John Deere GP

[Rob_F]

I recently brought my grandpa s Deere GP back for a winter project to get running. I m new to vintage tractors as well to this site. I believe it s a 1930 after running serial number (223725). I have the engine tore down to inspect everything and am working on getting it back together and noticed something funky with the exhaust/intake manifold.

It only use 4 bolts to attach but looks to have been designed to use 6. The manifold only has the 4 holes in the center with nothing on the outer ends. I attached a picture as well to explain what I m talking about. Any help I d appreciate it.

 

[Pete in MD]

Welcome to YT. I can't answer your question about the manifold but I do want to say it sure is in
nice shape. The serial number makes it a late 1930 model.

 

[Rob_F]

(quoted from post at 21:06:01 12/07/23) Welcome to YT. I can't answer your question about the manifold but I do want to say it sure is in
nice shape. The serial number makes it a late 1930 model.

Thanks! Valves were trashed. Took some work to get those free and cleaned up. Got new springs for it and everything looks good valve wise now. Valves and magneto are the only things wrong with it I think.

 

[Mark-Ia]

www.handjmachining.com for GP Valves and other engine
parts

 

[Rob_F]

I used them for the springs. Awesome company!! I have gaskets coming from Olsens as well.

 

[NY 986]

Keep posting on your progress.

 

[Rob_F]

Here is the intake that s on it. It looks like it s gotta be the correct one. Just am puzzled on the two extra mounting holes on the engine that aren t used.

 

[Rob_F]

 

[Rob_F]

 

[Rob_F]

 

[Rob_F]

 

[ET]

I think the extra manifold bolt holes may
have been used in a wide tread or orchard
version of the GP. Study the parts book if
you have one.

 

[Rob_F]

Ok thanks I ll look into that!

 

[Rob_F]

Anyone know a place to look for the air intake stack?

 

[Pete in MD]

This site might have what you're looking for.
YT parts for a GP

 

[Watthour]

If it helps, the '30 GP I had also did not use those outer bolts.

http://www.wwdsltd.com/files/1930DeereGPRunningOutside.jpg

There was also a '31 GP-WT in the stable that used only four.

 

[Rob_F]

Ok thanks.

 

[Rob_F]

Was prepping the head last night and found this floating around in the water jacket Was able to shake out about 8 pounds of rust/scale too from within. Should have better flow now!

 

[Watthour]

If it makes you feel any better, I dug about this much out of the top of a '29 GP that was in the collection. There was about as much or more volume (wet) in the bottom tubes that feed the sides of the head.

http://www.wwdsltd.com/files/1929DeereGPRadiatorContamination.jpg

Then there was the '30 GP that had the entire lower inlet at least 50% filled:

http://www.wwdsltd.com/files/1930DeereGPCoolingSystemContamination.jpg

 

[Rob_F]

Dang!!! I m thinking about trying anti freeze with that water water additive. Some guys say absolutely not only water other guys say they ve been doing it for years and no issues. Anyone have any thoughts???? All this rust build up is kinda scary.