winfield69
07-15-2009, 07:16 PM
I have an LS7 in my wife's 67 Camaro. I purchased the crate engine, harness and computer (stock Z06) from a reputable dealer about two years ago. It was initially up and running over a year ago and that is when the problems started.
It initially had a miss and was throwing a code that the cam and crank were not synchronized. After going through every other scenario with a local shop that specializes in late model GM cars with LS engines, we finally took off the timing chain cover and found a problem. With the crank at TDC, the cam was off by one tooth. Problem solved (or so I thought).
As long as the engine was partially apart, it seemed like a good time for a cam swap, because more power is never a bad thing. Right?
The shop was convinced that everything was great after they put the car back together. The car put 515hp to the rear wheels, and they said it ran fine. That was around March. I felt a slight miss at low throttle when I drove it home, but it did seem to run a lot better. At WOT, it would scream.
I have spent at least half this year out of the country, so I did not drive it much. My wife was pregnant, so she did not drive it at all. Over time, it has gotten worse (maybe as the temperature got hotter) to the point where it is undrivable. I'm at a loss to figure out what is wrong.
It runs good when it is cold up to about 150deg, and then it starts to run rough until it goes into what I think is closed loop operation at about 180 deg. Sometimes it gets a little better above 180, sometimes it doesn't. I initially had a colder thermostat and it never really warmed up completely. I changed to a stock thermostat with no improvement.
The engine is not throwing any codes, which is surprising as poorly as it sometimes runs.
The engine supplier has given me the finger, and said he can not help me because the problem was created by someone else (i.e. the original engine supplier, GM). I have no recourse against GM because I did not buy the engine from them. I later found out the engine is apparently a leftover from some factory backed racing program that was cancelled so it has no warranty. The stock pistons were swapped for forged ones by GM or a contracted shop, which could explain the cam being one tooth off.
I'm basically on my own and a little over my head. The only two shops in town that I know that specialize in LS engines have not been able to find out what is wrong.
The only things I can think of are:
* There is internal engine damage from the previous cam not being synchronized
* The intake air temperature is excessive from heat from the oil tank (see attached photo) and is causing problems with the programming
Does anyone have any other suggestions?
Does anyone know a shop in Texas that has the kind of experience needed to diagnose the problem?
Any assistance would be greatly appreciated.
It initially had a miss and was throwing a code that the cam and crank were not synchronized. After going through every other scenario with a local shop that specializes in late model GM cars with LS engines, we finally took off the timing chain cover and found a problem. With the crank at TDC, the cam was off by one tooth. Problem solved (or so I thought).
As long as the engine was partially apart, it seemed like a good time for a cam swap, because more power is never a bad thing. Right?
The shop was convinced that everything was great after they put the car back together. The car put 515hp to the rear wheels, and they said it ran fine. That was around March. I felt a slight miss at low throttle when I drove it home, but it did seem to run a lot better. At WOT, it would scream.
I have spent at least half this year out of the country, so I did not drive it much. My wife was pregnant, so she did not drive it at all. Over time, it has gotten worse (maybe as the temperature got hotter) to the point where it is undrivable. I'm at a loss to figure out what is wrong.
It runs good when it is cold up to about 150deg, and then it starts to run rough until it goes into what I think is closed loop operation at about 180 deg. Sometimes it gets a little better above 180, sometimes it doesn't. I initially had a colder thermostat and it never really warmed up completely. I changed to a stock thermostat with no improvement.
The engine is not throwing any codes, which is surprising as poorly as it sometimes runs.
The engine supplier has given me the finger, and said he can not help me because the problem was created by someone else (i.e. the original engine supplier, GM). I have no recourse against GM because I did not buy the engine from them. I later found out the engine is apparently a leftover from some factory backed racing program that was cancelled so it has no warranty. The stock pistons were swapped for forged ones by GM or a contracted shop, which could explain the cam being one tooth off.
I'm basically on my own and a little over my head. The only two shops in town that I know that specialize in LS engines have not been able to find out what is wrong.
The only things I can think of are:
* There is internal engine damage from the previous cam not being synchronized
* The intake air temperature is excessive from heat from the oil tank (see attached photo) and is causing problems with the programming
Does anyone have any other suggestions?
Does anyone know a shop in Texas that has the kind of experience needed to diagnose the problem?
Any assistance would be greatly appreciated.