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revisiting the thermostat issue
#11
Don C;266236 Wrote:The original design did not close off the hole, and is one of the reasons that (mostly) Pantera owners object to them. Due to manufacturing tolerances (especially aftermarket thermostats) and the way the thermostat fits in the groove in the block it's probably not possible to completely close the hole with that style of hat.

This same type of bypass is used on Ford's modular engines. However, it uses a different style of "hat". Did you see my article at:
http://www.7173mustangs.com/thread-351c-cooling-system

Thank you Don. Now I do have a better idea of how it is supposed to work. I printed off your article and I notice that the diameter of the 'hat' is .66" (as is Stant's), so obviously it will never completely seal, just restrict the flow. Water will always take the easiest rout.
I feel more confident using the t/stat I have now I know what's what.
Awesome help from all, which in turn will help others I'm sure.
Geoff.
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#12
Here's one of the problems with the parts they sell . These are both aftermarket t stats . The hat on the one on the right is installed deeper than the one on the left plus it is crooked . Poor fitting and/or poor operating factory parts is also what occasionally plagued this system when the cars were brand new.

I just get rid of the stock system and use a bypass plate or plug the factory bypass plate with a freeze plug with a 1/8" hole in it then use a Windsor high flow t stat and drill 4 small holes around the perimeter of the t stat . If you have an unmodified Weiand pump you have to do another mod.

[Image: robertshaw_333_192_4.jpg]

You can buy a t stat like this . This guy makes a new hat and insert from solid brass so it works properly . It also looks slightly larger and taller to insure a good seal.

http://www.ebay.com/itm/182107945649

[Image: s-l400.jpg]


http://www.ebay.com/itm/171476456933

[Image: s-l400.jpg]
  Reply
#13
barnett468;266276 Wrote:Here's one of the problems with the parts they sell . These are both aftermarket t stats . The hat on the one on the right is installed deeper than the one on the left plus it is crooked . Poor fitting and/or poor operating factory parts is also what occasionally plagued this system when the cars were brand new.

I just get rid of the stock system and use a bypass plate or plug the factory bypass plate with a freeze plug with a 1/8" hole in it then use a Windsor high flow t stat and drill 4 small holes around the perimeter of the t stat . If you have an unmodified Weiand pump you have to do another mod.

[Image: robertshaw_333_192_4.jpg]

You can buy a t stat like this . This guy makes a new hat and insert from solid brass so it works properly . It also looks slightly larger and taller to insure a good seal.

http://www.ebay.com/itm/182107945649

[Image: s-l400.jpg]


http://www.ebay.com/itm/171476456933

[Image: s-l400.jpg]

Thanks Barnett. As I said before, my decision is based on cost because of shipping and apparently import duty and the 30%+ exchange on the dollar. Next time I'm in the States for an extended time, I may order one and bring it back with me. I have my immediate question answered, not perfect, but I have had no problem with an even worse fitting stat. I don't anticipate any problems going with a Stant.
Geoff.
  Reply
#14
Stanglover;266260 Wrote:Water will always take the easiest rout.
Geoff.

Yes, water will generally take the easiest route. However, many factors influence the actual flow rate or quantity flowing. These factors are usually expressed as "friction". The roughness of the wall of the object the water flows through, elbows or bends, and protrusions all produce frictions to the flow, reducing actual flow rate/quantity. In the case of a protrusion, not only does the protrusion reduce the flow, the downstream eddies add additional friction to against the flow.

In the case of the thermostat and hat, mathematics tells us that about 20% of the opening remains after the hat closes off the opening. However, due to the size and shape of the remaining opening the actual flow will be considerably less than the 20%. How much will depend on what the frictions are downstream of the flow through the block and heads for the non-bypassed coolant, as well as the flow through the bypass.

Were you able to get the accurate dimension of the opening in the restrictor plate? I haven't been able to get that from anyplace, and haven't wanted to pull my thermostat housing bad enough to get it.

Thanks, Don



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#15
Don C;266363 Wrote:
Stanglover;266260 Wrote:Water will always take the easiest rout.
Geoff.

Yes, water will generally take the easiest route. However, many factors influence the actual flow rate or quantity flowing. These factors are usually expressed as "friction". The roughness of the wall of the object the water flows through, elbows or bends, and protrusions all produce frictions to the flow, reducing actual flow rate/quantity. In the case of a protrusion, not only does the protrusion reduce the flow, the downstream eddies add additional friction to against the flow.

In the case of the thermostat and hat, mathematics tells us that about 20% of the opening remains after the hat closes off the opening. However, due to the size and shaped of the remaining opening the actual flow will be considerably less than the 20%. How much will depend on what the frictions are downstream of the flow through the block and heads for the non-bypassed coolant, as well as the flow through the bypass.

Were you able to get the accurate dimension of the opening in the restrictor plate? I haven't been able to get that from anyplace, and haven't wanted to pull my thermostat housing bad enough to get it.

Thanks, Don

...3/4", his post, yesterday 8:52 am

Don't be afraid to try something new. Remember, amateurs built the Ark...Professionals built the Titanic! thumb

  Reply
#16
Thanks, I missed that. 0.75 is what I used.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#17
Don C;266389 Wrote:Thanks, I missed that. 0.75 is what I used.

Thanks Don and everyone else. It has been an interesting re-read on this subject. No doubt it will help many others (who we never here from) decide what is the best solution for their 351C's. I do appreciate all the responses which have cleared up my questions.
One thing I learned is that 351C are NOT the same as 351M or 400's. M's and 400's have cast in restrictors not brass and I'm thinking that the ID is a bit smaller as (and not to knock NPD) but the ones they sell listed for the 351C in the catalog are only .625" diam. 'hat' whereas Stant is .66" diam. What else I noticed was that they are marketed as Parts Master brand. The 180 deg. has a label listed for a 79 Bronco 351M /400, while the 192 is labeled for the 351C. Other than that, they are identical. Hmmm! ( I'll be taking them back)
Buyer beware I guess. Go with proven brands for Cleveland's or spend the big bucks and get the custom made ones.
I think we have covered all scenario's for now.
Geoff.
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