keltalon
Supporting VIP
- 3,474
- 959
- Jun 29, 2003
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Luthersville Ga, Atlanta,
Georgia
In a recently cam test that I was doing my oil pump failed and ruined my bottom end. This forced me to have to rebuild it. While I was in the process of tested I decided to give a set of cp pistons a shot in my new build.
I read a lot of good things about cp pistons from how they are used in NASCAR and the professional drag circuit to specific techniques that set cp pistons above the rest. Like everybody here we are always trying to use the best components in our engines so that we are as close to bullet proof as we can get.
I ended up going with a set. The first thing I notice about the pistons , that was different from the ross ones that was currently in the engine, was that the valve relief was cut very deep and that there were little material left at the edge of the piston. I thought this might be a concern in that it might create a hot spot in the cylinder but since nobody has had any issues with them in the dsm community I didn't linger on my concern I just went ahead with the installation of the piston.
Here are some other differences of the ross and cp piston. Ross was 8.5to1 compression the cp was 9.0to1. the cp pistons was a little lighter than the ross I can't recall the exact weight in grams but cp was lighter. But the main reason for my giving them a try was the advertisement of the low tension oil ring. Once I got the pistons I did notice that the cp oil ring had a significant less tension than the ross units. These are just some of the few physical differences in the two. The other differences was advertisement of the pistons. Cp advertisement concerning the benefits of their piston influenced had the greatest influence on my gut feeling that they were a better piston and this is was caused me to give them a try verses going with another set of ross. Don't get me wrong the only forged piston I have every used in all my engine build was ross and have yet to have any issues out of them
I guess sometimes we can't leave well enough alone. I put the engine back together and to make a long story short properly broke in the engine. Dialed in my tuned and the car was ready for some wide open pulls. Car pulled very hard and I was please with performance. I did notice a issue with coolant being pushed not much but enough to go into the reservoir in the upper rmp range so I turned the boost down and figured I would replace the head gasket when I got a chance.
After about 3000 miles I finally pulled the head. I could see where the boost was making its way into the coolant passages so I sent the head to the machine shop to be decked and ordered a new hks stopper head gasket. But I couldn't put the car back together because my concern about the way the pistons looked around the valve relief area the thin metal was being affected by the heat in thd cylinder. Here something to note , my car never saw any knock on dsm link. I never saw over 1450 degrees on my egt gauge and I run full e85. In fact all my tuned was the same as with the ross slugs.
I went ahead and pull the engine and broke it down. I did notice that the cp rings sealed like a charm the cylinder walls was nice and polished with no vertical piston ring lines and this is why I have faith in a custom set not to mention I had absolutely zero blow by . I have been working with cp on making me a set of custom pistons where the valve pocket is not as large as what comes on their stocking units they took note of all of my concerns and appreciated all of my feedback and recommendations and agreed to make a custom set that will soot my needs. It has been 5 weeks and still waiting on them to be completed. I agree with the thread below, Cp customer service stinks badly! I called cp sports compact manager 4 times he finally returned my call 3 weeks later.
JE or CP Pistons
I think custom cp piston will be awesome but the shelf units are a rebuild waiting to happen. here's a similar issue within the honda community reagarding cp thin valve pocket
Piston damage question - Club RSX Message Board
cp pistons not good? - Honda-Tech
bmw forum same issue Piston/Engine Pics - Worried About Valve Relief Cut - Need Help - Bimmerforums - The Ultimate BMW Forum
I need a new dyno and a new tune - Bimmerforums - The Ultimate BMW Forum
Before you decide to use cp 4g63 stocking pistons do your research. This information is solely provided to inform the dsm community so that a wise decision can be made by each and everyone of you when it comes to chosing a set of pistons for you build nothing more nothing less.
here are some pictures of my cp pistons If I had not caught the problem when I did I would have ended up like some of those honda guys >
I read a lot of good things about cp pistons from how they are used in NASCAR and the professional drag circuit to specific techniques that set cp pistons above the rest. Like everybody here we are always trying to use the best components in our engines so that we are as close to bullet proof as we can get.
I ended up going with a set. The first thing I notice about the pistons , that was different from the ross ones that was currently in the engine, was that the valve relief was cut very deep and that there were little material left at the edge of the piston. I thought this might be a concern in that it might create a hot spot in the cylinder but since nobody has had any issues with them in the dsm community I didn't linger on my concern I just went ahead with the installation of the piston.
Here are some other differences of the ross and cp piston. Ross was 8.5to1 compression the cp was 9.0to1. the cp pistons was a little lighter than the ross I can't recall the exact weight in grams but cp was lighter. But the main reason for my giving them a try was the advertisement of the low tension oil ring. Once I got the pistons I did notice that the cp oil ring had a significant less tension than the ross units. These are just some of the few physical differences in the two. The other differences was advertisement of the pistons. Cp advertisement concerning the benefits of their piston influenced had the greatest influence on my gut feeling that they were a better piston and this is was caused me to give them a try verses going with another set of ross. Don't get me wrong the only forged piston I have every used in all my engine build was ross and have yet to have any issues out of them
I guess sometimes we can't leave well enough alone. I put the engine back together and to make a long story short properly broke in the engine. Dialed in my tuned and the car was ready for some wide open pulls. Car pulled very hard and I was please with performance. I did notice a issue with coolant being pushed not much but enough to go into the reservoir in the upper rmp range so I turned the boost down and figured I would replace the head gasket when I got a chance.
After about 3000 miles I finally pulled the head. I could see where the boost was making its way into the coolant passages so I sent the head to the machine shop to be decked and ordered a new hks stopper head gasket. But I couldn't put the car back together because my concern about the way the pistons looked around the valve relief area the thin metal was being affected by the heat in thd cylinder. Here something to note , my car never saw any knock on dsm link. I never saw over 1450 degrees on my egt gauge and I run full e85. In fact all my tuned was the same as with the ross slugs.
I went ahead and pull the engine and broke it down. I did notice that the cp rings sealed like a charm the cylinder walls was nice and polished with no vertical piston ring lines and this is why I have faith in a custom set not to mention I had absolutely zero blow by . I have been working with cp on making me a set of custom pistons where the valve pocket is not as large as what comes on their stocking units they took note of all of my concerns and appreciated all of my feedback and recommendations and agreed to make a custom set that will soot my needs. It has been 5 weeks and still waiting on them to be completed. I agree with the thread below, Cp customer service stinks badly! I called cp sports compact manager 4 times he finally returned my call 3 weeks later.
JE or CP Pistons
I think custom cp piston will be awesome but the shelf units are a rebuild waiting to happen. here's a similar issue within the honda community reagarding cp thin valve pocket
Piston damage question - Club RSX Message Board
cp pistons not good? - Honda-Tech
bmw forum same issue Piston/Engine Pics - Worried About Valve Relief Cut - Need Help - Bimmerforums - The Ultimate BMW Forum
I need a new dyno and a new tune - Bimmerforums - The Ultimate BMW Forum
Before you decide to use cp 4g63 stocking pistons do your research. This information is solely provided to inform the dsm community so that a wise decision can be made by each and everyone of you when it comes to chosing a set of pistons for you build nothing more nothing less.
here are some pictures of my cp pistons If I had not caught the problem when I did I would have ended up like some of those honda guys >