Broken engine :(
06-17-2009, 09:12 PM
#46
Rennlist Member
David,
Sorry to hear about your engine. I was looking at your engine when I was over at Eurosport. One thing I'm convinced is that I won't be buying pump gas anymore. I will be using 100 octane from the track.
I hope you get your car back before Gingerman.
Dave
Sorry to hear about your engine. I was looking at your engine when I was over at Eurosport. One thing I'm convinced is that I won't be buying pump gas anymore. I will be using 100 octane from the track.
I hope you get your car back before Gingerman.
Dave
06-17-2009, 10:09 PM
#47
Nordschleife Master
I run 93 octane pump fuel in my race engines for years and have not had an issue with "bad gas". All of my 964 Cup car owners race on street fuel as well. I'm sure it can happen, but it would have been very bad gas to do the damage you are picturing. Detonation can be seen on the spark plugs and on the piston crowns, although I have seen it damage rings in a similar manner as the poor pictures you have. I think you'd need to inspect the parts in more detail to understand what happened. We check the end gaps of all of the P&C sets we use and very rarely do we alter them from the way the come from the box. I'd be surprised if an aftermarket chip would disable the knock sensor as most take the easy way out and only alter the main fuel and igntion tables. I can't think of a reason to disable the knock sensor on a chip designed for a factory stock engine.
06-17-2009, 11:28 PM
#48
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I run 93 octane pump fuel in my race engines for years and have not had an issue with "bad gas". All of my 964 Cup car owners race on street fuel as well. I'm sure it can happen, but it would have been very bad gas to do the damage you are picturing. Detonation can be seen on the spark plugs and on the piston crowns, although I have seen it damage rings in a similar manner as the poor pictures you have. I think you'd need to inspect the parts in more detail to understand what happened. We check the end gaps of all of the P&C sets we use and very rarely do we alter them from the way the come from the box. I'd be surprised if an aftermarket chip would disable the knock sensor as most take the easy way out and only alter the main fuel and igntion tables. I can't think of a reason to disable the knock sensor on a chip designed for a factory stock engine.
06-18-2009, 12:46 AM
#49
Rennlist Member
I would only suspect the ring gap issue if it were a re-ring, as Geoffery stated the P&C sets are generally good out of the can, but I've seen similar results on a "full rebuild" and after measuring the gaps post mortem they were way too tight, and the "new" cylinders were obviously originals. Don't get me wrong if you have a serviceable set of P&C's it's absolutely fine to do, but it takes a different set of checks during assembly...I'm not saying the shop missrepresented anything but often people don't completely know what original servicable parts go back into a "rebuild" motor unless you get the build sheet & tech notes from the PO. I'd also check the squirters to see if that piston was getting cooling oil, this could be due to a lack of oil on the back of the piston, and subsequent superheating of the piston, causing the piston land to gall and eventually fail... again this would not be a fuel issue but a oil problem...I still have a hard time with it being bad gas...
06-18-2009, 01:28 AM
#50
Rennlist Member
Thread Starter
06-18-2009, 09:28 AM
#51
Nordschleife Master
Geoffrey - what if the car sat all winter without stabil, or something like that? Could water in the fuel cause this poor detonation?
06-18-2009, 09:35 AM
#52
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If you are treating your RACE car like that then you probably have other issues from poor maintenance... I pump my tank dry if the car is going to sit for a prolonged period of time and always start with fresh fuel. A race car environment is a hostile environment and you want everything as fresh as possible.
06-18-2009, 12:52 PM
#53
Rennlist Member
Thread Starter
I run 93 octane pump fuel in my race engines for years and have not had an issue with "bad gas". All of my 964 Cup car owners race on street fuel as well. I'm sure it can happen, but it would have been very bad gas to do the damage you are picturing. Detonation can be seen on the spark plugs and on the piston crowns, although I have seen it damage rings in a similar manner as the poor pictures you have. I think you'd need to inspect the parts in more detail to understand what happened. We check the end gaps of all of the P&C sets we use and very rarely do we alter them from the way the come from the box. I'd be surprised if an aftermarket chip would disable the knock sensor as most take the easy way out and only alter the main fuel and igntion tables. I can't think of a reason to disable the knock sensor on a chip designed for a factory stock engine.
Cheers
DR
06-18-2009, 12:56 PM
#54
Rennlist Member
Thread Starter
Thanks Dave, fingers crossed.
06-18-2009, 12:58 PM
#55
Rennlist Member
Thread Starter
I would only suspect the ring gap issue if it were a re-ring, as Geoffery stated the P&C sets are generally good out of the can, but I've seen similar results on a "full rebuild" and after measuring the gaps post mortem they were way too tight, and the "new" cylinders were obviously originals. Don't get me wrong if you have a serviceable set of P&C's it's absolutely fine to do, but it takes a different set of checks during assembly...I'm not saying the shop missrepresented anything but often people don't completely know what original servicable parts go back into a "rebuild" motor unless you get the build sheet & tech notes from the PO. I'd also check the squirters to see if that piston was getting cooling oil, this could be due to a lack of oil on the back of the piston, and subsequent superheating of the piston, causing the piston land to gall and eventually fail... again this would not be a fuel issue but a oil problem...I still have a hard time with it being bad gas...
06-18-2009, 08:41 PM
#56
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Thread Starter
06-18-2009, 10:55 PM
#57
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06-20-2009, 05:38 PM
#59
Rennlist Member
Thread Starter
Update:
Well it is not definitive but we have several hypothesis we are pursing with the previous owner of the car and the shop that did the last re-build.
In the mean time Eurosport is putting things back together again with:
- race springs
- titanium valve guides
- new pistons and cylynders
- new bearings
- new rod bolts
- re-ground head
- Re-ground cam and cleaning all the little metal chips out of the engine (sounds expensive!!).
ANy other suggestions (bearing in mind I need to stay legal in Stock G).
Cheers
David
Well it is not definitive but we have several hypothesis we are pursing with the previous owner of the car and the shop that did the last re-build.
In the mean time Eurosport is putting things back together again with:
- race springs
- titanium valve guides
- new pistons and cylynders
- new bearings
- new rod bolts
- re-ground head
- Re-ground cam and cleaning all the little metal chips out of the engine (sounds expensive!!).
ANy other suggestions (bearing in mind I need to stay legal in Stock G).
Cheers
David
06-29-2009, 10:05 PM
#60
Rennlist Member
Thread Starter
Well the Eurosport guys did as promised and have my car back in time for my first race at Gingerman this weekend. Time to move on and forget about the pain and start enjoying the track. Thanks for all the help.
Cheers
David
Cheers
David