Technical electric or mechanical?

hey everyone,
looking for feedback on the electric vs mechanical fan decision.
on the verge of ordering a shroud to help my 16"electric pull fan(2200 cfm) or, installing a 14"mechanical w/ shroud.
i run a gm 350 stuffed into a 49' business coupe.
fighting over heating problems/boiling over.
any insight greatly appreciated.
thanks. Eddie-nyc

 

I would always prefer a mechanical fan over an electrical fan, both for cooling efficiency and for aesthetics. But use a standard fixed blade fan, not a flex fan. It will cost some HP and add some noise, but IMO it's a worthwhile trade off to ward off cooling troubles and improve the look of the engine compartment.

 

Remember the cooling Rule of Thumb. Runs hot at highway speed - not enough radiator. Run hot at low speed - not enough fan. Which is it?

Gary

 

I have used both and really don't have a real preference. It is just a decision that I make on a case by case deal.

I like a clutch fan myself, but I have been known to use whatever is laying on the shop floor. If you go clutch use a thermostat clutch and not a centrifugal clutch.

 

thanks for the reply Gary, too hot at high speed is the problem. i'll have to hack away stock brace for a larger radiator. just thought the right fan/shroud combination would help. cheers.

 

ok thanks. i'll look into mechanical fan components for the upgrade.

 

eddie, your not listening, you don't even need a fan at highway speed. I've built a couple of cars with electric fans with a switch to turn them off at highway speeds. A fan is not your problem. If your running hot at highway speeds you need a radiator. I prefer a mechanical steel engine driven fan if feasible but have used electric fans with good results as well.

Gary

 

It actually doesn't take much of a radiator to cool a mild small block that is properly tuned. Before I started hacking the core support I would look into the T stat. I use a Mr Gasket fast acting stat in my 355. Moroso also makes a good one they are about 11 bucks. They both use an old trick that hot rodders have used for eons, they have a few 3/16 holes drilled around the perimeter, it is to enhance high speed cooling.

Anyway before I started hacking and buying expensive stuff I would try that.

 

A stock specification '49 Ford flathead radiator ....IF IN TOP CONDITION....should easily cool a properly setup SBC.
You likely do not need a physically larger radiator, you need to insure you have a good radiator and the engine does not have other problems creating excessive heat..

Ray

 

Has it given you problems from the beginning?

 

eddie, if it was a T stat you'd run hot at low speed as well. Save your time and money and buy a radiator. That original 6 cylinder radiator in your car is not designed to cool an SBC.
Hnstray who said anything about Ford flathead radiator?

Gary

 

gary, you're not listening. i answered your question about highway speed and took your advice about increasing rad size. then shared my initial thoughts about the fan. (read again.)

 

6 or V8, I think it would cool an SBC........but not if it is a 68 year old corroded POS. A new radiator designed to fit in the same space of the original would have plenty of surface area with stock dimensions and a 3 row (or 4) core.

Ray

 

yes. always been too hot up top. (sustained highway speed.)

 

like i said, GM 350. all V8's to my understanding.

 

eddie, why replace the fan? If the fan was at fault you'd overheat a low speed. I don't want you to replace anything thats not necessary. Just trying to help.

Gary

 

you don't undertsand....i KNOW your engine is a V8, my reply was in response to Gman0046's comment about a 6 cylinder radiator...which was never mentioned as such.

Ray

 

thanks man, i like the sound of that. is there a part # and or temperature rating for this thermostat? cheers.

 

I hate to muddy up the waters here but sometimes boiling over and too hot are two different things. Example: your small block will run @ 210 all day long, but it may boil over at then temp. Bad rad cap or not enough rad cap is the problem there. Higher pressure cap or one that isn't too worn will cure that.

Now your SBC will not like to run a 220 for any length of time, that would be too hot.

Make sense?

Ray is correct in his evaluation of the radiator, we used to use those old 6 cylinder radiators all the time when ray and I were kids. But sometimes we had to get them rodded out. That is a service that it damned hard to find these days.

Looks like they have gone up since last year to about 15 dollars and the part number for a 180 is 4364 or MGR4364 if you are buying from Summit Racing.

If you go to your local autozone or like store and ask for a fast acting stat or a Mr Gasket high performance stat they should have one. 180-195 should get you where you want to be.

 

eddie, why not just remove the T stat and try it? Costs a lot less the buying a new one.

Gary

 

Well just for the fun of it there's an old (farmuseonly) truck(nothambfriendly ) and it had a v6 taken out and replaced with a MILD treefifty (350), running the same old V6 rad w/ shroud and all is WELL.
PS its an OBVIOUSLY small rad we had our doubts but so far so good.

 

i know and appreciate that you're trying to help, but please understand. I AGREE with you! i was conveying my thoughts about the fan BEFORE i read your advice. what you said about rad size for highway cooling makes sense, and helps greatly. thank you again.

 

just found your post Gary. i failed to mention that the rad had been replaced when new motor was installed. it's a larger alum one.

 

You guys should be rodding out your own radiators.

 

It's a Dodge/Plymouth Coupe not a Ford....At least a that's what is in the Avatar.
From what I have seen most OEM radiators of the period should cool a SBC very well. That is assuming the radiator is in good shape.

At top speed the fan becomes a nonissue. It's the same principle that supersonic jet fighters do not use wing mounted .50s They outrun their own bullets.
Here's some questions.....
Do you have good airflow through the engine compartment?
The air has to go somewhere. If the engine is in a pressurized void no fan or rate of speed is going push air through if it has no place to go.
Is air escaping before it gets to the radiator and engine?
Air is going to take the path of least resistance.

Remedy.....
Make sure that air is directed through the radiator. Make sure that air is directed around the engine and has a place to go....usually down and underneath....Maybe to the sides. Many cars had pans and seals to direct this airflow and they get tossed.

Is your radiator in good shape?
Is your cooling system clean and clear?
A block full of rust sometimes even casting sand will cause problems.
Is your engine in tune?
Is your engine assembled correctly?
Sometimes head gaskets installed incorrectly will cause problems.
Are the heads...block compatible?
It seems some 400s had problems with head....coolant passage compatibility....been a long time.
Has the block been bored close to it's limit?
The only thing you can do here is increase the cooling capacity of the system.
Is the water pump working and if so....Is it turning the right way?
With serpentine belts...some water pumps are reversed.
Start with the simple stuff then move on to the more complex.

 

not a problem to chime in Ray. happy to hear your views.
iv'e had both symptoms, pinned temp gauge and boiling over. tried pulling over at 220 deg to cool down.
and yes.makes sense about rad cap being a culprit. thanks too, for the thermostat info/ i'll check into it.
ciao. E.

 

This is the HAMB. You know--- *traditional* rods & customs.

The HAMB-appropriate solution would be a mechanical fan with a good radiator and probably with a shroud.

Default to an electrical fan if- and only if- a mechanical fan isn't sufficient.

 

The electric fan verses the mechanical fan debacle has been going on forever.

There is probably more threads on this subject than most anything else,I am no fan of electric fans and I have been outspoken about the subject,with that said if you run a mechanical fan the is a cheap aluminum flex fan your going to run hot,they don't move air and are inherently dangerous.

Centering the fan on the radiator,preferably the biggest that will fit and of steel construction and a quality radiator and you shouldn't have a problem,some applications require a shroud others don't.

I have said it before but poor planing in the building stage can make the difference,no room in planing for a engine driven fan and the electric is your only choice.

Tell use about the radiator and what engine/tranny your using.

All the cars that fall under the Hamb approved banner came equipped with mechanical fans and there is no reason why you can't use a mechanical fan. HRP

 

I'm late to the party but after reading these posts I'll toss in my pocket lint,
1. Thermostat like Beaner suggested (he knows his stuff),
2. radiator cap (not mentioned yet, proper pressure required for cooling,
3. fan shroud whether it is mechanical or electric,
4. and if electric don't hang it off the radiator core especially off an aluminum radiator. Build a proper shroud and hang the fan off of it.