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Piston and Cylinder crapped out

4K views 31 replies 8 participants last post by  palvarez05 
#1 ·
What can cause this kind of damage to the piston and cylinder? This was a brand new CP Carillo piston and OEM cylinder on a recently ported and polished head. Connecting rod was also new cp carillo, and new cams stage 2.
 

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#2 ·
Holy cow! That sucks. Cylinder looks like it may have gotten a little hot, may just be from the scoring. Not an expert at all, but I believe those cp pistons especially have to have their rings file fit to your cylinder, do you known If this was done? They are typically big to start with so you can properly gap them to the application, if this was not done then expansion make have caused them to bind up.
 
#4 ·
The piston was wrong size for the bore. Way too tight. Fine at room temps but once it heated it was tight so there is the results.

I build two stroke racing engines and if you don't take some off the top 1/2" of piston especially the little bit above the ring that needs .002" taken off(.004" total off diameter) the same thing will occur.

Rings with not enough end gap will cause similar damage. Were the rings checked/gapped during installation
 
#6 ·
Looks like detonation damage to me. From low octane, old gas, to much compression. CP pistons don't need any extra machining but the ring gap must be checked. What's your elevation and compression of the piston?
 
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#10 ·
No octane rating on the gas pumps?? Do you have regular and premium? You need to ask or do some research.

At basically sea level, I would rebuild with a CP 11:1 and run the best gas you can. If you find your gas is less then 90 octane I would machine around .030 from the piston dome. You may see a slight power loss but without detonation. Get a Stage 3 cam and a +3 throttle body will give more power.

Run a (diamond) hone thru the cylinder to see if it will clean up.

I also saw what looked like bent valves, be sure to check them.

Be sure to check the head for warpage and always use a factory head gasket.
 
#13 · (Edited)
I can at least help with the spelling..Nikasil is the coating. Sleeves are for going big bore. Sleeve would be the route I would go, and I would go big bore if I had to deal with your issue.

But as DEZ said, try to hone it first to keep cost low and then it would just be rings and piston. At least for the cylinder.
 
#14 ·
I can at least help with the spelling..Nikasil is the coating. Sleeves are for going big bore. Sleeve would be the route I would go, and I would go big bore if I had to deal with your issue.
The person that told me about the sleeve (geisekperfornance) advice I went big bore... But I am scared about reliability

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#16 ·
Both Cuervo and Geisick can take care of what you want done. Geisick is an hour from me, did my dyno runs and has been in the biz for quite a while as well. Terry has done quite a few big bores, I felt it just wasn't in the cards at the time for me.
 
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#17 ·
Cuervo says don't sleeve it, he rather bore it and coat it... Geisick says sleeve it... Wonder what route should I go... Or just buy a new cylinder all together.

New cylinder is 515

Cuervo is 450

Geisick is 375

Geisick claims his stainless steel sleeves make the cylinder stronger than oem.

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#20 · (Edited)
DON'T sleeve or bore a factory cylinder. It decreases the water jacket and then it runs hot. If you want a stock bore buy a factory cylinder or check with Millennium Technologies. They strip and re-plate factory cylinders. If you want a big bore cylinder get it from Cuervo with the bigger water jacket. If you go big bore you'll also need studs and a SCE head gasket.

FYI, years ago there were a rash of sleeved cylinders that after a few hours of expansion/contractions of dissimilar metals, the sleeve would slip out of position.

Have you checked your cylinder? It may be good! If you want reliability go with factory bore.
 
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#21 ·
DON'T sleeve or bore a factory cylinder. It decreases the water jacket and then it runs hot. If you want a stock bore buy a factory cylinder or check with Millennium Industries or it might be Millennium Technologies. They strip and re-plate factory cylinders. If you want a big bore cylinder get it from Cuervo with the bigger water jacket. If you go big bore you'll also need studs and a SCE head gasket.

FYI, years ago there were a rash of sleeved cylinders that after a few hours of expansion/contractions of dissimilar metals, the sleeve would slip out of position.

Have you checked your cylinder? It may be good! If you want reliability go with factory bore.
Dez you are awesome, you literally have a response for EVERYTHING! I am going to send them my old cylinder. I am trying to cut cost... The work they do seems top notch... Now if i could find a good used head at a decent price, i'd be happy. But ebay is full of heads at almost the price of a new one.
 
#30 ·
The design of the raptor 700 head, piston, cam and ignition at 11:1 compression will run on 91 octane without problems. Higher compression may be OK at higher elevations but will require higher octane at sea level. Yes, other design motors can run higher compression at sea level. Example is the YFZ450 at 14:1 on 91 octane.
 
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#31 ·
Smaller bores and combustion chambers can tolerate higher compression ratios. A Raptor is like a single cylinder V8, the large bore is more likely to encounter detonation than a 250 or 450 running the same octane fuel.
 
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