Need help..several issues
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Teching In
Joined: Aug 2009
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From: oklahoma
Need help..several issues Swapping a 2005 lq4 into a project..started and running for a minute raw oil enters exhaust ports of headers at cyl 4 and 6 as well as mist somewhere onto intake manifold. Compression at both cyl was 160-170...150k motor....so replaced valve stem seals..rockers, springs, pushrods all cleaned up..some sludge present. Engine came out of a fleet vehicle..replaced pickup tube o ring, but doesnt seem to oil real well at valve cover...no knocking or abnormal noises and engine otherwise has no fluid leaks..any thoughts??
TECH Fanatic
Joined: Jan 2018
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From: Dade City, Fl.
What are the compression readings of the other cylinders? Was the throttle wide open or closed during the compression test? Maybe perform a cylinder leakdown check. That will tell you much more about the health of the engine than a standard compression test.
Thread Starter
Teching In
Joined: Aug 2009
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From: oklahoma
The other cylinders average 175/190. I plan on getting a proper leak down gauge tomorrow.. Just curious when I injected air into the cylinders to assist changing valve stem seals, I could hear the air 'traveling' thru the head. Is that normal? Or should the valves essentially seal to the head? The leak down will give me some numbers although not sure I know how to interpret readings. Compression test throttle was closed. Appreciate any input...motor has absolutely no leaks or weird sounds otherwise...hoping worst case here is remove heads for cleaning/valve job.
TECH Fanatic
Joined: Jan 2018
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From: Dade City, Fl.
If the cylinder you were working on was at tdc, the valves should have been seated and sealing. So no you shouldn't have heard the sound of air flowing through the head. Read up on performing the leak down test. It is simple and the results are easy to understand.
Cylinder at tdc apply air pressure, read result. If tester shows leakage, listen for air at exhaust (leaking exhaust valve/seat.) Listen at intake( leaking intake valve/seat.) Listen at crankcase breather(leaky rings/worn cylinder.)
Cylinder at tdc apply air pressure, read result. If tester shows leakage, listen for air at exhaust (leaking exhaust valve/seat.) Listen at intake( leaking intake valve/seat.) Listen at crankcase breather(leaky rings/worn cylinder.)
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Thread Starter
Teching In
Joined: Aug 2009
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From: oklahoma
Performed leakdown test..all cup were well within 10-15% of applied psi....except for 2 ironically on the drivers side which I wasn't having problems with?. As when I performed the previous compression test, air could easily be heard traveling thru the heads and particularly at the air filter. I did notice some air release if I removed the oil fill cap and/dipstick...At 150k miles and with good cranking compression and the mostly positive results of the leakdown....What are the odds the heads simply need gone thru? I replaced valve stem seals on one head but could the valve be so carboned up to not seat?
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TECH Fanatic
Joined: Jan 2018
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From: Dade City, Fl.
It is certainly possible the heads could need a servicing, I picked up a set of 243 heads from a GTO with lower mileage. I sent them to TEA for their cnc porting and they replaced 5 worn valve guides .