Metal backed guide failed

[iferro]

Today I while cruising at highway speed ~70mph. I heard some clunking, loss of power and as I looked down my engine light came on then the truck shut off as I made my way to the side of the road. I tried cranking it over. It turned and fired but would not start.

Once I got the truck home I pulled the valve cover to check the timing chain. Turns out the steel guide on the driver's side had snapped just above the top mounting bolt and was wedged in the chain. I originally expected to find that the chain failed because the truck wouldn't start. Now I am thinking the chain skipped causing the timing to be off and possibly damaging some valves.

So I cranked the motor to tdc. Both crank and cam marks are spot on. I plan on doing a compression test tomorrow after work. Considering I didn't lose timing I assume the compression will be fine.

What could it be that caused the guide to snap? I did the 4 piece engnbldr kit in July. Everything went smoothly and I haven't had a related problem since. Is there anything else I should check? I'll have to swap in a new guide and will likely do both and the chain just in case anything was damaged.

 

[fourwd1]

Maybe just a weak part, or possibly an install issue.

 

[Ay Ay Ron]

how did the compression test go?

 

[KidVermicious]

What's in the engnbldr kit you put on? New tensioner?

 

[iferro]

Maybe just a weak part, or possibly an install issue.

I know both of these are a possibility. What I'm trying to figure out is if something else could have caused the failure.

how did the compression test go?

Spark plug #1 was seized (only 4 months old) and it was pouring rain last night. Will try again tonight.

What's in the engnbldr kit you put on? New tensioner?

Timing set (chain, guides, tensioner), oil pump drive, water pump and timing cover.

 

[joeynational]

maybe the tensioner failed allowing the chain to have allot of slop and prematurely wearing the guide? I think you had a faulty part somewhere.

 

[iferro]

Maybe just a weak part, or possibly an install issue.

I know both of these are a possibility. What I'm trying to figure out is if something else could have caused the failure.

how did the compression test go?

Spark plug #1 was seized (only 4 months old) and it was pouring rain last night. Will try again tonight.

What's in the engnbldr kit you put on? New tensioner?

Timing set (chain, guides, tensioner), oil pump drive, water pump and timing cover.

 

[KidVermicious]

maybe the tensioner failed allowing the chain to have allot of slop and prematurely wearing the guide? I think you had a faulty part somewhere.

A faulty couple parts maybe, because even if the tensioner lost oil pressure or failed otherwise, the guide should have held up. But there's no reason at all for it to break unless the chain went slack, so something definitely went south at some point.

Probably be worth calling Ted at engnbldr, [MENTION=139763]iferro[/MENTION]. Maybe he's got some insight, and I expect he'd be willing to work with you on getting those parts replaced.

 

[iferro]

Alright, so I got the compression test done. All cylinders were good and within a few psi of each other. #4 was a little lower than the rest. But they all have good compression.

I'll get in contact with Ted And get replacements.

Tomorrow I'll see if I can get it to start even if it's just for a minute.

 

[Thefishguy77]

Alright, so I got the compression test done. All cylinders were good and within a few psi of each other. #4 was a little lower than the rest. But they all have good compression.

I'll get in contact with Ted And get replacements.

Tomorrow I'll see if I can get it to start even if it's just for a minute.

I wouldn't fire it with out the TC being correct. Tensioner and all. If it jumps a tooth you could be pulling the head.


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