What temp is considered too hot?

Systems, Types and Experiences

What temp is considered too hot?

Postby sherwood park rexin » Sat Jun 04, 2016 12:21 am

Took the car for a 30 min drive, highway and city. Temp crept up to 200 a couple of times but for the most part stayed around 190. When I got to where I was going, let it run for about 40 secs, than shut off. As I was walking away she started spewing out the overflow. Lost about 1.5 gal. I don't consider 200 to hot for a 60's era SBC so wondering why? Only thing I can think off would be a burp of air in the system. Made a hell of a mess in the parking lot than made another after refilling and doing a good burp. Temps hit 200 on the way back but the antifreeze stayed where it was supposed to. What say the Gurus, could it have been a little air? Or is 200 too hot?
Gord
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Re: What temp is considered too hot?

Postby Richard Miller » Sat Jun 04, 2016 10:18 am

I would say 200 is not too hot ,, I have seen 220 on a hot So Cal day ,, water doesn't boil until 212 at 1 atmosphere , you have a pressure cap,, raises boiling point ,
somewhere in the system the water got hot enough to boil ,, you probably had an air pocket as you suspect and probably in the cylinder heads the water boiled when it sat and heat soaked ,, but you should be able to run around at temps lower than 200 ,, what was the ambient air temp ? its all about airflow ,, be sure air cannot bypass the radiator and cannot recirculate when fans are on ,, I looked for pics on your member page but none of your radiator setup ,, just be sure that all air entering under your bumper can only pass thru the radiator and not get around it ,, that was my original problem ,, once I fixed all bypass / recirculation paths my car actually ran on the cold side (about 160 ) except in really hot weather . I am redoing my system to a smaller radiator and going to a hotter thermostat to get it warmer ,, I once upon a time crewed on a formula 5000 car ,, it was running about 250 ,, head mechanic said it ran better hotter it got ,, but your car boiled after it was shutoff so you probably had a hot spot due to air pocket
Richard Miller
West Covina, Ca
'65 V8 Vair
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Re: What temp is considered too hot?

Postby sherwood park rexin » Sat Jun 04, 2016 10:44 am

Thanks Richard. Thats what I figured but thought I run it by. I need to enclose front of rad. I've closed off the rear vent under the back window and am using it for outside air to the carb. I think with the engine enclosed there is nowhere for the hot air to escape except along the diff. Maybe the rad enclosure would help keep it a little cooler. But long story short, I thought 200 wasn't bad. Temp yesterday was around 80 f.
Gord
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Re: What temp is considered too hot?

Postby Richard Miller » Sat Jun 04, 2016 4:22 pm

yeah in normal front engine cars air is blowing over the engine and that helps ,, our cars can only shed heat thru radiator or oil cooler ( which I need to add to mine ) .
I have been experimenting with different ways of getting air over engine ,, did you see Doug Hargroves car ,, he has a little wicker at front of engine compartment to push air in ,, of course you can leave the cover off and run around with your naked engine exposed
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West Covina, Ca
'65 V8 Vair
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Re: What temp is considered too hot?

Postby Charleston Nall » Tue Jun 07, 2016 12:41 am

Folks... SBC's don't start making HP until 220F outlet temp. 50/50 raises the boiling temp... 100% coolant LOWERS IT!!

Gord.... did you fill thru tall tube in the middle and not the radiator? Or have you changed that? I know you now have digital instruments so we cannot correlate with what I experienced.... but in SoCal it only overheated once...I forgot to turn on the fan! But I used to run 200 on the freeway in 100f SoCal heat... 3500 rpm [ 70 mph].

Richard... 60% of the trunk is cut away...no problem with airflow as after the front Airdam... it's a negative pressure behind / under the car..

I'd attach a photo, but it says there is no more space for pics..

Sorry, the board attachment quota has been reached.


Forgot I still have the pics in the cloud

Image
Patio"Matt" Nall
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Re: What temp is considered too hot?

Postby Richard Miller » Tue Jun 07, 2016 11:41 am

my original setup had a 33 inch wide 4 core copper brass radiator and 2 , 12 inch puller fans . it was set with the bottom of the radiator at the front and laid back about 45 degrees ,. aluminum panels at sides to close gaps to fenderwells . bottom of trunk cut out back to fuel tank and top of fenders cutout too ,, looked much like what you show here , also had a 6 inch conveyor belt rubber (tough stuff ) air dam at the pinch weld straight down . initial drives it would overheat . I realized air was going over the top ,, only a couple of inches between radiator and hood , so I got a large piece of foam rubber and put it across the top and that helped ,, but still warm ,, then I realized what I had missed which was that air could go out to the sides and up over the fenderwells between the inner and outer fender ,, stuffed foam up in there,,not elegant but it worked , on a cool day car in motion I ran right on the thermostat ,, just over 160 , 165 ,, no fans needed , stops were good to help warm it up a little ,, warm day in traffic fans on about 195 ,, on those cool days it was too col , engine started stumbling and coughing .. my point is simply that I found that if there is any way for air to get around the radiator it will take the path of least resistance rather than go thru the core ,, and if stopped with fans on there is not a low pressure area behind to draw air and if it can the air will recirculate around back to the front ,, I cannot tell from picture if there is space out at the sides of the radiator but if there is I think it will help to seal them ,, off topic ,, in left bottom corner of picture there is a blower ,, I have only recently seen this a couple of times and I wondered what it was ,,is that the factory air conditioning setup ?
Richard Miller
West Covina, Ca
'65 V8 Vair
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Re: What temp is considered too hot?

Postby sherwood park rexin » Tue Jun 07, 2016 10:06 pm

Yeah Richard, that was the factory A/C blower which I have removed. I think part of the issue is there appears to be a lot of gunk in the flow tubes to the engine, also the fact that I now use the rear window grill for fresh air to carb, therefore with the cover on the heat just sits there. Drove today for 15 mins( 28 C) and overflow was puking antifreeze after I shut it down. Gauge temp hit 202f. I fabbed up some tin to stop airflow from going around the rad. Thinking a high flow dual fan and shroud might also help. Matt, when topping up I use the tall centre fill pipe, not the rad. Also tube under vent cap is leaking a small amount around the solder joint and the overflow nipple is loose so I'm not sealing and could be drawing air back in as she cools.
Again, I don't think I should be puking thru the overflow at 200/210. Will do a rad flush tomorrow.
Gord
sherwood park rexin
 
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Re: What temp is considered too hot?

Postby Richard Miller » Tue Jun 07, 2016 11:37 pm

I am trying to decide what I am going to do for some new tubes to the engine ,, probably copper again ,, I have contacted a couple of coating manufacturers looking for something that could be used in steel pipe for corrosion protection , so far one replied that unless application was perfect the paint / gas tank coating could come loose and would be flowing thru the system,, no recommendation .. also regarding rear window vents , I opened up that area under the window and the air flows IN to the engine compartment .not what I expected initially , . interior of car with windows down is lower pressure than behind rear window ,, remember seeing warnings in vans to not drive with rear door windows open because exhaust fumes could enter ? I am playing with corvair heater blower fans ,, and a corvair engine cooling fan , looking to force air in there. hopefully you will get it sorted and can start driving it more ,, good luck
Richard Miller
West Covina, Ca
'65 V8 Vair
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Posts: 142
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Re: What temp is considered too hot?

Postby Richard Miller » Wed Jun 08, 2016 12:02 am

hi Gord ,, I just visited Stewart components website ,, this is from their tech forum ,, " The radiator cap should always be located at the highest point of the cooling system, and on the low pressure side (after the radiator core). " I notice that in the picture the radiator cap is on the tube leading to the top tank , this would be the inlet side before radiator , reason is that pump pressure can force cap open ,, check out their website ,, good info Stewart Components
Richard Miller
West Covina, Ca
'65 V8 Vair
Richard Miller
 
Posts: 142
Joined: Tue Mar 01, 2016 6:25 pm

Re: What temp is considered too hot?

Postby Richard Miller » Wed Jun 08, 2016 12:24 am

and I am back again ,, shutoff computer and walked away , then remembered something ,, in the picture ,, if you are still hooked up like this ,, the hose with the radiator standpipe /cap is going to the top of the radiator , I assume then that is the water returning from the engine to the radiator ,, ( just making sure I am on the right track here ) and the pipe coming up from the bottom is the return to the engine , hooked to the water pump inlet ,, I see no air bleed on that pipe ,, if you have drained and refilled the system there will be a large air pocket trapped in that spot that must be bled out ,, it can restrict or stop flow back to the pump .. take a look at the Greg Riley book on v8 corvairs if you can ,, he covers need for air bleed on pipes ,, I am sure that there are many members on this forum who have been there ,, where are you guys ?
Richard Miller
West Covina, Ca
'65 V8 Vair
Richard Miller
 
Posts: 142
Joined: Tue Mar 01, 2016 6:25 pm

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