[AT] 1935 JD B Testing progress.

[Dean VP]

I think I found the real problem on my 1935 JD B today.  I applied 30 psi of
air pressure to the carburetor inlet side of the manifold and air was
rushing out the exhaust pipe with all valves closed.  Apparently I have a
rust out in the manifold or a blown gasket between the input and exhaust
side of the manifold.  Started pulling the head today and have everything
loose except the water hoses. Will soon have everything off to see if
anything is visible.   I was hoping I wouldn't have to remove the manifold.
The manifold studs will not come out without twisting off. I'm going to try
to use a nut buster on the top nuts and see if I can get the nuts off
without breaking the studs. Then try to remove the manifold.  Was hoping I
wasn't going to have to do this but I'm glad I found the problem.  Will
probably be looking for a new reproduction manifold or good used one.
Leon???  Real progress today.

Dean VP
Apache Junction, AZ

-----Original Message-----
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Dean VP
Sent: Tuesday, November 24, 2020 9:35 PM
To: 'Antique Tractor Email Discussion Group' <at at lists.antique-tractor.com>
Subject: Re: [AT] 1935 Testing progress.

The later JD All Fuel JD B's, which had higher HP, had a compression of
70psi. Haven't found a reference for the earlier JD B"s.  But it surely
wouldn't be higher than 70.  The difference between cylinders of 7 1/2psi is
pushing the limits of acceptability.  These tests were with the tractor
cold. The compression test is supposed to be run when the tractor is a
running temperature. The next test to run is the manifold leakage test. Then
I probably will install the magneto and carburetor and get it running so I
can do a high temperature compression test.  I may just pull the tappet
cover and see if the lash is set right on the valves first. Now that I have
the right tools to do the testing I Can make some progress. 

Dean VP
Apache Junction, AZ

-----Original Message-----
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Dean VP
Sent: Tuesday, November 24, 2020 7:43 PM
To: 'Antique Tractor Email Discussion Group' <at at lists.antique-tractor.com>
Subject: [AT] 1935 Testing progress.

Was able to get the 1935 JD B out of storage and since I had the carburetor
and magneto removed during the winter storage we just pulled it to new
location for the winter. Since we were pull moving anyway I asked my friend
to pull me in gear  about the distance of the two blocks with the plugs out
to get the oil pressure built up for the compression pending compression
testing.  Then hooked the compassion tester and 7/8" to 154 MM adapter up
and had him pull me a 100 feet or so in gear and tested compression on each
cylinder.  Thew results were not as expected.   Got about 62 1/2" psi on the
left cylinder and about 55 psi on the right  cylinder.  I expected a much
larger difference between the two.  Not sure what it should be but sone
reason I expect 70 psi but I don't remember where that came  from.  But the
7 1/2psi difference by itself tell me I need to tear into this tractor.,  I
don't think.  Tomorrow I can do the manifold air pressure test.  If I can
complete that. He results o
 f that test will determine what I test next,


Dean VP
Snohomish, WA 98290
"Socialism is a philosophy of failure, the creed of ignorance, and gospel of
envy, its inherent virtue is the equal sharing of misery."
..Winston Churchill...

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