using dual pass radiators

[chevy art]

my buddy runs a 355 sbc in a buick skyhawk. it a pump gas motor with a supercharger. he has a serious overheating problem. cant even drive car to work for fear of overheating. he uses a dual pass radiator with a 16 lb cap. he has already torched one engine with this setup, even burning off the ceramic of spark plugs. he runs a good aftermarket waterpump and a good puller electric fan. i heard that double pass radiators need to run with a tremendous amontt of pressure to be effective. any comments of this bad situation my friend has with this setup. all inputs appreciated. thanks art in NY

[Roundybout]

Dual pass radiators do require a higher pressure to achieve the same flow volume as single pass radiators. They also reduce the velocity and turbulence required to get good heat transfer to the tubes. A high volume/flow pump can help as well as a high fin count radiator. Making sure the air is funneled through the radiator is important also along with ignition timing requirements at cruise speed. Sounds like a combo of things that may need looking at.

I'd have him try a high fin count aluminum/brass single pass along with that pump with a couple electric fans. Should be enough to cool a healthy big block in traffic.

[ClassAct]

Buy a better radiator. A two core with the biggest cores he can get. Ditch the electric fans if he has them. Get a high flow water pump and a Stewart Components thermostat.

[Racing68]

If it's street use, get rid of the double pass. The only way i've seen them work well is in circle track use. 1:1 pulleys at least 7000 rpm and no thermostat any thing less and they would overheat.

[ProPower engines]

my buddy runs a 355 sbc in a buick skyhawk. it a pump gas motor with a supercharger. he has a serious overheating problem. cant even drive car to work for fear of overheating. he uses a dual pass radiator with a 16 lb cap. he has already torched one engine with this setup, even burning off the ceramic of spark plugs. he runs a good aftermarket water pump and a good puller electric fan. i heard that double pass radiators need to run with a tremendous amount of pressure to be effective. any comments of this bad situation my friend has with this setup. all inputs appreciated. thanks art in NY

Is he running a T/Stat??? What temp??
He should get a 22-24 lb race rad cap as well. They do need higher pressure.
Also what muffler and exhaust tube size is he running??

[cjperformance]

What does his advance curve look like?
And yes, turf the double pass for street use.

[CharlieB53]

He needs to check the basics, water flow rate through the motor.

How old is the lower rad hose? Is the anti-collapse spring still in there?

[Geoff2]

Have a look at www.stewartcomponents.com. Some very good reasons NOT to use a DP rad.

[peejay]

He needs to check the basics, water flow rate through the motor.

That is the problem with dual pass radiators, they take more water pump pressure to flow the same amount of coolant through them. It also increases the likelihood of pump cavitation because of the drag on the inlet side of the pump, which is why everyone says you have to run a higher pressure cap.

[jeff swisher]

I used a small 19x22 dual pass FSR on the street in my 57 chevy with 350" no cooling issues at all.
No thermostat and I used an autozone HD water pump which had more impeller blades and a plate on the back of the impellers.

My cap was 13 psi.
But my engine is built loose and even the single pass without thermostat works fine.
Could be his piston to wall clearance is tight. I built one years ago .0015" piston to wall and it did in fact run hot and was way down on power.
This was old school long skirt cast pistons.
Ended up getting a new radiator that was 3 core copper brass that fit a 1977 Oldsmobile delta 88 and it had so much capacity it ran 160 f no matter what.

That was many years ago and I know those radiators are all gone.

[BLSTIC]

This might be unexpected, but what's the airflow through the radiator actually like? I've dealt with four cars now that were overheating messes simply because the airflow with their front-mount/aftermarket bar/missing parts/hood riser was done with madness rather than method.

I'd have to go measure it again on my current standard car to be sure, but I recall the pressure across the radiator going from .2"H2O at 80km/h to .6" and it being the difference between something that dropped coolant at every stop light to something that only switched the fan on when you were stopped for more than a minute.

It would be able to be tested with some clear tubing, a 2x4 and some food dye (although I have a real gauge). The prototype ducting and undertray parts were coreflute, duct-tape and bits of foam mattress.

[MadBill]

...
It would be able to be tested with some clear tubing, a 2x4 and some food dye (although I have a real gauge). The prototype ducting and undertray parts were coreflute, duct-tape and bits of foam mattress.

I use clear tape and a yardstick for the manometer.

[chevy art]

thanks for all the info. i will tell my friend to log on and look at all your responses art in NY

[stealth]

Wait a minute...

Tell us what pump
What fan
What ratio pump running at

Engine details?

What do u mean torched one engine

Porcelain off plugs sounds like something is way wrong other then cooling system

[chevy art]

hey stealth. engine is a 333 sbc aprox 10-1 comp. with a supercharger(not sure of type). im sure he said it was a good brand alum pump(maybe stewart). pulleys were not same. so it was not 1 to 1. was runnint a dual electric pusher fan and a 16 lb radiator cap. he burnt the chlinder wall from running super hot and had detonation. which is probably what wore the porcelain off the spark pluga. hope this helps with you analysis. thanks art in NY