Engine ID

[RichardS]

I have what I believe to be a competition motor of indeterminate age. The engine number reads 11013 which from the available data suggests pre-1950 16M and not competition. However, it has a through-bolted alloy cylinder and at that date only comp. motors had through studs and alloy barrels, the stud pattern doesn't match an iron cylinder so it's not had long studs added later. There is no date or model stamped on the case, which was normal, but a possibly spurious JCM1 in clearly different text also stamped on the case.

The crank may be original or may be (significantly) modified by someone as it appears to be lightened and balanced - possibly by JCM whoever that was. The surface rust is actually nowhere near as bad as it appears in the photo, digital cameras seem particularly unforgiving.

I'm not actually bothered, I'll use the motor in something of a bitsa so originality is not my concern, but everything about the motor is 'odd'.

Any thoughts?

Richard

[clive]

The engine number does not look to be from the factory to me.

[RichardS]

The text position, size and style (font) of the 11013 is consistent with other cases I have from '51 so I could believe that much is original, but the absence of a year and model is certainly strange. The fact that there is no sign of the cases being filed or ground to remove any stamping suggests it's 'original' in the sense that it's not been changed, the surface is very obviously virgin as-cast surface.

I guess if someone bought replacement cases at some point they would have come from the factory un-stamped and the buyer might then ahve added their own numbers - possible?

I have a set of '59 cases too and the stamping is competely different, a good deal smaller and a different font and all crammed over to the left half of the case. I guess stamps wore out and got replaced and I doubt the factory were particularly worried about details like that and maybe the guy with the hammer had his own set and preference for positioning.

[Joker_Bones]

Is there any evidence that the cases have been modified to the through stud pattern?
I have a set of road model model G80 cases that have through studs to suit an ally barrel... but you can they have been worked on to move the holes.
Dick Casey has a video on YouTube showing it being done.

[RichardS]

Is there any evidence that the cases have been modified to the through stud pattern?
I have a set of road model model G80 cases that have through studs to suit an ally barrel... but you can they have been worked on to move the holes.
Dick Casey has a video on YouTube showing it being done.

Hello Joker-bones, that's a fair question, but No, very definitely not. It's one of the first things I looked at/for.

[Joker_Bones]

I have a short stroke 350 competition engine. The engine number has no date or model just four digits and like yours in the correct looking size and font.
The fella I bought it from said it was a works engine, but I put that down to something someone selling it might say
I guess we'll never know.
Yours is a long stroke engine?

[SPRIDDLER]

I have a short stroke 350 competition engine. The engine number has no date or model just four digits and like yours in the correct looking size and font.
The fella I bought it from said it was a works engine, but I put that down to something someone selling it might say
I guess we'll never know.
Yours is a long stroke engine?

As an aside and it may be irrelevant to this discussion, but I've read in one of the nostalgia/biographical books or the Archives or heard from an ex-AMC employee that the factory supplied some dealers with blank (un-numbered) c/cases.