What do i have here...21-stud hybrid ?

[flatheadmurre]

So what do i have here ?
Some kind of later replacement block ?
It has the early front that will pass a pencil test.
Later exhaust outlets that are not sticking out a lot.
Raised intake deck.
I have bored it 3 3/16 and it has a LOT of meat left...i think it would take .125 more and be .100 left in the walls...have to ultrasonicly measure it.
Looks like a hybrid replacement to me...would be great if anyone can verify what it is and year of manufacture.
The 2 blocks in second picture is one normal -37 left and the odd 78 block right.

[deuce_roadster]

Are you saying the "odd" block has 21 studs and a "raised" intake area? If it is a 24 stud block I would say it could be a 41 Merc or perhaps made in Canada. I have never seen a block with 78 on it. I think might be a later block and miss-marked as 78. I see there is a pad for drilling into the oil galley.

[flatheadmurre]

21-stud raised deck.
Front that pass the pencil test but sides of a 239 engine.

[ford38v8]

1937-1938 was the last 21 stud for production motor vehicles. As Service Replacement short blocks continued to be needed for all pre-24 stud needs, these last 21 stud engines did continue to be manufactured for some time after those model years. Your block may be one of those manufactured as a short block service replacement. The block part number prefix was 78.

[flatheadmurre]

I thought it might be some later replacement...and if it has the cylindercores of a 239 as the sides indicate i will bore it 3.312 stick a merc crank in it and outrun the 24-stud boys

[Brian]

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Sorry Murre, 3.312 won't go; that bottom stud is in the road...
I've had one of those blocks, another feature is they have no freeze plugs in the pan rails. I am of the opinion that these were of wartime manufacture, the boss for that third oil port is normally drilled, tapped and spot faced....

[flatheadmurre]

Brian you´re probably right about wartime production since they came with thoose heads with the firing order cast into them.
Stud in the way and can´t be done...sounds like a challenge to accept

[Yoyodyne]

Originally Posted by flatheadmurre

Brian you´re probably right about wartime production since they came with thoose heads with the firing order cast into them.
Stud in the way and can´t be done...sounds like a challenge to accept

I'd love to have a block like that.


I'd plug the hole and move the studs .100. and do the same to the heads (or get aluminum heads specially drilled).

[Fordestes]

What is available as for gaskets with a extra large bore 21 stud?

[Yoyodyne]

As far as I know, the only answer is to punch a few extra stud holes in a 24 stud gasket.

[Brian]

I 'think' these blocks have a high nickel content too; I bet the water jackets are real clean- not all scaled/rusty?

[rotorwrench]

It looks like universal carrier engine. Some of these ended up in the English Ford cars after the war like the Pilot.

[Brian]

Pilot is a totally different casting, most easily recognised by the freeze plugs at rear of block.

[flatheadmurre]

I have pilot engines here to they have an extra hole for for holding the cores and thoose odd rods with 8BA style bearing inserts...but i can imagine ford used whatever they got to get production started.

[frnkeore]

Here is some original Ford dimensions that you can do the math from.

The center to center distance of center of the bore, to the center of the lower stud is 1.937.

The distance from the center of the bore, to the outside of the casting is 2.31.

Now, if they did use 24 stud cores, you could bore it 3.312 but, if they used 21 stud cores, the outside core diameter is 3.38.

[flatheadmurre]

Forgot to say it was a 3 1/16 tincan sleeve engine from start.
I will get back with ultrasonic measurements in the evening.

[rotorwrench]

Dagenham production likely was different than Canadian production at the Windsor plant. The 221 engines were used longer than in the US but they likely stopped production after the war. Ford USA made the 24 stud blocks after early 1938 and they never went back. When you see that oil port boss above the normal twin port boss on the back of the engine, it's generally of military origin or post war. The universal carrier dates back to before the 78 series engine production and I'd be sure that some were manufactured with the 78 series 21 stud engines.

I don't know about the Koln production or the French production but you can usually tell if they come from either of those sources.

[Graeme / New Zealand]

Originally Posted by flatheadmurre

I have pilot engines here to they have an extra hole for for holding the cores and thoose odd rods with 8BA style bearing inserts...but i can imagine ford used whatever they got to get production started.

C69A Canadian blocks had the 8BA style bearing inserts, I had one in my early 47 coupe. I remember seeing Pilot engines with the firing order cast on the heads.

GB

[flatheadmurre]

So i finally got time to measure the cylinderwalls and it´s not a regular 37-38.
Neither is it as thick in walls as a regular 59AB.
So my question is since this started as a tincan sleeved engine...did they come with thicker walls to compensate for the .083 bore when sleeves was removed ??
Date code on block says it was made -41.

[Ol' Ron]

Having worked in the machine tool industry for quite awhile. I can tell you that the engineering department of most companies are far ahead of the production items, such as blocks, in this case. At the Bullard co. The casting of experimental modifications of existing machines , was an on going process to improve the product. I assume the automotive industry did the dame. Most of these experimental "stuff" never sees production. However, when casting experimental cylinder blocks, a few may get into production just to us up the extras. Just like the shell molded crankshafts.