How would you check camshaft end-float in an OHV engine?

[stinkwheel]

When I come to fit new cams in my enfield 500 bullet, I'm supposed to set the end-float between the canshaft and the timing cover to between 5 and 10 thou". I can buy shims to achieve this.

I'm just not entirely sure how I go about measuring it given you can't physically get at them when the cover is bolted down.

Is it a case of putting the cam in the crankcase, measuring the distance the outer cam sprocket face is from the crankcase mating surface, doing the same again with it in the timing cover. Then adding those distances to the compressed gasket thickness, subtracting the clearance and that gives me the required shim thickness (that I split 50:50 each side of the cam)?

Or is there some sort of deformable material (plastic?) I can put in the gap, bolt everything together then pull it out and measure the thickness it's been squidged to?

https://lh3.googleusercontent.com/R6A6LpZXdSfOptdQag4k6jrJV5-spBQBwpTzJpr2lagEr8_y-wIzfRY6XeKTamtxW_m6HQpxRS6rOdQlPctIa5wPwEmenD-axkqgyPV0vqbBNOLWSRb6Wv658fXAYi6F_QJum-AMNQ=w815-h611-no
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[lingeringstin...]

I'd just get a bunch of shims (or something) and keep putting some in and bolting it on until it didn't fit anymore, and then take some out.

[Teflon-Mike]

Stuff called 'plastguage'.. or similar principle improvisation... Used to be 'the' thing for measuring squish clearances on 2T silly-heads....
Stuff comes in thin strips; you cut a short length off and put it into the hole you want to measure; clamp up the cases (or turn the crank-shaft) to squash it, and the take the case off again.. real plastiguage comes with a paper chart, you lay the squashed strip on and how much it's squidges out tells you how thick the gap it was squidged into was....
Alternatively, having carefully removed squidgy stuff, you measure how thick it is after being sqashed into gap with a vernier caliper...
Though alziemers may be kicking in, 'cos I haven't used the stuff for perhaps three dacades.. you sort of get the idea!
If I had cause now, I'd probably improvise with a ball of plasticene, making sure the faces squashing it were well oiled, and measure how thick it was after being squashed with digiometer!
PS remember to alow for gaskets if you clamp up 'dry' or not.
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[Triton Thrasher]

5-10 thou is a pretty coarse margin.

Just take a look at a 7 thou gap and judge the end float to be about the same, by sight or push-pull feel.

Or set it to turn freely, with the minimum of end float.
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[Pete.]

Stick a dial gauge against the end of the cam and give it a push and a pull. Watch gauge.
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[stinkwheel]

Umm. I think some people are misunderstanding the crux of this question. Or I didn't explain it very well.

When the cams are fully fitted, you can't get anywhere near them, you can't even see them, never mind touch them or measure anything.

They are entirely enclosed by the timing cover. Both ends are in blind holes. I wouldn't know if the end float was 1 ot 100thou" when that cover is on.

I was wondering about blu-tak, not sure how it behaves when squashed down that thin though.

There should be a picture at the bottom of my post above? You can see the cams in there (the furthest right thing is the exhaust cam) and the cover that goes over them.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Tankie]

Plastigauge spreads to a known width for a known clearance gap , to read it you just place a measurement gauge you get with the kit up to it
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Always learning, everyday is a school day

[virus]

[Robby]

Plastiguage it.

Of course, considering the quality of these engines from the factory, you may then have the only Enfield in the world with properly set camshaft end-float.

[Islander]

Another vote for plastigauge here.

[Triton Thrasher]

What about applying blue to the inside of the bushes in the timing cover, then test-fitting the cover, with the engine, complete with pinions, lying over on its drive side?

Pull the cover off again and see where the blue tidemark is, on the spindles.
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