Inner cam drive bearing

Normal for having the outer bearing removed (a shaft passing thru a single deep-groove ball bearing is like a spherical ball joint), and the axial position of the shaft is largely determined by the outer bearing being captured between the snap rings (the shaft is free to slide in the inner bearing bore although in operation the helix angle of the gears drives the shafts against the inner bearing which supports the thrust load) -- see the cross-sectional figures in Section B of the Mondial 8/QV WSM.

 

Christian, what Steve is saying is that the up and down play is simply the shaft changing angle a bit from the inner bearing which is fixed concentric with the outer bearing but allows the inner race and thus the shaft to deflect away from concentricity. My car had 36k miles and the inner bearings were fine— outer were loose as they take the load from the tension in the belt plus the grease gets cooked (inner ones lubed and cooled by oil.)

 

Are there any documented cases of failed inner bearings at all?
I had a complete cam drive bearings job at 90.000 kms since one seal was badly leaking. It was an expensive engine out job done by an official workshop and I didn't know about alternatives back then like just pulling the outer bearing to get access to the seal (I talk about the later camdrive bearings design). Thanks to FChat I know now better 20 years later and surely wouldn't go that route once more with the official workshop procedure (pulling the engine, removal of gearbox, removal of the drysump scavenge pump drive, etc.)
But regarding my initial question above; I still have my old inner bearings kept in my scrap box and they seem, that they would have lasted another many, many thousands of miles.
I would even dare to state, that they last forever.

Steve,
can't remember and can't identify the lettering on the outer race any more. Are the inner bearings also C4 (increased play) like the outer ones? If yes they would even show more play with the outer one removed.

Best Regards from Germany
Martin

 

I can't recall anyone posting a specific case of the inner bearing failing. When they moved the outer bearing in the later design (to reduce the pulley overhang), it not only reduced the radial load on the outer bearing to help it live longer, it reduced the radial load on the inner bearing by even more so should greatly extend its life too:
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I don't have any specific information if the stock inner bearing is C3 (extra radial play) or C4 (extra extra radial play), but I wouldn't be too concerned to use either (but would not use C2 standard radial play). Agree with your point that wiggling on the far end of a shaft mounted in a single C4 (or C3) ball bearing is going to feel even sloppier.

 

Steve - What denotes the cross-over point between your "early" and "late" designs?

Carb vs. injected? 2 valves vs. 4? Or something else?

Thanks - DM

 

Dave,

I'm not Steve, but allow me to answer
The design change took place during the carburettor car's era.
According to my parts books: (1980 GTB/GTS Euro carb, 1978 US-GTB/GTS)

Euro cars:
from engine no. 01105 GTB
from engine no. 03045 GTS

US cars:
from engine no. 00133 (all wetsump, therefore no mentioning of differences between GTB and GTS)

Best from Germany
Martin

 

Martin has already answered, but one thing that adds some confusion is that in the euro 308i-2V SPC they used the old design picture (but the parts in the list are correct for the later design). If you check the '78/79 US carb 308GTB/S SPC, there are two drawings -- one for the old design, and one for the new design (which is way better to convey the order of assembly in each design). I don't know if they made the same picture error in the US 308i-2V SPC (but it wouldn't surprise me if they did ).

 

They were good back then regarding confusion
Between Euro and US SPCs they swapped the illustrations. In one book the detail shows the late design. In the other book the detail shows the early design.

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I'm in the process of changing both inner and outer cam drive bearings because of lots of play on the aft drive gear. The forward outer bearing is fine, the aft gear outer bearing is toast - burnt toast. The inner bearings are both fine (I will, of course, replace anyway); but unfortunately the aft shaft is so badly worn that a new inner bearing just slips on and has a little play. It should NOT just slip on. New shaft and gear ordered and is on the way. Anyway, hope you have better luck than I.
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So tell me how did you remove the outer bearing? That's on my list for the next belt change.

 

More tools!!

But what is it called, Amazon wants to know!

Thanks!

 

Yes (you'll probably need to "pierce" them to pull them out and be careful about not scratching the sealing surface on the shaft, and need to be a little careful when installing them to not distort/fold the sealing lip and lose the spring, and not drive them in too deep IIRC - but if yours have never been replaced, I would. JMO).

 

Draper tool/ puller

 

Already have the pin socket. Draper tool search is on!

Thanks!

 

https://www.sykes-pickavant.com/products/pullers-and-separators/mechanical-pullers-and-kits/873

 

FYI there is a Draper tool company that do not show a bearing puller like that. There is a Sealey AK999 ( https://www.amazon.co.uk/Sealey-AK999-Blind-Bearing-Removal/dp/B000RO1HOW ) that I think is the same thing. If you notice something that I have missed please let me know!

 

and the Sykes tool...
https://smile.amazon.com/Sykes-Pickavant-09810000-Multipull-Housing-Bearing/dp/B00VTSHP82/ref=sr_1_2?ie=UTF8&qid=1539888808&sr=8-2&keywords=sykes+pickavant+bearing


I'll likely save the $ 360 and go cheap. I've never needed one before and may not live long enough to need one again. Unless this august group has other commentary .

 

It would be useful to know the ball diameters of the adaptors from the cheap Sealey tool.
But since it looks the same like Christian's (Chrill) it should fit.

Best from Germany
Martin