How to hold the Camshaft from moving?

PostPost by: pharriso » Wed Apr 21, 2021 2:07 pm

I'm in the middle of changing the head with the engine in the car, what is the best way to hold the camshaft still while torqueing the camshaft sprocket bolts (25-30 LbFt). Would it be to:

1. Tension the cam chain correctly & the hold the engine in gear
2. Hold the camshaft with Mole Grips
3. Jam something through the openings in the camshaft sprocket

The workshop manual is bereft of any instructions..
Last edited by pharriso on Wed Apr 21, 2021 5:25 pm, edited 1 time in total.
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PostPost by: lotusfan » Wed Apr 21, 2021 3:13 pm

Hi Phil

I did the same thing last year and I think I used a variation of 1. Certainly putting car in gear and hand brake on should work. I think I put a spanner on the crankshaft nut and jammed it against the chassis.

2 - mole gips is a no-no.

Another thought is one of the oil filter removal tools that uses a chain, the pitch would need to be the same obviously.

HTH
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PostPost by: nmauduit » Wed Apr 21, 2021 3:15 pm

3) definitely : I've made an ad'hoc tool for that purpose, a bit like a pin spanner with 2 socket cap screws attached to a flat bar so that I can hold the sprocket still while applying torque. It is also quite useful to reinstall the sprockets onto the camshafts...
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PostPost by: promotor » Wed Apr 21, 2021 5:09 pm

Camshaft sprocket bolts @ 45 lb ft? Isn't the figure 25-30 lb ft?
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PostPost by: pharriso » Wed Apr 21, 2021 5:27 pm

promotor wrote:Camshaft sprocket bolts @ 45 lb ft? Isn't the figure 25-30 lb ft?


You are correct sir, edited my original post :oops:

OK, how do you stop the Cams rotating? :roll:
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PostPost by: h20hamelan » Wed Apr 21, 2021 5:42 pm

Screen Shot 2021-04-21 at 10.39.49 AM.png
Screen Shot 2021-04-21 at 10.39.49 AM.png (124.67 KiB) Viewed 1545 times


I know this has a different mount bolt to the head, the idea is.
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PostPost by: promotor » Wed Apr 21, 2021 6:04 pm

pharriso wrote:
promotor wrote:Camshaft sprocket bolts @ 45 lb ft? Isn't the figure 25-30 lb ft?


You are correct sir, edited my original post :oops:

OK, how do you stop the Cams rotating? :roll:


Didn't want you having an accident with a bolt in a camshaft!

Last set I torqued I just torqued them once the engine was assembled and they didn't move when on a compression stroke. That was a new engine though with very good compression.
I would think 25-30 lb ft is achievable just on compression.
You can add a bit of compression to help you with your problem by putting good sealing tape over inlet and exhaust ports - this will make the engine harder to turn over and give you a bit of help.

Otherwise passing something through the cam sprocket to lock it will help but you don't want to mark the cylinder head so it's got to be strong but not hard enough to leave an impression!
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PostPost by: Mazzini » Wed Apr 21, 2021 6:37 pm

OK, how do you stop the Cams rotating? :roll:[/quote]
Otherwise passing something through the cam sprocket to lock it will help but you don't want to mark the cylinder head so it's got to be strong but not hard enough to leave an impression![/quote]

There was a fella I used to know, he would be ideal, he wasn't hard and he never made an impression :-)
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PostPost by: RichardHawkins » Wed Apr 21, 2021 6:51 pm

Phil,

I did the same as mnauduit
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PostPost by: rgh0 » Wed Apr 21, 2021 8:47 pm

I use the plastic handle of a small screw driver through the sprocket hole

cheers
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PostPost by: pharriso » Thu Apr 22, 2021 10:44 am

Thanks guys for the feedback, as suggested I jammed something through the sprocket holes. Not too difficult at just 30 LbFt :D

Onto the next operation....
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PostPost by: billwill » Thu Apr 22, 2021 2:28 pm

I always remove one of the bearing caps and put a small piece of cardboard, typically cut from a cereal packet, over the cam shaft, then put the cap back on and tighten to the normal torque. This stops the camshaft rotating, but is easy to loosen off to align the timing marks.

Don't forget to remove the cardboard before starting the engine !!!
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PostPost by: The Veg » Fri Apr 23, 2021 12:22 pm

3 Seemed the most obvious to me when I was working with the head, and taking precautions with the mating surfaces seemed obvious too.

Interesting about the cardboard under the cam cap- I would never have thought of that; might give it a try next time I'm in there.
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