My engine is knocking at idle. And it is getting louder with each autocross!

It appears to be coming from cylinder number three. The engine idles and there is no smoke in the exhaust.

At higher RPM’s there is a loss of power and it is running rougher. I don’t think it is a carburetor or ignition problem.

Is it cylinder or bearing knock?

Is it time to rebuild?

Hmmm?

sounds like it (pun intended)


i say drop the motor and take off the heads and inspect them first. might just be a valve seat trying to work itself out.
#3 is notorious for that as it runs the hottest ...

Andy

I'll give you three choices....

Valve seat,

Piston slap,

or a rod getting ready to break.

Of the three, the piston slap is not as catastrophic as the other two.

Feeling lucky?

Ken

Broken rings...

Try adjusting the valves and make sure you pull out the valve adjuster screws and look at them closely. About a year ago mine started making a knocking noise that I though was in the bottom end but turned out to be a worn down valve adjuster screw. It was brand new too but had worn flat. I guess that one didn't get the proper hardening or something. Swapped it out, did an oil change and it's been great since.

-Rob