Shewman's High Flow Thermostats

[51 MERC-CT]

Originally Posted by john in illinois

Thermostats for model A's are made with modern thermostats ground down as pictured above. They have an 1 3/4 " thin tube tig welded to the rim to stabilize the unit in the hose. Don't know if this would flow enough for a V8.John

Seriously doubt that these would be sufficient.
There is a considerable difference between a standard stat and a high flow stat.

[FlatheadTed]

I made these up and ran these in a flathead, in the summer I took them out as my radiator is marginal .With the shroud I now run or a better Radiator I think they would work fine .One hole is enough ,more holes than that I would think it would defeat the purpose of a thermostat.

[Old Henry]

51 MERC-CT, Don't know how you figured the inside diameter of the Robert Shaw 330 that would be left after trimming off what could be trimmed but what do you figure it for the 370 high flow? Could it be made to fit my 59A?

[jdl]

Pictures are of a original Stant 330 from the 1960's just adding to the info:

[jdl]

Outside dia of rim 2.125.. inside dia of stat 1.567

[Old Henry]

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I think I see now how this type of thermostat works and why it probably would not work in my 59A. This style is made for the bottom to sit in a large space with the water surrounding it rather than in the neck of the 59A head where the water has to pass by the "cup" on the bottom. It works great for the first environment because when the cup is lowered the water flows unobstructed over it and through the stat. But, in the neck of the 59A head the cup would be obstructing the flow of water unless it extended down into the more open area below the neck. If the cup sat in and then lowered into the narrow neck it would be blocking the flow of water that would have to pass around it on the sides in the narrow space between the cup and the sides of the neck.

Darn, I thought I had something there that would be an improvement for my 59A. I guess that's why that style of stat is not sold for the 59A heads.

[51 MERC-CT]

Originally Posted by Old Henry

I think I see now how this type of thermostat works and why it probably would not work in my 59A. This style is made for the bottom to sit in a large space with the water surrounding it rather than in the neck of the 59A head where the water has to pass by the "cup" on the bottom. It works great for the first environment because when the cup is lowered the water flows unobstructed over it and through the stat. But, in the neck of the 59A head the cup would be obstructing the flow of water unless it extended down into the more open area below the neck. If the cup sat in and then lowered into the narrow neck it would be blocking the flow of water that would have to pass around it on the sides in the narrow space between the cup and the sides of the neck.

Darn, I thought I had something there that would be an improvement for my 59A. I guess that's why that style of stat is not sold for the 59A heads.

And still here's another thought

[Bluebell]

So how do you get it in and out?
Good thread!

[51 MERC-CT]

Originally Posted by Bluebell

So how do you get it in and out?
Good thread!

Split with two flanges (left off for clarity) Have to leave something for the imagination which seems to be harder and harder to find.

[ford38v8]

Bluebell, you soak it in vinegar first, then it should suck right in there like a raw egg.

[Old Henry]

So, here's the rub:

The inside diameter of the 59A radiator hose neck is 1.5+"



The outside diameter of the cup on the smaller 330 Robert Shaw stat is 1.567"



Probably would not even fit inside of the neck. Even if it did, the problem is that the water must flow around the cup of the thermostat and over the top edge of it before it can go through the opening. Although there appears to be some possible passages in the bottom of the cup they would not be sufficient. So, no Robert Shaw stat will work in the 59A. Darn.

[flatmotor40]

Will not work on Offy heads inside dia of heads has to be ground out.Have to use standard thermostats and grind od to fit under hose

[Old Henry]

From another related thread:

Went down to O'Reilly's and compared the NAPA 111 thermostats to what is now being sold for the 59A. (NAPA didn't have one in stock) Looks like the 111 is a higher volume to me. What do you think?

Current replacement on the left. Stant 14157, aka NAPA THM 111, aka O'Reilly's some other number on the right.





The 48 mm on the Stant is equal to 1 7/8" - exactly the outside diameter of my head neck. The rubber gasket can be removed but may not be a bad idea for keeping the stat from "floating" up as they tend to do. AND, the BIG BONUS (for those who really care) - look where it's made!!

[51 MERC-CT]

Put em' in a pan of boiling water and compare them with the valves open.

[Old Henry]

Originally Posted by 51 MERC-CT

Put em' in a pan of boiling water and compare them with the valves open.

Will do, IF I buy them. I didn't have my camp stove to perform the test on O'Reilly's counter where the pictures were taken. I did measure the openings and the Stant opening was larger than the other so should be higher volume.

[Old Henry]

Just in case anyone thinks I'm getting a bit fanatical and obsessed with finding the right thermostat (as I think G.M. just suggested in a related thread) here is my response in that thread to his offer to send me some free NAPA 111 stats with 8 holes drilled in them.

"G.M. I appreciate your offer and your concern but I don't think you understand my unique need in the way of a thermostat. I don't just drive my car on the beach in balmy weather like those in your part of the country do. I drive my car all year 'round at all elevations from 262 feet below sea level at the bottom of Death Valley to 14,256 feet at the top of Mt. Evans and from 0° in the middle of the winter here in Utah to 100+ degrees in the middle of the summer here, and that is while climbing mountains. I'm quite sure that a thermostat riddled with holes would be fine for the hot temperatures you drive in but I'm looking seriously for a thermostat that will work at all of the temperatures, all of the seasons, and all of the elevations that I drive year 'round without having to ever change them or remove them for any drastic change of circumstances. That's why I'm trying so hard to find a high volume "real" thermostat that will totally close off all flow at 0° to get me some quick heat in the dead of winter as well as have higher than stock flow in the heat of the summer climbing the highest mountains. Price is not an issue. When I find what I'm looking for I won't care what it costs. Overheating in the summer and freezing in the winter are worth any price to avoid."

"So, thanks but no thanks on the "holey" stats offer."

[G.M.]

Henry you are not going to find any modern stats that fit in the top of the heads in the water outlets that don't greatly reduce the flow and cause hot problems in hot weather. To get the full flow the stats need to be mounted in the hoses on 32 to 48 years. There are two problems one is securing the stats in place and the stat clearing the ID of the hose. With hose mounted stats they are away from the hot water in the engine with water backed up in the hose behind the stats. To make the in hose stats operate faster on warm up a small amount of water is bled through the stats. To prevent problems with the stats moving in the hose Bob's stats are located in the top of the hoses and sit against the brass radiator inlet tubes staying in place. I have 4 sets in various Fords and they work perfect in all temperatures from 50 to 95 degrees. A lot of others use Bob's stats and have worked for them also in colder weather than I drive in. As far as distance traveled I have put 115.000 miles on my 39 convertible on a lot of trips driven at 65 MPH for 2 10 hour days. Plus other old Fords I put a lot a lot of miles on. 39 P/U from Florida to Nova Scotia and back plus used it as a daily driver for a few years. Get a set of Bob's stats and if they don't work send them back. G.M.

[Joe AZ]

Just another thought on this..........when I was young, growing up in Minneapolis, it was common for us to exchange thermostats between hot and cold weather. Henry.....maybe there's not a perfect answer for "year round" use. Maybe you need to consider switching stats for the season.......JMO
Joe

[Old Henry]

Joe, you might be right. I actually tried that for a couple of years - took the stats out in the summer and back in in the winter but I got tired of it and my engine doesn't run well if it isn't kept at normal operating temperature in the summer. So, I continue my quest for the ideal solution which is not Shewman's concoction. With all that I've read about overheating problems I have a suspicion that my engine block may well have some casting sand in it blocking some passages and that may be why I have a little more trouble keeping it cool than others do. If that is the case there may not be a "stat for all seasons" that will work for me. Time will tell. I continue my quest. Thanks for your response.

[dude]

I could be wrong,but the idea behind drilling holes in the stat is to allow the air to burped out when filling the radiator. It really has nothing to do with the performance of the stat.
The newer stats (because of their size) don't allow you to drill holes around the outside.