Allison V-1710-C15 Engine Number Location?

[Mr.ModelT]

Hi All!

Haven't made much progress yet on my Allison reactivation as it is put away for winter, but I have a question that has been on my mind for a while, and I have yet to get a complete answer. This is of course nobody's fault and those who have helped have been tremendously helpful thus far.

I'm trying to pinpoint the exact location of the Engine (production) number on my C15 series engine.

All 2,551 C15 and C15A series engines produced before the war in 1940 - early 1941 where each being hand stamped with their production number from Allison (Also matching the engine number on the ID tag). Once the War started, this was quickly abandoned.

I received a few leads to clear up the vague descriptions I had read in the past, but Dan Whitney offered the most detailed location description, thought he could not pinpoint it for me exactly. He insists that number was stamped "On the upper half of the block/Crankcase, in the Vee between the cylinders, up near the Gear Reduction Case flange towards the front of the engine":

I have asked if there was an exact location or a photograph of a known number on a surviving engine (Like Engine #899 / A-200012 which now resides in airframe 41-13297), but cannot find anything definitive.

I have scoured my engine and cleaned in this area as best as I can and so far, I have not found it. I could be skipping over the top of it, but I just don't know exactly where I need to be looking. I fear that it may have been wiped out by this weld repair done by the Army at some point during the War:

This Number appears on the top of the Gear Reduction Housing but does not line up with this engine or correlate to any known C15 that is not already accounted for.

This was originally Stamped "505", then later over-stamped "605".

I know it is likely a longshot, but does anyone have any more detailed information (or photo examples) of where the Engine Number SHOULD be stamped?

~Mr.ModelT

 

[MiTasol]

There are several internal locations for the engine serial (like on every bearing half) but they will be no use to you.

The only other external place I know of is on the engine data plate which is presumably is missing from the left side between the mount pads.

You could try asking the NASM or the Museum of Transport and Technology (MoTaT in Auckland NZ) for photos of the serial as they both have a C15.

 

[Mr.ModelT]

There are several internal locations for the engine serial (like on every bearing half) but they will be no use to you.

The only other external place I know of is on the engine data plate which is presumably is missing from the left side between the mount pads.

You could try asking the NASM or the Museum of Transport and Technology (MoTaT in Auckland NZ) for photos of the serial as they both have a C15.

Thanks so much for your reply!

Yeah, these engines are loaded with different SN#s, but none really mean anything about the engine.

Sadly, you are correct. The tag is missing, stolen off this engine likely to complete another engine about 25 years ago. I'm trying to "back door" a production so I can positively ID it.

To get you caught up, this motor is one of the 624 C15s built and delivered to the US Army Air Corps in 1940 for US P40 production. Of those, I believe it was one of the 299 engines shipped to Curtiss-Wright for installation in a P-40B or C. Regardless, we do know for a fact it was one of the 140 engines (105 aircraft, 35 spare engines) shipped to Hawaii between January-April of 1941 and assigned to Wheeler Field. It was in an Airframe and one of the 56 active P40s sitting on the flight line on December 7th and was one of just 27 that survived undamaged and airworthy. I further believe it was one of the 17 aircraft that were ferried back to the mainland (California most likely) for training use in January 1944 as it was still flying in June-July 1943. It's return to the mainland would be the only way for it to easily be available to send up to my High School in late 1944 and spend the next 50 years as a study aid.

I would like to learn it's history, what airframe it was in, and how it got to my High School between January-September 1944.

Contacting the NASM in DC is a great start. I will reach out to both NASM and the museum in Auckland.

 

[MiTasol]

I just remembered that on the later engines the serial is also stamped into both crankcase halves near the rear engine mount. This may also apply to the early engines.

I also just remembered that GregP has some fairly recent Allison overhaul experience and may be able to provide other locations. I should have linked him in earlier. I must be getting old (shudder).

 

[Mr.ModelT]

I just remembered that on the later engines the serial is also stamped into both crankcase halves near the rear engine mount. This may also apply to the early engines.

I also just remembered that GregP has some fairly recent Allison overhaul experience and may be able to provide other locations. I should have linked him in earlier. I must be getting old (shudder).

View attachment 873068

You might be right! I'll check this weekend, see if there is a Serial Number there!

 

[Mr.ModelT]

I just remembered that on the later engines the serial is also stamped into both crankcase halves near the rear engine mount. This may also apply to the early engines.

I also just remembered that GregP has some fairly recent Allison overhaul experience and may be able to provide other locations. I should have linked him in earlier. I must be getting old (shudder).

View attachment 873068

So, I finally had a chance to inspect for a serial in this location and there is "a" number, but I'm not sure what I'm looking at.

It is stamped (what looks like) "24Q9", but could also be "2409" .

I went through my C15 Serial Number list and the Master V1710 Serial Number list and there is no "2409", "249" or "24Q9" (which is not a valid Serial Number format).
I also sent an email to the NASM about confirmation about locations of stamped Serial numbers on early blocks.

 

[MiTasol]

Just for interest what is to the left of the weird number and ends in N?

'N again?

 

[Mr.ModelT]

Just for interest what is to the left of the weird number and ends in N?

'N again?

Here is a better version. When I cropped it, I guess I cut it off.

Looks like "IN" "24Q9 IN" or "2409 IN"

Maybe "Inspected"?

 

[MiTasol]

Thank you. Inspected would typically be a smaller stamp with a surround. So long since I saw one I cannot remember what it looked like.

 

[Mr.ModelT]

Thank you. Inspected would typically be a smaller stamp with a surround. So long since I saw one I cannot remember what it looked like.

I'm guessing you are thinking of this mark. They are all over this engine..

 

[MiTasol]

Yes - that is the one. Heat treated parts have an additional stylized HT in a surround as well.

 

[Mr.ModelT]

Yes - that is the one. Heat treated parts have an additional stylized HT in a surround as well.

I've seen those as well on one or two things if memory serves. Still confused on the "Serial Number" I found. I'll see what Dan Whitney has to say.