Engine Problem- Piston

[Tony, NY]

I have this "forever" project AV8 with a '51 Merc bored .060 over, and numerous other things done to it, that's 10 yrs in the making. It was running and on the road briefly this year. It has probably 5 running hours on it.
Here's what's going on. Last week I started it and revved it up a little and all of a sudden smoke starts coming out of the breather. Pulled the breather and could feel pressure pulses coming out. Shut it off and did a compression test.
Zero on number 4. Pulled the intake, nothing unusual. Pulled the pass head and found a hole in the piston.
Apparently, last winter when I tore it down to do something, it swallowed a small nut down the intake passage when it was off. No damage to valve.
So today I find out that those pistons (Silvolite cast) are no longer being made. What can I do? Put a different one in that cyl? Can I replace them all without doing any machine work? Thanks in advance.

[JSeery]

You should be able to replace all the pistons with a light cylinder honing as worse case. You could just replace the one piston as long as the weight matches the existing pistons. Was the head damaged?

[GOSFAST]

Originally Posted by Tony, NY

I have this "forever" project AV8 with a '51 Merc bored .060 over, and numerous other things done to it, that's 10 yrs in the making. It was running and on the road briefly this year. It has probably 5 running hours on it.
Here's what's going on. Last week I started it and revved it up a little and all of a sudden smoke starts coming out of the breather. Pulled the breather and could feel pressure pulses coming out. Shut it off and did a compression test.
Zero on number 4. Pulled the intake, nothing unusual. Pulled the pass head and found a hole in the piston.
Apparently, last winter when I tore it down to do something, it swallowed a small nut down the intake passage when it was off. No damage to valve.
So today I find out that those pistons (Silvolite cast) are no longer being made. What can I do? Put a different one in that cyl? Can I replace them all without doing any machine work? Thanks in advance.

Hi Tony, I have a few sets of the same type pistons on the shelf here, same size, +.060". I have the rings also.

They more than likely weigh the same as your Silvo-lites?? Do you happen to know the weights on yours now? I'll be able to estimate whether or not your facing any serious issues, but I don't believe you will. They should be somewhere around 415 grms and with a 120 grm pin??

Thanks, Gary in N.Y.

P.S. Give me a contact number and I will get back to you. Things go quicker for me by e-mailing me at [email protected] I can't get pricing until Wednesday, this is when I return to work. I have the same ones in the photo below but in .060".

[Tony, NY]

Sponsored Links (Register now to hide all advertisements)

JSeery. No head damage.
Gary. I don't know the weights, but I'll get a scale and let you know.
Thanks. Tony