Well gents, here is where I am now.
Took the whole thing back to the bones. A soon as I removed the PRs the motor spun free. Checked the timing from the cams on back up and all was correct. I did find that the cam tensioner was worn and had some small pits so I'm going to replace it.
I pulled the rocker covers and everything looks good. I'm going to check for any spring binding once the PRs are all adjusted. Thought I would put in some new oil separator umbrellas while I'm in there.
So, what the heck valve spring pressures do these things run? I can see now why there are lifter failures!! I'm in high gear and I can feel every ramp of the cam, even a little kick back if it rolls off the lobe just right.
Are there different length lifters for twin cam motors? About the only thing that I can think of now is pulling a lifter and measuring against stockers that came out.
The resistance and kickback is caused by a combination of many factors... Spring pressure, cam profile, ramp design, overlap, compression... (but you've pulled the plugs, right?)
Lifters are all the same length. Even if they weren't, as long as you're using adjustable pushrods it would not matter. As long as your cams are timed to each other and your cams are timed to your flywheel, and you're properly positioned as you set the pushrod length, you're fine. As mentioned earlier, after the lifters bleed down, you should be able to spin the pushrod with your fingers (as long as you are still positioned off the cam).
Should we assume you've not changed from stock rocker arms to roller rocker arms If you've changed to roller rocker arms, your rocker box lids need to be clearanced, otherwise the rocker arms will interfere with the webbing in your lids. But if you've retained the stock rocker arms, it's a non issue.
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Topic: Crank Timing (Read 2619 times)