Shims for rocker gear

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Garry
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Shims for rocker gear

Post by Garry »

I have a Rover 3.5 with reconditioned cylinder heads that have had a light skim ... I am running a Kent 214 fast road Cam and am using the original push rods and lifters. The cylinder heads are fitted with composite head gaskets.

I read in the Real steel catalogue that if you are running a fast cam you will need to fit shims under the rocker post to avoid the valves hitting the pistons. Has anyone had any experience of this? and can you offer any advice as to whether I should fit the shims or would be safe without them

Many thanks


mgbv8
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Post by mgbv8 »

You fit the shims to set the average pre load for the lifters Garry.

If you are using a higher lift cam you will need to have the valve guides machined down to stop the springs binding or the spring caps hitting the guides.

To determine whether or not the valves will hit the pistons you need to do some basic measuring and confirm that actual valve lift for a start.
Perry Stephenson
MGB GT + Rover V8
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Now looking for 8 seconds with a SBC engine
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kiwicar
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Post by kiwicar »

"To determine whether or not the valves will hit the pistons you need to do some basic measuring and confirm that actual valve lift for a start."
Hi
the best way is to trial assemble one piston onto the crank (no rings) and put a head on with an old gasket with the cam and all the valve gear. Stick a layer of warm plastercean on the top of the piston a turn it over by hand, measure the dents in the plastercean to see how much clearance you have, maybe repeat with a couple of other pistons, but 1 at a time.
You can do virtually the same if you are not doing a full rebuild at the time, you need to be a lot more carefull as you can't feal what is going on so well and you really need to use the plastercean in thin strips.
Best regards
Mike
poppet valves rule!
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