A1 displacement

cstaup · Unread post by **cstaup** » January 8th, 2008, 6:18 am

What is the displacement of a Mutt engine. I keep getting this question and have no answer.

Horst · Unread post by **Horst** » January 8th, 2008, 7:15 am

We just have had a good discussion in the mod section about the manufacturers of the 151 engine. Seems like two companies are referenced, Continental and Hercules. Why there is no reference to Ford being the designer of the MUTT is still at least for me a surprise. I have seen information that the 151 engine design was developed further from some civilian Ford engine available in the 60ies. We all agreed that a lot of information is just copy and pasted between different web sources and even books, even if the information is not verified for being correct or not. Therefore any information on various web sites have to be taken with some grain of salt, I would only believe either a TM or a company information (like the AM General sales brochure for the M151A2)

The displacement should be 141 cu-in. Actually the AM General decal for the M151A2 says 141.5 C.I.D. The horse power rating seems to dial in at 71hp at 4000rpm or 65hp at 3500rpm.

For the engine I have installed, I do have the dyno sheet from the rebuild, unfortunately it is only showing % of rated hp, not the absolute value.

Spike · Unread post by **Spike** » January 8th, 2008, 10:10 am

The first engine was called a Ford L142 (rounding up the 141.5) it was made by Ordnance Continental. There is limited information about this, as Horst noted cyberspace (mis)information perpetuates and is often recycled regardless of the accuracy.

The Hercules has a Maximum BHP rating of 65 @ 3500 RPM

113lbs of torque @1800RPM

141.5cid

The actual horse power would translate into about 55HP (using the WAG formula)

The bore and stroke is 3.875X3

The statement: "The horse power rating seems to dial in at 71hp at 4000rpm or 65hp at 3500rpm." Sounds logical, but being a numbers guy this didn't add up to me (or calculate across in a linear equation

). Someone is thinking of their high school physics; horsepower = rpm x torque / 5252 ... But it doesn't jive and there is a ceiling. So, I went to the source and got the above captioned data from Hercules.

Rainman · Unread post by **Rainman** » January 8th, 2008, 10:30 am

Thanks for all the info guys. All I have to add is that my M151A2
is stored a few hundred yards from a Hercules Engine plant in
Massilon, Ohio. Not sure if they'd have any old information, or
exactly what they do these days, but I beep the horn every time
I drive by. Next time I'm down there an they are open, I'll stop
in and ask a few questions.

Rainman

Horst · Unread post by **Horst** » January 8th, 2008, 5:30 pm

Spike,

Thanks for correcting me. After a second thought it would not make sense to an engine manufacturer to NOT give the maximum horsepower rating. What is still possible of course I would think, that the almost same engine in a 151 with different carb jetting (and/or cam) would make the 71hp. Meaning that the standard catalog engine from Hercules is slightly different to the 151 application. Especially as we know that this engine was used in different applications (Hawk missile loader, generators,...). But to be clear, this is speculation.

What I do certainly think is that my M151 feels much more powerful than my M201 with the Go Devil. More than 5hp difference, but that's again an opinion :)

A1 displacement

A1 displacement

engine info