I know this may be a very subjective question depending on HG thickness, decking, etc, but what "should" "good" compression look like on a 7MGTE? My engine came from a wrecked car that I can only assume was good based on the previous owner's description. It was supposedly rebuilt with forged internals and a HKS metal HG...no idea how thick, though. With a T67 it supposedly dynoed at 440rwhp at one time...not sure how much boost. I've been losing a little bit of coolant (not sure if out the overflow or into a cylinder) so I decided to pull compression the other day. All 6 cylinders were at 119-121 (cold). I've seen some other threads here where folks have mentioned varying readings between 150 and 160. Should I be concerned with 120?
As far as coolant loss goes, I have an after market catch can and it is full...I do know I get a little bit pushed out the overflow hose, but not sure how much when driving. I pulled the cap last night and had my son start the car...immediately saw flow (cold motor), so that tells me there is no thermostat in it. I'll be installing one in the next day or so...any suggestion on temp rating? I also replaced the cap last night with a Stant 13lb one. I was running the cheap Chinese one that came on the radiator when I bought it...noticed the system would hold pressure even after the engine cooled down. Not a lot, but enough to make a hiss when I opened the cap. Not seeing any blowby when I pull the oil cap while running nor is there any oil in the coolant or coolant in the oil. I lose about a quart after a couple of days of normal driving. My temp also creeps to about 200*, but takes quite a while to get that hot...I'm fairly certain no thermostat is causing that, not leaving coolant in the radiator long enough to cool. I have a 2-core aluminum radiator and dual 1550cfm fans controlled by a thermostat fan controller. My temp probe is installed on a hose adapter on the upper radiator hose.
Sorry for the long post...thanks in advance for any insight to my coolant loss and whether I should be worried about 120psi of cold compression.
-- Mike
As far as coolant loss goes, I have an after market catch can and it is full...I do know I get a little bit pushed out the overflow hose, but not sure how much when driving. I pulled the cap last night and had my son start the car...immediately saw flow (cold motor), so that tells me there is no thermostat in it. I'll be installing one in the next day or so...any suggestion on temp rating? I also replaced the cap last night with a Stant 13lb one. I was running the cheap Chinese one that came on the radiator when I bought it...noticed the system would hold pressure even after the engine cooled down. Not a lot, but enough to make a hiss when I opened the cap. Not seeing any blowby when I pull the oil cap while running nor is there any oil in the coolant or coolant in the oil. I lose about a quart after a couple of days of normal driving. My temp also creeps to about 200*, but takes quite a while to get that hot...I'm fairly certain no thermostat is causing that, not leaving coolant in the radiator long enough to cool. I have a 2-core aluminum radiator and dual 1550cfm fans controlled by a thermostat fan controller. My temp probe is installed on a hose adapter on the upper radiator hose.
Sorry for the long post...thanks in advance for any insight to my coolant loss and whether I should be worried about 120psi of cold compression.
-- Mike
