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RE: engine not cranking

To: "Jason B Lonon" <j_lonon@lycos.com>, <mgs@autox.team.net>
Subject: RE: engine not cranking
From: "Larry Hoy" <larryhoy@prodigy.net>
Date: Tue, 9 Jan 2001 17:42:46 -0700
Jason, you have a long list here.  First of all since you replaced the starter 
and now it doesn't start I'd re-trace my steps.

Either you aren't cranking the engine fast enough; or, something else went 
wrong when you changed your starter.

If you changed your points, timing, or removed all the plug wires at the same 
time this is likely where the problem is.

If you have spark, I don't think you need to worry about how strong it is.  
It's probably strong enough.

Your compression sounds low.  You would like to see at least 100 psi as a 
minimum and all cylinders should be within 15% of each
other.  130-140 psi and 10% would be better.  But the car ran before you 
changed the starter, and low compression is something that
doesn't happen over night (hopefully).  I'd look somewhere else.  I'd also read 
up on how to do a compression test.  I'm suspicious
of your readings.

Seems like your fuel test indicates you are pumping fuel to the carbs.  The 
fuel leak might be coming from your float bowl.   I
assume you have two SU carburetors?  There are floats in the carburetor bowls 
that operate a valve, if the fuel pump is working and
the valve(s) don't shut the fuel supply of you'll have fuel everywhere.  You 
might try tapping the carbs with a leather, wooden, or
rubber mallet and see if the leak stops.  If it does the float valves are bad.

If you have spark and fuel, all you need to make the engine run is to have it 
all happen at the right time in the right quantities.
We can assume, unless you messed with the carbs, that we need to deal with 
getting things to happen at the right time.

Try this.

Pull the #1 spark plug.  Rotate the engine clockwise by hand until the #1 
cylinder is at TDC (this will be easier if your remove all
the plugs).  You can confirm TDC under the car by looking at the timing marks 
on the crank pulley (I think that's were the marks are
located on a 72).  Both valves should be closed at this point.  If they aren't 
rotate the engine until they are closed and the
piston is up.  Now turn the engine back counterclockwise enough to go past 
about 10 degrees before TDC.  Then back clockwise and
stop at 10 degrees before top dead center.  Leave it there.

Loosen your distributor, pop the cap off, hopefully the rotor is pointing in 
the general direction of the #1 cylinder.  If it isn't,
it's time to verify that the engine is at 10 degrees before TDC on cylinder #1. 
 If after you verify #1 cylinder is at TDC and it is
still not pointing at the #1 cylinder you have some other things going on, but 
that's a different discussion.

Check the points visually, make sure they aren't pitted.  Gap them at .015.  
Turn on the ignition (don't crank the starter, just
turn on the ignition.  If you crank the starter start all over), and rotate the 
distributor slightly and look for the points to
spark.  At the location where they spark is where you want them set.  Tighten 
the distributor.  Remember where the rotor is
pointing, put the distributor cap back on.  Don't forget to tighten the 
distributor

Put the #1 plug (or plugs) back in the car.  Remember where the rotor was 
pointing?  Take that plug wire and hook it to the #1 spark
plug.  Then go to the next wire counter clockwise and hook that to #3 spark 
plug, then the next wire counter clockwise and put it on
#4 spark plug, then the last plug wire put it on #2 spark plug.

Now your car should start.

If it does I would recommend you re-time it dynamically using the 
specifications for a 1972.

Good luck.

Larry Hoy
>-----Original Message-----
>From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net]On
>Behalf Of Jason B Lonon
>Sent: Tuesday, January 09, 2001 2:32 PM
>To: mgs@autox.team.net
>Subject: engine not cranking
>
>
>---I know this is a very common thread, but I've not had too much success
>scanning the archives with the same kinds of symptonms/knowledge
>I've acquired about my pour B's problem. (It's a 72)
>     To start with, it was running in good shape. Then one day I
>got caught in a rain storm, and the starter died on me. I eventually
>replaced the starter, and the engine will now crank, but it will not fire.
>     I have re-checked the timing, it is good. I have cleaned out
>the carb to make sure no gas was gummed up in it. I have checked
>for spark, and I am getting spark from the plugs. The problem is,
>I'm a relative newbie with MG's, and I don't have the personal feeling
>for what constitues a strong sprak, or, something else I've been
>wondereing - is my starter motor turning over the engine fast enough?
>It 'sounds' slow ... but how can I really tell unless I know what
>it is supposed to sound like, and I only had the car a few days before this 
>happened.
>     I bought a cylinder compression kit at the local parts store
>and tested the compression (in an effort to make sure I really was
>on TDC.) What kind of numbers should I get? I was only getting a reading just 
>over 60 psi...?
>     And finally, I noticed when I flood the engine (to see if any
>reaches the plugs) I get gas leaking out from under the intake manifold ... is 
>that normal?
>Thanks ahead of time to anyone who might have a suggestion for my next task.
>
>Jason B. Lonon

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