I think the engine in my truck is an 81A...

[third_edition]

My new pickup needs an engine overhaul and my first challenge is to pull out what I believe is an 81A 221CI (not original).

It has a 3spd transmission, and a closed drive train (although I was told it is not original - for that matter the chassis and running gear were all swapped out - I think they put car parts in).

Question #1: can the engine and transmission be pulled together and is there somewhere I can go for step by step instructions?

Question #2: this is not the original engine - is it worth spending the money to overhaul? Flathead parts (blocks especially) are fairly rare up here in the great white North. I know I need to have it inspected for cracks, but can it even take an overbore (and if so what would the max be)?

Your comments would be appreciated.

Thanks,
George

[rotorwrench]

The 81A 221 CID engine would be 1938 up to the start of wartime changeover to military production in early 1942. I assume your vehicle is somewhere in that era but you didn't indicate that. There is nothing wrong with the 81A and since it is a 24 stud variant with the later in block water pumps, there is a lot of interchangeability with 239 CID and post war 59 series engines. Up until 1942, the passenger cars and commercial pickups shared pretty much the same drive train and frame with exceptions in 1941.

The condition of the engine will determine whether it is worth performing an overhaul. Some of the Canadian manufactured stuff is a bit different than the US manufacture but the 81A may be US manufactured too and most stuff is interchangeable. Most of the Canadian stuff had a C in the part number prefix so you can tell where it's from.

There are shop manuals available and each vehicle had an operator's manual which are reprinted now. There is a good shop manual available that is based on the Canadian wartime manual and it is very good but we need to know what year of vehicle you have.

Welcome in to the Barn.

[flatjack9]

What year truck do you have and what makes you think it is an 81A?

[ford38v8]

From your public profile, I see that you have a '39 1/2 ton pickup. The chassis and running gear for your truck is the same as for a passenger car of the same year, with the possible exception of some minor parts carried over from the previous year, as was sometimes done with commercial vehicles. The internals of the transmission are one place that you may find to be an earlier part: A quick check of the large fork within the shift tower will reveal either the much preferred 91A number, or the earlier 81A number, which would have an inferior synchromesh. I assume you found the 81A designation on the heads, which would be the only place you'd find that number, and would be correct, although it would not by itself identify the engine block as being correct. If your truck has a differential from a car, it may also have a lighter rear spring, and in fact, your whole drivetrain may have originally been the optional underpowered 60 hp engine, coupled to a 4.44 ratio differential. You may now have the preferred 3.78 ratio differential? Your hubs would originally have been wide 5, which, with hydraulic brakes on cars, would have only been available in 1939, though carried over on light trucks, as was the closed driveshaft.

[flatjack9]

Some of these engines had 81A cast in the bellhousing, but probably would not be visible in the chassis.

[Mike in AZ]

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welcome to the 'Barn....got pics??...lol....Mike

[jetmek]

That sounds like the right engine for a 39 My response to question 2 is that if the block is not full of cracks or bored to 060 then its worth investing in...I don't like to go over 060 bore on those as the cylinders are thin and if its already there sleeves is an expensive solution.

[third_edition]

Thanks for your advice, I have some pictures which I will upload this evening.

George

[KGS]

Are the exhaust manifold ports are extended away from the block about a 1/2 inch? That was a feature of the '38 to around '40 or '41 (24 stud) blocks. After that, they were flush with the block.

[flatjack9]

Many of these engines had the thin steel sleeves. It was common practice to knock them out and bore to 3 3/16.

[third_edition]

These are the best photos I have (I took them the day I picked the truck up). It is blocked in by snow right now, which is why I am planning my next steps to get it back on the road...

[third_edition]

I'm not sure the pictures will be very helpful, I suppose I need to pull it and disassemble to get a better idea of what it is.

[hotrodA]

The 59AB in my 32 looked the same, so I decided to start pulling it apart one piece at a time, oil pan first. Surprised to find no sludge, and spotless bottom end. Next the intake manifold, and it was the same, with new lifters and cam. Pulled the stuck waterpumps and the water jackets were spotless. New pumps, fired it off and it runs cool with great oil pressure. Moral to the story, looks can be deceiving. It might run.

[Barlea]

That's a Ford Canada 81A, lots of those in Canadian post-war trucks and cars as a smaller option because there were no six cylinder options until '56.

[third_edition]

Another question... was the 239CI used in Mercurys starting in 1939 a different casting or was it the same casting only bored out to 3.1875? Would this engine take an overbore to 3.1875 (239 CI)?

[flatjack9]

I'm sure there were internal changes to the cores.

[Kube]

Originally Posted by third_edition

Another question... was the 239CI used in Mercurys starting in 1939 a different casting or was it the same casting only bored out to 3.1875? Would this engine take an overbore to 3.1875 (239 CI)?

Different casting. However, they appeared nearly identical externally.

[rotorwrench]

I believe the Canadian 99A engine blocks have a raised "99" cast into the block on the front right side. The ones made in the US had "99" stamped into a deck surface but only on some. I think the stamping stopped completely in late 1940 or so.

[third_edition]

Thanks to all for your advice and comments, I will post my progress and I am sure I will have plenty of other questions

[91A-77B]

Where are you in Ontario? I'm in Paris,ON and can offer you some help, if you want to call. 416.886.3454. Bill