VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 engine block cracking 1939 chev

hi all
how common is it for the engine blocks to crack at the back behind the push rod cover it run horizontal just behind the lifters about 2 cylinders long to the front of the engine
do these engine suffer from cracking should I look for a newer 235 block as this ones no good thanks tony

My '39 block cracked on the left side. Did it while on an extended trip. When I broke out the side of the block with a hammer I found it full of rust packed in to the level of the crack.
It may have been frozen at one time causing the crack to start or just from the heat and rust.

"In the good old days," welders would repair the cracks in cast iron parts. The exhaust manifold on my car was welded back together by a CRAFTSMAN with many years of welding experience. I had cleaned up the manifold and painted it with a coat of POR 15 manifold paint then hung it to dry on a ceiling hook. The next morning I found it in two pieces on the floor. The coat hanger, I used for wire was not attached well enough for the weight. The weld has held for over 10 years and hardly noticeable.

Today you would need to find a welder specialized in welding cast iron, not so common. The block would require a thorough cleaning and professional checking for additional cracks before spending the money on the welding. Here is a link to previous discussions on this topic.

Engine Crack

Good luck, Mike

hi all I have found some more blocks can someone please confirm numbers for me I believe I have 2 1937 blocks number
stamped by pump r93995 cast on block 1788201
also another block cr81377 cast in block 1788201
and I think this one is a 39
stamped by disturber r1991022 and cast in block 838957

is one block better than the other I would like to use the 39 block as its a 39 chev but if the 37 is a stronger block I would look at using it
can I use the 39 head and push rods on the 37 block and the 39 valve springs and leave the extra springs by the lifters off

also still quite keen to learn about the newer engines is there one that is better to use than others some of the guys reckon that one of the truck 235 engines were good to use as they revered higher thanks tony

The first two are 1937 blocks. The one with the R prefix was from a right hand drive car and the one with the CR prefix was from a right hand drive light commercial vehicle. The 1788201 casting number was used on Canadian blocks for 1937.

I think you are right on the other being a 1939. The serial number is in the correct range for 1939 but I don't have a record of the 1939 Canadian block casting number.

Tom

If it is a 1939 engine it will have a single bolt holding down the vacuum advance and it will be more or less in line with the stamped number. The 1937 and 1938 used two bolts. The info. I have lists the block casting number for US and Canadian as 838941.I find no record of your number but if it has no rear main bearing seal it is a 1939.

Tony,

As no one answered your question about the 235, let me have a stab at it.

If you can find a 235 in the 1958 or 1959 year range, it is my understanding that they are about as good as it gets.

Gene, or someone else can attest to the merits of those engines over the 1954 to 1957 ones. Although the differences may be minor, still there are some.

If you are going to rebuild your 39 engine, I wish you were closer to me because I have a NOS 1939 crankshaft that you could have free of charge. To send it to you would be prohibitive owing th the high cost. It would cost $100 US to just send it to Arizona.

Good luck to you whatever your decision becomes. I would opt to stick a 235 in the car. BIG improvement.

Best,
Charlie

thanks all for your replays and offer of a crank I have spoken to the person who does my engine overhauls and we will go with the 39 block as we should be able to use a lot of the parts again as this engine has only just been overhauled which could be a big saving and I will look out for a 235 block just incase it happens again they can be hard to find over here

Chevgene if I were to use a 37 block would I need a 2 bolt 37 disturber or would a 39 fit I could block one hole off thanks

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The 1937 and 1939 distributors are the same but the vacuum advance and the bracket below the distributor is different.