496 overheating
 

Hello, the car is a 1972 Ventura. I originally had a be cool radiator with two one inch tubes, the radiator is 26X19" and the core is 22X19. I had a 2700 cfm electric fan with a shroud on it and the motor would creep to ~230-240 and I would shut it off. The weird thing is that if I let the car sit at an idle, and dont drive it, it never gets over 200. As soon as I start driving it, it slowly starts creeping up. We figured that the radiator must be clogged as it was an old radiator so we bought a new triple pass FSR crossflow radiator. We are still using the same fan and shroud and it runs a little cooler, but still gets to 220-230. I am wondering if a mechanical flex fan with a shroud would have a good chance of solving the problem. I think the electric fan and shroud may be causing more airlfow restriction than anything and that the mechanical fan would help. Below is the fan and shroud I am thinking about as well as the fan and shroud I currently have. Does anyone have any experience with a mechanical fan and shroud like the one I am looking at?

This is the exact fan and shroud I currently have.
http://cgi.ebay.com/ebaymotors/64-67...mZ150125394870

This is the flex fan I am considering
http://www.jegs.com/webapp/wcs/store...44431_-1_10115

This is the shroud I am considering, I may run two, one right side up on top and the other one upside down on the bottom.
http://www.jegs.com/webapp/wcs/store...56129_-1_11483

If it matters, I have a march pulley kit with a long water pump

Thank you
Adam

1st off you did good by getting another raditor....i think your problem lies in the speed your running water thru the block...
at this time is sounds way too fast.......this explains why it heats up when you start moving the car in gear.The manual water pump speeds up with the crank speed therefore starts circulating the water faster...The water is not in place long enough to draw heat away from the block..

what size pulley do you have on the water pump and what are you using where your thermostate goes ?.......Your gonna need a restrictor in place to slow the water down.....most people just take the center out of the thermostate and place it back under the water neck..
try this 1st before changing pulleys...the next step would be to change the pulley to a slower rpm pulley...but i think the restrictor will help a bunch

Brian

It currently has a 180 thermostat. The water pump pulley is 5 inches and the crank pulley is 7 inches which would spin the pump pretty good. I will have to try a restrictor plate. Do you have any experience with the mechanical flex fans? Is there a reason that you say it is a good idea that I got a new radiator?

Thanks,
Adam

Do you have the fan sucking or blowing, that can make a difference when driving.

I originally had one sucking, now I have both. Going with both make a little difference but not much.

Adam

If you have the fan pulling air into the radiator through the grille, I would agree with bjuice, its probably thermostat related, the water is traveling through the radiator and block too fast to be cooled down when rpms are up.

Have you tried it without the shroud, that looks like it would trap alot of heat, but I have never ran one like it.

Adam...no paticular reason for the radiator you had..however the cross flow is an ideal radiator.. i run one of those also with no over heating problems...many do not know of this company but a few guys left "Griffin" radiator and opened up their own Raidiator shop here in the upstate of S.C.....their name is "KARRHOUSE" out of Anderson S.C....they will custom make any radiator for anyone..i have a custom CROSS FLOW MADE with 2 ros of 1.5 inch tubes...for $330.00......

take out your thermostate and take the center of the thermostate out ..this should just leave a flat metal shim with a 3/4 inch hole...

try this 1st..its quick, inexpensive and may just work.....

if it doesn't help enough your going to have to slow the water down by placing a different pulley on the water pump that will slow the water down...


yes i have had some luck with the flex fan's..they are good on a true street car that see's a lot of street driving...keep your electric fan on the car and make sure what ever side you have it mounted on thats its pushing or pulling the right direction.

i think you will find that when you slow the water down you will not need a electric fan.

i have a 511 bbc in a 3,000 lb camaro...i run a CSR water pump and i have an adapter ( see jegs part#555-53087 page 70) that comes off the top radiator outlet that allows me to run a #12 braided line into a #12 fitting that bolts over the waterneck...so you can see how i restrict it..
i can make a full pass and come right back around into stagging for another pass and it never gets above 185 degree's

take a look at ( jeggs part#555-51105 page 71)..this is what the restrictors look like if you bought one instead of making your own..


i have Years of round track experience as a Pit man and garage monkey, we have diagnosed and fixed many overheating problems..,from spiining a water pump to fast to fabricating a high tech shround with vent ducts etc...

i would bet A SHINING PENNY...you place a restrictor in place of your thermostate ...1st.....then 2nd if it doesn't cool it down enough...get a pulley to slow it down..

thanks- Brian

I'm having the exact same problem? :evil: I have a 10 1/2:1 540 in a 3100 Monte Carlo, Griffin radiator 3000 cfm electric fan..had it pulling air from the back side of the radiator, now in the process of moving it to blow thru the radiator. I also had a 160 thermostat, then put a 190 in and no luck. Also, tried taking out the antifreeze and put in straight distilled and water wetter..which I believe kinda helped? I did put a March underdrive pulleys on, which still didn't help...HELP!!!??? Think taking out the thermostat and running just a restrictor will help me too? Thanks in advance for the good info already!

yes i think it will...water moving to qucikly thru a block is the culprit in many situations...try the restrictor..also make sure your cooling system is purged really well...One air pocket will cause you a heap of problems.

when i purged mine i left my electric wtaer pump on for 30 to 45 minutes straight with cap off front wheels elevated 3 inches off the ground.

deadenbear makes a bolt on water neck that will purge for you but its expensive plus its something you can do on your own..

BRIAN

I have a question. If I gut out the thermostat wouldn't it flow at the same rate, but now all the time? By the way thanks again.

its really hard to tell cause a thermostate has been known not to perform as it should....Running hot sometimes is hard to define such as a car cutting back...too much fuel or not getting enough fuel.

with this said by eliminating the mechaincal function of a thermostate you will isolate the problem......i know i have went on saying water moving to quickly thru a block will cause heat problems...but also water moving to slow or not at all will cause the same problems..

when you gut the thermostate you are taking the guess work out of the thermostate situation....

i'm i making sense///LOL//or i'm i confusing you ?... :lol: :D ..

give it a try and see what happens..

let us know.

Brian

I will let you know how things work. It will be a few weeks since I start night turns tonight :cry: !! Whats your feelings on coolants? Thanks again, Doug

Thanks for the replys, I am taking the shroud off and adding another pusher fan that I had laying around. I will try a restrictor and a larger water pump pulley if that does not help.

Adam

it s probably best not to run the ANTI FREEZE coolant off the shelf..if you ever blow a head gasket it can do some extra damage to your engine such as wiping out bearings etc....

to be honest i have run anti-freeze in some of my motors in the past but never hurt anything such as blown head gaskets etc...if its a street /strip car i would run it in a heartbeat....I WILL NOT run it in my 632..

but we do in our street strip cars "our" meaning me and the wife...
she had an over heating problem with her 406..i had a 160 thermostate..i took it out and placed a 3/4 restrictor..and no more problems with over heating...

its been nice speaking with ya....and remember there is no such question as a dumb question..
i am not a motor builder but i pride myself as a good tuner and maintenance man on my stuff

Brian

Did a plug check and found antifreeze in the number 8 cylinder. Had the head pulled and the gasket looks OK. The head is off getting checked for cracks. The block was checked before the motor went together so I would think it is OK. The machine shop guy said that there is a chance that the valve guide is leaking. I'll keep you updated.

Adam

Finally got around to running my new setup with restrictor...now-------I have a 3/4" restrictor (gutted thermostat) and still heats up. Doesn't seem to heat up as quickly but I had to shut it down because temps would start climbing quickly after it hit 200 degrees. Manual fan time or smaller restrictor? I'm about to give up...Help!

Copied this off another site, it may help.

I bought my 80 Bu with 12"dual electric fan unit(Flex-a-lite #210) and now that I drive it on hot days it runs warm..I went to Atco last week and it was 85-87 outside and in that heavy traffic on route 73 the engine temp was up at 205 on some on the trip,on the way home it was 70 out and still ran at 180...now going back to my old 87 SS Monte I tried 2 12" fans and found it wanted to go over 210 all the time,till I remove them and installed a 19+" Flex fan (Flex-a-lite#1319) and that droped the temp a lot.............So I bought one for the BU and it was 83 out today so I went out for a test and even in traffic it would not go over 165 and when the traffic started moving it went down to 155.So you want a hell of a good fan try a 1319 Flex-a-lite............... :COOL OLDHEAD,PS: Thats using a stock shroud with the 1319

firestone

Any updates?

The problem is solved. First, all of the exhaust valve guides were leaking, the #8 cylinder was the worst. They were bronze. We were told that on big block heads, for some reason this tends to happen with bronze guides. We replaced the guides with steel ones. Block, heads, and head gaskets were checked and were OK. The motor was put back together and it cooled much better, but still had a little trouble. We took the electric fan off and bought a non flex mechanical fan. We had a custom shroud built and it completely solved the problem. It just sits at 185 when the car is moving. If you stay in one spot idling for a long time it will creep up, but if it is driven for 1/2 a block it drops back to 185. I think a larger radiator would solve that but I am happy with how it does now. Thanks for all the help.

Adam