GPW block

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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artificer
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Re: GPW block

Post by artificer » Mon Sep 23, 2019 7:25 pm

If you are into boring & new pistons make sure the block is really checked carefully for cracks/leaks especially thickness around the bottom of the bore.
GPW's are problematic in that area & often boring will kill a cylinder or 2 making for much higher repair bill.
I would grind the crankshaft as well & fit bearings to all cam journals, to suit the shaft.
Close up all the tolerances.
Get a Saunders timing chain & you'll be running like a Swiss watch!
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TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: GPW block

Post by Mike Kelly » Wed Sep 25, 2019 1:24 am

Good news. The stuck plug came out, its actually a 9/32 " head.I filed the damaged head down to 1/4 and used a quarter drive socket

The crankshaft does need grinding , its worn . I measured the rod journals at 1.927" which is a rather odd Size

The camshaft journals look smooth the larger one is 2.1855" , the replaceable bearing measures at inside diameter of 2.1895"

The other 3 can journals are: 2.122, 2.0595 and 1.6225
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Re: GPW block

Post by artificer » Wed Sep 25, 2019 2:34 am

Cam shaft to block is, when everything else is done, oil pressure is lost/diminished.
Ford V8 cam bearings can be used/adapted & I think a Perkins for the last one.
One can get a list & it was MartySocal who posted something regarding dimensions of bearing sizes years ago, from memory.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: GPW block

Post by Mike Kelly » Thu Sep 26, 2019 1:31 am

I'm guessing the rod journal standard size is 1.9375

Do they normally grind the journals to the exact size ? There must be a 1 to 2 thou gap for the oil , so are the shells slightly over the nominal size ?
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Re: GPW block

Post by Wolfman » Thu Sep 26, 2019 7:00 am

Correct. Journals are ground on size.
1.9375 would be 1 15/16 and standard size. In the U.S.A.
Your 1.927 rod journal has already been ground to -.010 under size.
1.927 is not bad. If the journal surface is smooth and in good condition.
You need to check each journal at two angles. up & down and again cross way to be sure the journal is round. No flat spot.
The flat spot can be caused by the pressure on the power stroke being applied to the same spot on the journal, over and over.
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Re: GPW block

Post by Mike Kelly » Mon Nov 11, 2019 2:36 am

Been cleaning the engine bits with citric acid and a wire wheel . exhaust manifold has a nasty crack . its a early oil pan with riveted type plug . This Texas 44 rebuilt engine was green not grey.
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Re: GPW block

Post by Gary C V » Mon Nov 11, 2019 9:06 pm

Hi Mike, mate the engine would have been Ford grey when it left the Ford factory, and seeing its gone through a
overhaul it would have been painted olive drab ''green'' as per army fetish for green.

Cheers
Gary

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Re: GPW block

Post by nick peters » Tue Nov 12, 2019 1:33 am

Hey Mike
Good to read your getting along well with your engine project. I noticed you said your dizzy may be from a willys car. Maybe it would be worth your time and show it to Ron Geddes down in Melbourne. I 'm sure you'll know him hes a long time member of the Victoria military vehicle club. Anyway Mike hope your Morris projects are also coming along :)
regards Nick

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Re: GPW block

Post by Ron Geddes » Wed Nov 13, 2019 5:26 am

Hi ---- What is the Engine number? The inlet manifold maybe I from a ealier Willys car most likely the same one that the distributor came from maybe a few photos of those parts close up to see
Ron

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Re: GPW block

Post by nick peters » Wed Nov 13, 2019 11:34 am

Hey Ron
I think Mike will confirm that the engine is GPW 75283. If that is indeed correct, then according to Johns book Standardised war time jeep book. That dates it as coming from a gpw manufactured during October 42.
regards Nick

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Re: GPW block

Post by dpcd67 » Wed Nov 13, 2019 1:49 pm

Any good auto machine shop will hot tank and magna flux before they do anything else, and any decision on what course of action to take can only be made after that happens. Guesses on condition, dimensions, and short cuts, may, or may not, work as planned.
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Re: GPW block

Post by Mike Kelly » Fri Nov 15, 2019 4:06 pm

One strange thing is: The exhaust manifold does not have the auto heat control mechanism, it has a manual lever that you push to three positions marked , the shaft was stuck solid, I drilled it out .

I cleaned the block myself with a hot caustic bath . Cant see anything wrong to the naked eye. Cleaning the starter motor ATM, I polished the commutator in a lathe , the brushes are worn but should be OK for years.
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Re: GPW block

Post by nick peters » Sat Nov 16, 2019 12:19 am

Hey Mike
Was that the correct engine number ?
regards Nick

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Re: GPW block

Post by Mike Kelly » Sun Nov 17, 2019 2:05 am

nick peters wrote:
Sat Nov 16, 2019 12:19 am
Hey Mike
Was that the correct engine number ?
regards Nick
Hi nick. Yes the number on the block matches the rebuild tag number
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nick peters
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Re: GPW block

Post by nick peters » Sun Nov 17, 2019 4:06 am

Hey Mike
All you need now is the early gpw to drop that engine into :D
regards Nick

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