HarleyTechTalk

Hi,

So my late shovelhead started making some noices yesterday, and for now, I will not drive it before i figure out whats wrong.
Are any of you guys able to give me a hint about where to start looking for the error?
As a non-mechanic - my best guess would be main bearing of some kind

Edit: It's only in the verry low RPM range that it can be heard.

Video:
https://www.youtube.com/watch?v=uA9Gq56tuGI

  Fwiw ,,mine was making a noise kind of like that , it was the rear ex. Valve guide

Thanks man - I hope this is valve related aswell.
I really don't want to pull the engine appart if I can avoid it

It could be several things, maybe a lifter not pumping up.
You can use a compression tester to determine if there is a bent valve.

http://www.autozone.com/test-scan-and-specialty-tools/compression-tester/actron-compression-tester/87580_0_0/

Great idea, Tobias - i'll get one of those, and make a compression test.

Do a lifter adjustment per the SM and see if it goes away. Sounds like a lifter went dry. Dirty

After my 76 sits all winter it can sound a bit like that for a minute or two. (lifter)

sounds like a fubar lifter to me..

Tobias is wise. Everyone should have a compression gauge. A comp test is the first thing we do to anything that comes in the shop, cuz all else is futile if the "squeeze" is missing from "suck, squeeze, bang, blow".

It never hurts to pull a lifter block and inspect the rollers and cam lobe with a BRIGHT light.

Can't tell real well from the video but I'm thinking severe spark knock or a broken/collapsed piston

Hard to tell from a youtube video vs. being there, but for unusual noises I tend to start with the old mechanics stethescope and try to pin point the source. It ain't an exact science since sounds carry clear through the motor, but very often you can localize to valves, rocker box, tappets, bottom end bearings, and sometimes pistons. Another handy diagnostic tool is a lazer thermometer. I point at same location on front/back cylinders to see if they are both running close to same temperature. Compression test, along with a plug read, is also pretty quick and easy to get some diagnostic info as already stated.

-JW