Chevrolet coolant condensor can

[Grant Bowker]

I measure the CMP can as very close to 6-3/4" diameter (including the rim, just because that is the easier dimension to take) and very close to 8-1/2" height (again including the rims) - so shorter and fatter than what the commercial reproductions. Getting into the detail, there is a difference in the water connection (as opposed to the central vent tube) on the bottom of the can between the cans made to mount on the cab side and those made to mount under the floor. In the attached photos, the underfloor mounted tank(s) is the one with the water connection on the side opposite the mounting straps so that the connection is (almost) at the low point of the tank whereas for the tank ponted on the side of the cab, the connection is closest to the cab and less exposed to damege. The can with dark green paint is the side of cab version, the others are the under floor version. The commercial reproduction construction more closely resembles the side of cab mounted CMP cans (both appear to have been mounted vertically rather than on an angle under the floor).

If only one version were to be reproduced, the one for use under the floor would probably be better (less volume of water sitting in the can at rest).
Also attached is a page on the condensor can from Convoy Magazine (Years ago, I did ask Marc Montgomery if it was acceptable to share the content of Convoy. He said it was OK.) The Convoy Magazine version is the under floor mount version.

There have been a number of discussions of the condensor/overflow/expansion tank/can over the years. One at http://www.mapleleafup.net/forums/sh...9647#post49647 included a drawing from Bruce Parker, attached to try to group information. Bruce's is the side of cab version.

CMP condensor can bottom.jpg CMP condensor can top.jpg

CMP Condensor can from Convoy Mag No.2.jpg chev overflow can.jpg

[Mike Cecil]

If you wisk that info down to your local sheet metal shop, they should be able to provide a quotation to manufacture a small quantity.

In Australia, I'd be talking with Cecil & Co in Bayswater, Victoria, who have the necessary rollers, Philidelphia seamer, bottom edge rollers, and soldering setup - the only difficulty I can see is the pressed dimple in the top.

It is a straight-forward can-making process with a few quirks in terms of soldering in the tubes and the pressed dimple in the top.

Mike

[Grant Bowker]

The pressed dimple is actually in a smaller part a bit less than 1-3/4" diameter that gets soldered into a depression in the can top. Make yourself a hardwood form and tap, tap, tap with a light (I used 8 oz.) ball pein hammer. The seam up the side is just two 180 degree folds brought down on each other with a grooving tool (and maybe soldered for better sealing). The rolling of the can body - well, small slip rolls are getting cheaper or you could do a series of small bends on a brake as some of the originals look like they were done that way (if spaced at 1" each bend would be a bit less than 20 degrees, if spaced at 1/2" they'd be less than 10 degrees). The part I need to experiment with is the top and bottom. The depression in the top to receive the part with the dome is easy, a depression in a plate or hardwood and press in the depression (only as deep as the thickness of the sheet metal) with a close to size washer (can adjust sizing of the depression a little to suit the available washer or turn down an oversize washer). The reinforcement for the threaded outlet in the base appears to be spot welded and solder sealed in place. I've done the experiments to be confident the parts described can be made by a stubborn idiot. I haven't figured a plan yet to do the folded edges on the top and bottom. They need to be at least close to truly round to give the can an acceptable shape and the folds accurate to hold the can body. The folds aren't large and as a result a bit more care is needed. More thought and trials are in order. I'm pretty sure the straps/legs were spot welded to the body before top/bottom were added.

[Mike Cecil]

The top and bottom joins are rolled edges - done with a set of two shaped rollers in a top & bottom seamer that clamps the top and bottom in place against the rolled edges of the body. First stroke rolls the body edge over the top of the top (or bottom depending which way up it is), the second stroke flattens it against the side of the clamping plate at top. Each end is done individually.

The top and bottom pressings are round with a depressed edge all round.

The body is a rectangle of sheet steel with the points notched, ie cut at an angle, so that they don't catch or foul the edge roller when rolling the top & bottom edges.

Same manufacturing technique as making the great Aussie 'Billy' can, and I've made plenty of them during my senior school and university breaks. Of course, that is with the right machinery for the job, but if only making one or two, Grant's methodology and tooling sounds fine.

Mike

[Hanno Spoelstra]

Excellent info, guys! I have moved this thread over to the restoration forum.

Who's going to have a run of these cans made? I am good for one, I'm sure there are many others in need as these tanks seem to be missing most of the time.

[m606paz]

Hi Boys!
All production Chevrolet CMP have this overflow tank?
Regards

[Hanno Spoelstra]

Originally Posted by m606paz

Hi Boys!
All production Chevrolet CMP have this overflow tank?
Regards

Hi Mariano, yes they all had an overflow tank. Cab 13s , at least.
Earlier ones had the tank on the left front fender, later ones had them fitted under the mudguard.

[8threcce]

Originally Posted by Grant Bowker

I measure the CMP can as very close to 6-3/4" diameter (including the rim, just because that is the easier dimension to take) and very close to 8-1/2" height (again including the rims) - so shorter and fatter than what the commercial reproductions. Getting into the detail, there is a difference in the water connection (as opposed to the central vent tube) on the bottom of the can between the cans made to mount on the cab side and those made to mount under the floor. In the attached photos, the underfloor mounted tank(s) is the one with the water connection on the side opposite the mounting straps so that the connection is (almost) at the low point of the tank whereas for the tank ponted on the side of the cab, the connection is closest to the cab and less exposed to damege. The can with dark green paint is the side of cab version, the others are the under floor version. The commercial reproduction construction more closely resembles the side of cab mounted CMP cans (both appear to have been mounted vertically rather than on an angle under the floor).

If only one version were to be reproduced, the one for use under the floor would probably be better (less volume of water sitting in the can at rest).
Also attached is a page on the condensor can from Convoy Magazine (Years ago, I did ask Marc Montgomery if it was acceptable to share the content of Convoy. He said it was OK.) The Convoy Magazine version is the under floor mount version.

There have been a number of discussions of the condensor/overflow/expansion tank/can over the years. One at http://www.mapleleafup.net/forums/sh...9647#post49647 included a drawing from Bruce Parker, attached to try to group information. Bruce's is the side of cab version.

Attachment 115471 Attachment 115470

Attachment 115472 Attachment 115473

Sorry for my late reaction on this thread since I'm now confronted with the search of a condensor.
Are there any pictures that show how the condensor is hooked up to the radiator??

[Grant Bowker]

The connections are on the bottom face of the can(vertical on the long axis). The connection in the center is open to atmosphere as a vent. The off-center connection is connected by tube to the overflow on the radiator neck.

[Harry Moon]

I've seen a few of these NOS that when used rusted out within a pretty short period of time. I use mine for show and use a black plastic oil bottle zap strapped next to the radiator for the real overflow and return.

[Grant Bowker]

I've wondered whether the various gas tank sealing products might work for sealing and rustproofing the interior of the condenser cans. I hadn't really looked in past to see how they perform in warm/hot conditions (shouldn't have to worry about much over the boiling point of your coolant).
One review on POR15's web site says they used it with success on a coolant recovery tank.
KBS coatings say their tank sealer is good for up to 500 degrees (assume Fahrenheit). Thy also give test results for chemical exposures.

At least the CMP coolant recovery tanks aren't under either positive or negative pressure...

[cordenj]

Recently acquired this brass Condensor Can, marked C-124238, from a long-term CMP collector.

Single pipes at each end. Has been painted olive green in the past, no other colour.

Were these fitted to early CMPs? Pre-dated the shorter steel versions?

Thanks

[Alex van de Wetering]

Were these fitted to early CMPs? Pre-dated the shorter steel versions?

John, as far as I know Cab 11's were never factory fitted with the condensor can, but you do see them on most, not all, Cab 12's delivered from the factory. So, I am guessing they were introduced somewhere in 1941. These are all the "normal" smaller size cans though.

Could your can be from an MCP truck maybe?....or something armoured.....Fox, Otter???