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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23002
Location: Oklahoma City
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 Posted: Tue May 20, 2025 10:50 am Post subject: Re: Jeremiah's 73 412 restoration project |
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| Jeremiah Berger wrote: |
| raygreenwood wrote: |
| Jeremiah Berger wrote: |
Ok so what about the VW stamp in the pulley? Is that just coincidence that this lines up with tdc in that quadrant? Or do any of the other pulleys have a VW stamp like mine?
Also considering what you are saying the weight is actually in the same quadrant in each instance correct? Let's call it 730-1030...
If I put my logo mark at bottomdc I get my weight at about 930.
That is some consistency I guess being all in the same quadrant? |
Forgot to look for the vw logo. Checking later.
Ray |
Thanks Ray, I'll check back in a bit. |
Ok.....I looked at three of the four fans I have handy. One is disassembled and in hindsight I should have checked it as well because if it has bus timing mark on the pulley as well a 0 for the 411/412 timing it would have been one more indicator.
It literally took me 30 minutes to find ANY VW stamps and no two were the same size/diameter. Very faint. One hidden by aftermarket paint and the other two were shallow and rusted over.
So....
Fan #1 is off of my engine. It is a spinner style with the rubber nosecone. It's positions are known to be factory. It has the "0" for TDC and the red mark for 27°BTDC....and the bus timing mark on the pulley......and it has the VW logo corresponding to "0"/TDC.
Fan #2 is a flat faced bus style fan from a bus. It has no "0" for TDC like those used on 411/412.....but placing it with the locating pin at about 10:30 and counting fins over to find where TDC is.....you can see the bus timing mark on the pulley at ~10:30-ish.....and yes....there is a VW logo at the 12:00/ "0" position.
Fan #3 is kind of a mess. It has been disassembled....and painted black all over including the aluminum section. It has the spinner style, cone shaped aluminum section and it has a "0" for TDC so it was originally a 411/412 or 914 fan. But, it has a timing mark in approximately the right position for the bus but it's not a factory made mark. It also has one at 180° to the bus timing mark so someone had made marks to be able to find TDC on all four cylinders.....and its VW logo is at ~3:00 position.
So I would call this best intelligent guess from two data points that the stamped VW logo on the pulley should be at 12:00/TDC.
A great way to get a good cross section of data points is to ask the guys in the bus forum to put their engine at TDC by the timing scale and see if a VW logo appears on the pulley at 12:00.
I will also add this information to both of my threads on type 4 fans. One thread is all about all of the different timing marks and the other one was linked here already about recentering the fan pulley.
If this turns out to be a common item.....VW logo at 12:00 TDC....it can help a lot of people.
Ray |
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Jeremiah Berger
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Joined: September 16, 2018
Posts: 132
Location: MAINE
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| Posted: Tue May 20, 2025 11:24 am Post subject: Re: Jeremiah's 73 412 restoration project |
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Ok, well I in the meantime have talked to my machine shop vw guy about rebalancing it and he wasn't really set up but could send me with a crank to the place that does his balancing or something...but he then says he's got piles of fans if I want to come get one and can have one.
So I saw you response and called him back and he said I could come look through them all I want.
If I find out they are all stamped at tdc then I'm good to go.If not I will just grab a new fan.
I also have a type 2 bus parts guy real close and I can see if he has any fans I can look through if I'm indecisive with what the machine shop has to look through. He said he has piles of them, so we'll see.
I might be able to do that tomorrow so I'll post an update afterwards. Thanks again for the help. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23002
Location: Oklahoma City
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| Posted: Tue May 20, 2025 1:23 pm Post subject: Re: Jeremiah's 73 412 restoration project |
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| Jeremiah Berger wrote: |
Ok, well I in the meantime have talked to my machine shop vw guy about rebalancing it and he wasn't really set up but could send me with a crank to the place that does his balancing or something...but he then says he's got piles of fans if I want to come get one and can have one.
So I saw you response and called him back and he said I could come look through them all I want.
If I find out they are all stamped at tdc then I'm good to go.If not I will just grab a new fan.
I also have a type 2 bus parts guy real close and I can see if he has any fans I can look through if I'm indecisive with what the machine shop has to look through. He said he has piles of them, so we'll see.
I might be able to do that tomorrow so I'll post an update afterwards. Thanks again for the help. |
The other way to look at this is ...that if you get the pulley back on very well centered with the dial indicator....and you then have a noticable imbalance....ther are ony 4 positions that there could be.
I would just loosen it back up, take the pulley off and rotate it 90*....recenter it....and run it again. Yes, its tedious but it can get you back to where it ws when it left the factory.
If you end up having to do this with the engine in the car....thesimplest way is to make a bench top board with three dirt cheap skate bearings on a piece of MDO board with the dial indicator mounted on the board.
Once you get the hang of this you can put a fan on the board and get it recentered in roughly 10-15 minutes of work.
An even easier method if you set up this board...once you get one fan perfectly recentered, but three fixed pins on the board that bear against the pulley ring at 120* apart so you can take a fan bolted to its hub....put it in the bearings with the four bolts loose and the three fixed pins around the perifphery will push the pulley ring the center position the econd you put the fan in the jig...and then just tighten the four bolts. Done. Ray |
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Jeremiah Berger
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Joined: September 16, 2018
Posts: 132
Location: MAINE
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| Posted: Wed May 21, 2025 8:32 am Post subject: Re: Jeremiah's 73 412 restoration project |
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Well after climbing through an attic full of vw parts and looking at a good 10+ fans I can conclude that the VW emblem is not an indicator of tdc.
In fact I was able to find a total of 5 since so many where rusted or painted I couldn't even find the stamp on them.Of those five three where at bdc one was at 3 o'clock and I believe one was at 9 o'clock as well ...
So it seems like it is by chance that the ones you have are lined up at tdc...
It's a 1 in 4 chance.
So the pulley was likely stamped on the line all in the same spot, but then that was taken and matched to the aluminum fan. At this point there was a 25% chance that it could end up at tdc so not surprising that you have some and a good chance there are a lot out there that it does line up
But I would conclude that it is not an indicator.
I got a new fan. It has the 0 and the type 4 timing mark.Its in the sonic cleaner...I will paint it without taking it apart and move forward....
Moral of the story...DONT DISCONNECT THE FAN FROM THE PULLEY. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23002
Location: Oklahoma City
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| Posted: Wed May 21, 2025 11:19 am Post subject: Re: Jeremiah's 73 412 restoration project |
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| Jeremiah Berger wrote: |
Well after climbing through an attic full of vw parts and looking at a good 10+ fans I can conclude that the VW emblem is not an indicator of tdc.
In fact I was able to find a total of 5 since so many where rusted or painted I couldn't even find the stamp on them.Of those five three where at bdc one was at 3 o'clock and I believe one was at 9 o'clock as well ...
So it seems like it is by chance that the ones you have are lined up at tdc...
It's a 1 in 4 chance.
So the pulley was likely stamped on the line all in the same spot, but then that was taken and matched to the aluminum fan. At this point there was a 25% chance that it could end up at tdc so not surprising that you have some and a good chance there are a lot out there that it does line up
But I would conclude that it is not an indicator.
I got a new fan. It has the 0 and the type 4 timing mark.Its in the sonic cleaner...I will paint it without taking it apart and move forward....
Moral of the story...DONT DISCONNECT THE FAN FROM THE PULLEY. |
 ....unless you mark it!
I have concluded though that somewhere either near the end of 411 or in the middle of 412 production....they started making fans that would work on more than one vehicle....like buses and 412's or maybe even 914's.
Hence why over the years I have found more than a few fans that have both:
1. the engraved marks on the aluminum fan portion....various combinations of the 0, the red 27* BTDC mark, sometimes another black mark correspsonding to something in between the two, some fans with no 0 and only a black or red mark.....and....
2. Also having a "0/TDC" mark at approximately 10:30 position on the pulley ring that cooresponds to the offset bus plastic or metal timing scale.
If you can find a fan like that....or just put the bus TDC mark or the 411/412 TDC mark on the pulley ring yourself.....you will never again have an issue with disassembling it and getting it out of balance.
Oh...and do yourself a favor. Go ahead and set up the dial indicator and make sure the pulley ring is concentric to the fan casting of your "new" fan.
The problem is that over the years, so many owners could have done so many things.
Also, if you can....get a good spare fan.
My original 412 fan is missing two blades. One was me doing the stupid and one was something that fell into the fan. They are 180* apart so I will do a others have done and smooth off the nubs and/or knock out two more to keep it balanced in all four quandrants. I will keep it as a spare.
It can happen to anyone. Get a spare fan. They will get less and less available as time goes on.
also if you have not seen it....here is a good thread about type 4 fan timing marks from the 911/914 forum.
https://www.thesamba.com/vw/forum/viewtopic.php?p=8776292&highlight=#8776292
Also in that thread is a guy with a fan that has no "0"...but also has the VW symbol at TDC.
I cannot tell if I am halucinating but it almost looks like a small "0" symbol hiding in the rust above his VW symbol????
Ray |
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Jeremiah Berger
Samba Member
Joined: September 16, 2018
Posts: 132
Location: MAINE
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| Posted: Sat May 31, 2025 3:51 pm Post subject: Re: Jeremiah's 73 412 restoration project |
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Finished the engine today! Just need to put the exhaust on and it's ready to mate to transmission and install....
I am back to where I was 10 years ago and in need of the first part I ever tried to find.. if anyone has one let me know. I had some ideas of using other materials but it is a tricky piece because it has to flex into place and have the flat section where it is sandwiched between the intake and lid.
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