Startup Fail

rschmid123

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Finished rebuilding my 3v engine. When I went to start it, it cranked fine but struggled to start. When it did start there was some serious clanging from the engine, as though something were loose. My first guess was the timing/valve train. When I pulled the valve covers, I found three roller followers cracked in half. When I pulled the timing cover, everything looks as it should, however I have not yet verified the timing marks are still (or were) correct.

My question is, what could cause the rollers to crack? Is this an indication the piston came up while the valve was open and slammed the valve up into the follower? I'm really hoping there could be another cause, otherwise those three valves are probably damaged. The crack is complete (two pieces) and side to side on one side of the roller (roller was intact)

Appreciate any feedback on this.....
 

Midlife Crises

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That’s a pretty good indication the cam or cams are out of time. Valves, guides, followers, lash adjusters and pistons can all be damaged easily when valve to piston clash occurs.
 

Dino Dino Bambino

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My question is, what could cause the rollers to crack? Is this an indication the piston came up while the valve was open and slammed the valve up into the follower?

I hate to be the bearer of bad news but that sounds exactly like what happened. A look inside the relevant cylinders with a bore scope would probably confirm that. Prepare yourself for pulling the heads as the next step.
Can you post some photos or a video of the crank and cam timing marks so we can see them?
 

rschmid123

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Thanks, I'll try a scope to see if anything is visible, but I think I will pull the heads. In pretty deep already and that's the way to be sure. If I don't and there's a bad seat or bent valve stems I'll be putting my head in the oven......:angry1:
 

86GT351

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Thanks, I'll try a scope to see if anything is visible, but I think I will pull the heads. In pretty deep already and that's the way to be sure. If I don't and there's a bad seat or bent valve stems I'll be putting my head in the oven......:angry1:
I would scope first. Don't go through the extra labor if you don't have to. Prepare for the worst and hope for the best.
 

eighty6gt

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Looks like truck 5.0's 2011/12 are about $3,000 these days for something with just over 100k miles.
 

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