| Author |
Message |
    
Ali
| | Posted on Sunday, September 29, 2002 - 08:01 am: | 
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RPI sells Felpro comp head gasket but warns that the comp ratio can get lowered as much as 1%. On a 4.6 engine, this will bring the c/r to 8.35. I'd like to hear some thoughts on this. What're the pros/cons with either of these type of gaskets. Lower c/r means torque at lower end but less power, no? RPI says comp head gasket is better for post '96 cyl heads due to smaller comb chamber size.
Please enlighten me.
Thanks. |
Randall Smith
| | Posted on Monday, September 30, 2002 - 06:01 pm: |
|
The 4.0 & 4.6 engines have the thicker gaskets. These engines also have much smaller combustion chambers to match the engine.
Putting the thicker gaskets on a 3.9 engine without skimming the heads (or using 4.0 heads) will lower the compression ratio by about .8
Almost by definition compression = torque. So if you lower the c/r, the torque will drop. Power is a funtion of engine torque and speed, so it will drop as well.
There is nothing wrong with the steel gaskets if installed properly, and you change the coolant every two years. If you want to switch to composite gaskets, your heads need to change too.
Randall |
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