'48 "running when parked" club

[Clubless]

Picked up a "running when parked" '48 cub back in January, but just started messing with it this week. Took the hood/tank off to see what things looked like. It has been converted to 12v system with magneto, external coil and what looks like a Delco 10si alternator. Went ahead removed alternator, 4 position light switch and tattered original wiring harness along with some mystery wires that all connected to starter post. Put in a battery to verify I had a working starter in order to perform engine compression test, starter good. Removed carburetor and valve cover to check valve clearance, good there. On to compression test, got surprisingly good "dry" and "wet" numbers. Removed and looked inside of distributor cap which looked new, decided not to check points at this time. Wired up cub with minimum wires needed to run. Put inline spark-plug tester to check for fire at plug, good there. Buttoned up valve cover, re-installed carburetor, added some antifreeze/water mix to radiator, mounted pony tank, and last but not least, "primed the pump". Turned on gas, pulled ignition switch on, then pulled on starter rod. She came to life immediately. Smoked at first until it burnt off the oil from wet compression test. Watched the oil pressure gauge steadily move up and up and up and up, then noticed oil oozing out from under oil filter cap. Decided that something was not right with oil gauge pegged out. Put on another gauge off different cub and got same result. Decided to call it a day and start researching the issue on here.

Found a number of threads regarding extremely high oil pressure pointing to the engine pressure regulator valve (PRV). When I removed the PRV spring, I found it was bent in a couple of places. The experts on here said spring needs the correct amount of tension and be straight. It took several attempts to remove the valve/piston with my tool. Once out, I noticed a slight gouge and small burr on the piston. Cleaned up with fine sandpaper. I installed a spring out of another cub and restarted engine. Oil pressure gauge still moved to extreme right. Both gauges being used are the original (non-numbered) gauges. I remembered that one of my other cubs had a 0-75 pressure gauge, so I grabbed it and put in on. Started engine and watched the indicator needle bounce/fluctuate around mid-way of the gauge, it never did settle down to a steady reading. Not sure a new spring from our good friends at TM Tractors is going to solve issue, but what else could it be?

PRV spring

After reinstalling the PRV, I noticed what appears to be a weld just below the bottom water hose. Any thought on why this weld was needed?

Weld

Like most of these old tractors that have been put out to pasture, it has a lot of issues to work through. I'll post updates as I move through the list.

Clubless

[John *.?-!.* cub owner]

From my experience, from the first cubs up till about mid 48 had a weak spot and many cracked and leaked oil right where that crack is. ON later models the problem was not near as bad.

[Bob McCarty]

The picture looks like there is a crack above the right tower clamp.

[Clemsonfor]

The picture looks like there is a crack above the right tower clamp.

I think that one could just be in the paint?

[Dale Finch]

The picture looks like there is a crack above the right tower clamp.

I think that one could just be in the paint?

The paint doesn't look thick enough to show a crack like that.

[Glen]

Hi,
Half way up on the 75 lb oil gauge isn't terribly high oil pressure.

The Cub and LoBoy service manual says a Cub engine has 35 lbs of oil pressure, that is probably for a new engine.
The oil pressure may be less when the engine warms up.

The oil filter cover bolt may need tightening, or the cover may need a new gasket, or a new sealing washer under the bolt head.
One or more experts on here have said the paper gasket for the cover works better than the rubber gasket.

The oil pressure regulator valve should be free to slide in the bore it fits in. Be sure to put it in with the spring going into the hole in the one end of the valve.

[Barnyard]

The picture looks like there is a crack above the right tower clamp.

Good eye Bob! That ear is about ready to break off. I would not spend a dime on that motor.

crack.jpg (8.52 KiB) Viewed 395 times

[Clubless]

Geez…I guess my “to do” list has come to an abrupt end !!

[Cubfriend]

Seen a couple broken like that in the past. Not the paint!

[coppersmythe]

Geez…I guess my “to do” list has come to an abrupt end !!

Good morning from the sticky , hot , deep south . you may not be too quick about "abandoning" her . i would not put a loader or snow blade on her , or go across a freshly hilled garden "sideways" in second gear . But, with the other cubs in your stable , you have options . i had a very similar cub , and used for several years to cut grass . strong compression , 35-40 lbs. oil pressure , the repair looks good , like a gusset . and, i wonder how long that crack was there , 50 + years ? SPEND BIG $$$$ ON HER ? NO . Just put her on light duty .just my 2cents and experience with mine . coppersmythe..................PS: engine brace ??

[Glen]

Hi,
You can buy a used engine block at J P Tractor Salvage, at the bottom of the page.

People on here have talked about them, they have said they have good service.
The experts here probably know more about them than I do.

[Clubless]

Does Berlin still make his engine brace? Really don’t want to give up on this cub yet.

[Don McCombs]

PM him. His user name is bezirk.

[Clubless]

PM sent to Bezirk

[outdoors4evr]

Why not have it welded? Seems worth a try.