Having problems and would like your input.
05-20-2008, 08:49 AM
#1
Having problems and would like your input. I went to the track saturday to run my car on the jug one last time before I start on the front mount turbo install. To make a long story short I had moved the rev limiter up to 7200 through the pressure of someone at the track and taged the rev limiter a couple of times when I missed a gear trying to powershift (I normally dont powershift). Anyway the car started a popping at high rpm, on nitrous and off the nitrous. It slowed down 4mph on the last pass I made on the bottle and it scared me. Its running open Hooker long tube headers right now so as best I can tell there arent any unusual ticks or noises of anykind. It will however try to die at idle every once in a while though.
I have a 224 cam with all the goodies that come with the package from Thunder including comp 918 springs, titanium retainers, & hardened push rods.
So far I have taken both valve covers off and noticed that the PCV valve was blown out of the back of the drivers side valve cover but still attached to the vaccum line. All the rockers appear to be tight, couldnt find any up and down slack. Next I guess I'll pull the rocker arms and start looking for a bent push rod even though I know its pretty unlikely to bend a hardened push rod. If that shows nothing I guess its on to a compression & leak down test.
I appreciate any input and also would like to know if the motor has to be hot for the leak down test
I have a 224 cam with all the goodies that come with the package from Thunder including comp 918 springs, titanium retainers, & hardened push rods.
So far I have taken both valve covers off and noticed that the PCV valve was blown out of the back of the drivers side valve cover but still attached to the vaccum line. All the rockers appear to be tight, couldnt find any up and down slack. Next I guess I'll pull the rocker arms and start looking for a bent push rod even though I know its pretty unlikely to bend a hardened push rod. If that shows nothing I guess its on to a compression & leak down test.
I appreciate any input and also would like to know if the motor has to be hot for the leak down test
05-20-2008, 05:49 PM
#6
OK, have the plugs out. All 8 look good, no signs of pre ignition at all. I guess I'll do a compression test tomorrow and see what I got. How many PSI (range) per cylinder is good for a 56k mile motor that goes to the track about twice a year? Havent used but 3 10 bottles of nitrous since ive had it.
BTW. I did a scan with my HPT & there are no DTC's other than the usual wheel speed sensor DTC I get from running 27's on back and 26's on the front.
BTW. I did a scan with my HPT & there are no DTC's other than the usual wheel speed sensor DTC I get from running 27's on back and 26's on the front.
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05-20-2008, 10:04 PM
#8
I made a motor pass & missed a gear trying to powershift, the next run I granny shifted paranoid from the first run,spun off the line & through 1st and ran a 11.41 @ 126.6mph, the 3rd run it started breaking up doing the popping thing & ran a 11.7 @ 122, thats when I got scared. It normally would run 11.80's all day long on just the motor.
05-21-2008, 09:25 PM
#9
OK, did a leak down test and all 8 cylinders were in the green.
(1) 33% (8) 10% (7)15% (2)20% (6)15% (5)17% (4)15% (3)28%
These are in firing order incase you didnt catch it, Is there anything else I can do to make sure everything is 100% OK?
Here's a pic of the leakdown tester I used so you can get an idea of what the "green" is.
(1) 33% (8) 10% (7)15% (2)20% (6)15% (5)17% (4)15% (3)28%
These are in firing order incase you didnt catch it, Is there anything else I can do to make sure everything is 100% OK?
Here's a pic of the leakdown tester I used so you can get an idea of what the "green" is.