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1950 & 1952 SCHRAMM 35 Pneumapower Compressors - Wisconsin VM4/VP4

K-Tron

Registered
This past weekend I picked up a nice pair of complete 1950's SCHRAMM 35 Pneumapower compressors. The sale included a lot of new sheet metal, parts and the original Schramm owners/parts manual. Before picking up these units, I researched Schramm compressors, and found out that they made three Pneumapower compressors, a 20cfm unit out of a VH4D, a 35cfm unit out of a VG4D/VP4D, and a 75cfm unit out of a VG4D driving a VG4D turned into an air compressor. I know that my units are both VP4 engines with VM4 blocks on the compressor side. The VP4 engine has a 3-1/2" bore and a 4" stroke. The VM4 cylinder jug on the compressor side has a 3-1/4" bore and a 4" stroke. It is evident that Schramm made their own camshaft for this engine as the pistons on the compressor side two cycle, with the intake valve guides plugged up. It is a very interesting design. I have been looking for one of these units for years and finally found a pair I could afford. I plan on restoring one of these units/trailer and all, and mechanically restoring the other to mount on my GMC truck as a backup compressor for my air start Detroit Diesel. They are certainly unique, and there is not a lot of information about them online. Hopefully this thread will answer a lot of questions and get some Schramm knowledge flowing,



Chris
 
Last edited:

Jim Arras

Registered
Age
50
Chris,

I sell parts for the Schramm compressors, let if you need any. Schramm made other sizes in the Wisconsin/Schramm conoressor than what you have listed.

Jim arras
419-722-0774
 

K-Tron

Registered
I managed to get my 1950 Schramm Pneumapower 35 running today. The 1952 unit was in good shape when I picked it up, the 1950 was seized. I stripped the nicer unit completely down to a bare block, as I plan on thoroughly rebuilding it before it goes into my truck. The 1952 unit has real nice pistons, cylinders and rings in it. The valve guides however are in real bad shape and will need to be replaced before I cut the valve seats and lap the valves in. In the mean time, I spent some time working on my 1950 unit which was seized up. I was able to pull the heads, lubricate the engine enough that I had it free in a couple of hours. It looks like the 1950 unit had some serious mouse infestation, as there were nests throughout the air cavity, oil pan, and everywhere. A thorough cleaning of everything, allowed me to get the engine turning nice and freely. At that point, I pulled the distributor cap, cleaned and lubed up the main shaft, spark advance, filled and set the points, and cleaned the cap. I found a pair of good plug wires, fit a pair of new Champion D-21 plugs, and tested for spark with a good 6volt coil. I rigged everything up, and could not get it to run on anything but one cylinder. I figured it just wasnt getting fuel, so I pulled the Marvel Schebler VH-32 carburetor and rebuilt it. It was actually in pretty nice condition despite its age. The carburetor on the 1950 had water in it and the floats/fuel bowl will need to be replaced for sure. I ultrasonically cleaned and rebuilt the carburetor on the 1950 unit, and put it back on the compressor, and the same result occurred. It still ran on one cylinder. So I pulled the cylinder head off of the engine half, cleaned the valves, cut the valve seats and lapped the valves back in. After putting it all together, I had good compression on both cylinders and I could get it to run half way good on a little bit of fuel. Unfortunately in the process of removing the air shrouds to remove the valves, the standoff which holds the bracket for the governor sheared off in the exhaust manifold, and the brass pivot on the carburetor butterfly broke off. So it currently runs without a governor. I found out shortly after I had the engine running that the air line running from the pilot to the governor was causing the engine to pump engine oil into the air tank. I removed the line, and plugged the fitting on the governor so that oil would not leave the engine. Hopefully my Schramm book covers the plumbing of this unit, as either the pilot on mine is no good, or everything is plumbed wrong. As soon as the engine gets going, its compressing air. The load from the compressor is so large that it stalls the engine at low speed. The load is so great that it does not throttle, which may be partially due to not having the governor installed. Now that it is running, it should not be long before I figure out the air system. It just seems like there is a fine line between air pressure, when the pilot valve opens, spring tension on the unloader valves, and when the air cylinder unloads the compressors and bypasses the throttle butterfly in the carburetor.




Chris
 

K-Tron

Registered
I was pretty surprised to see that Schramm used Air-Maze air filters on the compressor side of the engine. The engine side uses an oil bath air cleaner like what can be found on your typical VH4D/VG4D, etc etc. Although the engine had about 2 gallons of water inside it, all is nice and clean. It is really nice that Wisconsin went the extra mile and painted the inside of all of their engines with glyptal!



Chris
 

K-Tron

Registered
The carburetor on the 1952 unit has definitely seen some better days....It has been full of water for some time, and will need a new float and float bowl at this point in time. The engine and compressor pistons however are in like new condition. I found a receipt inside my Schramm manual for $550 which covered the cost of two new cylinder jugs, two VP4 and two AFH pistons, rings and head for this compressor! The valve guides for whatever reason are extremely worn and will need to have bushings fit into them, or they will need to be replaced. Note the "intake" valve guides are plugged on the compressor side of the engine. A couple of the valves were quite sticky from sitting all of these years. Note the custom Schramm valve guides on the compressor side with 1/8" air line feeding into them,




Chris
 

K-Tron

Registered
The pistons look great!
I will check ring gap, ultrasonically clean the pistons, refit the rings, sandblast the cylinder jug and hone the cylinders before putting it all back together. At some point this unit had the latest split skirt Alcoa aluminum Wisconsin pistons (DB-183-D and DB-160-D) put into it, which is surely a nice touch!



Chris
 

K-Tron

Registered
The governor bushing has a bit of wear on it, so it will be replaced in time. The crankshaft journals look good, as does the end play on the crankshaft. I plan on removing the cylinder jugs, sandblasting the cylinders, paint stripping the block, and thoroughly cleaning everything. There were a couple loose valve keepers, lockwashers and lots of dirt inside this engine from "on-site" repairs in its previous life.



Chris
 

K-Tron

Registered
Unfortunately I have not made any more progress on the 1952 unit as of now. I started working on the 1950 unit which was seized up, which will be seen in the upcoming pictures



Chris
 

K-Tron

Registered
I ultrasonically cleaned the VH-32 carburetor. It came out really nice. Note the brass housing for the air cylinder which idles the engine after the compressor has been unloaded.



Chris
 

K-Tron

Registered
After bolting the rebuilt carburetor back in place, the engine still ran on just one cylinder, so I pulled the cylinder head and proceeded to adjust the valves. The fellow who owned these units was in the sandblasting business, so there was about 3/8" of dirt/grime/concrete paste all over this thing. I powerwashed most of it off on day one, but I obviously missed all of the dirt in the vee of the engine. No wonder why the engine was running on one cylinder, the old fuel turned into tar preventing the valves from seating.



Chris
 

K-Tron

Registered
The valves, intake and exhaust ports cleaned up nicely. This engine definitely ate something in the past, what it was I am not sure, looks like it was a chunk of metal. Hard carbon usually does not make such pronounced indentations.




Chris
 

K-Tron

Registered
Lapping the valves by hand was a royal pain. I spent over two hours lapping these valves to get a good seal. The one intake port in particular had very deep pitting which took a very long time to lap out. I really wish I had a Neway valve seat cutter....




Chris
 

K-Tron

Registered
Fitting and adjusting the valves was a piece of cake. I use the grease trick to keep the valve keepers in place... What threw me off was that Schramm recommended a 0.010"-0.012" valve clearance for both the intake and exhaust valves. Usually Wisconsin specifies 0.008" for the intake and 0.016" for the exhaust. Note the exhaust valves on the outside with the (1.130" o.d. 3.063" long 0.150" wire valve springs), and the inner intake valves with the (1.078" o.d. 3.285" long 0.122" wire valve springs)




Chris
 

K-Tron

Registered
I made up some new intake gaskets, mounted a new cylinder cover, turned the fuel on, and away she went...See video in post #4



Thats all for now,


Chris
 

Daric J

Registered
Pretty neat, Chris, thanks for posting! This is very interesting, as I have a VP4 on my log splitter, and a willys jeep flathead 4 cylinder air compressor- which uses the center 2 cylinders for the compressor. It is quite a load compressing air! Good stuff!
 

etd66ss

Registered
I have one of these I got from my brother for doing work on his 1970 Corvette.

I use it to run a sandblaster.

I'd like to restore it someday.

Definitely a thread I will be following.

---------- Post added at 02:52:42 PM ---------- Previous post was at 02:41:27 PM ----------

You say you got a lot of extra sheet metal? Mine needs a hood if you have one you can part with.
 

AngrySailor

Subscriber
Last Subscription Date
01/31/2020
"...to mount on my GMC truck as a backup compressor for my air start Detroit Diesel"

I wonder if he has an extra air starter for a DD:O
 
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