[abefromen]

This vid is right after the cam break in..........

https://www.youtube.com/watch?v=6gMrPfenKjU

Zero miles on this engine. Break in went well with 30 weight break in oil for 25 minutes at 2K RPM.

Filter cut open after break in. Other than a lot of dirt and grit that shouldn't have been there I didn't see anything problematic. Obviously it was poorly cleaned.

This thing rattles and knocks so much at idle it's obvious it isn't right. I've heard diesel engines that were quieter.

Engine was bored .040 over and fitted with SRP forged pistons part number SRP153983
These are 4032 pistons and SRP recommends clearance for these at .0030-.0035 with a 4.200 to 4.600 bore range.....and .0020-.0025 with a 4.000 to 4.200 bore size.

Even though this is a low compression stock cammed grocery getter engine, bone stock in every way, and telling the builder I wanted quiet pistons, the builder for whatever reason set these up with .005 clearance.....I questioned this and was told:

"Tight piston clearance cause many issues such as over heating, the potential for rings to stick, loss of power and premature wear.
You need to have confidence in my ability to engineer a quality engine build. The extra clearance built in was .001”.

That's all fine and dandy but these were set up beyond recommended specs.

Unfortunately it has to come out and done over because the noise is extremely objectionable.
Oil pressure at hot idle is an ok 20 PSI with the 30 weight break in oil. Changing it to 10-40 after break in yielded a few extra psi.

Rods and mains are also set a little on the wide side too at .0028 and .0032 respectively.

I would like opinions as to the noise although I am guessing it's the pistons, idk.

Before I ran it I contacted a few builders who specialize in Pontiacs, including Butler, and ran the piston clearances past them.........they all questioned why it was done this way on a low perf non race engine and said I may hear them.

It was run with belts off too and the converter disconnected and it was the same, although I knew that was not the issue because the accessories and torque converter were run on the engine before it was removed for the rebuild and everything was totally quiet.