belt change gone south

Actually, no. If the car is running when you start a belt change and you swap belts correctly there is really no chance of mechanically catastrophic consequences. The timing may be off if it was off to start, but it won't change more that that dictated by the manufactures tolerance in belt length (and that typically come out less than a degree). And lining up the marks doesn't insure correct timing. Fact is, whatever the timing was set at the previous belt change, swapping a belt correctly will restore the engine to that timing, with in less than 1 degree, provide the old belts haven't jumped at tooth.

If you are worried about timing be dead nuts, balls accurate there is only one way to be sure, time the engine.

 

In reality it is the norm and perfectly acceptable if it is known to be good to start with.

 

Removing the cam covers if fairly straightforward. Remove the retaining nuts, and they should just lift off. If your engine has the marks on the sprockets, you could get the Ferrari tool and use that method.

I don't think 15 degrees on the crank is going to damage anything. Only make sure to move things back in the opposite direction that they were moved out of place. If the cams moved clockwise, move them back counterclockwise. You certainly don't want to move them a full revolution to get back to the timing marks.

I've never used the cam locks. With the Ferrari, 1 cam always seems to move a little bit once the belts are off. It's a sudden snap that's likely caused from valve spring pressure, and the unique position of that cam. But with everything marked, it's easy to turn that cam back to the marks before installing the belt.

I believe the Ferrari method of tensioning the belt is to turn the engine over by hand for 2 complete revolutions, then tighten the tensioners. I would modify that procedure by watching the position of the tensioners while you turn the engine, and tighten them at their most extended position (tightest belt position).

If you do take the cam covers off, leave them off until the belts are done, then check your valve clearances. Valve seats wear faster than the other components, so there is less and less clearance over time. If they are too tight, you will have to change the shim size to get more clearance.

 

This is why it's worth putting timing marks on the cam pulleys. Easy thing to do and saves time and guesswork later. Keep in mind that each of the 30 cam pulley teeth are 12 cam degrees or 24 crank degrees. I suggest you get the help that has been offered as this is not a good place to learn from-- it can get expensive very quickly.

Around TDC (exhaust) the valves are near the piston and moving faster than the piston. If you know which side of TDC the cams and crank are we may be able to advise which way is safe to turn each, by how much, and in what order but it would be safer to lift the valve covers and the cams (and check clearances while in there.) good luck

 

It would be nice to have a valve adjustment chart for the Ferrari motors. Perhaps someone could make one up ?

http://www.zx-10r.net/forum/attachment.php?attachmentid=395466&d=1490747862

 

link doesn't work-- probably requires membership.

 

Worked ok for me...too bad I don't have a Kawasaki!

 

I would avoid going there then. Seems like an attempt to justify high charges.

 

I'm glad you said it.

Best
Martin

 

Distributors?

Removing the covers is easy but getting them back on in such a way they dont leak is less straightforward and also requires new gaskets.

 

Not much work. I once made an Excel-sheet.
No fancy graphics, but here it is attached, if useful for anyone.
Feel free to download, delete the values in the first row, print a blank chart and fill in by hand while working on the car.

Best
Martin
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Not to mention thoroughly cleaning the sealing surfaces on the heads, especially on the front, what is a major PITA.

Best
Martin

 

If someone used a little sealant in the past to optimize the gasket it can be hard work to lift off the covers. I have seen folks who used a pry bar and damaged a lot of things. A broken cover is the worst case. The really big trouble is NOT just finding a replacement afterwards.
I was in the same situation after my purchase of the car. Had to use some wooden wedges to carefully lift the completely baked on covers.

What's the sense behind modifying factory procedures?
Did anyone ever see a belt slipping or fail because it was installed strictly following the factory directions?
And why should I tension a belt more than necessary? To put more permanent load onto the tensioners? Or onto the camshaft bearings, which anyway look like they would have to be tenderly treated? (my own personal impression)

I think it's exactly those kinds of 'modifications', which generally lead to a big percentage of trouble.

Best
Martin

 

Absolutely right! The factory procedure optimizes the tension for the entire run of the belt, TAKING INTO ACCOUNT that tension varies slightly over a complete belt rotation. Arbitrarily tightening it as has been described can cause excessive tension and greater possibility of stretching/breakage.

 

This might help the original poster. Remember that the timing gears reverse the direction of rotation so the crank turns clockwise from the front and the cams anti-clockwise.
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I would argue that the factory procedure is what's arbitrary. In the course of turning the engine by hand, the belt can be very slack in some positions. I certainly wouldn't be tightening the tensioners at that point. And I don't believe there is any way for the tensioners to "over tighten" a new belt.

The method I had described is also described in Birdman's "Method #2". And although he attributes this procedure to Ferrari, the shop manual doesn't actually say anything about watching the position of the tensioners. It just says to turn the engine over twice, and then tighten at the TDC position.


Replacing Ferrari 308 Mondial timing belts

 

Got leaks eh ?

This can be solved with Permatex Ultra Black. On both sides of the gasket, and a nice dollop at the O-ring /head/cam box cover/ junction. I learned this from a Ferrari old timer.

 

But Service Bulletin SB 10-9 does.

 

So it does !

http://ferrari.cdyn.com/service_bulletins/sb10-9.pdf


I guess I've been using the Ferrari method all along...

 

It seems very daunting to do this procedure, but the smallest amount of common sense and mechanic experience does the trick. Take it slow...take pics...mark everything...lock down cams...count teeth on belts and transfer markings...mark where belt meets gears...make a template with a board and some nails and recreate the belt position (old school trick)...did I mention mark your belts? Disassemble...reassemble. Scary, but not rocket science. Be careless and you're screwed

 

Wow, all that belt marking/teeth counting/cam locking/template fabricating makes my hair hurt.

 

Yea, those teeth on the cam pullies, if you don't set it right, those teeth will bite you.

 

I found it very difficult to gauge this by eye. Do you guys use a dial gauge to find the maximum extension of the tensioner?

 

You can feel it with your finger as you rotate the engine over. No need to go crazy with a dial
indicator.