FAN

I need some help. I am told that to increase the cooling for my engine I should use a standard diameter crank pulley and use a 356 - 36hp generator pulley. It will over-drive the fan slightly giving better cooling. True or false? If true where do I get a 356 pulley and will it fit on an alternator shaft?

Hey Robert!

I can't even pretend to have anywhere near the expertise that others on this site possess, however there are a few basic laws of physics that apply to the function of the cooling fan..

With regard to the cooling fan, after a certain rpm that fan is not capable of moving any more air regardless of the rpm's generated by pully sizes. I notice you are located in Arizon so my guess is that it gets pretty hot where you live. IMHO your best bet is to install an external oil cooler with a thermostatically controled electric fan (automatic with a manual over-ride for you to use at your discretion). This would be in conjunction with the stock oil cooler (keep that where it is). If you are unable to do this yourself, I would guess a ball-park figure for a shop to install it would be around $300-$400 depending on configuration.

Anyway, that's my two cents worth - I'm sure there will be plenty to follow!

Robert; there's about an 11% increase in cooling when using the 356 pulley; VS equips their cars with them. You can get them at www.klasse356.com or at www.mamotorworks.com and yes, they'll fit the VW generator/alternator.

Isn't a 356 fan or a welded balanced VW fan also recommended for the higher revolutions since the stock VW ones can fly apart?

Wolf; if you're not going to beat on it there's no need. On the other hand if you're going to race it or rev it up by all means get it.

Hi Robert: When I was in Az. I too was running a tad hot. When I was there you guys were hitting in 120 degrees, whew it was hot. I sincehave changed my fan and houseing to a 911 type with a twelve blade fan. By doing this I now don't have a dog house oil cooler. I have two external oilcoolers with a fan. Now the thing is it runs very cool. Hammering along my return trip from Pasa Robles , when I pulled up into my drive, the fans ran about twent seconds the shut off. It is an expensive change over but in my opinion well worth it. My brother lives in Clarksdale Az. and I make that trip with no heating problems whatso ever. I too would recomend an aditioal cooling fan, you will notice, it will run cooler in traffic. You can have one of those sand dune places do he work for if you want. You have a couple good ones in your area. Ray (oldman) goodluck.

Thanks for all the info guys, but at the prices they want for a 356 pulley I think I will just go with a stock one and an external oil cooler with thermostat, which I already have.

FYI jake Raby did a big cooling system test about 2ys ago. Interesting read. Here is one of many links
www.shoptalkforums.com/viewtopic.php?t=64410

Robert, am I missing something? At www.klasse356.com the price for a pulley is $17.25 for the inner half and $9.00 for the outer half. That's certainly less expensive than retrofitting the engine with external oil coolers....

The 356 upper pulley coupled to the stock Type 1 lower pulley increase fan drive ratio from 1.58:1 to 1.93:1.

In my testing of this pulley with all the stock and aftermarket shrouds the 356 pulley was good for a 25 degree head temp and 10 degree oil temp reduction.

The negatives are the fact that the increased drive seriously reduces the point when a fan explosion can occur RPM wise. I had a stock, non welded fan explode at only 5,000 RPM, where generally that fan would not explode to well past 6,500 RPM with the stock ratio.

basically, if you want to run the 356 pulley, do so but use an OEM cooling fan and have it WELDED AND BALANCED! don't buy one that comes from China!

with the 356 pulley fan speeds at 6,000crank RPM are almost 11,500 RPM at the fan!

Here's an interesting article on VW cooling fans.

http://www.offroadvw.net/tech/wes/fan.html

Great article Dave!

Hey Dave!

Great article on fan cooling! I learn something useful everytime I visit this website. Kinda like "Mythbusters" for Speedster replica owners.

Thanks for sharing that info!