Thread: Need Help LOW COMPRESSION
11-08-2009, 04:56 PM #1
Need Help LOW COMPRESSION
I just checked the compression on my 08 Motor and the compression is low on 1 and 3 is 120psi and on 2 is 115psi so I am going to be rebuilding my block and maybe the head also new valves. I am not familiar with these motors so If I have it rebuilt I want to upgrade the weakest links for example I had an 01 Ford Lightning that I was putting 525 to the wheels I couldn't put out more power because my short block would go and the weakest link was the rods the pistons and crank would hold way more power but the rods would always go. So my question is on RXP motor since I am getting it taken apart what would be the weakest link that I could upgrade? I just don't want to replace all the internals if not needed.. I would appreciate all the info given
11-08-2009, 05:57 PM #2
Those compression numbers are not out of spec. if its a 185,215 or 255. Engine type is important to tell whats ok and what aint. No one makes an engine that has perfect compression between cylinders all the time so they have allowed %20 on most.
11-08-2009, 06:00 PM #3
I remember read a thread not to long ago a member had low compresion on all 3 and did something with the timing to bring it up.
11-08-2009, 06:04 PM #4
It's a rxp-x motor witch should be the same block as an 08 215... I figured 120psi is already on the low side.. maybe the exhaust valves might not be closing all the way since they tend to corrode...
11-08-2009, 06:05 PM #5
11-08-2009, 06:08 PM #6
So I might not even need to do a rebuild, I'm going to take it up to Duke and see if he can get it right...
11-08-2009, 06:14 PM #7
11-08-2009, 06:17 PM #8
11-08-2009, 06:43 PM #9
Make sure you have a realiable gauge too.
11-08-2009, 06:57 PM #10
- Join Date
- Aug 2009
- Beaumont, Texas
maybe you can reseat the valves, by removing the retainers and go to your local car parts and buy that tapping paste and the sucking tool to reseat the valves,
since you will be having the head off it wont hurt to do this.
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