[steve25]

Once you posted the photos my thoughts went to the same possible issue as stated in post 20 that the Cam retention plate might be loose.

You should check this possibility out before you fire the motor again because the Cam moving forward and back too much will shorten the life of the lifters and Cam lobe’s.

[sdbob]

Good luck, hope you find this problem.

[HWYSTR455]

I was going to guess fuel pump eccentric, loose/damaged. It looks pretty worn, you may want to pop the cover.

If it's loose, the tab can slip out of pocket and drag, pop could be it coming out of the pocket.


.

[Joe's Garage]

You've eliminated the easy stuff, so dig on in.

Just pull the timing cover off and you should (hopefully) know EXACTLY what the noise is.

Agree with Steve25 that you should not run the engine any more until you rule out that the cam retaining plate has gotten loose. Don't kill your cam and lifters.

It's gonna take you a couple hours and then you'll know if the engine needs to come out or not. Fingers crossed for you.

Less damage = better.

[chiphead]

Spent the last couple of nights pulling the front cover off to get at the timing chain assembly.

The fuel pump eccentric was in place, but high miles and worn. It will be replaced. The cam timing gear bolt was tight, and the retaining plate bolts were tight. I loosened all the rockers to check the endplay before I loosened any of the cam bolts. Not much endplay, hmmmm, the clue phone is ringing.....

Looks like I've got insufficient camshaft endplay. There is a groove worn into the factory retaining plate. I re-used this plate when I slapped the cam in there, but I know I wouldn't have reused a plate with that much wear. The front of the cam shows some metal transfer from the plate. The snout on the cam gear measures .126-.127" and the plate is about .123-.125" depending on how you measure it. So I'm guessing it was on the tight side of spec? What is allowable camshaft endplay?

I'm not saying this is is THE problem, but it's for sure A problem. Can I clean up the cam snout with 400 grit?

I've got new plate, eccentric and bolts coming from Butler. What else do I need to check while I'm in there?

[grivera]

Originally Posted by chiphead

What is allowable camshaft endplay?

I believe the spec is .003-.010

[mgarblik]

All the stuff in your pics shows significant wear. But, IMO, you haven't found the source of the noise you described yet. A light scraping noise is all you would hear from that stuff. At worst a single (tap) when you snap accelerate the engine. Going to have to go in deeper unfortunately.