Type 4 Fan assembly questions

[captain_kapow]

Are the critical dimensions of the 411 fan, crank hub and smog pulley the same as that of the Vanagon assembly?

Are there benefits of one fan assembly over another?

Vanagon fan part # 070 119 113 A

411 fan part # 021 119 113 N

I ask because I am rebuilding a spare engine for my Vanagon Westfalia, and I was about to send the rotating assembly out to be ballanced (fan, crank, pistons, flywheel etc). I spent some time and effort restoring the fan assembly from my donor engine, but realized that the hub size is different than that of the vanagon. This raised questions about the assembly as a whole.

I am wondering if the 411 assembly will play nice with the vanagon fan shroud? If not I will need to pull my van off the road and remove it's fan assembly to use while balancing the rotating assembly.

I have attached photos of the assembly I restored as a visual aid.

Any insight is appreciated.

[raygreenwood]

If you took the fan apart....it MUST....now be trued on a lathe or live center as it NEVER goes back together straight. The pulley section has upwards to .025" of radial play in its bolt holes. Its tedious to do. You can do it on the crank at home...hand turning the engine over....with a dial indicator and wheel point in the pulley groove. Tighten the bolts just snug.....Turn....measure....tap.....tighten.

Then it MUST be balanced as a seperate assembly before adding it into the parts pile for overall engine balancing.

As far as I know the main fan design should be fine for vanagon. I would check with the vanagon guys on here or the Samba for sure. The hub is different....but the mount to the fan should be the same. The fan is largely the same. The differences in fans out there are mainly the floor of the fan on the inlet side. 411 and early 412 and early bus had the aerodynamic snout....all later models used the fan with the drive dog for the smog pump.

Seriously....if you took the fan apart and did not spend the time to true the runnout of the pulley.. the vibration will throw belts, is hard on the alternator bearings and the crank seal and # 4 main bearing. Ray

[oprn]

Interesting! I took mine apart to clean it because it was such a mess, then I always give the steel parts a light coat of Tremclad paint...

Thanks Ray I will true it up.

[captain_kapow]

Thanks for the warning!
Looks like I will be correcting the run-out on a lathe.

[captain_kapow]

Thanks for the warning!
Looks like I will be correcting the run-out on a lathe.

[captain_kapow]

If you took the fan apart....it MUST....now be trued on a lathe or live center as it NEVER goes back together straight. The pulley section has upwards to .025" of radial play in its bolt holes. Its tedious to do. You can do it on the crank at home...hand turning the engine over....with a dial indicator and wheel point in the pulley groove. Tighten the bolts just snug.....Turn....measure....tap.....tighten.

Then it MUST be balanced as a seperate assembly before adding it into the parts pile for overall engine balancing.

As far as I know the main fan design should be fine for vanagon. I would check with the vanagon guys on here or the Samba for sure. The hub is different....but the mount to the fan should be the same. The fan is largely the same. The differences in fans out there are mainly the floor of the fan on the inlet side. 411 and early 412 and early bus had the aerodynamic snout....all later models used the fan with the drive dog for the smog pump.

Seriously....if you took the fan apart and did not spend the time to true the runnout of the pulley.. the vibration will throw belts, is hard on the alternator bearings and the crank seal and # 4 main bearing. Ray

So I attempted to get the pulley straight.
I couldn't get it to work with my cheap lathe, so I used some V blocks.

The radial runout started at about 0.025", and I got it down to about 0.003".

Is 0.003" close to what I should expect? I'm not sure if I'm dealing with a practical limit, or if there is more centering to be had.

Here's a photo of the setup.


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[raygreenwood]

Excellent! I have done the same with a crank in a case on an engine stand. Bear in mind.....you may be seeing surface imperfections in paint in the .003" range. The critical area to the fan belt harmonic is in the valley of the pulley. Give it a spin and check there as well. Also check the runnout of the crank on bearing #4 closest to the tapered snout. You may find some of the runnout there. In any case... .003" is pretty good.

Also..are you using a wheel tip on the dial indicator? That really helps. Ray

[captain_kapow]

Excellent! I have done the same with a crank in a case on an engine stand. Bear in mind.....you may be seeing surface imperfections in paint in the .003" range. The critical area to the fan belt harmonic is in the valley of the pulley. Give it a spin and check there as well. Also check the runnout of the crank on bearing #4 closest to the tapered snout. You may find some of the runnout there. In any case... .003" is pretty good.

Also..are you using a wheel tip on the dial indicator? That really helps. Ray

I didn't have a wheel tip, that's why the tip isn't in the v. Just a ball tip. I'll see if I can track a wheel tip down.

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[raygreenwood]

Mcmaster carr has them. Kind of pricey for stainless steel. The aluminum ones are about $25
Ray