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Rb26 Compression Test No6 Very Low All 175 No6 Is 110

GD51LA

By GD51LA,
in Engines & Forced Induction

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GD51LA Mentor

GD51LA

Posted
Posted

is it my rings?

1'2'3'4'5 are 175, throttle flat

number 6 is 110?

put 5ml of oil in number 6 went from 110psi to 130

put 5ml in number 5, went from 175psi to 205psi

are their any other tests i can do?

low kilometre standard engine

GTSBoy Grand Master

GTSBoy

Posted
Posted

Could be rings, but you'd expect a much bigger improvement on #6 than on one of the good cylinders on the wet test. So on that basis you'd expect a BHG or bad valve or something else (like all the bad options like a cracked piston, cracked head, etc etc). Valve most likely.

Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

warm the car up, and test it again.

i once had a cyl read 80 when the rest were 130, then i tested it again 2 weeks later and that cyl was back to normal again. have no Fn idea why.

tested it after i purchased new engine internals btw. guess they were not needed... at least for a few months after when something else let go

Blackkers Experienced

Blackkers

Posted
Posted (edited)

DISCLAIMER: I may be wrong (If I am please someone correct me, I love learning about this shit)

Your wet test results showed a bigger improvement on a normal cylinder (weird right?). This suggests that your cylinder bore in #6 is likely okay; it points towards head gasket problems or something in the head.

I'm no guru but I'd be checking for symptoms of head gasket problems first as they stick out like a sore thumb.

edit: also I just wanted to mention that those comp. numbers sound a bit high. Anyone else think the same?

Edited by Blackkers

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