View Single Post
Old 06-24-2011, 09:50 PM   #2
pwpanas
Supra Owner
 
pwpanas's Avatar
 
Join Date: Oct 2005
Location: GA, USA
Posts: 2,209
pwpanas is on a distinguished road
Default

Quote:
Originally Posted by tayman1975 View Post
Ok i got the compression readings off my 2jz GTE motor. Cylinder 5 is at 125lbs and cylinder 6 is at 150. The rest are at 160lbs. The shop noticed brassy color fittings in cylinder 5. What do you think this is. Doesn't sound like a broken piston ring. what do think it may be. Is it possible it may just have a bad head gasket you think.
Do you mean brassy color filings (not fittings)?

Did you notice any damage on the #5 spark plug when it was removed?

Note that the headgasket is made from a much harder metal than the (aluminum) cylinder head. If you have headgasket damage, you'll almost for certain have head damage too.

Most times, too much boost on pump gas damages the ring lands near the valve recess in the piston. Either way, unfortunately, it sounds like you will need some engine work...

To avoid low compression and metal filings in the cylinder either 1) run less boost, or 2) run race fuel, or run alcohol+water injection, or convert to E85. That's a hard and fast rule - violate it and the engine will always get damaged from detonation. When fuel detonates, it explodes like C5 or TNT instead of burning like gunpowder. No engine internals...no matter how expensive...can stand up to detonation. The bone stock 2jz-gte can easily put out 1000hp with high octane race fuel, and absolutely no engine damage. With 93 octane {(r+m)/2} pump gas and the oem timing curve, never exceed 16psi (1.12 kg/cm2) of boost.
__________________
Phil '94 Supra Turbo, 6spd, 'APU'+
Displacement is no replacement for boost.
Life begins at 30psi.


NB: Please consider posting any help requests in a new thread instead of asking me for help privately. About 99.9+% of the time, private help requests end up covering great information that could be very valuable to other forum members. If you have a good reason for needing the help request to be private, I'll consider it. If not, then why not give everyone else the opportunity to pitch in too, and/or learn from the information? Remember, there's no such thing as a dumb question. We're all here to help within this family of Supra owners.

Last edited by pwpanas; 06-24-2011 at 10:19 PM.
pwpanas is offline   Reply With Quote