Harrison Oil Coolers Used on Early Trans-Am Camaros

[OCTARD]

Harrison oil coolers were used on several early Camaro Trans-Am cars, and were available over the counter at GM dealerships.  Well, these oil coolers were also used on many other GM race cars, including Corvette Grand Sports, many of the Can-Am competitors, Formula 5000 cars, and on numerous non-GM cars and engines as well.

The GM part number seen and quoted most often for the Harrison oil cooler of choice is 3157804.  Much of the "How to Hotrod" manuals and other sources from the late '60s and early '70s note something to the effect of them not being ready to use as is. They further specify that these coolers need to be cut apart and modified so that the oil flows into one end of the cooler and out the other.

The first pic attached shows a 1978 dated, 3157804 oil cooler that I have.  It flows from one end to the other.  From the plating wash that exists on the whole unit, it would seem that it came this way new.  If it didn't, someone took the time to dip/plate it as per original after the modifications.

The second pic attached shows quite a lot of original Harrison oil coolers, mounting brackets and other hardware that were offered on an eBay auction several years ago.  Note the various ends and fitting provisions on these 3157804 oil coolers.

Does anyone know if Harrison/GM ever offered these oil coolers with the flow (and fitting provisions) going from end to end?

-Chad

[Bruce302]

Those are very neat, but I have also seen the version with the bolt on removable top plate, and even a Holman Moody version on the Smokey Yunick Camaro.
I believe some are adapted from aircraft use.

Any details on those ?

Bruce.   

[Jon Mello]

Chad,

I have seen several of these 3157804 Harrisons that went in one end and out the other but I had assumed they had been modified by an owner. Like you, I had read the comment in "How to Hot Rod..." about how these were not adequate without making them a cross-flow design but my race car ran in Trans-Am with the 3157804 with the inlet and outlet on the same end and they never had a problem. I have seen a picture of the Bud Moore Cougars with these same Harrisons mounted in them. It would be interesting if we could figure out if Harrison did make a factory modification to them.

[Jon Mello]

Chad,

Robert Lodewyk sent me these 5 photos of an NOS Harrison oil cooler that he owns which is dated 1982, 5 years after yours. You can see that the inlet and outlet are on the same end. The '66 and '71 dated ones that I have are the same as this '82 version. The part number stamped on yours is the same as ours, which is strange if it was truly originally made as a crossflow design. Unless this was something GM did during a very brief run, all I can think is that somebody changed it.

[OCTARD]

Thanks Jon and Robert.  It's good to know that there were the single sided outlets after 1978. 

Jon, your note about these coolers most likely not being offered with outlets on each end is what I would lean towards as well.

I only asked the question because the alodine coating on this one cooler of mine seems fairly consistent over the areas of potential work... and the aluma-prep before alodin-ing would have taken off the ink stamps. 

Perhaps the person who did the mod of the cooler just spotted in the aluma-prep and alodine to preserve the ink, but that seems like a lot of care not normally shown for such a mod carried out long ago.  The fellow I purchased from wouldn't have cared, and he certainly didn't do the mod himself.

Oh well, it was worth asking.

-Chad

[Jon Mello]

You're welcome, Chad. We'll keep an eye out for another '78 dated one and see if that one is also single sided or not, just to be thorough with the research.

[klvn8r]

Just found this page of the forum....nice!  I've got a big/thick Harrison that came on the Buzz Dyer car....it has a Harrison tag attached to it, and I assume that it is crossflow too.  I'd like to I.D. it if possible....is there a website etc?  I think it was on the car when it was built in the mid 70s.  I'll get pics too.

klvn8r

[Jon Mello]

Show us some photos. I don't know of a website that ID's oil coolers but maybe somebody else does. Harrison made a bunch of other styles but I think they were made for airplane applications.

[klvn8r]

Here's a start....the tag on it is HARRISON  Part # 8532262   Serial # DD-2631  "Core Oil Cooler".    This thing is pretty big and stout, and big fittings on one end only....we say "crossflow"....what say you?  We were joking that it was big enough for a helicopter or    I'll get some pics in here as soon as the batteries are recharged and my wife can download them from the camera.   I also took some pics of my brother's 69 A/S Camaro for y'all, along with my Racemark seat, and a pic of my American Racing T/A 70 wheels.

klvn8r

[klvn8r]

Thank you, wife, for loading pictures for me!  This is the Harrison that came on Buzz Dyer's car from the mid 70s.

klvn8r

[klvn8r]

Photo 2

[klvn8r]

photo 3.  Note:  one end has no provision for outlet.

klvn8r

[Jon Mello]

Wow, that's a big one. I do not recall seeing one like that before but Harrison made many different types and styles of these things. For some reason, GM specifically called out the 3157804 version (as seen earlier in this thread) as the one they recommended but that would not mean that was the only one allowable to use for Trans-Am racing. With the inlet and outlet on the same end, I would not consider it to be a "crossflow" design. Did you see the Racemark seat for sale on ebay?

[klvn8r]

I guess, "crossflow" wouldn't be the right term, but 180 degree or something like that.....it changes direction, how's that?   
I need to look up the seat.....I've got a picture of mine, but didn't get it posted last night.  Maybe tomorrow.  Thanks for the heads up!

klvn8r

[Bruce302]

Hopefully someone will have a pic of the oil cooler in the Edelbrock owned ex Yunick Camaro. It has Harrison oil cooler with a detachable top plate that has the threaded bungs in it. The top plate has a Holman Moody casting mark. There was also a factory plane top available, and the same style of cooler was also used in aircraft engines bolted straight to the block.

Bruce.