Something In my #5 Cylinder?

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TT5.9mag said:
Are the heads off of this engine yet?
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Yes, pulled the engine on Saturday. 7 of the 8 pistons were damaged but luckily the heads still look good and none of the cylinders appear to be hurt. The short block is at the machine shop. As long as the bearings all still look good and check out I'll just be putting in new pistons and rings. Probably go with a little more ring gap this time.
 
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Any pics of the pistons? I’m just curious. Any broken ring lands? When you order pistons, ask the manufacturer to drop the rings .100 if they can for more strength in the crown. Most will do it for a small charge and it’s good insurance. And on the gaps, there’s a good saying. Gap em to large and only you will know. Gap em too small and everyone will know.
 
TT5.9mag said:
View attachment 1715423252 Any pics of the pistons? I’m just curious. Any broken ring lands? When you order pistons, ask the manufacturer to drop the rings .100 if they can for more strength in the crown. Most will do it for a small charge and it’s good insurance. And on the gaps, there’s a good saying. Gap em to large and only you will know. Gap em too small and everyone will know.
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I like this thinking, the stability is based on the ring spread and skirt..keeping it squared in the cylinder...so if that isnt compromised...good idea.
 
Of course none of it matters if the bores aren’t round but the last few turbo motors I’ve done I asked the piston manufacturer (icon, and wiseco) to drop the whole ring pack. Neither had a problem with it. On some stroker pistons you can get in to trouble with the oil rings getting in to the pin boss but even that you can work around.
 
Walker out of curiosity, are you measuring air inlet temp at all?
 
No I'm not. I would hope they aren't too high since I'm spraying the water meth but no way of knowing right now.
 
Typically guys talk about latent heat of vaporization and the temp drop across a carburetor with a blow through setup. Freiburger says they loose 100 degrees across the carb on their blown, blow through bonneville car. I just wondered if you had any first hand data.
 
Walker434 said:
Yes, pulled the engine on Saturday. 7 of the 8 pistons were damaged but luckily the heads still look good and none of the cylinders appear to be hurt. The short block is at the machine shop. As long as the bearings all still look good and check out I'll just be putting in new pistons and rings. Probably go with a little more ring gap this time.
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I just had the same thing happen to me, ring popped a chunk of piston off, piston chunk smashed the plug. Make sure to look over your heads good, the exhaust valve in that cylinder had bent from smashing piston chunks between the valve and valve seat. It looked okay and I was about to call the heads good. Spinning the valve in a drill is an easy way to see if it's still straight.
 
Charlesvolare said:
View attachment 1715436265 View attachment 1715436266

I just had the same thing happen to me, ring popped a chunk of piston off, piston chunk smashed the plug. Make sure to look over your heads good, the exhaust valve in that cylinder had bent from smashing piston chunks between the valve and valve seat. It looked okay and I was about to call the heads good. Spinning the valve in a drill is an easy way to see if it's still straight.
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Thanks for that real world advice. What was the combo? Were you running boost?
 
Walker434 said:
Thanks for that real world advice. What was the combo? Were you running boost?
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N/A 360/904, worked magnum heads, 11.2:1 static compression. The KB pistons I was using are know for needing a bigger end gap on the top ring. I suspect with you running boost your rings might've been too tight or plugs too hot or a/f did something weird or a combination of it all and detonated. I gapped this next set of rings slightly larger than the KB recommended spec, hopefully no more worrying about it and gives me room for a power adder later down the road if I want. Hopefully I can finish getting it back together now the fall semester is over and I'll have time to work on things.

I'll have to make a trip down I-40 and come see your car race sometime, looks like a pretty cool build!
 
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Charlesvolare said:
N/A 360/904, worked magnum heads, 11.2:1 static compression. The KB pistons I was using are know for needing a bigger end gap on the top ring. I suspect with you running boost your rings might've been too tight or plugs too hot or a/f did something weird or a combination of it all and detonated. I gapped this next set of rings slightly larger than the KB recommended spec, hopefully no more worrying about it and gives me room for a power adder later down the road if I want. Hopefully I can finish getting it back together now the fall semester is over and I'll have time to work on things.

I'll have to make a trip down I-40 and come see your car race sometime, looks like a pretty cool build!
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Got it thanks. Yeah this time around I'm giving it a little more ring gap. I think too hot of plugs and too much timing to start out were my culprits. Hopefully I've learned my lesson. I don't think I screwed up on the air fuels though. Let me know if you ever get to Nashville and I'll let you know if I ever end up racing in Memphis.
 
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