Hi: Moving this info from my other thread (http://www.914world.com/bbs2/index.php?showtopic=354921) to give it a more relevant title.

As indicated, I tried hard to rule out valve clearance as the culprit and feel it must be something else in either the valve train or worse.

Video 1: Cold Start https://youtu.be/5XBiv7zarvw
Video 2: Warmed up & noisy https://www.youtube.com/watch?v=JFfPNDZkSnk
Video 3: More noise https://www.youtube.com/watch?v=9fOrGUK6wZs

Please let me know if you have any ideas on the cause or other diagnostic steps. (FWIW compression is not abnormal.)

Thanks,
Ron

Hard to tell from the videos but sounds like valve train or maybe an exhaust leak. It also sounds similar to hydraulic lifters that aren’t pumped up. Do you have hydraulics? If you’ve ruled those things out, it may be a rod knocking…but that has a slightly duller sound. I’m sure the engine gurus will chime in with much better info…

Thanks Ian - no hydraulic lifters.

Hopefully others will chime in on this - not sure what to do next.

Ron

Any idea at all how many miles on the bottom end? Sounds like most of the benign problems have been mentioned. You said the sound almost went away after adjustment, then came back with a vengeance. So since I did not see metal under your valve cover here is my wild shot. From what you have stated I would guess a cam lobe is flattening out or tappet is failing.

I would do another valve adjustment. Paying close attention to push rods and wire being in the correct location.
914 engines are very noisy. So you might be hearing the other suggestions or you may have piston slap or you may be fine for another 20000 miles.

Matt

Thanks guys - good input.

Shivers, no idea on mileage and the Odo is broken but 3 years ago the PO spent $3K on suspension and brake work plus a full tune-up including valve adjustment and the shop did not call out any issues on the repair order. According to the seller, he then put it in storage and it "ran fine". It's taken me a month to get it running again and I can't honestly recall if it made this noise right away or has gotten worse since I've been able to run it for a while.

Anyway, I think I added confusion by implying the noise went away after the last adjustment. It just happened that then the engine was cold. That's when it's quiet.

So far I've adjusted the valves at least 4 times, each time taking more care, so I'm losing faith in that as a cure. As noted in my other thread, I was going to pull the rocker arms off to look for anything out of whack and I guess I will go ahead and do that.

But it doesn't look possible to pull the rods and extract lifters without dropping the engine. Is that correct?

Thanks,

Ron

Is it possible to have lost/dropped something that got into your fan shroud? Really hard to distinguish noise via video but start simple...

Does this car have headers? If not, where is the j-tube? That's a big open hole for the noise to come thru. The idle is pretty high too.

Thanks rhodyguy:

No headers, just took the J-tube off to remove and restore HEs and muffler. Been meaning to block that off but there's so much noise bouncing off the pavement and out the side I'm not sure it will help much. But will do it.

Yes, idle is one of the things I've been chasing, along with rich mixture and revs cycling up and down. Deep into the whole TPS, CHT, MPS, fuel pressure enchilada but finally got sick of the clattering and decided to attack that before spending more time and money on drivability.

Going to fully inspect the rockers and anything else I can remove this weekend.

Ron

+1 on valve inspection / adjustment.

For what it’s worth
My motor has significant piston slap cold
But it gets much better when the motor warms up and the rings expand/everything expands