Rocker noise or piston slap? Vid inside

[OrangeCrush 86]

Well, I finally got the 331 running. Within minutes my fears may have come true; bad piston slap.

When I originally built this engine the piston side wall clearance was at the edge of the limit (bores too big). Unfortunately I had a college student budget and couldn't afford to have a entire block machined again. So I assembled it, bash me if you want.

It's pretty hard to hear in the video, but if you listen hard after I give it a little rev you can hear it just as it comes back to idle.

I just finished shimming the rockers .030 per the other thread I made.

What do you guys think?

Movie is ~20mb so you may want to right click and save as.

http://www.zeroentity.com/stuff/331.MOV

[mnstang]

i can't dl anything that big, but it's probably valvetrain.

[OrangeCrush 86]

i can't dl anything that big, but it's probably valvetrain.

What can you DL?, I can compress it for you. I was hoping you would chime in.

[SDK]

What makes it a 331?? You can find a good short block for cheap and then just tranfer your top end.

[OrangeCrush 86]

What makes it a 331?? You can find a good short block for cheap and then just tranfer your top end.

Um, the rotating assembly. I would have to get another block, have it bored .040, then get it clearenced. I would rather not do that as it is probably ~$700 worth of machine work.

[SDK]

I could download it and that is a pretty heavy knock. Sounds like it's from the bottom end.


It kind of sounds like an exhaust leak. It's hard ot tell from video

[SDK]

Um, the rotating assembly. I would have to get another block, have it bored .040, then get it clearenced. I would rather not do that as it is probably ~$700 worth of machine work.

So it would just be a 302 if you used say, the shortblock I have forsale?

[lasered]

sounded like valvetrain personally

[gutlas5]

sounded like some pistons rockin

[gutlas5]

sounded louder when idling down after you would rev it. is that correct?

[OffShore]

you cant tell from the video, assuming this is a new engine, what was your process to adj the valves?

[Old Man]

If you are "at the edge of the limit" of clearance it should be ok. Marine applications call for increased clearance. Recheck you valve train.

[Akromix]

valvetrain.

[Macs Stang]

Sounds like valvetrain that is out of adjustment.

[OrangeCrush 86]

Dammit lol, I just did redo the valves. Well tomorrow I will take those shims back out and see if the sound goes away.

And yes, the sound is only really there when it comes back down to idle.

I put this .030 shims in today. I hand tightened the rocker bolt to zero lash while the lifter was on the base circle of the cam, then torqued to 20 ft/lbs. Just about all of the valves took approximately 3/4 turn to reach 20 ft/lbs.