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Thread: Over-revving SR20VE Head

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Posts: 1-10 of 13
2012-05-09 17:04:23
#1
Over-revving SR20VE Head
Last year decemeber I was running at the track and all of sudden there was a loss of power and it sounded like a subaru engine. I believe I might have over-revved because my JWT ecu didn't have a limiter. It was a stupid mistake I made but you live and learn. I have Brian Crower springs and retainers which should have been good up to 9K but I believe I took the car to close to 10K.

A compression test was done and cylinder 1 had zero compression. The head was pulled and inspected. There were no marks on the piston and all valves looked fine. Both the piston and rings from cylinder 1 were also pulled and they looked fine. The only thing which looked strange to me is that the cylinder 1 exhaust rocker arm had a noticeable space between itself and the shim and the retainer also had some small gouges in it.

Do you guys think it would be fine if I just replaced both exhaust valves for cyl. 1 and see if it fixes it? Or is there something else that I need to check for? I would appreciate any advice.

Setup:
Engine
SR20VE built by Andreas Miko
9:1 compression
SR20ve cams
Valve Springs & Retainers
Z32 Maf
740cc Nismo Injectors
Nismo Fuel Pressure Regulator
G Spec Lightweight Pulleys

Tuning
JWT ECU tuned for the above @ 4 bar fuel pressure

Turbo Setup
Precision 6262E Journal Bearing (Exhaust Turbine A/R .63)
Protech Equal Length manifold
Full 3" exhaust
Tial 38mm Wastegate (15psi Spring)
Tial Q 50mm Bov (11psi Spring)
Greddy Profec B Electronic Boost Controller

Last edited by boost96 on 2012-05-09 at 17-13-36.
2012-05-09 17:09:34
#2
did you pull the valves out of the guides? They could be bent on the stem and you would not see it. The valve should slide out with no resistance. If they don't then the valve or the guide could be messed up.
2012-05-09 17:14:55
#3
Originally Posted by cortrim1
did you pull the valves out of the guides? They could be bent on the stem and you would not see it. The valve should slide out with no resistance. If they don't then the valve or the guide could be messed up.


the mechanic pulled one of the valves out and he said he didn't see anything wrong with it. however, I'm wondering now if the guide could be messed up like you are saying.
2012-05-09 17:18:48
#4
from the pic of the shim it looks like one of the retainers is coming off the valve stem. this would cause the shim to stick up and eventually the valve to drop.
2012-05-09 17:36:42
#5
Originally Posted by cortrim1
from the pic of the shim it looks like one of the retainers is coming off the valve stem. this would cause the shim to stick up and eventually the valve to drop.


thanks for the info. do you think I would jus need to replace that valve then? or is there something else that usually needs to be replaced when something like this happens?
2012-05-09 18:01:07
#6
Originally Posted by boost96
thanks for the info. do you think I would jus need to replace that valve then? or is there something else that usually needs to be replaced when something like this happens?


I would fully disassemble the head and inspect everything.
2012-05-09 18:11:39
#7
Originally Posted by cortrim1
I would fully disassemble the head and inspect everything.


OK thanks.
2012-05-09 19:45:47
#8
If your running the SR20VE throttle body check the throttle screws. Mine looked like that after it sucked it into the motor and got caught between the valve and head. could be a broken springs too.
2012-05-10 00:43:02
#9
Originally Posted by BlueRB240
If your running the SR20VE throttle body check the throttle screws. Mine looked like that after it sucked it into the motor and got caught between the valve and head. could be a broken springs too.


i am runnin the sr20ve TB but my screws are all there. I plan to remove them and put loctite before I run again.
2012-05-10 03:32:13
#10
The valve is bent it has to be.
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