Timing chain guide

[Dave WM]

Never experienced any bucking or backfiring or any other odd running of the engine. And all this happened AFTER a 3600 mile nearly non stop but for some few hour rest stops.

[Dave WM]

Maybe the non stop running could have somehow created vibration enough to fatigue the metal? oh more info, no overheating at all, good oil pressure the whole trip. Never let it run low on oil, burns about 1Q every 1000 miles, I would top up the oil at every fill up (approx. 300 miles) adding a few oz of oil each time.

Edited September 29, 2019 by Dave WM

[Dave WM]

Or maybe it just wore thru the plastic part, the chain starts beating on the metal to a point where it grabs the very top (see how its kinda peeled down in the pic) and whamo!

[Reptoid Overlords]

When I get back home ill check.

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053-90400

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[Av8ferg]

Maybe it was a manufactured defect and finally failed.


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[Av8ferg]

Found this in my Nissan L Series Engine Rebuild book. Might be what happened to you.




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[Captain Obvious]

Definitely weird. Would be more confident in a repair if we knew definitively knew what really happened.

That tight side guide is normally under such low stress. I'm having a hard time understanding how a worn chain could cause that failure. That side should always be tight, regardless if the chain is worn or not. Maybe it's in there slapping around side to side and hit some harmonic. Slapping against that guide and setting up some resonance until it broke the mount.

Regardless... Let's not do that again. Ever.

[Captain Obvious]

8 hours ago, Reptoid Overlords said:

053-90400

Cool. Those are available all over the place for cheap.

And you said it definitely has the timing gashes on the back of the gear?

[Dave WM]

ok popped for the OSK kit from a local supplier, good price too! Not much more than the Oreily kit was going to be. If I am going to make my trip to Alaska via the Yukon, I need Dat Boi it top shape.

[Reptoid Overlords]

Just to safe about terminology, You mean this timing gash right?  If so then yes.  The picture I attached was taken 2 weeks ago during re-assembly of my engine. 

It has 2 links which are darker than the rest of them to align with corresponding indicators on the cam/crank sprockets/gear.

1 hour ago, Captain Obvious said:

Cool. Those are available all over the place for cheap.

And you said it definitely has the timing gashes on the back of the gear?

 

[Dave WM]

I am all set for the chain, got the TDC checked, found the two bright links on my existing setup, on over the #1 on the cam sprocket the other over the dimple on the crank sprocket (3 o clock). I confirmed my TDC with a dial indicator held in the #1 hole while I cranked on the crank bolt put back in the crankshaft. I was reading the Datsun book, I see they recommend some gasket sealant around the water holes on the block to cover, I assume the rest is not the much of an issue. I was going to do that around the oil holes to and from the pump as well. I spent quite a bit of time trying to get as much of the old gasket scraped off, one of the advantages I suppose of not having parts is I tend to spend more time prepping and cleaning. The v notch was directly over the timing mark on the camshaft retainer, so I assume my OE chain was no stretched at all, but after seeing all that gouging I made me worry hence the new chain. That and the fact that I don't really know what went wrong so replace it all...

Edited September 29, 2019 by Dave WM

[Captain Obvious]

10 hours ago, Reptoid Overlords said:

Just to safe about terminology, You mean this timing gash right?  If so then yes.

Yup. That's exactly what I meant. So the ITM has the timing marks, and according to Dave, so does the OSK.