[five7kid]

I've never been really happy with the cooling performance of my current set-up. It's a Griffin aluminum radiator, 6-cyl position, no tranny cooler, with a stock replacement water pump and "high performance" 160 degree thermostat from Summit (forget the brand). It will go above 180 even in cool weather, cruising or stop & go, and when it's warmer, 190-200, with excursions above 205, especially when pulling off the freeway. This spring I removed the engine driven aluminum flex fan for a puller electric that pretty much covers the radiator, didn't really change anything.

I'm thinking the water pump is the culprit. I picked up an aluminum unit with backing plate, hope to install it this evening. Before I do, I'm going to flush the system good & proper as well. Picked up another thermostat (supposedly the best one available) to try as well.

Sure hope this takes care of it.

 

[ThrashN]

Maybe the coolent is pumping through to fast, not staying in the radiator long enough to cool down.
Just a thought

 

[five7kid]

I've considered that. The best way to prove that would be to remove the thermostat, which I could do.

Early results indicate the surging temps have disappeared. Putting the bypass hose back on probably did more than anything else for that. I took the back plate off of the old water pump, didn't see anything wrong (was in a hurry, didn't think to try to spin the impellor on the shaft). The thermostats were of the same design, (forget the brand of the old one, other than supposedly being a "super stat" from Summit).

I alos found some pieces of flat hard plastic on top of the tubes in the upper tank. Still baffled as to where that came from - had to have been left there by Griffin. It was fun digging them out with long needle nose through the cap mount.

 

[ThrashN]

One more thing to consider. Is the pump turning the correct way?

 

[five7kid]

Yep.

 

[Daz]

Timing maybe?

Or maybe just fan is not big enough.Im using a stock 87 IROC rad and dual fans and it stays cool all the time.One other thing to consider is how fast the fan is spinning.How is the electric fan wired.I have mine wired straight to the battery and use one relay for each fan. Mine is permanently on.I have to figure out a way to stop blowing relays though.I go through them at least one a season.


Daz
BBC in a thirdgen Camaro

 

[five7kid]

The fan is wired directly to battery power, switch operated. It seems to move a lot of air.

It gets hot whether cruising on the street or down the highway.

Timing is 38 total mechanical plus vacuum.

I can't remember now if the bypass fitting(s) had a restricted opening. If so, I've got full open fittings on now, I may need to get a smaller opening type in there to restrict the amount of hot coolant that goes back into the pump.

 

[Daz]

IsYour fan is mounted in front of the radiator?..If not then maybe its too small..or the direction is reversed. I seem to remember a picture of your motor with a fan in front of the car(Carburetor board TGO).That fan looks a little small I think. 38 degrees plus of timing seems high too fo timing

 

[five7kid]

It's a different fan than in that photo. Puller mounted behind the radiator, as big as can be mounted directly on this radiator.

BBC's like a little more timing than SBC, and this is at 5800' elevation. Retarded timing tends to overheat more than advanced timing.

 

[Daz]

I agree with what you said..but the only time I see total timing needing over 40 degrees is when you have a big cam and not so good flowing heads..

 

[Johnnynova]

I cruise around 170-180. Griffin rad 27 x 19. 17" flex fan with 1/2 shroud, Aluminum CAT waterpump( I know it's offshore but it works great Ebay $70 new)
March Seperpentine underdriven pulley's no thermostat, 12-1 compression.38 degrees of timing. Was you engine driven fan shrouded??
Hope this helps.

 

[five7kid]

The engine driven was shrouded.

I pulled the by-pass fitting and welded a flat washer to it to restrict the flow. It seemed to help a little, but it still got up to 200 on me yesterday and was only high 80's out.

Perhaps pulling the thermostat is the next logical step.