Engine displacement from casting numbers

[RonJ]

Hours of internet research has not provided a definitive answer.

I am interested in learning what engine size is in my car.  
I was told it is original but some points made in another topic lead me to question that.

It is a Canadian car with Dodge emblems.  The ID plate says Model D25C.

The engine number indicates it could be from a 1940 Plymouth (but says 23”) based on documents and the Allpar website, Flathead Six and other groups and forums.

I will remove the plug on #6 as suggested to determine the stroke but the diameter of the bore will be still be a question.

Can the actual engine be determined from the casting numbers below?

Stamped P10C6262

Above the starter 666029

On the head -K158   1139403

On the block A307

On the manifold 1116291

 

 

[rallyace]

A P10 motor would be 201 cubic inches. They had standard overbores and I think the max was 0.060" which would not add much to the displacement.

[Los_Control]

 

56 minutes ago, RonJ said:

Text removed .... Sorry was meant for another thread 

Edited December 23, 2022 by Los_Control

[RonJ]

Thanks.  And here I was thinking I had the powerhouse 230 cu in.

At least this one runs quite smoothly.

[andyd]

The problem you might have is that while the engine might be stamped "P10" if its a Canadian built car then rather than the 23" engine with a 201 cube engine it maybe a 25" engine as Canadian built cars were supposedly all 25" engined cars and therefore be a 218.8, 228 or 250......measure the head length and check the stroke via that plug over # 6..........andyd 

[RonJ]

This morning proved that someone has been down this road before.

The engine for sure is 25”, however the plug above #6 is either stripped or is an odd size.  A 3/16” Allen wrench just spins and a 7/32” does not go in the opening on the assumption it was an Allen head.  I’ve listed the casting and serial number in the flat head forum to see if anyone may know more or have a Canadian cross reference.

[Sniper]

It might be metric.  The bleeder fittings on my rear brakes use an 8mm wrench but have SAE threads, go figure.  I found this out when I went to replace one because the hex was rounded off and my SAE wrenches wouldn't work. 

[RonJ]

That’s interesting.

I’ll try it, but likely I’ll have to trim an “Easy Out” to the right diameter and insertion depth but may not go through the trouble at this stage.  I have been given some detailed information on the Flathead Six Facebook page.

The summary is that it is likely a 218.06 cu in. from a 1940 Plymouth.

[RonJ]

Just for reference for those that may find this thread in the future.

It is not the spark plug that is being referred to.

The plug is above #6 cylinder is located as shown by the pencil.

Unsure of what the original purpose was.

[RobertKB]

I own a D25 which is the Canadian 1946-48 Dodge. If the engine is original to the car it is a 218. The engine serial number should also start with D25. 

[keithb7]

A Canadian 25" long 218 ci engine This is 3 ⅜" bore x 4 1/16" stroke. Be aware that this is a very different engine than the USA 23" 218 engine. The USA 218 is 3 1/4' bore x 4 ⅜ stroke. 

[Sniper]

1 hour ago, RonJ said:

Just for reference for those that may find this thread in the future.

It is not the spark plug that is being referred to.

The plug is above #6 cylinder is located as shown by the pencil.

Unsure of what the original purpose was.

 

the original purpose was to set the timing. 

[RonJ]

Makes sense.  Never would have thought about using #6 instead of #1.

Now I really need to work at getting that plug loosened, just in case.

[keithb7]

If you look at #1 you’ll see the thermostat and related parts are in the way of where a timing pin hole would sit. 1 and 6 are in the same position of crank throws. So they put the timing pin above 6, where it could sit easily. 

[RonJ]

Very informative.  I’m learning every day.