Whoops. Time to start over.

[Lusk Racing]

Looks like I'm not going to the track in the near future. Since Probe doesn't make this particular piston any more, looks like a full set will be in order. Last time I ran the car was Pinks All Out in Topeka last summer. It was like 110 degrees. I guess the combination of hot, poor machine work, and lean mixture was enough to liquefy part of the piston. At first I thought it was a ring gap issue, but the ring is not damaged, and there are no marks in the head or the piston that would be there had there been a solid chunk of piston dancing around in there. Bummer for me.

[CRASH]

I've got a Scat forged 347 rotating assembly for sale in the classifieds.

Just sayin'.

LOL !

-Aaron

[VETTKLR]

ouch

What kind of heads were you running? That's interesting that you can see on both pistons, the crescent temper marks of where it was getting hot as hell.

[stevo]

Is that a hole or a bad spot in the cylinder bore? Or just a trick of the pic?

Stevo

[Lusk Racing]

ouch

What kind of heads were you running? That's interesting that you can see on both pistons, the crescent temper marks of where it was getting hot as hell.

Pro Topline Pro Action Heads 210cc intake runners. I think the crescent you are seeing on the #3 piston is actually flash reflection.

[Lusk Racing]

Is that a hole or a bad spot in the cylinder bore? Or just a trick of the pic?

Stevo

Optical illusion.

[turbostang]

That sucks.

Just out of curiosity, how do you get poor machine work out of that?

[VETTKLR]

Pro Topline Pro Action Heads 210cc intake runners. I think the crescent you are seeing on the #3 piston is actually flash reflection.

Ok, I gotcha. You think that Twisted Wedge brow was the weak link? What does the #1 piston look like when you bring it up to TDC? Reason for the question is because I sprayed a 302 one time that did almost that exact same thing to the #1 piston and scorched #5 pretty good.

[Lusk Racing]

That sucks.

Just out of curiosity, how do you get poor machine work out of that?

I didn't have the block torque plate honed. The chunk of piston lines up with the head bolt almost perfectly. From what I understand, if you don't torque plate hone the block, you can cause an imperfection in the cylinder wall when you torque the head on. That then allows the compression to blow by the ring in that spot. Usually not an issue, but when you are building a lot of cylinder pressure and lean the cylinder out(which small block fords with single plane intakes are notorious for doing on 1 4 5 and 8) you basically create a blow torch in that area. I would have to have the block torque plate honed to see if that is actually the case, but since the block is already on the outer edge of .040 over and it is a stock block, I am not going to waste the money. So maybe poor machine work was a bad choice of words, I should have said poor choice of machine work. LOL.

[Lusk Racing]

Ok, I gotcha. You think that Twisted Wedge brow was the weak link? What does the #1 piston look like when you bring it up to TDC? Reason for the question is because I sprayed a 302 one time that did almost that exact same thing to the #1 piston and scorched #5 pretty good.

All the rest of the pistons are fine. Were you running a single plane intake? Could attribute what happened to what I mentioned above. Lean condition in the outer cylinders.

[turbostang]

I didn't have the block torque plate honed. The chunk of piston lines up with the head bolt almost perfectly. From what I understand, if you don't torque plate hone the block, you can cause an imperfection in the cylinder wall when you torque the head on. That then allows the compression to blow by the ring in that spot. Usually not an issue, but when you are building a lot of cylinder pressure and lean the cylinder out(which small block fords with single plane intakes are notorious for doing on 1 4 5 and 8) you basically create a blow torch in that area. I would have to have the block torque plate honed to see if that is actually the case, but since the block is already on the outer edge of .040 over and it is a stock block, I am not going to waste the money. So maybe poor machine work was a bad choice of words, I should have said poor choice of machine work. LOL.

I'd like to see someone prove that, or at least in THIS case. Just for the records, torque plate honing is not going to make any appreciable difference in performance - more than anything, it would promote longevity...errr not to the point of melting a piston. We're talking .0002-.0005" difference in accuracy, if that.

I'd lean more towards the incredibly THIN piston area between the bottom of the valve pocket and the inside edge of the rings. I've seen MANY of that type of piston fail EXACTLY like what you've posted.

I'd be looking for a piston with the proper valve reliefs and not a dual purpose piston with 2 sets of reliefs.

[Lusk Racing]

I'd like to see someone prove that, or at least in THIS case. Just for the records, torque plate honing is not going to make any appreciable difference in performance - more than anything, it would promote longevity...errr not to the point of melting a piston. We're talking .0002-.0005" difference in accuracy, if that.

I'd lean more towards the incredibly THIN piston area between the bottom of the valve pocket and the inside edge of the rings. I've seen MANY of that type of piston fail EXACTLY like what you've posted.

I'd be looking for a piston with the proper valve reliefs and not a dual purpose piston with 2 sets of reliefs.

Eh, could be, it doesn't really matter at this point what the fail point was. I agree with the single valve relief statement and will be going with a custom piston the next time around and have it torque plate honed, just in case. When I first built the engine and bought all the parts, it was my first stroked high performance set up, and it was a fairly mild hydraulic roller at that time, so all the parts came off the shelf. Live and learn. Fact is, if you are going to build something that pushes the envelope and go pound the shit out of it, eventually you are going to break something.

[turbostang]

Eh, could be, it doesn't really matter at this point what the fail point was. I agree with the single valve relief statement and will be going with a custom piston the next time around and have it torque plate honed, just in case. When I first built the engine and bought all the parts, it was my first stroked high performance set up, and it was a fairly mild hydraulic roller at that time, so all the parts came off the shelf. Live and learn. Fact is, if you are going to build something that pushes the envelope and go pound the shit out of it, eventually you are going to break something.

agreed... Good luck with it, get 'er done!

[Lusk Racing]

agreed... Good luck with it, get 'er done!

Thanks.

[VETTKLR]

All the rest of the pistons are fine. Were you running a single plane intake? Could attribute what happened to what I mentioned above. Lean condition in the outer cylinders.

Oh fa' sho! Vic Jr intake with a Gemini Twin plate and Holley 650 DP sitting on top.