7 Blade vs 5 Blade Fan

[Ron H]

I'm in need of a new fan for my rebuilt '63 318. Motor running hot upwards 220. It has the original 4 blade and have heard that a 7 blade is best and some say a 5 is enough. I have shroud on the way. Any advice and anyone have a suitable fan to sell?
Thanks..

 

[moes]

a 5 blade clutch fan with a shroud will be plenty for a 318 motor to keep it cool while idling at traffic lights and driving at low speeds

 

[Ron H]

Just to give ample details for my question; motor is fairly well tricked up a little hotter cam, bored.60 over, 5-way VJ, mech lifters...

 

[Ron H]

Adding to my earlier post/question: Will a later mopar fan fit assuming the span of the 4-bolt pattern is the same?

 

[66Satellite47]

If you're at 220 you need to look at more than number of fan blades. Radiator condition, T stat, core plug removal & scrape out the crap out of the block.

 

[Ron H]

Motor was totally redone, block boiled, complete machining block/heads new pistons, rods, bearings, HP pump, etc. etc, headers, 3" exhaust, X pipe...radiator was boiled, flushed, checked...you name it. What's been mentioned is the stock radiator with 4 blade fan and no shroud is too wimpy now for the higher HP/compression; but before thinking on another radiator, some are saying they've done fine with a 5 or 7 fan and shroud.

 

[66Satellite47]

Well that's a different deal. A bigger fan sure could help some. My 5 blade clutch fan, aluminum 26" radiator w/no shroud worked great with my 500" aluminum head 10.5 CR motor. Held under 200 for 2+ hours at a few stop & crawl show events at 90*+ temps. Give the 5 blade clutch setup with a shroud a try. Good luck.

 

[oldbee]

Maybe go with 5-blade and no clutch? Oughta work.(and a shroud)

 

[Ron H]

OK, I got an original shroud ordered from a fellow member (have to order the mounting brackets waiting for a reply as yet) and between our posts found a 7-blade 18" fan on eBay indicating from a "late 60's" B-Body. The fan on mine is 18" and would assume (hope) no issues with bolting it on from what I'm told. Only other issue I'd think with the new fan is proper spacing from radiator if my spacer doesn't fit...
Hey appreciate your advice!

 

[oldbee]

For sure a 7blade would work. Good luck, let us know.

 

[Ron H]

Seems like more 7 are around than are 5 so went with it. Will let ya's know and post some photos of the looong and pricy rebuild! Not a project I'll do again two is enough and had my very handy dad around the 1st time sure missed him this time!

 

[Bobo]

I'm in need of a new fan for my rebuilt '63 318. Motor running hot upwards 220. It has the original 4 blade and have heard that a 7 blade is best and some say a 5 is enough. I have shroud on the way. Any advice and anyone have a suitable fan to sell?
Thanks..

 

[rrTor-Red]

Question for you here Ron H. Do you have A/C? If you do, use a 7 blade. IF the car creeps higher than even 200 degrees with a 7 blade, then I'd look at other issues...i.e-water pump, T-stat. Water pump can be wrong for your app (like A/C or not). T-stat could be sticking. Even if T-stat is new or fairly new, I've seen some take a crap right after installing . Just my 2 cents

 

[Ron H]

No A/C. Yeah the T stat was mentioned earlier too. A bud says I should just take it out since never drive the car winters and I have heater bypassed due to an irritating drip from valve I toyed with and gave up. (Carb now is electric choke.)Had it disconnected for years any maybe 2 or 3 times it would have been nice to have. Another irritation is the shop put in stop-leak **** after engine rebuild saying they always do this. Have a tough time buying this as one fitting (pump) showed leakage, incorrect hose fitting, and leaked later too; a correct fitting is on it now. I plan to flush the system out when doing the fan/shroud install. For all I know until I look, the stat could be clogged with the stop-leak stuff.

 

[rrTor-Red]

I'd have that shop clean ALL that crap out of that "Stop leak" stuff. Should NEVER have to use that crap after a rebuild/block hot tanked/etc. and would hope you get some $$$ refunded for it. It's not a shop if "they always to this". That stuff is everywhere in your engine and I'd guess it's the cause of the high temps. WOW!

 

[66Satellite47]

I'd guess you've homed in on the problem. "Stop leak" can really screw up a radiators performance. I'd sure find another radiator shop if they need to use it after a radiator rebuild. It likely won't screw up the block water flow, sure could on the T stat, water pump should be OK.

 

[Ron H]

Yeah I could not get a straight reply on this after a super costly rebuild! And like you everyone I've talked to including three guys that were mechanics and couple others well versed on engine work said they never used this ****. No body said they used the stuff after engine build! Take a nice clean motor and make the radiator look like a septic tank!

 

[JimKueneman]

a 5 blade clutch fan with a shroud will be plenty for a 318 motor to keep it cool while idling at traffic lights and driving at low speeds

I have a counter argument to that. My 318 will barely say under 215 in traffic with the factory HD cooling system (New Glen-ray 26" radiator, fan clutch, 7 blade fan and new motor). You can NOT run the AC in 110F days in Arizona in traffic.

I am about to prove if a NOS pump solves my problem since the GMB after-crap-market pump died in the first 5 months. Cooling is all about surface area of the radiator and the gallons per minute the pump can move.

 

[Ron H]

Since installing the 7-blade fan I got off eBay and shroud I bought from a forum member I bead blasted and painted, and then using a toothpick for an hour opening some bent fins; it has made a big difference with cooling. I also removed the stat since I have heater bypassed and have electric choke/headers anyway. Using laser temp before/after, it's been running some 20-degrees cooler than it was. I've been running mostly water so far after some flush additive having flushed the system three times now before I'll put in a 50/50 anti-freeze mix. This is to really clean out that stop-leak **** that engine shop tossed in. So far so good. As I understand this is the exact factory setup with A/C equipped car that year (63). I can't say what will happen if it's 100 degrees out as we seldom see these temps in WI; but reckon we still have some hot weather before the snow flies here for me to find out..

 

[JimKueneman]

Since installing the 7-blade fan I got off eBay and shroud I bought from a forum member I bead blasted and painted, and then using a toothpick for an hour opening some bent fins; it has made a big difference with cooling. I also removed the stat since I have heater bypassed and have electric choke/headers anyway. Using laser temp before/after, it's been running some 20-degrees cooler than it was. I've been running mostly water so far after some flush additive having flushed the system three times now before I'll put in a 50/50 anti-freeze mix. This is to really clean out that stop-leak **** that engine shop tossed in. So far so good. As I understand this is the exact factory setup with A/C equipped car that year (63). I can't say what will happen if it's 100 degrees out as we seldom see these temps in WI; but reckon we still have some hot weather before the snow flies here for me to find out..

View attachment 500916

Please keep us posted as to what happens when you go to 50/50. The theory and data I have seen I would predict the temperature will increase by about 10 degrees F by going from pure water with additives to the 50/50 mix. It is hard to get 2 days to be the same for a good comparison though.

Jim