Overheating or bad gauge?

[Excaliber]

...in two to four weeks SPF could loose their Shelby endorsment, or so "rumor has it".

Acutally the "rumor" is more like 2 to 4 months, you heard it here first.

I was just talking to a guy at SAAC-35 who had a crack in his expansion tank on an FE. Of course they crack and leak, they do that a LOT. THAT is why I'm going to run Evans waterless coolant and a near zero pressure system, save my expansion tank, hoses, fittings, head gaskets, intake gaskets, spiking temp gauges and all the other evils associated with water and pressure. That's dinosaur technology, give it up, water systems suck.

[Mark IV]

Originally Posted by Excaliber

...in two to four weeks SPF could loose their Shelby endorsment, or so "rumor has it".

Acutally the "rumor" is more like 2 to 4 months, you heard it here first.

Aw, common Ernie. This crap is beneath you. I hear rumors that say California will fall into the Pacific in 3-4 weeks!

I could tell you the real story, but then I would have to kill you............

[Got the Bug]

Originally Posted by Excaliber

...in two to four weeks SPF could loose their Shelby endorsment, or so "rumor has it".

Acutally the "rumor" is more like 2 to 4 months, you heard it here first.

I was just talking to a guy at SAAC-35 who had a crack in his expansion tank on an FE. Of course they crack and leak, they do that a LOT. THAT is why I'm going to run Evans waterless coolant and a near zero pressure system, save my expansion tank, hoses, fittings, head gaskets, intake gaskets, spiking temp gauges and all the other evils associated with water and pressure. That's dinosaur technology, give it up, water systems suck.

What does the licensing deal between Shelby and SPF have to do with a bad gauge?

[jhv48]

Replace the thermostat!

[Voyager]

Now have 800 miles on Superformance/KC 408 engine. I’m still experiencing sporadic short-term overheating. The gauge temporarily spikes under optimal conditions (like steady 45 mph cruise), and then comes right back down to normal within a couple minutes.

Will go get a new thermostat and surge/expansion tank cap.

What temp thermostat…180?

What pressure expansion tank cap…13 psi?

Bob

[Randy M.]

I had a similar but not exactly the same problem. Turned out to be a intermittantly failing radiator cap. It would randomly loose and then retain pressure. Consider replacing the cap. They are cheap enough.

[Excaliber]

One of the things Evan's coolant recommends, for max cooling affect, is to block off the by-pass hose. Based on that I would have to guess a by-pass is a non-critical component when it comes to cooling. It may even prevent max cooling because of it's recirculation flow.

I think it's primary function is to supply hot water quicker to the heater/defroster (on normal cars)?

[madmaxx]

Bypass is to allow water to always circulate and not allow pump to cavitate. I do not think that is your problem. Is the port on the water pump blocked off? I wonder if you have the correct water pump, maybe you have reverse rotation instead of standard rotation.

[Voyager]

The water pump has 2 ports. One goes to the heater and the other has a plug in it. The water pump is an Edelbrock 351W spec'ed by Keith Craft. Drove it last weekend in the 90s and the temps would shoot up from 80C to 100-110. Turing the heater on brought them back down to normal. Next weekend I’ll try the new thermostat and see what happens.

[Barnsnake]

I'd bet the lack of a bypass is exactly your problem.

Without the bypass there is no circulation within the engine when the thermostat is closed. In that case, you can have boiling water/steam in the heads while the water near the thermostat (and temp sender) is still relatively cool. Once the heat gradually migrates into the intake manifold the thermostat opens and you get a scalding blast past the temperature sender. The water then circulates through the radiator and everything cools down. The thermostat closes and the cycle repeats.

Turning on the heater provides an alternate bypass.

Add a bypass hose. Soon!

Jim

[Blas]

The bypass hose allows water to circulate through the block while the thermostat is closed. It allows for a more even warm up without hot spots. You indeed may have a sticking thermostat. You should consider using a "Balanced Thermostat" style thermostat. Better flow and I believe they fail "open". Would be interesting to run without a thermostat and see if the temp spiking still occurs. Be sure to install any new thermostat with the weep holes on the flange at the top and install the thermostat in the correct spring orientation. (engine vs. radiator)

[thudmaster]

How about posting a few pictures of your engine so we can see which water lines you have or don't have............

something like this

[Excaliber]

Is this 408 a 351W block, bored and stroked of course?

351C requires a by-pass style thermostat. BUT, some after market 351C water pumps don't have the by-pass hole in them, in which case, the by-pass is blocked off due to the pump. It doesn't matter then what t-stat you use, by-pass or regular. Jaguars and Hemi's are two other examples of engines that use a by-pass style thermostat.

Being it's a KC engine I guess Keith would know what kind of pump and t-stat were in play here and why, apparently, the hose by-pass is blocked. Perhaps a call is in order...

[Barnsnake]

Based on the picture, it's a Windsor.

If it's a Windsor and it has a thermostat, it needs the bypass hose.

The Cleveland's bypass is internal and is progressively blocked as the thermostat opens.

[Excaliber]

The point I was trying to make is, just because it's a Windsor doesn't mean it HAS to have a by-pass. It depends on the heads and water pump if the stock style by-pass would even work. Put Cleveland style heads on your Windsor and you won't have a working by-pass. I'm thinking KC had a reason for blocking off the by-pass, which by the way, is NOT required for any engine, it's just nice to have for a street engine. Closing it off will increase over all water flow gpm (increasing cooling capacity).

I don't think it has anything to do with the problem this thread is addressing. I'm thinking the primary problem is: Air in the system or a sticking thermostat which is opening/closing erratically.

[thudmaster]

Barnsnake that is my engine, I am trying to get him to take one like it........mine has the by pass. I am trying to see if his does.

[Voyager]

Will post some additional pictures of the engine water lines tonight.

Will put the "Balanced Thermostat" in this weekend.

Will call KC later today.

[Tonkin NZ]

Great to see you fixed it. I have SPF2828 and had to replace the thermostat end as the needle had broken off and fused closed. Only 500mls but it had the same issues as you described.

[Rwillia4]

I have a KC engine. Mine also had a by-pass blocked. This was not installed by KC and I would put in the bypass hose ASAP. I was about at the same point of my engine break-in where you are and the rubber cap failed blowing coolant ALL OVER. There is a huge amount of PSI built up on the back side of that thing. It is suppose to allow a controlled amount of flow to so you don't get surges of water blasting by at different temps.

[Excaliber]

Great to see you fixed it.

I missed that part of how, when it was fixed? I thought we were still waiting for an update on this issue?

Like KC, I'm not convinced the by-pass hose is the problem, nor am I convinced it is required in all cases.