59AB with A head

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59AB followed me home last week . Trying to pice some history of this motor before I start ripping into it . I noticed it has A heads on the motor. Don’t know the reason
Does anyone know if there advantage . I thought A head would be lower compression . Would that head be from a 24 stud 221 Like a 40’

I get some time in this crazy world and pull the heads off

Stay healthy

 

[Kube]

An "A" head on your 59 series block will cause a lot of grief if they were not modified.
The valve to cylinder center line was increased for the 59 series blocks. Just slapping on "A" heads without modification will cause the valves to hit the cylinder heads.

Modified and installed has no advantage over the AB heads.

 

[alanwoodieman]

I have the KR Wilson tool to open A heads for use on 59A engines. Really is a broach tool to open up the valve chamber. Done this on two engines, as Kube said saw no noticeable change in performance-really they were done for looks

 

[rotorwrench]

The engines went into production in early 1945. As far as I know, they all had the same valve angles at introduction (late wartime change). I read a post by Bruce Lancaster where he stated that the 59A-6050-A (59A) heads had 77-79cc chambers and the 59A-6050-B (59AB) heads had 73.5-75.5cc chambers. This would indicate that the change was designed to give better performance with the more modern blends of fuel after the war. They should be interchangeable with any 59 series 239 block. Now the 41A 221 replacement block, I don't know. It may have had the 59 on the back but it wasn't the same block and the 239.

A person runs into problems using the old prewar parts like the big"A" head (81A) on the later post war engines.

 

[Kerk]

A friend had the "A" heads on a 40 he bought and when the car was taken for a long drive and it got up to operating temp. there was a ticking noise which turned out to be the Valves hitting the heads after finally pulling the heads which had been shaved. Replaced with a pair of std. heads and problem solved! Turns out another friend had the same problem and shared the info. kerk

 

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Im glad I posted . Lots of interesting reading , thank you all .Heres picture of the A head I pulled after work today .The picture Also shows a 59AB Head for comparison that has been milled

 

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Photo

 

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The motor was a freebie . A Friend was given the motor from a restoration shop . He talked to the mech. and said it was totally rebuilt before it came to the restoration shop. Well after totally restoring the truck it over heated. Change radiator., water pumps ,dissy . THe owner of the truck said stop and put in another motor .
After I rip it down I'm going to pressure test the block and go from there.

 

[G.M.]

Carpenter had truck loads of A truck heads from the
Canadian Government. They used them to protect the
new engines when they shipped them. I ground the A
off of the ones I received over 40 years ago and after
over 125,000 miles the engine still runs cool and doesn't
use any oil between changes. When the engine runs cool
it doesn't get as black, it stays at a very dark yellow. G.M.

 

[Tinker]

You can always mill a head to add compression. Till you mill it to much or it's been milled before. But that's a different discussion.

The 24 stud motor came out mid 1938. Yes they were 221's like the 81a and 91a. Not till the 59a they went to 239 in 1946.

Aftermarket heads for the 59a denoted A-B suffix relevant to engine banks. Interesting discussion.

 

[cas3]

since you have the heads off, and story's about overheating, i would get the block vertical, remove the water pumps, get a really long skinny screwdriver and scrape the bottoms of the water jackets. it should have been done at rebuild, but maybe not. i always say" rebuilt by who, and what did they do" . could be a bunch of crap in there, like this...thats one side, blow gun and vacuum cleaner sleeved down to fit inside.

 

[rotorwrench]

The 239 was introduced with the Mercury in 1939 as the 99A engine. You can put 59 series heads on the 99 series of engines but you can't put the any of the early heads on the 59 series 239 unless you cut the valve reliefs in. The 81A head was the first head used on the 99A engine but they changed to a purpose made head for them somewhere in 1940. They also had the 99T head for the optional 239 CID truck engines that were available on special order.

After the war, a lot of rodders used the Big A 81A heads for the compression ratio they gave but the deck coolant ports are different. The 59 series of heads have a better gasket design for cooling the rear of the engine and the 59 series heads had different coolant ports to work with that design. The left and right heads are interchangeable. Sometimes you find an engine with a 59A head on one side and a 59AB head on the other but I would want the 59AB heads for better cooling and better compression myself.

 

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Thanks for everyone input . I’m all ears .
Couple thing I notice after I pulled the heads , Valve pocket we’re cut . I’m going to use the AB heads I have when I reassemble . I will mill after checking clearance .

Next is for a motor that still has clean piston top there was no cross hatch and the bore was as shinny as chrome .
Going to try to make time to pull the valves today .

 

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Forgot to show you guy the surprise when pulling the head .