Problems If Steel Camshaft Thrust Washer Not Installed?

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pantah_good

pantah_good

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1972 750 Combat engine (201202), with a 2S cam (that has oil scrolls, breather hole, and tach drive), and a timing side bronze camshaft bushing with the flange facing the drive side. With a flanged camshaft bushing, apparently it is ok to not install the (p/n 06-2601) bronze camshaft thrust washers with tabs, but what if the (p/n 06-1086) beveled hardened steel thrust washer was also left off? At present the engine reassembly is at the point of the cases bolted back together.
 
BAD DOG! Rub your nose in poo, or hit yourself with rolled up newspaper. Fix now, or fix damaged engine later...

Mike B
 
Surely the answer to your question is based on whether or not your cam lobes line up properly with your cam followers, and how much cam end float you have...
 
I'm afraid setting/checking camshaft end play is still a mystery to me. Can't find anything about that in the manual or the Hemmings DVD.
 
Just push and pull on the thing and see if it moves much!

Hopefully an expert will chime in with proper figures, but id have thought anything close to 10 thou wouldn’t be far out. Should feel like a loose tappet.

If you’ve got the right cam for the cases, and have left both washers out, surely it will have massive end float?

Worst case scenario from too much float is interference between the wrong cam lobe / lifter.

I also thought those thrust washers were there to stop the tacho drive gear milling the bush away...?
 
Fast Eddie said:
I also thought those thrust washers were there to stop the tacho drive gear milling the bush away...?
Click to expand...

Yep, that's what Mick Hemmings was saying. The camshaft shucks side to side .216"/5.5mm, but nothing is attached to the timing side of the camshaft. Cases and cam are the same ones I started the rebuild with, likely the original ones.
 
pantah_good said:
With a flanged camshaft bushing, apparently it is ok to not install the (p/n 06-2601) bronze camshaft thrust washers with tabs, but what if the (p/n 06-1086) beveled hardened steel thrust washer was also left off?
Click to expand...

pantah_good said:
Hemmings DVD.
Click to expand...

If you have the Hemmings DVD then Mick explains this in detail on disc 2 (from 18:50) especially why it's important to fit the hardened steel thrust washer.
 
Yes, that's why I'm worried about it not being there. I was just wishing maybe somehow the cases wouldn't have to come apart again.
 
[QUOTE="... I was just wishing maybe somehow the cases wouldn't have to come apart again.[/QUOTE]

Sadly, they do. The clearance MUST be checked and properly set with an appropriate thrust washer. If you don't do it now you will just worry about it and wonder if/when it will fail! Bit the ol' bullet and take 'er back apart. :(
 
I know, wishful thinking. I've got to start searching camshaft end play. Wasn't anything obvious in the INOA Tech Digest either.
 
I’m pretty sure Comnoz once told us that .25mm is the figure. Which is ‘as near as makes no difference’ to 10 Thou.

You really should ensure the lobes are aligned with the followers, if this is done, I do not believe the precise end float figure super critical, so set it so it feels like a loose tappet and you’ll be fine.

Well, that’s how I did it anyhow.
 
You need a DTI to measure accurately, but if you can just feel it move in and out its 3 thou as that is the minimum human touch can feel. You can add shims until the cam just starts to bind and then take a 10 thou shim out.
 
With human touch I have to be almost 1 millimeter:oops:, would that's what have was able to cause the fast wear (7500 km) of my camshaft?

I am going to change it and well to verify that he has to have little side game.

Thank you very much Kommando.
 
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