360 and threadlocker

Crank bolt for sure. The 360 is a pretty buzzy motor. Locktite is not a bad thing on them. Never seen it on the cover screws though. Take a really good look at the 5/8 hydro tensioner. They are still breaking by the inner bolt.

This is one of the updated ones.
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No, same breakage as before the redesign. They just moved the stress point closer to the bolt. Without the stronger bolts this and many other motors would have blown up. Still a few have but no one seems to be talking about it.

 

Brian since the 355 uses the same tensioners are they having that break/cracking problem. Sorry for the hijack Brian S. Regards, Vern

 

Has not happened on 355 to my knowledge. The 360 because of the longer stroke has a more pronounced high frequency vibration. It is not noticeable in the car. We were told of it at school in 99. We were warned that it was almost certain that a retrofit vibe damper was on the way. We were even shown what would be involved for installation but it never happened. Besides the possibility of it vibrating thins loose that are not well tightened it seems to be cracking those tensioners.

Those tensioners were improved and were part of the variator campaign but the redesign just shifted the weak point from the radius where the material thins down to nearer the bolt. I have been considering what could be done as a field mod.

 

Brian,

Is there enough clearance to the belt to weld a plate on to the tensioner body as a field modification? If you have a bad one with broken ear and want to send it to me I can weld on what I mean. Also, someone could easily copy the oem desing in a CAD program and thicken the ears where it breaks and then have them cut out of billet steel or Ferrari-ish cast crap metal

 

I have considered a plate that just goes over the ear to be held on by the one bolt to spread the load. There is not lots of room there. Making a new part would require removing all the internals from the old piece. They are really not designed to be taken apart so I don't know how successful that would be.

I think I am going to experiment with the bolt on support idea.

 

If you're that short how about a couple of phone books?


And the weather here is always good.

 

Brain,

Thanks for sharing the information. In your experience what is the frequence of this failure, out of roughly 20 services I have seen one failed which makes me think replacement should be at least as frequent as the belts. Also the bolts are addressed in bulletin #1236 but I don't have the bulletin for the tensioner itself - do you happen to know if Ferrari addressed the tensioner in a bulletin and if so what the number of that bulletin is.

 

It was the same TSB as the variators.

The failure is more common on cars that see a lot of high revs. It was a big problem on the Challenge cars. Its rare on a street car but as you and I have seen, it happens.

My ratio is probably double yours.

 

I meant 40:1.


Half....Double..........whatever.

 

Since the tensioners mechanism is a hydro type I would think that appling the heat of a welder to it would ruin the inner workings of the unit. Regards, Vern

 

Rifle driver,

Have you ever checked to see if there is slight mismatch between the mating surfaces of the ears as they sit on the engine? If there is even the slightest mismatch then stress will be built into the tensioneer mountings as you torque the ears down. Then vibration and any stress risers in the tensioneers yield failure. Just for laughs you might try hand tightening down one end of the tensioneer to see if the other end you can slide a feeler guage under the other ear. If yes that could be a contributing factor right there. This problem is accelerated with cast metals. If the problem cannot be solved without significant field work you may only be able to progessively torque the ears to spec like doing head bolts.

 

The ear on the tensioner that does not break is rubber dampened so I would think it could handle some missalignment. What occured to me when I saw the only broken one I have ever seen is that the rubber bush had completely sacked out and the steel center insert was hard against the cast tensioner housing. If you look at the photo Brian posted you can see the bolt is off center as well. It seemed to me like having the one side bubber mounted puts a lot of load on the other ear and that is why they break - the only one I replaced was the early style with the thinner ear, I figuered the heavier casting would correct the problem but it appears not. I believe that getting rid of the rubber bush and having both sides solid mounted would help the mounting strength but the tensioner probably needs the vibration damping of the rubber bushing.

 

The new tensioners do not have a thicker ear. Only the radius where it thins down from the main body is different. That radius is where they used to break.