83958 Major - 2016 - Timing System Controls

Here is a reference pic of Table 5:
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At the last Major in 2008, item #37, the tensioner bearing support had a scored shaft. The bearing had spun on its shaft. Locktight 680 was used to secure the bearing on the shaft.

At this Major, the shafts will be replaced with new.

In this pic you can see the old shaft, with Locktight still remaining.

The Locktight requires heat for removal. After the bearing was broken apart in the press, all that remained was the inner race, frozen solidly on the shaft. The Locktight worked very well in this application.

Some heat was put on the race (mapp gas torch) while the bearing was under load, and it popped free right away. The heat was nowhere near the 500 or so degrees that Locktight cite. Differential expansion seemed to be all that was required.

Life Is Good!
vincenzo
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Here is a pic of the passenger side cam belt tensioner assembly. The old parts are shown on the right and the new, replacement parts are shown on the left.

New wavy washers, nylocs and a new roll pin are complimented by a new retaining bolt and their matching washer components. The bolt and two large 'washers' are actually an integrated, matching assembly. Note the collar on the bolt shaft immediately below the hex - it accurately retains the 5mm thick washer which provides a very stable support for the next washer which retains the bearing.

You can see remnants of the Locktite shaft/bearing retaining compound on the right side bearing shaft. It worked well, but not as well as the new shaft will work!

Rgds,
vincenzo
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...in place, cocked and ready to go.

Orange witness marks indicate that the final torque (or pressing) has been applied. The 8mmx1.25 nylocs went on with 28Nm.

The bearing bolt will get torqued after the belts.
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...with the new parts on the left
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...in place, cocked and ready to go.

Orange witness marks indicate that the final torque (or pressing) has been applied. The 8mmx1.25 nylocs went on with 28Nm.

The bearing bolt will get torqued after the belts.
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- All threads were clean and dry with new nylocs throughout.

- The passenger side tensioner's helicoil looks like it was trying to back out. The thread closest to the bearing is not holding the helicoil tightly. WATCH for this at the next service and reevaluate.

- An extremely thin bit of grease was applied between the tensioner body and traveling block. It was only enough to wet the surface and not enough to creep out of the interface

- Both bearings were a very close tolerance slip fit. They only slid down the shaft with perfect alignment. No lube or locktite - just clean and dry.

- The new, thick washers under the bearing bolt's hex had machining marks on one side.... at the next service, don't mistake them for scoring due to a rotating bearing!

- The OEM nyloc retaining the tensioner spring was a double high nut. Since this is a VERY lightly loaded application with no dynamics, I replaced it with a single high, Class 10 nyloc.

 

True statement.... however the Locktite 601 did an excellent job at my last service! If new parts were not available, I would not hesitate to use it once again.

For more discussion on this issue, see this thread from my last service:

http://www.ferrarichat.com/forum/technical-q-sponsored-algar-ferrari/189045-tr-tensioner-bearings-slip-fit.html

Cheers!
Vincenzo

 

FYI - here is the 601 cut sheet. Not as good as new parts... but still an effective tool.
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