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Re: Low Compression, 77 Midget 1500 cc

To: "William M. Gilroy" <wmgilroy@lucent.com>,
Subject: Re: Low Compression, 77 Midget 1500 cc
From: johnhaynes@som-uky.campus.mci.net (John Haynes)
Date: Thu, 8 Oct 1998 23:24:10 -0400 (EDT)
At 02:29 PM 10/8/98 -0400, William M. Gilroy wrote:
>My 77 Midget (1500 engine) has an oil leak down low
>by the dipstick.  I thought it was the pan gasket.
>After I put in my new dizzy I found that I was leaking
>even more oil.  I found that the oil is not coming from
>the pan gasket but from the dipstick hole.  I checked 
>the oil, it is full but not over full.  The valve
>cover vent is not plugged.  I still get the leak if I 
>run the engine with the valve cover vent disconnected 
>from the carb. at the valve cover.  Now I figure that the
>problem is excessive crankcase pressure even though the
>the crankcase is vent is work.  I then ran a compression
>test and these are the number I got:
>
>       Cylinder 1:  135 psi dry / 155 psi with oil
>       Cylinder 2:  40 psi dry / 60 psi with oil
>       Cylinder 3:  75 psi dry / 90 psi with oil
>       Cylinder 4:  135 psi dry / 170 psi with oil
>
>I ran my compression tests with all of the spark plugs in, and
>I squirted a couple shots of 20-40W engine oil into the cylinders
>for the tests with oil.
>
>Now I am wondering what are my options.  I think they range
>from a complete rebuild to doing nothing.  I would like something
>in the middle.  First exactly what do these number tell me?
>Like cyl 4 is it just a set of bad rings and cyl 1 is a set of
>bad valves and maybe rings.  What is the correct answer?
>What are good numbers for compression?  What would I see on a
>newly re-built motor?  Could I get away with just re-ringing the 
>pistons and a valve job.  I am trying to explore my options.  I 
>would like to avoid a full engine rebuild at this time. 
>I can see where that would lead me to many other things (hotter cam, 
>paint the car since the engine is out, weber, headers, etc.) and
>I currently don't want to do all of this stuff.  Maybe down the
>road but not now if I can avoid it.
>
>Thanks in advance,
>
>Bill
>-- 
>Bill Gilroy
>77 Midget
>E-mail:    wmgilroy@lucent.com
>Telephone: 732-957-4775
>Fax:       732-957-4775
>
>    Hello Bill
          Remove all the plugs. Pour one tablespoon of 30 wt oil into # 3
cylinder. Screw your compression tester into #3 spark plug hole. If the
compression comes up to around 130-175, you have worn
rings-pistons-cylinders. If there is no change, you have burnt -worn valves.
If the oil blows out the #2 spark plug hole, you have a blown head gasket or
warped head.

Sam Haynes
TR3 Original Owner


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