351 Cleveland thermostat restrictor

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Mister 4x4

Too Big to Sneak
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1971 Mustang Mach 1
Since the stock 351 Cleveland thermostat restrictor isn't available, what about using something like this (drill out the center of the one on the left):

10003234_2.jpg


http://www2.cougarpartscatalog.com/waterrestrictplate.html

 
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do not drill it out . . install it as is and install a windsor style thermostat and all will be well with that part at least.

 
Interesting - so, blocking off the bypass completely (well, aside from the 5mm pinhole) and using a Windsor style thermostat will have the same effect as a proper Cleveland set-up.

Can you explain that? Since the coolant will be flowing in "bypass, thermostat open" mode regardless of whether the thermostat is actually open, how will this help with cooling? (Seriously, I'm at a loss here).

 
if you are interested

page #3 shows the conversion above.

http://www.7173mustangs.com/attachment.php?aid=30013

"West Coast Classic Cougar (WCCC) offers an alternative, that grew out of Pantera owners

seeking a way to keep their cars running cooler, as overheating was an ongoing problem with

those cars. Someone discovered that by soldering a penny in the opening of the restrictor/bypass

plate he could use a Windsor thermostat and seemingly solved the overheating problems.

WCCC designed and produced a solid restrictor plate that requires the use of a Windsor style

thermostat. It does have a small hole in the middle of it to provide a way for trapped air to

escape:"

 
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yes, the problem is not the concept of the cleveland system . . the problem is the design and parts used . . this system did not seal all the time when it was new which is why guys were changing it on new cars . . there are some cars that have the clevo system and theirs work just fine, but if you get rid of it, you 100% eliminate it as a potential cause of overheating.

the problem is that you can not actually see the system in operation so there is really no way to tell if it is sealing or not . . if you install the block off plate, it will seal.

if you have an aftermarket water pump that does not have the bypass, you should drill the bypass hole in it if you use the block off plate.

also, you can drill three 1/8" holes in the perimeter of your thermostat if you use the plate.

 
Last edited by a moderator:
Thanks guys - I should've done the 'search' for this information, as while I was posting this I knew it had already been covered.

Mine's been weird. When I had nothing on the front end of the car (no fenders, hood, grille, none of the under hood accessories and components in-place, etc.) it ran cool as a cucumber during initial break-in with me lighting it up with my laser thermometer. Seems like once I got the car all back together in the driveway (with the temp gauge working), everything seemed fine with the gauge not creeping up past about 1/3 to 3/8 on the gauge. When I was rolling from the car show parking slot back to the trailer, I noticed the gauge had shot up to slightly over 3/4... almost to 7/8 and had even burped out some coolant. Turning the heater on seemed to help bring the temp down back to almost 1/2... which caused me concern with the [most likely] missing restrictor plate (I don't remember re-installing it when I built the engine) and whether or not I had actually gotten the correct thermostat.

I'm thinking I'll be doing the Pantera fix - since getting Cleveland proper thermostats seems to be a trick at any local auto parts store (these days, with everybody using the computer, rather than their experience and/or knowledge of the parts).

 
just order the part online, easy.

auto places always have the incorrect parts in the computer system.

 
I am using an 180* thermostat with the bypass plate in and I can't get the temp pass 184 with the AC on and 100+ outside temp. When I look at the temp gauge it only reaches the first tick mark. I thought the gauge was off so I connected the efi monitor and it verified the same temp reading as the gauge. Thinking about putting in a 192* thermostat to bring up the engine temp.

 
just order the part online, easy.

auto places always have the incorrect parts in the computer system.
+1, look up the part number in the article referenced above and order it or take it into the parts store. I just looked, and the local NAPA store has the 180 and 192 degree thermostats in stock for $6.65. Amazon has the Stant 13468 (180*) and 13469 (195*) for less than $6.00.

 
We have all the correct factory set up and just decided we won't take her out when the temp is over 100. That wouldn't be so bad if we weren't in AZ. I think we may try the Pantera option and see if that helps once I confirm our gauge is reading correctly

 
I am using an 180* thermostat with the bypass plate in and I can't get the temp pass 184 with the AC on and 100+ outside temp. When I look at the temp gauge it only reaches the first tick mark. I thought the gauge was off so I connected the efi monitor and it verified the same temp reading as the gauge. Thinking about putting in a 192* thermostat to bring up the engine temp.
That's GREAT news, J. I'll take that over overheating, any day.

Thanks for sharing! ::thumb::

 
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ok, unfortunately the block off plate will not compensate for an inadequate cooling system . . if anyone wants to know how to keep their car from overheating when its over 100 degrees, feel free to let me know...also be prepared to spend some cash because you will be buying some parts.

one of the things to do to reduce engine temp is to tune your distributor to your particular engine . . if your timing is too low for your engine, it will be more difficult to make it run cool.

.

 
I'm not sure if I would call it "inadequate" just yet, considering that I most likely don't even have the right thermostat and most likely am missing the stock restrictor plate. After reading some of the other references, apparently having the heater hose circuit opened up and bleeding heat through the heater core is doing what it's supposed to in the absence of a non-functioning bypass circuit.

I haven't had much luck with electric fans on other vehicles I've owned, so I currently have a monster 7-blade big-block clutch fan that fits the correct shroud & standard [for an H-Code] radiator, but everything is new. I might have to play with timing a bit, but right now it's set at 16* BTDC (non-vacuum setting) and running strong with great throttle response. I'm thinking that if the problem persists once I get the thermostat/restrictor plate situation squared away, then I'll definitely be looking into a better cooler solution.

 
I'm not sure if I would call it "inadequate" just yet, considering that I most likely don't even have the right thermostat and most likely am missing the stock restrictor plate. After reading some of the other references, apparently having the heater hose circuit opened up and bleeding heat through the heater core is doing what it's supposed to in the absence of a non-functioning bypass circuit.

I haven't had much luck with electric fans on other vehicles I've owned, so I currently have a monster 7-blade big-block clutch fan that fits the correct shroud & standard [for an H-Code] radiator, but everything is new. I might have to play with timing a bit, but right now it's set at 16* BTDC (non-vacuum setting) and running strong with great throttle response. I'm thinking that if the problem persists once I get the thermostat/restrictor plate situation squared away, then I'll definitely be looking into a better cooler solution.
Eric,

I think I have a spare restrictor plate if you need one.

 
Eric,I think I have a spare restrictor plate if you need one.
Thanks, J - I think I'm going to just order one of those WCCC "Pantera" restrictor plates (like the one in the original post) and get a Windsor thermostat, since that's probably what the local O'Reilly Auto Parts store sold me and is already in there - LOL.

I'll keep ya posted, though. Appreciate it, Brutha! ::thumb::

 
obvious things like a different fan or a better radiator will lower engine temps.

but, some options for lowering temps.

It is not uncommon using a lower heat range spark plug during the warm months in the south west.

so for example you would run autolite 23 or 24s in the summer and 25s in the winter.

making sure you have a shroud and a air deflector on the top of your rad and condenser if you have A/C.

That shroud between the rad and condenser can make a huge difference in dropping temps

anti collapse spring in the lower rad hose, many people forget about this spring and you could over heating at highway speeds.

running lean, and or retarded timing.

check your plugs are they bone white and have specs in the porcelain.. you need more fuel. richen up the jets a little maybe increase the pump shot.

retarded timing increases exhaust temps

are you running the vacuum advance? the vacuum advance will help lower running temperatures. lots of people are confused by the vacuum advance and plug it then only run off mechanical advance, big mistake.

an adjustable advance is the best.

water pump speed, many people mess around with under sized pulleys to increase HP this runs the pump slower and contributes to overheating.

change the Coolant Mix, 50/50 is fine for the winter but you could go to distilled water with 10-20 antifreeze mix in the summer.

Gas: go to a higher octane, yup it will make a difference if the motor is right on lean edge you could be pinging and not know it which increases combustion chamber temps. you could try filling up with the highest grade gas in your area and then throw in an octane booster and see what happens over a couple of days of driving. then you could make a decision based on the results.

limiting timing: all in by 3000 rpms isn't good sometimes, you want more initial timing to drop idle temps but you can have mechanical or vaccum timing come in too fast and cause the engine to go lean too much. this will require adjustment to the spring tension in the distributor or vacuum advance adjustment. you could also limit total timing.

external trans cooler for an automatic. removing the transmission cooling load from the radiator will drop the temps of the coolant.

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there are tons more you can do or parts you can change on top of all this.

 
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