knocking noise after messing with ignition

[kord]

Late model 2.1l WBX previously ran good. Today I tried running the ignition timing significantly out of spec. When turning key to start it would begin to start but then kind of seize and fail to go further. Tried a couple times, acted the same. Returned to previous good ignition setup.

Now it runs good like before but has a new knocking noise associated with cylinder #1 that matches RPM. If I remove its spark plug wire from the distributor, the noise goes away. Add the wire back and about 40 seconds into the idle it returns.

ignore my rough rocking idle - a preexisting issue
https://www.youtube.com/watch?v=32ETJ8mCWWM

Is it lifter noise that will go away with some driving or a more serious problem? Haven't driven it yet.

Thanks for any suggestions.

[Wildthings]

Sounds like you have advanced the timing so far that when a cylinder fired it was stopping the engine from reaching TDC.

Not sure why your present noise would go away when you remove a plug wire as it sounds like a leaked down lifter. What can happen with hydraulic lifters is that if you start a cold engine and then shut it down before the oil gets warm and thins out, the lifters may leak off very quickly, so the next time your restart the engine one or more lifters may rattle a lot and take forever to pump back up. I have had the best luck with 5w40 synthetic oil, the lifters pump up fairly easily when using it and almost never leak off at all if the engine is shut down hot. I presently have a crankcase full of 0w40 but it is too early to know how well it really works.

Do you have weird pulses coming from your exhaust that correspond to the shaking?

[Sodo]

Don't drive it like that, you could burn a hole in a piston.

Get the timing set correctly.
Pay someone to do it, or buy this $30 timing light & set it yourself.
It takes about ten minutes.

https://www.amazon.com/dp/B07NVCZQ5G/ref=cm_sw_em_r_mt_dp_pmvvFbT68CN51

Here in Seattle there are chain stores Autozone and O'Reilly's that offer 'free tool rental' maybe you have them in your area?
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[Igeo]

I hope it's a lifter as Wildthings suggests. And as WT said, by overly-advancing the timing, sometimes the combustion is occurring so early during the compression stroke, that the engine fights itself. That's what you were experiencing, and it's hard on the engine. I suppose it's possible that you have damaged that rod bearing, and the reason it quiets down when that cylinder is disabled is because with no combustion, that piston/rod assembly can sort of float through the cycle with less pressure on the crank journal.

When you revved it, the oil pressure goes up and masks the noise. After the engine returns to idle, the oil pressure drops and the rod makes noise again. I hope I'm wrong. How many miles on this engine and what is the hot oil pressure? Why is it idling poorly?

If it's a rod bearing the noise will get worse. If it's a lifter, it will likely pump up and quiet down. Here's hoping.
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1987 Westfalia 2.1 WBX Manual

[Bassyaks]

Take some timing out of it

[kord]

I started the engine again a few hours after the video was taken and it ran in place at different RPM's for about 10 minutes without the knocking noise. I hope it dodged a bullet there. I will drive it tomorrow and see how it feels and sounds.

I agree that the timing was so wrong that the engine was fighting itself as I tried to start it. The video was recorded after it was returned to the previously ok timing but with the new knock I couldn’t identify. I didn't want to take it for a test drive if that noise was clearly more serious than a lifter to someone else.

Thanks everyone for the ideas and suggestions. I'm a mechanical noob learning lessons the wrong way. I'll study more before I proceed next time. Otherwise I'll need to become a mechanical expert to fix my blunders.

[Igeo]

Good news on a hot day. 99 degrees in Oakland.
Anyway, 35 - 40 degrees @ 3,000 is the spec I think.
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1987 Westfalia 2.1 WBX Manual