I am in the process of finalising a top end rebuild of my 1956 Dominator 99. Having fitted the cylinder head complete with new pushrods, the off side exhaust rocker arm appears to be binding ( after setting the tappet clearance ) on the inside of the head. The inner spring ( thackery ?) washer pushes the rocker arm over to the off side preventing a clear vertical lift. The other exhaust rocker arm is fine as is the two inlets.
The new push rods are approx., 0.035” longer than the book standard but not sure that this is the problem. I had no problems with the tappet setting etc., prior to the rebuild.
Any advice would be more than welcome.
George
I would check the action of…
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To shorten the pushrods.....
Thanks Robert. Any advice as to the best way to remove the steel end cups from the aluminium rod to enable me to reduce the rod length ? I assume that they are a press fit and heat will expand the aluminium.
As a matter of interest the valve seats were recut which will have moved the valve position which will have acerbated the problem.
George
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Heating the alloy rod won't…
Heating the alloy rod won't help, heating the steel end and chilling the ally rod may.But its all about the wiping action of the rocker over the valve tip . Getting that right is the target.
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I agree ....
Yes Robert I agree , but to correct the geometry I will need to shorten the push rods.
George
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I would check the action of the tappet over the exhaust valve tip . The movement should be centered on the centreline of the valve or you will get excessive wear of the guide due to side thrust. You could shim the rocker to move it a little away from the head contact.Might be worth checking the fitted length of the valve in case its too long . If the valve action looks wrong then the overlength pushrods once shortened could sort out both problems.