Piston options from other non-305cc engines?

[wombat200]

You could always buy some of those bore-in liners available occasionally on ebay & bring it back to standard bore.....

Rob.

[305racer]

That cylinder is trash fo sure. .............lm

Those 250 sleeves are undersize for even a standard piston. .........lm

Right, I wasn't wondering if they would take a 60mm piston, just looking at them as an option for replacement sleeves.....at the expense of 55cc.

I know you know already LOUDMOUSE, but for those that don't, this is why I'm exploring big overbore pistons:



I'm not even sure that a 3mm overbore will take that junk out. I thought it was bad when I pulled the engine apart, but I bead blasted it and all the rust was removed and left the really knarly voids in the pic.

I'll second LM on that call (LoL). Any good automotive machine shop should be able to do a resleeve to whatever bore size you want.

[65ShelbyClone]

I landed a standard bore cylinder set, so I'm not desperate to fix the old ones anymore. I knocked the old sleeves out without heating because they were barely in there to begin with.

Back to doing a bigbore; How much do the 750 flat tops lower compression? If it's no lower than 9:1, I'd still consider it.

[LOUD MOUSE]

How do you plan on installing the new sleeves? They will require boring to standard size. I'd bet that the compression will drop to +- 7 LBS. Take a look at the dome of a correct piston then figure it as flat across the top and you will see how much top mass you will lose. Not a good idea at all what with the gas/crap we get today. ..............lm

I landed a standard bore cylinder set, so I'm not desperate to fix the old ones anymore. I knocked the old sleeves out without heating because they were barely in there to begin with.

Back to doing a bigbore; How much do the 750 flat tops lower compression? If it's no lower than 9:1, I'd still consider it.

[65ShelbyClone]

1.) How do you plan on installing the new sleeves? They will require boring to standard size.

2.) I'd bet that the compression will drop to +- 7 LBS. Take a look at the dome of a correct piston then figure it as flat across the top and you will see how much top mass you will lose. Not a good idea at all what with the gas/crap we get today. ..............lm

1.) Easy, call in a favor, hehe.
2.) I haven't cc'ed anything, but based on the factory rated bore, stroke, and compression ratio, it looks like the stock chamber is around 16cc. All things being equal, a 63mm overbore alone would take the compression up to 10.5:1. Once I find out the volume of the stock piston dome, I can figure how bad a flat top will lower it from there.

[LOUD MOUSE]

I WILL NOW ASK WHAT IS THE BIG DEAL WITH THE WRONG PISTONS IN YOUR ENGINE? I KNOW THAT THERE ARE PLENTY OF GOOD PISTONS AVAILABLE FOR YOUR ENGINE AND I WILL ADMIT THAT THE ENGINE MAY BE AS MANY OTHERS IF YA USE THE REGULAR PISTONS BUT WHAT'S THE DEAL WITH THE OTHER PISTONS?????????????????
YA WANT TO SAY I HAVE MY OWN? YA THINK THE ENGINE WILL BE STRONGER? YA WANT TO SAVE $$$$$? I'LL ADMIT THAT YOU HAVE EXPANDED MY ATTENTION WITH WHAT IT IS YA MAY WANT TO DO. SO "DO IT" AND HAVE A BALL. .................LM

1.) How do you plan on installing the new sleeves? They will require boring to standard size.

2.) I'd bet that the compression will drop to +- 7 LBS. Take a look at the dome of a correct piston then figure it as flat across the top and you will see how much top mass you will lose. Not a good idea at all what with the gas/crap we get today. ..............lm

1.) Easy, call in a favor, hehe.
2.) I haven't cc'ed anything, but based on the factory rated bore, stroke, and compression ratio, it looks like the stock chamber is around 16cc. All things being equal, a 63mm overbore alone would take the compression up to 10.5:1. Once I find out the volume of the stock piston dome, I can figure how bad a flat top will lower it from there.

[65ShelbyClone]

Well, I thought it might be worthwhile exploring a bigbore option that doesn't involve paying multiple hundreds of dollars for used vintage Webco kits and the like.....

Why put electronic ignition on one of these if the breaker points work just fine? Because we can!