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Draker

Rebuilt L20b Timing chain noise (by the oiler)

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Was deck or head shaved? Had same issue,ran for yrs like that. Adj idle up to 950-1000rpm,so it did make much noise that way. I ck mine tho timing cover opening. So i could see what was goin on at all rpms(no oil mess). Chain would flop around at certain rpms.

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I'm not sure what is causing the sound. I just got home from Al's place. Noise seems noticilbly louder after 30 miles. Looks like the dime will be not be making the trip. Time to pull the engine and check it out. Also the intake leaks coolant... fuck.

 

I got pics and video of the noise from earlier. Not after the drive...

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I didnt, just ran out of time.

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Only does it at idle? Take on a trip and just limit your idling

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I just thought of something remembering our conversation earlier today...., you mentioned that the chain made rattling noise while idling but when reved up the rattling and knocking went away....I'm thinking the timing chain tensioner spring might have broken...

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I suppose anything is possible but installing that spring is like stuffing 5 pounds of shit into a 4 pound bag. Even broken it would be a tight fit.

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Ya, that fucker gave me battle when I built mine, it boggled my mind how a part so small could put up such a fight :rofl:

 

Dunno, just tossing that as a possible...

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Doubtful that's the cause.

 

The L-Series race motors get the spring cut in half (just to make pulling the head and/or doing cam changes easier) and they never make noises down there.

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Makes sense...

 

Ya pump needs to come off for inspection, the other thing that comes to mind is a spun bearing, probably #1, pan will need to come off to inspect that, the motor I bought from Julian had a spun bearing, couldn't tell until I took apart all rods from crank, visual inspection didn't reveal the problem in this case, crank shaft was trashed and cylinders badly damaged by the metal in the oil.

 

This is how it looked...

IMG_20140524_165936.jpg

 

IMG_20140524_165751.jpg

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Maybe....

 

Pull the dizzy out and grasp the top of the spindle with needle nose pliers and try turning it side to side. I imagine there is some play but if really loose maybe it's f'd up.

 

One last thing is the crank bolt tight?

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Maybe....

 

Pull the dizzy out and grasp the top of the spindle with needle nose pliers and try turning it side to side. I imagine there is some play but if really loose maybe it's f'd up.

 

One last thing is the crank bolt tight?

That and/or the cam bolt. He says they are tight.

 

A rod bearing could be the noise. If you catch it in time, you could just polish the crank with some super fine emery cloth and put a new bearing in. You can do that without pulling the motor. If you didn't catch it in time............!

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I'll check these. I'm out at the datslocos camp out at shasta so it will probably next weekend. I'll be sure to follow up with my findings. I'll get the videos posted also.

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No updates. Taking a bit of time away from wrenching.

 

Here is the video from before Shasta. It sounds worse than this now.

 

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To me it unfortunately sounds like cylinder #1 or possibly #2 rod bearing, as the rpms go up so does the intensity of the knocking, I would drop the pan and take a good look at both, get a good grip on them and see if they move, also manually turn the motor to look for visual anomalies as the crank is turning.

 

I'm not sure what time and if I'll be home this coming weekend, but I'll be more than happy to come over and help you find/fix the problem, bud.

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Doesn't sound like a rod bearing to me. The pitch and frequency are too high.

I factored that in since its a phone audio, the pitch is deceptive from my experience taking video of my engine running compared to live actual audio, but that's just my 2 cents, hopefully it's not something major.

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It's not a rod bearing. It's the chain. Bearings would be reflected in the oil pressure. There would be fluctuations at the very least. The sound is coming from the front cover. It's easy to isolate. 

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