slimbobaggins

My friend gave me this truck with a shot engine (I've got another build up thread going on here ). I decided to put a junkyard engine in because the crank was extremely difficult to spin by hand, so I expected spun bearings.

Apparently what happened is the steel chain guide my friend installed broke, why I don't know, and wrapped itself around the crankshaft timing gear. He had just put a new timing chain, guides, etc in the engine 3 months prior to the engine dying.

Anyone have any input on what might have caused this? I'm in the process of putting the same parts from Engnbldr on my junkyard engine... and I'd like to not repeat the failure.

HighLux

Parts are quality....I would have to bet he didnt threadloc the tc guide bolts or forgot to torque them or something.


I cant be 100% but 99% of me says someone goofed.

I can vouch for the engnbldr parts. I had a great experience 2x from them.

slimbobaggins

Well I don't know for sure his parts came from Engnbldr... that's where I got mine from... but his guides look identical to mine.

All the bolts on the guides and tensioner were tight, nothing was flopping around.

On the plus side, I can probably sell at least this bottom end. No telling if the chain skipped and bent all the valves in the head, I don't have it off yet.

HighLux

Def the first time I have seen that. I bet Ted at engnbldr might have a theory if you sent him those pics.

Sorry you are forced to spend money and do work when you hadn't planned to.

wyoming9

iTrader: (1)

From the pictures it looks like the chain either broke or came off the sprocket first causing all the carnage.

something installed wrong or defective part

HighLux

Some nasty carnage nonetheless.

slimbobaggins

Chain is in one piece, no obvious damage to the cam sprocket, I can't get the piece of the guide off the crank sprocket for further evalution. The tensioner had some grooves ground into it. The chain links have "06B" stamped on the side of them.

The entire timing system was completely in tact when I pulled the cover off, save for the piece of guide jammed in the bottom.

With a breaker bar on the crank bolt, I was still able to muscle the engine all the way around past the guide... the engine would spin easily for 180 degrees, and then very difficult for 180 degrees, which ended with a clank. Obviously the difficult part was when I was spinning it over the piece of the guide.

wyoming9

iTrader: (1)

Going from pictures one works with what one sees.

Then it can only be one of those freak things a flaw in the guide that failed after a short time at rpm to say the least.

slimbobaggins

Oh yeah I know, I should have been more clear in my earlier posts.

I just emailed the pics to engnbldr to get his opinion.

HighLux

Just really weird. I bet that made a racket.

slimbobaggins

He was on the interstate when it went... said when it happened the whole truck jolted like he'd hit something.

slimbobaggins

Response from Ted:

HighLux

Wow....replied this late at night? Amazing. I buy his theory.

engnbldr rocks.

slimbobaggins

Yes he does.
Just to finish posting the conversation, in case anyone needs this info later...

wyoming9

iTrader: (1)

I was going to mention a failed tensioner in any case it was a loose chain that caused the failure.

Not a bad guide.

Yes Ted is awesome Us older people can be a wealth of knowledge at times.

slimbobaggins

The tensioner appeared to be okay when I tore it down, but now that you guys mention it I have no doubt that it was the cause. Just because it looked okay now doesn't mean it wasn't stuck before. The bolts that hold the DS guide in place are also ground down on the chain side, so clearly the chain was rattling around in there.

Believe me, some of us younger guys can appreciate the wealth of knowledge you older guys have. At least 50% of everything I know I can directly thank my dad for, and the other 50% I can thank my dad for imparting on me the perseverance to seek out knowledge and learn how to do things.

daved5150

iTrader: (1)

Good thread here. Check and see if the tensioner arm hangs up at all when you press it in....if it sticks. I've heard about that top oil pump bolt - to be careful and not over torque because of it protruding too far and hitting the tensioner.

I am in the process of doing a timing chain job on my 94. I bought an OSK (Made in Japan) kit (w driver's side steel guide) from Putney's (22reperformance.com). I have heard nothing but good things about Ted and his parts at engnbldr.com. I learned something today in reading what Ted had to say about the steel guides. On my truck, I got as far as rad out, valve cover off, pulleys off, AC compressor off, and power steering off....I'm on other things now with her, so I'm going to leave the t/c kit for last. I had to pull the front diff and center link to get out the oil pan because the driver's side guide was cracked...with pieces in the pan. I was going to do a head on t/c R & R, but seeing that she has 175K miles and it was probably replaced before with the head on (w all the silicone that was at the front of the pan/block). Sooo, I already had an OEM head gasket and new set of head bolts....head is coming off.

Maybe the kit your friend bought was a cheap Made in China Ebay kit with a crap tensioner?? Or maybe the bolt bond the tensioner? I looked into the different kits out there and some are made elsewhere with the tensioner being Jap made. I looked into Ted's stuff and can't remember about his tensioner at all. Good luck with the job, bro.

Gizler00

iTrader: (1)

That's pretty crazy. Puts more perspective in the steel vs plastic guide decision. If I was plastic it wouldn't have done that.

I'm also going to say the chain broke or guide bolts were not torqued down.

slimbobaggins

Neither are the case. I pulled the engine out and tore it down myself. I considered trying to fix the engine in the truck, but what led me to pull it out (and purchase a junkyard engine) was:

1) The crank was extremely difficult to turn by hand for 180 degrees of travel. I know now that it was because 180 degrees of the gear have a guide wrapped around it, but at the time I suspected spun rod bearings were causing the binding.
2) With the engine still in the truck, I attempted to do a compression check, and didn't read any compression at all on the first two cylinders. Now it's possible that maybe the threads in the head are mucked up and the compression was able to leak past the tester, but now that I know what failed, I suspect that the chain skipped some teeth when it happened, which in turn bent a bunch (or all) of valves.

In either case, when I tore the engine down yesterday, the chain looked beautiful, the guides and tensioner were held firmly in place by their bolts (no loose bolts). The truck was only driven for about 3 months from the time everything was replace to when it failed, so aside from the broken guide, the parts look new.

I've also now looked at the top oil pump bolt (which is actually a stud/nut combo, not a bolt... no idea if that's factory or ???) and it does not protrude past the surface of the timing cover, so that isn't the culprit.

I can snap another pic of the mounting bolts for the guide later on, but they've clearly been ground down by the chain. As Ted said, the chain had to have slacked off and the previous owner drove it for a while for those bolts to get ground down like that. He's not a car guy, so he may not have though much of the additional noise... or if the exhaust was leaky or something, perhaps he didn't even hear it.

When he had the maintenance done, they didn't drop the pan and clean out the pieces of the broken factory guide. So at this point I'm going to guess either the tensioner was overtorqued causing it to stick, or maybe the truck had low oil pressure from pieces of guide plastic circulating throughout it, causing the tensioner to malfunction.

Either way, I don't regret buying another metal guide. This one (which I got from Ted) is identical to the one that's broke in there... but I am a lot more meticulous with my vehicles than the previous owner was, so I doubt I will run into this issue once I get the truck back together.