Are these Keith Black 150 pistons worth re-using, or scrap?

[robroy]

Good day!

Back in What's this loud tapping sound from my new engine?, the Keith Black Hypereutectic (model 105) pistons were removed from my doomed FE and handed over to me.

All this time I haven't known quite what to do with them! I'd like to know whether or not they're still usable despite the somewhat minor scratches on their skirts. Or are these scrap now?

Based on these photos, would y'all be willing to give me your opinions? I created a poll in this thread to make that easier, if you're inclined to use it.

All of these photos may be clicked upon to view super high resolution editions, for checking out the details.

The piston tops look fine to me:




It's the skirts that are scratched:






I found "060" cast in to the pistons, and noted that Keith Black sells the 105 model set up for a 60 thousands over-sized 390 bore. This has to mean these pistons are made for that bore size, right?



Here's the Keith Black Web site for these pistons: Model 105

Thanks very much for the fantastic advice!
Robroy

[robroy]

Here are a few more photos, in case they help. Thanks for checking these out!







Thanks for taking a look!
Robroy

[BobbyFord]

I wouldn't have a problem using them. Yes, they appear to be .060 over.

[robroy]

Good evening Bobby, thanks for your reply!

I wouldn't have a problem using them.

Is that because the surface of the metal on the skirts isn't ultra important?

Do the skirts come in contact with the cylinder walls normally, or do only the rings contact the walls?

Yes, they appear to be .060 over.

Great!

Thanks for your fast and helpful reply Bobby!
Robroy

[BobbyFord]

The skirts will contact the walls but the walls are iron and the piston is aluminum. Someone would probably clean up and inspect the scratches but they're not a problem, IMO.

[Dragon]

I would lightly hand buff the sharpness off the edges our use a very fine hone stone to deburr them then coat them will molykote and go racing.

[fordman]

when doing any sort of hand "sanding" of any piston or cylinder. you "sand" around in a circle to keep them round. do not "sand" in a up and down motion.

i had a concrete saw. that the piston and cylinder got scratched up and i was told to sand it with 1200 grit sand paper in a circle. and i was able to sand the rest of the cylinder jug and piston down to where the grooves were gone. i put a new ring and gaskets in the motor and it runs reall good now. not bad for free and about 20.00 in parts.

so they can probably be saved.

[70_F100]

I've seen much worse that ran for many years!!!

[DuckRyder]

I agree with one minor dissent to the majority in the poll.

KB pistons are not "premium" pistons and hyper pistons are somewhat delicate when it comes to forced induction and tuning issues. So I voted "mid-range" build...

The other issue is that they are .060, and most FE's that is pushing it...

They could be a good candidate for some skirt coating too...

http://swaintech.com/store.asp?pid=10964

http://www.jet-hot.com/sdfcoatings.html

[Ranchero50]

I would eBay them to recoup some cash from the fiasco. Do you ever honsetly plan on using them vs. the nuisance of having them set around?

Jamie

[dustman_stx]

Do NOT use those. Send them to me for proper disposal.

[averagef250]

I second the ebay vote.

Odds of using those pistons in anything is small. KB's are not known for being very rugged. Get a few bucks back and let someone else get a deal on them who needs them.

[fireguywtc]

To add on to what Robroy has already told you, we have been discussing putting some of the old parts that came from his failed motor and use them in a build for my 67. While considering all my options, we wanted to make sure these parts would be useable for my purposes in the 67.

If you have not seen my thread here it is: http://www.fordification.com/forum/view ... =3&t=49888

My goal is 300 hp to the rear wheels. Since my recent eastimates have continued to escalate for crank hp to compensate for parasitic loss, I am figuring now of building the engine closer to 400hp at the crank to ensure I meet my rwhp goal. I do not plan on racing this truck or anything extreme, but I want it to be sporty, dependable, and fun to drive. I think these pistons would serve my purpose just fine.

If I do decide to go this route, I am going to find a good rebuildable core 390 and have it rebuit or may try and rebuild it myself. I will use as many of the usable parts the Robroy has laying around just occupying space.

My only concearn now is going .06 over and any future complications that may come from that. I have been told before that the FE is good to be bored up to .08in over and still be reliable, but I have not be able to verify this.

Thank you all so much for all the help.

[Ranchero50]

Decent compression and a good torque cam and you'll be happy.

I used to worry about going .60" over but anymore it's just another block and piston set if it overheats.
Jamie