Hello all,
I've been fussing alot about my engine lately, and, thanks to some
of you, I decided to buy and use a compression gauge on my MGB. Now, I
know _something_ is wrong, but I'm not sure what (or what the
possibilities are). Anyone know what these results mean:
Cylinder Compression With Oil In Chamber
1 110 lbf 120
2 116 125
3 >> 26 << >> 26 <<
4 108 120
Now, my book says 130 is the normal value. I assume this means
that 1, 2, and 4 probably have bad rings, but how bad are they? Is any
deviation from 130 unacceptable, or can the compression fall quite a bit
before rebuild time is required (not recommended, mind you, required).
That is, were #3 110 too, would this be acceptable to continue to drive
like this until it worsened, or is this bad enough that it would be
fouling plugs very quickly and causing the engine to run very poorly.
That said, even I can recognize that # 3 is probably the big daddy
of problems with this engine. But, I don't know what it points to. So
far as I can tell, the head and block are not cracked over that cylinder.
Could the rings have 'exloded' off the piston altogether without causing a
seizure of some sort? Is a valve stuck or broken? Do I likely have a
hole somewhere? Is now the time to take the head off and take a look at
the top of the piston and the valve seats on # 3, (and, is it time for a
rebuild as far as the other rings are concerned)?
BTW, the engine still starts (and did so after the compression
test), but still runs rough as heck. I can't hear anything that sounds
like a piston head floating around in the cylinder, but I can't really
tell it running on three cylinders either. It doesn't quite backfire, but
it makes a deep 'gurgle' like note that sounds like a really weak backfire
(it's nothing like a shotgun, it's not any louder than the normal exhaust)
at idle, it doesn't sound like the healthy exhaust sounds. I can't
describe it very well, I guess that's obvious though, ehh?
Suggestions and diagnoses gratefully solicited, ummm, help!
Thanks in advance in case I get too involved with the 'B to be courteous
later!
-Scott Allen
js-allen@students.uiuc.edu
"At dawn we will face the greatest test of our resolve. But I
say this: though starving, hunger will not weaken us; though diseased,
illness will not cripple us, and though weary, exhaustion will not claim
us. We can fight knowing that all true Reiklanders will forevermore
honour our valiant gesture of defiance, even though our bodies be left to
feed the beasts of carrion.
Mind you...we could always surrender." -Rick Priestly's Siege
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