Cooling problem

[Seymour Snerd]

More pictures, less talk.

Hey, that's cheating! You just moved the talk into the picture! :laugh:

Seriously though, how does the heater get bled in a GT40 context where it is another high point? Do we need another bleed?

 

[Jac Mac]

Hey, that's cheating! You just moved the talk into the picture! :laugh:

Seriously though, how does the heater get bled in a GT40 context where it is another high point? Do we need another bleed?

On initial fill of coolant where the likes of heater hose layout could entrap air it might be necessary to remove those hoses until coolant flows from them.
If the system in question has a problem such as a head gasket leaking that continually pushs air into the heater core all the bleeds or purges in the world wont help..you need to fix the problem.

In Bobs case he could fit a length of clear plastic tube to the overflow on his header tank & tie it up to a rafter or beam in his garage, fit a plain 'cap' that only seals the upper seal area of the header tank [ cut the spring & seal bit off an old cap ], then run the motor, if he has a H/Gasket problem or the system is 'making air' there will be a constant stream of bubbles getting pushed up the plastic tube, In Bobs case he could first run the pump only to observe the system being purged until the bubbles cease, then start the motor to observe if the system is still making air... then turn the pump off with engine still running...if it still makes air then its obviously got a problem.

 

[Steve26]

Alan,
I was not asking for help I was trying to explain to Bob how I "solved" a similar problem with my car. When Mark answered Bob it raised a question with my fix and I found I still had a problem. Using Marks advice today my problem (the same as Bob's) is fixed! I drove the car 35 miles and it works better than it ever has. I'm posting this so Bob can see that Marks fix will in fact work. I'm not sure why you think this should go on another post as it's answering the original question Bob had. Bob, I now have the cooling system per Marks explanation and it works great. Hope it works for you as well.

Steve

 

[Seymour Snerd]

I'm not sure why you think this should go on another post ...

No worries, everyone's happy.

 

[Mark Clapp]

Steve, glad your cooling system is working well. It's like curing cancer when you get it right.

Bob, sorry I missed the pic of your manifold bleed line.

JacMac, go catch that bus that you're late for. Sorry for the extra reading I caused you.

 

[Steve26]

Hi all, here's a quick update. I took the GT out yesterday afternoon and ran it good and hard (55MPH in first,96MPH in 2nd) and I still have a problem pushing coolant out the catch tank at high RPM (5000~6500 RPM). I see very stable temp (180) as long as I stay at 5000RPM or less, you would never think there was any problem but above that I'm "pushing" coolant out the overflow tank. The only thing I have left that I can change with the plumbing would be to move the 5/8th line that runs from the bottom of the expansion tank to the water pump. The 5/8th line currently runs to the top 5/8th inlet on the water pump that would normally have a 90deg. hose from the thermostat housing, I'm thinking I should run it to the big main inlet (suction side) of the pump with a T fitting. When the car is warming up I can see coolant running into the expansion tank from the 1/4" bleed lines from the radiator/intake manifold with the cap off (20lb. cap) and it must be returning to the system because the coolant level stays constant. When I have the lower hose off I'll put a spring in to prevent any possibility of collapsing. Any thought's? Thanks

Steve

 

[Don Hoffman]

I hope this will help.
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Break it down to the basics it is a closed loop with a recirculator pump.
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With mechanical pumps they need to be slowed down as the factory motors rarely if ever rev high rpm’s. High rpm’s would cause pump cavitation (boiling the water at the pump impeller). A smaller crank pulley or larger pump pulley from factory size would fix this.
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With an electric pump the easiest way to detect flow would be electrical motor load (amperage draw with voltage). High flow high amps, low flow lower amperage check label on the motor for ratings. If the voltage from the alternator increases with engine rpm so will pump rpm and flow or cavitation. This will need to be monitored.
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With either (mechanical or electrical) if a thermostat is not used, remove the valve from the thermostat and reinstall the perimeter flange back in the housing this will make the required restriction needed to keep the water in the block to remove the heat
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Any pump should keep the water pressure higher in the block than the radiator. This keeps the water from boiling and the restriction or thermostat is the separator for the high to low pressure side.
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Engine timing above 38 degrees advanced will create to much engine heat and will burn pistons. With the short and loud exhaust you may never hear the motor ping so it is best to rev set the timing. Mark 36 to 38 degrees advance on crank pulley and with timing light rev the motor to see max timing.
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Radiator cross flow should also be checked and may need to be rodded out. If there is not enough flow across the radiator the pump can draw a lower pressure causing the water to boil, this would push steam into the block, as steam will not remove heat the engine will overheat quicker pushing past the rad cap.
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In permalink # 8 the drawing I think it shows the overflow tank plumbed to the pressure side of the thermostat. I am not sure if the drawing is correct but the overflow should be plumbed to the radiator side of the thermostat.
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The pump suction on the radiator should help pull the water from the block and not push it out the cap
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I also agree with adding the wetter water. When I supercharge my lotus I added it and the motor temp dropped by 10 degrees, I am sure the cooling fan on/off points are lower but it also makes a lot more power.

 

[Steve Wood (PANAVIA)]

I had this same issue with a Stewart pump in my cobra -- it also built up pressure as it was cavitating (sp>?) - I solved the issue with switching to an edelbrock pump.However I do also remember a vintage BOSS 302 service note that their water pumps had revised impellers to deal with high RPM, - unforgivably, most things that you can do to relieve this issue RPM issue,- will cause problems if you need to operate at idle or low forward speed.

I hope you can find a happy medium somewhere !

Steve

 

[Steve26]

Don/Steve,
Thank you for your help and great information. I will work on this this weekend and start eliminating things one at a time and see if I can find a solution. I am running a 180 thermostat at the moment and have not had an overheating problem yet but I can see if I was running a track day I would as I continued to loose coolant at high RPM. It might be that I do have to find a happy medium because 99% of my driving is on the street and 6500RPM is never necessary but is lot's of fun. I hate to change the pulley and move the problem to where I spend most of my time driving. If there is a pump that will work at any RPM up to 6500+ that would be worth whatever it cost. Thank you again for your input and great help, I'll keep you up to date as I learn anything.

Steve

 

[Mark Clapp]

Hi Steve, I have my 5/8" line from the bottom of the expansion (fill) tank to the side of the water pump (heater hose fittings) as you are thinking of doing. I have the normal bypass hose (90 degree bend) from the thermostat housing to the top of the water pump. This may lower the pressure in the system that is forcing out coolant.

 

[Steve26]

Hi all,
Well I changed the bleed line from the manifold from 3/8th to 1/4 and have done nothing else but drive it hard for about 50 miles and it seems to be working fine! I have had it to 6500 in both first and second many times and have cruised at 5000+ in first for a while (man it sounds good at 5K!!!) and have not lost a drop of coolant. It has been hot here in Seattle the last few days so I think I can call it good. Thank you to all of you that helped with this, what a great forum.

Steve

 

[Seymour Snerd]

....have not lost a drop of coolant...... Thank you to all of you that helped with this, what a great forum.

Cool! (so to speak)

Now, whatever happened to Bob? (or should I say "What About Bob?")

In our last episode his GT40 was handing him back a quart of coolant whenever he parked...

 

[Bob Stoeger]

Hay Guys,
Sorry I should have answered this weeks ago but have been very busy with work and life. Anyway the problem that I had has been solved and the car runs nice and cool now. Here is what took place, I finally pulled the engine and took it to my new engine builder who tor it down and started from scratch. I originally bought this engine from a guy complete but never run, My mistake!! never buy an engine that you can't see run. anyway my new engine builder found a lot of things wrong with the engine. Lets just say $4000,00 later it runs perfect and I also got another 30 HP out of it to boot now its at 490 HP not bad for a little small block ford. Thanks to all of you guys that helped me out with your ideas, special thanks go to Frank Catt for all his help.
hope to get a lot of miles on it come spring.
Bob