[AT] 1935 JD B Testing progress.

[Dave Maynard]

Dean, food for thought.  I once had leaking exhaust manifold gaskets on the
small block chevy 350 in my pick up. The bolt heads had rusted from the
original size of 9/16 to about 7/16 and were pretty much seized to the
casting and no getting them loose. With no other choice, I used a small
angle grinder and ground off the heads carefully as to not wreck the
manifold. Pulled the manifold off and unscrewed the stud part out with my
fingers! Just put in new bolts and was good to go. You might try that.

Dave Maynard

On Wed, Nov 25, 2020, 8:46 PM Dean VP <deanvp at att.net> wrote:

> 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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