Pulleys and Fans

I have read several posts discussing the advantages of changing to different pulleys and fans to lower engine temps. I read about "welded fans", "356 pulleys" but cannot seem to find a single post that really discusses this well and provides recommendations with definitions. When discussing pulleys, I assume the one generally refered to is the one on the alternator. Can one or more of you that are better educated in this arena than I provide some more detailed information.

Thanks much

Troy

Well, Troy, 356 generator/alternator pulleys are smaller in diameter as compared to a regular VW one so when you install one in lieu of the original one, it will make the fan go faster and thus get more air movement from the fan. Welded/balanced fans are used for engines that are going to see higher revs; that is done to prevent the fan from self destructing at such RPM's. I can tell you that my VS came from the shop with the 356 pulley; check to see if yours did too. I can also attest to the fact that the fans on VS cars are the regular ones and not the welded/balanced variety.

Thanks Ricardo, now for the tech question: what is the diameter of a standard pulley and for the 356 pulley so I can tell which I have.

Troy

That's a difficult question but I know Steve O'Brien can jump in and answer that one; he measured the one in my car and told me it was the 356 style. Next best thing would be to compare it to a regular VW one side by side and you'll know for sure right away.

OK so what is the diameter of the one on your car

I checked a couple of parts sites and noted that 356 fan pulleys are three pieces front, rear and hub. Is this the setup that those of you that have them installed use?
Troy

Troy, checked mine and it looks to be around 3.75" give or take. And yes, it's a three piece number and it fits the Bosch alternator perfectly.

Ricardo,
Thanks very much. Noting that the 356 is a 3 piece unit it makes it clear that mine is not. Now for another question. Since the 356 fan does not seem to use shims, how do you adjust belt tension?

Troy

The unit in my car has lots of shims; inside and out just like in any regular VW. In fact, real 356's do use shims too.

They don't have shims if they don't need them, but otherwise the pulley adjustment is exactly the same as the VW version.

Thanks guys

The 356 upper pulley coupled with the stock lower pulley from a TI increases drive ratio from 1.58:1 up to 1.9:1.

I did see benefits of this drive ratio change with EVERY cooling system I tested in both head and oil temps. The change has a few drawbacks that you have to accept to gain its solid 25 degree decrease in head temps and 15 degree difference in oil temps. These numbers were a constant through the testing no mattter the shroud..

* YOU MUST HAVE A WELDED FAN! The fan sppeed increase will get you to the exploding point of your fan at a much lower crank RPM than the stock pulley. Even witha welded fan you can still have issues above 6,000 RPM so try not to take your engine over that point with the high ratio drive. DO NOT ATTEMPT THIS UPGRADE WITHOUT A WELDED FAN!!

* You will lose some HP... Wityh the added drive ratio the fan is placing more load on the engine. As a general rule as I tested all the shrouds I saw a 6HP +/- loss with the ratioed fan across the board with every shroud. The higher the RPM the more the HP loss, but remember that an engine that is cooled better will be more efficient and therefore will make some extra power so on the road you may have the same power you did with hotter heads and it won't be notable

* If you have a generator instead of an alternator the voltage regulator will hate you because the unit is being turned like hell by the increased ratio so watch for some overcharging symptoms.

Thats about it, good luck- you don't want to blow a fan- trust me..

Jake:

Good post....I often wondered whether a welded fan would be needed - just seemed like it made sense to add one while changing the pulley since you don't have a lot more to remove to get at it and I already thought it would be spinning a lot faster...

Do you have a list of Summer events you'll be at on your website? Might like to catch up with you and your traveling show.......

gn

Thanks Jake, advice well received and I will certainly take it. The cost of the fan is a lot less than the alternative.

Now for the next chapter: Anyone have suggestions for a source for a good welded fan?

Troy

Troy; there's lots of vendors offering them; check Hot VW's Mag. Bugpack, EMPI and others manufacture (or modify them). Otherwise you can't go wrong with Gene Berg. I know the Gene Berg is $100.00. I checked on the CB Performance website but couldn't find it offered.

Thanks Ricardo.
Have a good weekend. We have our first sunny weekend in a long time here and It's time for a drive.
Troy

Gordon,
Thanks for the compliment.

I have abandoned the show scene for the remainder of this year. I have 3 big contenders all fighting for a national championship in SCCA E & F production this year and we are wide open working on their development in hopes of a huge title that has not come the way of the aircooled engine in 20+ years.

The only show I will be at is after the national race in September at Circle Yer Wagens in Sevierville Tennessee on the first weekend in October.

BTW- I weld and balance fans for 40.00 you simply send yours to me for the 1 day service. I only do this to the original German fans however..

Wow Jake; that's a great rate; how do you know if you've got a German fan in your car?

"Hey Hans, dis guy ist askin 'how you know you have und real German fan in your engine'?"

"Oh, Fritz.....you are such a kidder.....EVERYONE knows how to tell if der fan ist really German, don't they?"

"Ya, Hans, you ask it, 'Hey, Spraken zee Deutch?' und if it says, 'Ya!', ist German, no? Ha, Ha, Ha!"

"Ya, und if it is stamped mit "VW" und it has der part number '113-119-031' on it, und is stamped 'Germany" or 'Deutchland', it comes from der Fatherland, no?"

"Ya, Hans, und if it has "Hecho en Mexico" or "Brazil" or "Taiwan" stamped on it, ist NOT a real German part, no?"

"Ya, Fritz.....those should be trown-avay ast Junk!"

"Ya, Junk!....OK, back to Verk!"

Ya vol.... my Cap-i-tan, das iz da vay du explan der goud and der bad blowderveel!

Capi-tan Gordo: Das forgenzee to give ya der vubber seal at Carlisle
u vanted ....dus u vant me der send avay tu u ....ya ?

Alan:

No, but zat Jerome guy, out in der Vest, he might need some, ya?

Maybe you shoot ask him vat he's gonna build fer hist vindow-siden, ya? He vonts to ride in der rainen, but vy, I ask you, Vy? Alls he gonna do ist get Vet boots!!

Jerome......You gonna make zee Vindow-siden und do you need der rubbergasketen?? Maybe you gonna email Alan before he trows it out??

Guys you crack me up!...I guess it's very difficult to find new German VW units nowadays right?

No....ist easy....chust go to der junkyarden und find un old Volkswagen for pull-apart.

Maybe you cund find der old, grizzly VW mechanic like Fritz, und see if he vast und "Packratten Guy" und maybe he hast un or der unner his bench or in his cubbords, ya? Dey pretty cheap dat vay, too!

Maken sure, tho, dat you getten der Gud Vons from 1971 - 1973 for der vider fan blades (und getten der shroud mit generator mounting plate with it) und THEN you can usen der bigger oil cooleren back dere, und then you can make ICE on dat engine it'll be runnin so cool!!

Hans, Der "Factory VW Guy"

Ya, Ya, ic bien need der rubbergasketen.

I vil emailin heir Alan with mine request.

Dos anybouten have a goot sauerkraut recipien?

Jerome

Ya, My Grandmuddern (both of 'em) had recipies for der Saurkraute, but they never wrote dem down....one was for der Purple Saurkrauten - Ach der Lieben! Wast really gut, too!

Now, mit un Irish wife, all I ever get is das Silver Floss from der Val-Mart Sooper-Center!!

Off to see der little Liebchen und Future Speedsterer!!

gn