Current FLOWCOOLER thermostat is not OEM

More simply than stories of more or less fair competition between dealers, what is the RIGHT diameter the hat needs to be to work properly with the OEM bypass plate?

I would hardly call what Flowcooler has done “fair competition”.

I would call it a great disservice to current and all future owners of any Cleveland engine that has the Flowcooler thermostat and/or bypass plate installed.

we already have enough problems with our pantera vendors selling Windsor thermostats, and telling us that everything is fine. 🤷‍♂️🤷‍♂️😡😡

even if the current owner understands the difference and installs both pieces as an assembly, the next person working on that engine will correctly assume they are dealing with OEM bypass plates and thermostats, and will (if they are lucky) purchase correct OEM parts that will not function correctly with the flowcooler parts.

that isn’t fair competition, it is more like deceitful advertising and total disregard for the obvious and inevitable problems their proprietary approach will cause future owners.

as to your question on the diameter of the hat, I do not know. But I do know to trust Tim Meyer to provide what is correct

Larry

@lf-tp2511 posted:

as to your question on the diameter of the hat, I do not know. But I do know to trust Tim Meyer to provide what is correct

Larry

Just take a caliper, a "Tim Meyer" or OEM thermostat and measure, it's not a trade secret, it's a plug in a hole that doesn't require long and expensive engineering studies neither by Ford, nor by Tim Meyer, nor by Flowcooler.

And for the competition I said "more or less" fair, it was to not say "unfair".

Nobody to take a vernier caliper and measure a thermostat?

.680”

Since the hat was formed rather than turned on a lathe, there is a small variance in the diameter.  It varies from 0.672" to 0.677".

John

Thanks for the answers but it seems to be a lot more complicated than I thought.

- Rocky you measured a "Flowkooler/Robertshaw" thermostat with the reference 333-180 at 0.680 so very close to what is indicated on the packaging (11/16 = 0.6875). But it would apparently be the one that Larry says he does not match OEM by pass plate.

- JB1490, you are talking about 0.672 to 0.677'' but your photo shows 0.75'' (12/16'') on a "Robertshaw" whose reference is not visible.

- The one I bought from Summit with the Summit reference 333-180 SUB (I admit I didn't pay attention to the mention SUB when I ordered) but in a FlowKooler packaging reference 333-180 only measures 17.10 mm (0.673'') so a little less than the 11/16 indicated on the packaging.

- I also have a Motorrad whose hat is even smaller: 16.60 mm (0.654'') ........

I visited the FlowKooler website and,  If I understood correctly, they say the 333 series is made for the OEM bypass plate but only available in 180 and 195°F and indicate 11/16'' diameter; it is only if you want 160°F that you have to choose the "substitute" which is in fact a 330 which must be installed with an "alternative sized by pass" but without specifying the diameter, just "alternative sized".

FlowKooler would therefore sell 333-180 and 333-180 SUB which would be different and Summit would sell 333-180 under the reference 333-180 SUB????? So the error would be more at Summit than at FlowKooler?????

TimMeyer gives him no indication of the diameters!

Furthermore, the hole in the bypass plate measures exactly 19.23 mm = 0.757''.

This leaves a circular space 1.05 mm wide, i.e. an approximate section of 60mm² = 0.093 SI. On a total surface of 0.45 IF it represents 20%, it is not negligible and would prove Larry is right, all the FlowKooler would be SUB ?????

The one measured by JB1490 seems more suitable but this time with a very small clearance of 0.0035'' all around which seems very little especially if we consider the "precision" of the centering.......

It is therefore impossible to know with certainty what it is exactly and
it would therefore be really interesting to know precisely the exact diameter of the Ford OEM or TimMeyer thermostats. Or the diameter of a FlowKooler substitute bypass plate.

@rene4406 posted:

I visited the FlowKooler website and,  If I understood correctly, they say the 333 series is made for the OEM bypass plate but only available in 180 and 195°F and indicate 11/16'' diameter; it is only if you want 160°F that you have to choose the "substitute" which is in fact a 330 which must be installed with an "alternative sized by pass" but without specifying the diameter, just "alternative sized".

FlowKooler would therefore sell 333-180 and 333-180 SUB which would be different and Summit would sell 333-180 under the reference 333-180 SUB????? So the error would be more at Summit than at FlowKooler?????

UPDATE ‼️

Rene hit the nail on the head. The description at summit ending with SUB is confusing and incorrect.

as Rene and Mike Drew have found, ordering that thermostat from summit does result in receiving the correct OEM high flow Cleveland thermostat

I called and spoke to a flowcooler technical representative, who understood the Cleveland cooling system.

for unknown reasons, they only have the Cleveland 333 series in 180° and 195° versions. Therefore, to supply a 160° thermostat (which is too low for all but maybe a dragstrip engine), they used a 160° Windsor thermostat and made their own bypass plate.

as for the hat diameter and the bypass diameter resulting in a permanent coolant flow, even when fully “closed”. All other Ford small blocks accomplish this constant  coolant recirculation with an external hose.

I still think the best source for a correct 333 series Cleveland thermostat is Tim Meyer, who invested this time and money to keep them available after Robert Shaw temporarily discontinued them.

Larry

But then the thermostat measured by JB1490 which we do not see the reference and seems to measure 0.75'' what would it be?

And what is the interest of the permanent coolant flow, even when fully “closed”?

@rene4406 posted:

J

And what is the interest of the permanent coolant flow, even when fully “closed”?

I think you’re going to have to track down a Ford engineer for that answer.

🤷‍♂️🤷‍♂️

Larry

My earlier post shows the hat diameter is 0.675".

This is a pic of the front of the above package.  ( I chose not to open the sealed package)

John

Here is a pic of an older FlowKooler 333-180.  The pic shows a diameter of 0.675", and varies from 0.675" to 0.681".

John

Okay, I'm all wrong, I've never used this kind of caliper and I went too fast, I only read the dial and therefore .75, I forgot to put 0.6 in front to make 0.675 .

So 0.675 is definitely the RIGHT diameter with OEM by pass plate.

Tracking down a 60s Ford engineer, I'm afraid is a little tricky, especially from France but, if my Pantera has overheating issues when it will be on the road again, I'll try to machine one bypass plate with a bit smaller hole, around 0.71'' to see if it's better. I even think that it must have been tried for a long time by all the specialists of the Cleveland and am curious to know the results of their tests.