[Rickrock]

What year is your RZR? I’m getting ready to go to AA’s big turbo I have a 16 and currently run his E85 tune. I asked him about swapping to the upgraded head gasket and he said no not needed. Could the new thicker head gasket lowered the compression and caused issues? I have a buddy who’s telling me I should go to the new 4 layer vs the stock 16 two layer.


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[shubb1282]

2016, I’ve asked that, waiting for response, he’s out for the weekend though. Here’s some dried off piston pictures

 

[FordTruckMan]

What year is your RZR? I’m getting ready to go to AA’s big turbo I have a 16 and currently run his E85 tune. I asked him about swapping to the upgraded head gasket and he said no not needed. Could the new thicker head gasket lowered the compression and caused issues? I have a buddy who’s telling me I should go to the new 4 layer vs the stock 16 two layer.


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2016, I’ve asked that, waiting for response, he’s out for the weekend though. Here’s some dried off piston pictures

Well, it's only a picture, and I'm viewing this on my phone, but it doesn't look like there is any pitting to me. I am not an expert and have seen only a handful of damaged pistons in person, but that just looks like a normal piston.

As for the thicker gasket lowering compression and causing issues, I can't imagine what issues that would cause. Lowering the compression would reduce the risk of detonation, so if anything it would help lol.

 

[15rzrhubbard]

This photo is hard to see yes, but it shows pistons 40 miles ago with no pitting, piston is black like it should be.


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[15rzrhubbard]

Damn phone won’t let me put up photos. Says contact administrator


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[shubb1282]

This photo was 40miles prior while doing head gasket.

 

[15rzrhubbard]

IMG_2359.PNG


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[AftermarketAs]

This is a very rare failure on an XPT motor for sure. Our calibrations use all factory parameters to establish and deal with knock. With these parameters we've seen 26+ PSI on pump gas (accidentally) with a hot timing curve and the motor went undamaged. Being that Shane was running a thicker head gasket and a tune meant for a stock 16 head gasket (safer yet), detonation should have been extremely unlikely unless there was a very lean condition. The same calibration he was running is being ran on hundreds of other XPT's. I did build him a tune for the thicker head gasket, but that was not being ran. That makes this whole thing even more strange.

We have seen spark plugs fail and drop out. I had this happen on one of our shop RZR's and luckily it did not do any damage. I have never seen a valve stick on this motor as the sodium filled valves take heat very well, but anything is possible. Did you ever check to see if any coolant was found in your intake plenum? We have seen intercoolers fail and while I'd doubt that was the case here, it could hydrolock the motor and cause valve failure.

-Mike

 

[MCB Performance]

One should always remember that every chamber COMBINATION has a distinct efficiency "area" that is easily disrupted. The combination includes piston shapes as well as head chamber, quench pad(s) and valves. Particularly when dealing with 4 valve "pentroof" designs you must be wary of dead spots created when killing gas speed (IE thick gaskets).

In other words is VERY easy to believe that decreasing compression via head gasket is helping reduce Detonation when if fact YOU CAN INCREASE the likelihood if the fuel migrates prior to developing proper mixture motion.

Again add in the fact that the charge is highly pressurized and the equation becomes more critical.

Still not convinced I see detonation on that piston as much as simple dirt intrusion. Hard to tell without it being in hand. The rings will tell the story.

If you want to lower compression, do it with chamber mods or better yet the correct piston please.

Lastly, I prefer to see these Prostar chambers "softened" if under significant boost as well as an actual Inconel valve being used. In stock form the Stellites are certainly a good piece but they are not designed for the power increases (IE HEAT) that many folks are obtaining.

my 2 cents Scott @ MCB

 

[15rzrhubbard]

Well guys at it again, and this time new engine from different vehicle had 63 miles on it, running perfect. Swapped it out to my vehicle drove around for maybe 15 mins 1/4 throttle. Then moved to half throttle then check engine light came on. Misfire cylinder #2 immediately pulled over, changed belt plugs still had code. Still running, not the bestGot it home took off valve cover to check timing looks like both sprockets jumped one tooth. How is this possible ? Motor is a 2017 xpt and is the engine toast or valves bent. ???


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[FordTruckMan]

Well guys at it again, and this time new engine from different vehicle had 63 miles on it, running perfect. Swapped it out to my vehicle drove around for maybe 15 mins 1/4 throttle. Then moved to half throttle then check engine light came on. Misfire cylinder #2 immediately pulled over, changed belt plugs still had code. Still running, not the bestGot it home took off valve cover to check timing looks like both sprockets jumped one tooth. How is this possible ? Motor is a 2017 xpt and is the engine toast or valves bent. ???


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Are you using all the same peripherals from the first engine? IE, coil pack and plug wires? There could be an issue there. As for the timing...WTF. Does that year engine have a chain tensioner than works off oil pressure? If so maybe you spun the clutch the wrong way when changing the belt and jumped timing? I don't know just grasping at straws here, your luck is worse than mine and that's saying something. I feel for you, I hope you get it resolved.

 

[shubb1282]

Stock 2017 XP Turbo engine went in so it has the mechanical tensioner. New engine had stock spark plugs and stock injectors on it, not used from old engine, spark plug wires were from old engine. Only work done do it was head studs at boondockers tune had been done by packard when engine was run for 60 miles on previous rzr. One thing not mentioned when he first got the check engine light and shut it off, when he pulled the spark plug one was bent with no gap like contact had been made. Spark plug was in same position as one that broke in last engine. Other spark plug had normal coloring no evidence of problems. He has started it again, like he said and ran shortly, then turned it off, both spark plugs came out again and looked fine. Pushing on chain he said it didn't feel loose and didn't deflect as much as some of the pictures you see in the xp 1000 threads that had problems. Teeth on gears look brand new still to me when lookin gat picture.

 

[RZR_Scott]

Cam timing or spark timing isn't going to hit a spark plug. Wrong plug, wrong piston, wrong rod could. Or over machined head or deck. You say stock engine so I guess that leaves wrong plug.

 

[shubb1282]

Would be pretty weird as new engine with those spark plugs were running with no issues in my rzr last time it was run about 2 months ago. He just took the engine with components on it and plopped it in his ride, no middle man

 

[FordTruckMan]

Any chance the spark plug was dropped? If it's the correct plug and it wasn't dropped and damaged, then I would suspect the jumped timing caused detonation which bent the plug tip. You said head studs were done, is it possible the timing was not correct when it was reassembled from doing the studs? Assuming you have to pull the cams to do the studs.

 

[shubb1282]

Head studs were done with only a couple miles on the machine at Boondockers was with them and packard for first 30 miles of its life, all tuning done after head studs so would have thought it rested its head then if timing was off. No impact mark on spark plug, can detonation close a gap on these things? I can’t find any threads of a XPT jumping timing, not sure how this could happen. Anyone know if it’s catastrophic when these do have improper timing? Read some old stuff from alba on 900’s where he said it usually doesn’t make valve contact

 

[FordTruckMan]

Head studs were done with only a couple miles on the machine at Boondockers was with them and packard for first 30 miles of its life, all tuning done after head studs so would have thought it rested its head then if timing was off. No impact mark on spark plug, can detonation close a gap on these things? I can’t find any threads of a XPT jumping timing, not sure how this could happen. Anyone know if it’s catastrophic when these do have improper timing? Read some old stuff from alba on 900’s where he said it usually doesn’t make valve contact

I have seen detonation close a gap on an '03 cobra, so I would assume this would be no different. As for jumping timing, I don't know how else it would occur either. I also do not know if this is an interference engine, where the valves can reach the piston if out of time. If it is, then yes catastrophic failure is possible. If not, then no, the timing alone would not cause damage, just detonation if the timing jump were to cause that.

 

[15rzrhubbard]

Head studs were done with only a couple miles on the machine at Boondockers was with them and packard for first 30 miles of its life, all tuning done after head studs so would have thought it rested its head then if timing was off. No impact mark on spark plug, can detonation close a gap on these things? I can’t find any threads of a XPT jumping timing, not sure how this could happen. Anyone know if it’s catastrophic when these do have improper timing? Read some old stuff from alba on 900’s where he said it usually doesn’t make valve contact

I have seen detonation close a gap on an '03 cobra, so I would assume this would be no different. As for jumping timing, I don't know how else it would occur either. I also do not know if this is an interference engine, where the valves can reach the piston if out of time. If it is, then yes catastrophic failure is possible. If not, then no, the timing alone would not cause damage, just detonation if the timing jump were to cause that.

Unfortunately the motor is a interference engine. I just don’t see how this is possible? Both motors ran perfect ! Before installing the tuner. One motor had 900 miles no issues put tuner on and motor went. Second motor no issues for 67 miles. Put 5-8 miles on it at 1/4 -1/2 throttle went a little past and that’s when shit went down again. Same cylinder. I mean this one is still running but now out of time for what reason ??? And I’m not sure if there has been damage past the bent spark plug. Called mike at AA and he assured me the tune is used in a bunch of vehicles no issues..


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[AftermarketAs]

Just thought of something Shane... might be wise to check the connection or even change your detonation sensor? It's a basic sensor, I've not seen them fail. But if you did run into constant DET and it didn't pull timing to correct that could be an issue. They correct fast to prevent any engine damage.

 

[15rzrhubbard]

Just thought of something Shane... might be wise to check the connection or even change your detonation sensor? It's a basic sensor, I've not seen them fail. But if you did run into constant DET and it didn't pull timing to correct that could be an issue. They correct fast to prevent any engine damage.

Mike,

Are you talking about the knock sensor ? On the back of the block with a 14mm bolt ? If so it’s brand new off the new motor.


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