Phil,
I would agree with John. A leak down test can be more accurate. I've done
them with a Mighty Vac Pump. But the numbers quoted on your compression test
are fairly consistent, especially the 2nd set, maxed-out after more cranks.
Even the earlier numbers only have a variance of less than 15% between the
highest & lowest. I have had some engines run decently even when the
compression was quite low. Uniformity is the key item. Oil always improves
the readings - unless you have bad valves. So don't worry, be happy!
Cheers,
Fred Kuzyk
Morgan Sports Cars International
http://mycomm.excite.com/mycomm/browse.asp?cid=.4g3TS2kkNzU
Where the membership is free and anyone in the world can post photos, links,
event dates, articles, discussion, files,
& meet for real-time chat on Morgans!
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----- Original Message -----
From: Phil Roettjer <Phil.Roettjer@quantum.com>
To: <morgans@autox.team.net>
Sent: Friday, October 01, 1999 11:40 AM
Subject: RE: Compression Issues
> John,
> You didn't mention what compression you saw on the first stroke? Did you
see
> 90+ or more? I also usually keep turning the engine over until the reading
> stabilizes and use that as the final reading. I also find that putting oil
> in the cylinders always brings up the compression, even on the high
reading
> cylinders. So the 150 reading with oil would probably be 160.
>
> Anyway if you are seeing over 90 psi on the first stroke and all your
> readings settle out close to 150 psi, I would say you do not have a
problem.
>
>
> Regards,
> Phil Roettjer
> 67 +4
> 67 MGB
>
> > -----Original Message-----
> > From: jpavone@vanstar.com [SMTP:jpavone@vanstar.com]
> > Sent: Friday, October 01, 1999 9:25 AM
> > To: morgans@autox.team.net
> > Subject: Compression Issues
> >
> >
> > I recently ran a compression test on the nearly stock Ford 1600
crossflow
> > in my 59' 4/4 1600 during the course of a tuneup . The compression test
> > showed 150, 131, 132 and 149 on cyls 1 through 4 when cranking the
engine
> > 8
> > times. Adding oil to the two low cylinders pushed thier compression up
to
> > 150 each. However, if I turn the engine over 13 times, without adding
oil,
> > the reading is 152, 149, 148 and 151. The engine runs fine, doesn't use
> > oil
> > or smoke and the plugs look normal. The engine only has 3000 miles since
> > being freshened with new rings, bearings and valve springs. In a
> > previous
> > life the engine was fully rebuilt (including new pistons, valves etc)
and
> > run for only two races in a vintage Formula Ford. As it was originally
> > fitted to a race car, it is a bit "loose" in specification. Therefore,
the
> > piston to bore size is a tad on the generous side but within factory
> > allowances. I could probably borrow a leakdown tester to look into this
> > further. Should I bother? Any thoughts or comments would be
appreciated.
> >
> >
> > Regards,
> >
> > John
> >
>
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