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More on the leak down test on 1275 engine

To: spridgets@autox.team.net
Subject: More on the leak down test on 1275 engine
From: Adrian Jones <adrianjones747@earthlink.net>
Date: Thu, 18 Jan 2007 21:30:31 -0500 (GMT-05:00)
Nothing definite, I'm afraid.

First off, the Harbor Fright tester broke the second time I used it.  Took it 
back for a replacement and that broke too.  The first dial (psi) seems to be 
working OK but the second dial (% leakdown) shows a reading, even when 
disconnected from the air supply!  With air, the needle shoots off scale and 
pegs against the wrong side of the peg)

Think I'll take it back and make my own, as several of you have suggested.

OK, meantimes, just using the first dial, which indicates air pressure coming 
in.
With the regulator adjusted to give 90 psi on the tester dial, the reading 
dropped to  71, 76, 82, 71, (when connected to plug holes 1, 2, 3, 4), 
respectively.
I started over, with the regulator adjusted to give 100 psi, and the reading 
were (from plug holes 1, 2, 3, 4) 92, 92, 82, 88.

Doesn't make any sense to me either.

In all cases, the pistons were on the firing stroke at TDC, as indicated by the 
position of the distributor rotor.  It took several slight tweaks to position 
the piston so the air did not push the piston back down but I always started 
again and regulated back to 90 (or 100) psi before reconnecting the air into 
the cylinder.

In all cases, I heard air escaping from the valve cover filler hole but when 
the air was pumped into #2 I heard it coming out of #3 plug hole as well.  
Also, when connected to #3, it came out of # 2 plug hole as well.

If I had to guess, I would say the engine needs new rings (at least) and the 
head gasket is blown between 2 and 3.  (However, there is zero oil in the 
antifreeze and vice versa).

Would that be about right?  I'm still cornfused about the 150 psi compression 
readings that I got at the weekend, though.

Like Frank sys, I really should get this fired up for real - maybe this weekend 
I can clean out the carbs and give it a go.

Regards,  Adrian




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