to seat the tensioner. I was still about 1/8th inch shy. the issue is that the tensioner must seat square on the three studs which requires serious hand strength in a very tight space. So do you knock the tensioner in place to seat it the rest of the way ? I am concerned about damage to the stud threads doing so. Is it really that tight? - should it slide in place relativey easily? am I still missing something to get that tensioner to seat?...everything else is going great - cams locked - marks in place - all teeth seated and slack all at the tensioner side..want to finish this off - hard to think it is this difficult just to get the belt on with the tensioner. All experienced advice welcome.

 

I don't try to fit all 3 bolts in 1 go. I get one bolt in, then swing the bracket into place (against the belt). Then get a 2nd bolt into place (from there, the 3rd bolt is easy.) It can take some effort, yes.

 

Perhaps the tensioner bearing could be inserted last, sliding it on the shaft and belt simultaneously.

 

Thanks Thorn, Conan.. I'm using the pivot/swing method -- but the assembly really want to fit down squarely on the studs (all 3 studs a once).. The pivot worked ok for the rear bank - (although not as smooth as I would have hoped) but the front bank is a true fight and I fear for those stud threads... Conan -- I'd like to try your method - but I am shy to try and remove the bearing from the assembly shaft - for fear of the bearing coming apart and then having to reorder a new bearing etc... I will fight it some more today with a bit more confidence from this thread - I do say - I enjoy working on the car and being a long-standing part of this community - thanks so much for your help and time. --- stay tuned..I am hoping for success today.

 

Yes, hope it sorts out ok ... I know the bearing is also a tight fit on the shaft but should slide easily. On the bench, it might be easier to see if the bearing tends to come apart ...

As a side note, I had to replace all studs due to threads were badly damaged. I noticed they do not have normal fit threads into the block, but instead maybe DIN 4H instead of 6H ... and they were really hard to remove. Good to know in case you might want to remove a stud to get the tensioner assembly on.

 

Here is a dumb question, do you have the correct belt size? Measure your new belts with the old ones. Sometimes they ship the wrong belt even with the correct part number.

 

That sounds like a nightmare! Good to know but after a few days fighting it I would be really pissed to know that it was wrong. Of course I won't have that problem in the future but wow.

Lester

 

Friends,

I neglected to post as I have a 2 vale so it may not be relevant here, but experts helped me when I did mine. The first time I locked my cam caps etc. But eventually started doing it as they suggested. I had the car at PM1 marked all my camshafts at seals and new and old belts on cams pulleys as I am not an expert . HA I found that on my car I needed the cams pulleys to move a few degrees to slip the belt over. Replaced them always, but never had to remove the tensioner to do this just have it locked in the loose position. On my car the belts are easy getting to them is the PITA.... Good luck

 

Thanks all... I do fear for the threads but so far the pivot method worked ok on the rear bank -- removing the studs seems like a genius simple way of doing this .. but they are long studs and locking them in properly with the tensioner in place might be problematic -- good info conan to know if I need to replace a stud -- I really hope not.. as for the belt size -- yes -- I did check the part number on the belts as well as measured them up vs old -- I am through and methodical that way. However -- the rear bank install was kinda smooth and the front so far nearly impossible so I began to wonder if they were indeed a wrong belt. It was the right belt but still weird that one seemed to "stretch" a little better than the other. It is clear that it would be easier without the cams locked -- but no way I am that experienced - I'd rather tear a belt installing it (and then trying a fresh belt) than bend a valve messing up the timing. I hope I have success this weekend. I do have the tensioners fully retracted -- funny if they would only retract another 1/8 inch -- this would be a breeze -- but then you wouldn't need a Ferrari dealer to do them -- hmmm maybe they engineered them that way...

 

Maybe you can assemble the tensioner, put on the belt on the tensioner side, then move the crank just a tiny amount tightening up the tensioner side belt run. It might give you the clearance you need to slide the belt on the last pulley.

 

First, do change the tensioner bearings. Yes, they just spin, but they will stop spinning when the grease dries out over time. I suppose you could clean and re-grease the old bearings, and that would probably work. Clean and grease the tensioner springs as well.

I've never locked the cams. Mark them. One might snap to a different position, but that won't damage anything. Just move it back to the correct position by hand. The trick is to take up all the slack in belt. You might have to move the cams a tooth, and then turn them back. With the slack taken out of the belt, the tensioner should go in without too much trouble.

 

Voila' , Success -- the pivot method (thorn) is the only method that had a chance -- I like the security of the cams marked AND locked in place for the belt change - doing a cam timing - something else again-- odd -- the rear bank went in rather smoothly. I felt confident -- the front bank was quite the fight. It seemed like the belt was a teeny bit tighter than the rear one -- (manufacturing tolerances?) I was sure to have the bearing fully retracted but it was tough to swing (pivot) it into position since you can't place it on the studs "square." I have done this before putting the bearings on last - with the assembly in place - but that was way too hard and I worried about damage to the bearings and the tensioner assembly. Good news is that the front bank spark plug removal was a breeze -- thank you all -for guidance -- now on to the hose refresh and the HT wires and all ignition bits. Working on the car has kept me sane during the cover lockdown!