William,
My '73 Spitfire (yes, the source for the hated 1500) had the same symptoms,
it started pumping oil out the dipstick hole. Upon tear down I found that
between the 8 compression and scraper rings originally installed, 5 were
broken with one of them in 1inch pieces. At the time the engine was showing
almost consistent readings of 110 across the board. The oil rings were
doing double duty as compression rings too I guess.
There is a possibility that you could have a bad head gasket, but I wouldn't
count on that too much. On the plus side most of the parts for the rebuild
are still reasonable.
Jim
> -----Original Message-----
> From: William M. Gilroy [SMTP:wmgilroy@lucent.com]
> Sent: Thursday, October 08, 1998 1:29 PM
> To: midgets; mgs
> Subject: Low Compression, 77 Midget 1500 cc
>
> 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
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