No engine serial number

[muleboss]

I have a cub engine that does not have a serial number.
Known about engine- Mfg 9-11-K
Firing order numbers very crude. Could probably not read first 2 numbers if I did not know what they are.

Casting number on block-355741 R6
# 2 stamped in block above 3rd pan bolt on left side (as sitting on tractor)
Letter "L" just left of oil filler (dipstick)
Front cover- 651 674 R1
Oil pump cover- 251398 R1----L IH 7

I do not know what year this was suppost to come from.
I bought it in a pile of a tractor that was in many pieces.
Was told the engine had been replaced and this was original to tractor.
Can not tell you any other parts numbers from tractor as it was parts and I do not know which ones they are.

Question is, Why no serial number on engine.
Thanks Bob

[Eugene]

Don't know the answer.

I have a NOS engine block, Casting code 5-16-X, with no serial number. This one came from someone who purchased several crated NOS engines from military surplus.

[RaymondDurban]

Engines with no SN's are replacement blocks from IH. Only complete engines were stamped with a SN. Your engine was replaced at some time in the past, with the internals swapped over.

There are many around, here are two that were at last years OK Cubfest.

[muleboss]

Raymond, Thanks for the answer. That would mean that cub has had 3 different engines.

[RaymondDurban]

I have a cub engine that does not have a serial number.
Known about engine- Mfg 9-11-K
Firing order numbers very crude. Could probably not read first 2 numbers if I did not know what they are.

Casting number on block-355741 R6
....

Bob, I did a search on the forum for the 355741 block PN and yours was the only hit. I have a question for you about the block, hopefully you still have it.
Was/is the PN raised cast lettering or was the original PN ground off and then the new PN stamped into the cast?
Did the engine have an extra casting in front of the oil filter housing to accept a plug into the water jacket?
Thanks!
Raymond

[muleboss]

Raymond,
Yes the numbers are raised, as they should be,
Yes there is a plug in front of the oil filter housing.
Bob

[brewzalot]

Raymond or Bob,

I have a 61 cub ( 218968) with all correct casting numbers(G) except for the engine-I will get them all to you for the database. I too have a plug in the casting by the oil filter and no serial number. The block part number has been ground off, I think , and then stamped 355741R1. The engine date code is 4*18*W, can you tell me what I might have or what year that may be?

thanks,
Tim

[RaymondDurban]

Tim,
You have a 1951 U-1 power unit engine installed in your tractor. The reason that yours and several other members here on the forum have these same PN engines that have the SN ground off is a mystery it seems.
Thanks for the data, and I'll take the rest of your information any time!

[brewzalot]

Can you tell me how you determined its a 1951(w) and not a 1973 (w) year block? Am I reading you correctly that my 355741R1 PN is only the second one you have come across, all the others are 251341R_ ? Or did I miss a thread somewhere? Always curious about the history of things.

Also, I can not send a pm for some reason, would you know why?
thanks-tim

[Barnyard]

Can you tell me how you determined its a 1951(w) and not a 1973 (w) year block?

Tim, a 1951 block would either be part number 251341R2 or 251341R3 . The part number for a 1973 would be 251341R8. There were changes made to the blocks over the years and ech time there was a change the number after the "R" would change.

[RaymondDurban]

Can you tell me how you determined its a 1951(w) and not a 1973 (w) year block? Am I reading you correctly that my 355741R1 PN is only the second one you have come across, all the others are 251341R_ ? Or did I miss a thread somewhere? Always curious about the history of things.

Also, I can not send a pm for some reason, would you know why?
thanks-tim

Tim, there are two clues that gave me the information needed to determine that your engine is from 1951 instead of 1973.
First, all U-1 and later the UC-60 power units used the 355741Rx part number blocks. Production of the U-1 began in 1949 and ended in 1957 when IH changed the designation to the UC-60. The UC-60 power units then ran through at least 1971, but admittedly may have gone on for a short time longer.
Second, your 355741R1 with a W cast code could only have been made in 1951 because of the R1, as by 1952 the blocks were already in R4 revisions.
I have come across a few more 355741 blocks, and plan to release that information with the next database update. The 251341Rx part number blocks were used in the Cub and LoBoy tractors as well as the balers and combines.

[brewzalot]

Thanks for clearing that up for me, its great to see the patience you have for the new guys.
tim

[RaymondDurban]

No problem Tim, glad I could clear things up for you!

[brewzalot]

I noticed the number Z 577 stamped into the block on the ledge right behind the exhaust manifold (by the #1 piston) on my 1951 U1 power unit mentioned in this thread. Does anyone know what that number is for or refers to ?

Tim

[RaymondDurban]

I noticed the number Z 577 stamped into the block on the ledge right behind the exhaust manifold (by the #1 piston) on my 1951 U1 power unit mentioned in this thread. Does anyone know what that number is for or refers to ?

Tim

Tim, I'm having difficulty picturing where the numbers are stamped on your engine. The #1 piston is by the fan, the #4 piston is buy the touch control. The normal engine SN is by the #4 piston, stamped into a flat spot on the casting. Is this where you are seeing the numbers? Can you post a picture of what you are seeing?