How are 28-29 and 30-31 radiators different?

[CabrioletDon]

Boy, am I frustrated! I've spent a lot of time and more than a few pennies recently trying to get my '30 Cabriolet correct by replacing the front cross member including pulling the engine/transmission, welding up holes, setting all new rivets, repainting the frame, etc. Re-installed the radiator today...and it does not seem to fit correctly--it's sitting too far forward with about 1 1/2" inches between the radiator and the forward end of the water pump/fan shaft. After some searching at various vendors, I see that there are two versions of radiators being sold, one for 28-29, and one for 30-31. Since I've changed the front cross member from the incorrect 28-29 to the correct 30-31, do I get a new radiator as well, or can I make the old one work? Besides the mounting holes, are there other differences? I'm not trying for a fine-point car, but am trying to do everything I can correctly. Would appreciate any advice or direction!

[J Franklin]

Install the rods from the firewall as they were, and see how far off the hood fits. the rods have some adjustment capability.

[juke joint johnny]

That looks like a 28 crossmember you have in it now with the solid engine mount and the raised pads for the rad. That will only work with a 28-29 style body .

The 30-31 crossmember has a yoke for the enginne mount and lower pads to mount the rad

[Steve Plucker]

I agree with JJJ...IT APPEARS THAT you have the early 1928 front cross member shown in the photo OR ARE WE NOT SEEING THE COMPLETE PHOTO?...OR, as you say...did you replace that with a 30-31 front cross member? (The raidiator shell connecting bracket is in the way)

Please review this if you get a chance:

http://plucks329s.org/pdf/frame/Evol..._Assembly2.pdf

Pluck

[rotorwrench]

The radiators are not the same since the belt line and radiator are shorter for the 28/29. The pads on the 30/31 cross member are shallow and don't raise the radiator up as high.

I suppose the pads could be modified but it may be easier to change the member out.

[CabrioletDon]

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Hi, Steve...it's been awhile, but you and I communicated about the correct cross member for my car before, and I went through your article carefully before buying and installing the one that's shown in the photos. It does have the lowered pad area on each side, as well as the hole for the overflow tube. I believe that the number on this was A-5020-B. This was a NOS cross member, and I checked it carefully against the photos in your article before installing. This morning, I took the radiator off and took some additional photos, and would be interested in your opinion, as well as any of the other talented and experienced folks on here!

[Steve Plucker]

Don,

Ok...now that we have that settled...

Where are your measurements when the radiator is stright up and down and not tilted forward?

Could that be the reason for your 1-1/2 inch distance?

If squared up...it should move the radiator towards the shaft.

It also looks like the radiator is not sitting fully on the front crossmember...I am not familiar with the 30-31 set up.

Pluck

[juke joint johnny]

I'm glad you have the right crossmember .I would hate to think of doing that job over!!

That looks like a new rad you have there .I thought the mounting holes on the support bracket should be in the middle of the bracket .what happens when you take out the mounting bolt does it line up then?

[Bob C]

I looked at an old 1930-31 radiator I have and the mounting hole
is to the rear also.

[CabrioletDon]

Hi, Steve and Johnny...just so you know why I'm questioning and seem to be mystified, I inherited this car from my father when he died in 2010, he had been assembling it over the previous 20 years or so. Wish I could ask him about some details, instead I'm having to sort out and correct issues as I go, like the cross member. The radiator seems to be pretty new or at least re-cored, I'm not sure what its origin was. It fitted correctly on the car when it had the 28-29 cross member on it, and with me learning as I go, I figured that a radiator was a radiator, and that it would fit on the new (and correct) cross member. It looks, though, like the radiator mounting brackets have holes that are too far to the back (off center) so that when the radiator is installed, it's sitting about 3/4" or maybe 1" too far forward, and the front of the radiator is hanging off of the cross member. The brackets look like there may have been a hole forward of that (see one of my first photos in this thread) that was filled in, or maybe that's just a press mark from forming. Steve, when the radiator is stood up straight, I still have about an 1 1/4" from the back surface of the radiator to the front of the water pump/fan shaft, and a rough fitting of the previous upper radiator hose looks as if it will be about 1" or more short. I would be up for modifying the radiator by drilling new mounting holes, on the other hand, if there are other differences between the 28-29 and 30-31 radiators like height, fittings, etc., I may need to sell or trade the existing radiator for the correct one, so I hate to start drilling or modifying without knowing the correct route. Any direction or clarification will be much appreciated! I just hate not knowing which direction to go... Thanks, Don

[CabrioletDon]

Not to dwell on this too much, but the more I learn, the more I realize that I don't know enough! In comparing the viewable features of radiators on Brassworks' website, I'm not sure what it is that I have. The return neck of my radiator looks like Brassworks' 30-31, but the design on the upper tank looks like the "pyramid" beading of the 28-29, not the "vertical column" beading of the 30-31. The only thing close looks like their "transitional" model for the very end of '29. I'm more confused than ever!

[GRutter]

Dimensionally, 28-29 radiators are different from 30-31. I would think you would fight problems with upper radiator hose alignment, radiator shell alignment, and hood alignment if trying to use a 28-29 radiator with a 30-31 body. I would think the top of the radator tank would be visible from the front of the vehicle due to the different core dimensions.

[Bob C]

In stead of looking at the distance between the fan shaft and the core what is the distance from the tip of the fan blade when at the 6 o'clock position. Also how
does the water outlet line up with the radiator inlet?

[Steve Plucker]

Don,

I wish some more 30-31 guys would chime in here.

I am at a loss since I do not have any 30-31 stuff to look at.

I know that you are very close to two national MAFCA clubs in your area...one in Leavenworth and one in Topeka.

If push comes to shove I would try to contact a few members from these clubs with 30-31 vehicles and personally view their vehicles for their truness.

I have a few names to give you if you see fit.

Pluck

[CabrioletDon]

Thanks, GRutter, BobC, and of course, Steve Plucker for giving me info and your perspectives!
BobC, I measured the distance from the front of the fan blades to the back of the radiator core (fins), and it's about 1 3/4" as best I can tell, and that looks to be too much, and way more than it was with the old cross member. It looks as if the return neck (top) on the radiator and the neck on the engine would line up fairly well if they were closer, but my old upper hose is a little more than an inch too short. Steve, thanks for your offer for names of local members--I'm afraid I've got such a hybrid situation (maybe a transitional radiator, definitely not the same return neck as a 28-29, etc.) that I couldn't tell much while in the car other than they're all different.
I spent some time going through Brassworks' website today, and I thought I might call those guys on Monday and see if they could give me some dimensions and specs so that I could compare apples to apples.

[J Franklin]

Have you installed the 2 rods from the firewall yet?

[CabrioletDon]

Hi, J Franklin...thanks for the suggestion, unfortunately, my project is a total restoration, so I have no body on the car. Even more complicating is the fact that it is a Cabriolet, so the body components are all separate and are positioned relative to the wooden door latch posts and the wood subframe. Repairing and fitting the body to the wood subframe is next once I get the basic car running. Thanks, Don

[juke joint johnny]

I've looked at a couple 30-31 rads I have and I think the holes in the rad mounting brackets are to far back mine seem to be 1"5/8 to 1"3/4 from the the front of the rad to the center of the hole . Mine only hangs over the frame at the front of the crossmember about a 1/4"

I think it is a new rad and sometimes the don't get the measurements right

[katy]

Do you have the correct '30-'31 water outlet on the head?

[rotorwrench]

Photos can always be deceptive as far as the cross member was concerned. That all looks to be spot on. Model A radiators have been reproduced for a long time since the model A era. The tube count and fin count will get a person to know if it is an authentic reproduction but it may not tell a person if it is original or not. Putting originality aside, it's also questionable if the last recore was done with originality in mind or was it done to make it fit the early type cross member. The mount holes look OK to me but that is the outer frame fit and not necessarily the core fit. A person can try to fit the shell if you have it.

It's too bad you don't have another 30/31 model A cowl to place on the frame and check the support rod and hood fitment. A person needs to know the top to bottom dimension of the 30/31 type radiator for comparison on height of the one you have.

[Bob C]

Do you have a screw on cap or 1/4 turn? I measured my 1930 and the measurements
are fan blade 12 o'clock to core 1 3/4" tip of shaft 3/4" blade 6 o'clock 3/4".

[J Franklin]

I am beginning to think you should leave this part of the project until the body is in place. To get things running just use the radiator as is for now. I think you are working/worrying too far ahead.

[CabrioletDon]

BobC...The radiator has a 1/4 turn cap. I'm sure the fan that's on the car is different than yours, as it's a 4-blade, vs the original 2 blade, and the shaft literally sticks out as far as the blades themselves.

J (Franklin), maybe you're right...this car has run twice before--once in about 1992 when it was originally assembled, and once in the fall of 2018 before I discovered the cross member issue. I just hated to let the engine/trans/bearings/brakes sit too long while I work on the body...I've had the oil pan off and cleaned it out, but since the coolant channels in the engine have had water/coolant in them they are probably rusting now. I will begin assembling, welding, fitting the body components on a build table to avoid the wear and tear on the frame, but I figure it will be a year or two before all of the components are ready to go on the frame.

[GPierce]

I’ve got. 30-31 radiator in my attic. Would a picture of that help?

[CabrioletDon]

Thanks, GPierce...when you get a moment, I would love a photo of the radiator you have, and if the lower mounting brackets and holes are possible to show, that would be very helpful to begin to figure out what I've got and why it is not fitting correctly. I'm also working on getting some specs and measurements for the 28-29 vs. 30-31 radiators, which I'll post here when I get them...maybe they will help someone in the future!

[ryanheacox]

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As long as the water neck is a 30-31 the hose should be a straight shot from the neck outlet to the radiator inlet. If the radiator were a 28-29 I don't think it would line up at all. The 1/4 turn cap would also indicate a 30-31. Also, just slip the radiator shell over it, if it fits then you're good to go.

[GPierce]

Hope this helps. If you need somthing else let me know.

[CabrioletDon]

Thanks so much for taking and posting these photos for me, GPierce, they were very helpful! What you showed is similar to my radiator in some respects (neck outlet, mounting brackets, etc.), but different in some ways, too. I talked with Lee at Brassworks yesterday and sent him some photos. Along with his assessment and your photos, I believe that my radiator is not OEM, but probably was made in the 80's or 90's to fit a 30-31, although some of the visual details are from the 28-29, like the design on the upper tank. From what I've seen and been able to put together so far, the 28-29 radiator core was shorter and wider at about 19 3/4" tall x 19 1/8" wide, where the 30-31 core is taller and skinnier at about 22 1/2" tall x 18 1/8" wide. The number and shape of tubes and and fin count (and profile) seems to vary widely based on the originality and cooling efficiency of what's needed--all the way from round tubes to oval tubes to flat tubes, and from as few as 5 fins per inch all the way to 10 fins per inch. Like many other decisions on our cars, I guess mine will come down to how much do I want to spend for the best cooling, the most original look, and the best fit. Thanks everyone to contributing to this question!

[Purdy Swoft]

The radiators used on the 30-31 cars were taller than the radiators that were used on the 28-29 model A cars . The radiators that were used on the pick ups and AAs were the same as the 28-29 radiators until around june 1930 . The taller radiators that was used on the AA trucks after june 1930 were thicker than the tall 30-31 car radiators .