Cooling Fans, Early / Late 1.7 and 2.0 A Comparison. Options

[Sleepin]

I had a question: Can I use this late 2.0 fan on my early 1.7? A search didn't yield much, and most of the responses I got was "I dunno, it should work".

Well here is what I found:

I had an early 1.7 that was missing way to many fan blades for me to want to use:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0090.jpg)

Here is the front of the early fan and the factory screw (note: this uses the same wrench as the factory CV bolts do):
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0085.jpg)

The early fan and factory bolt has an 11mm contact surface once it exits the fan:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0086.jpg)

I wanted to measure the depth as well, just to be sure. 20mm:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0087.jpg)

The only other measurement I could think of was this one:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0095.jpg)

[Sleepin]

Now the late (1976) 2.0 Fan (note this has a hub for spinning the air pump):
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0089.jpg)

A longer bolt on the late model than was on the early model, but still a 11mm contact surface:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0094.jpg)

The same 20mm depth:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0092.jpg)

And the same "backspacing":
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0097.jpg)

Now I printed off the Pelican timing mark template:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0108.jpg)

Here is where I did have a question...this is the early 1.7L fan, and it does not match up with the Pelican template. Does anyone have the answer?
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0103.jpg)

I have learned that you just need to watch for the bolt length. If the bolt is too short, you will not have sufficent contact area to hold the fan on. If you have too long of a bolt (say a late bolt in an early fan) you will wipe out the oil seal on your block. Using the bolts that come with the fan work well between the engines, given an 11mm contact area outside of the fan.

If you need to restamp the timing marks with the Pelican template, just make sure you are printing it at 100% and not 110%. (IMG:style_emoticons/default/wink.gif)

If you think that four blades are not reason enough to seek out a replacement fan, just do the math. 31 blades, 3 missing = 10% loss of cooling efficiency. Just something to think about and dont turn the engine over with a screwdriver on the blades!

[Katmanken]

You didn't even mention the balance issue with the missing blades...

Nothing like adding an unbalanced load to a crank shaft that can spin over 5K (IMG:style_emoticons/default/blink.gif)

[Sleepin]

(IMG:style_emoticons/default/agree.gif) I figured it was a given. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/biggrin.gif)

[McMark]

Here's one thing to note right off the bat, although it's minor, the '0' is TDC and the red notch is 27*.

Also, I'm not sure if early T4 bus or 411 motors came with that 'early' style fan. Those motors, at least the bus ones, didn't read the timing through the hole in the fan housing, so they are marked differently.

So, while I'm not sure, you could have an early bus fan and not an early 914 fan. Can you still read the part number on the early fan? It would be stamped in blue ink on the inside surface of the fan.

[McMark]

Try this, lie both fans 'upside down' on your work bench and clock them both so the crank alignment pin is in the same location. Then transfer the timing mark locations to the back face. I bet your early fan just doesn't have a TDC marking and the red notch is still at 27*.

[Sleepin]

Try this, lie both fans 'upside down' on your work bench and clock them both so the crank alignment pin is in the same location. Then transfer the timing mark locations to the back face. I bet your early fan just doesn't have a TDC marking and the red notch is still at 27*.

I did this Mark, just by laying the two fans on top of each other and eyeballing them, it appears that there is not a TDC mark. Not sure what the mark on the early fan is though.

(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0113.jpg)

[Sleepin]

Here is the back of the early fan:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0102.jpg)

Here is the back of the 1976 fan:
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0107.jpg)

[sixnotfour]

1.7 litre engine They are 5 degrees before TDC (static timing mark) and 27 degrees before TDC (dynamic timing mark).

[Sleepin]

Makes total sense! Thanks Jeff!

[Cap'n Krusty]

Nevermind. Sleep fogged my brain ......... The Cap'n

[TheCabinetmaker]

Is he not viewing the fan from the rear?

[Sleepin]

Here is a pic of the early bolts on the late fan. Notice the 4.5mm contact area (ie. Don't do this):
(IMG:http://i171.photobucket.com/albums/u307/Sleepin1974/Dads%20914/108_0091.jpg)

[McMark]

Eric, is it coincidence that your login is Sleepin' and that last picture looks like eyelids closing? (IMG:style_emoticons/default/idea.gif)

[Sleepin]

No, that was a "it is so cold the camera shutter wouldn't open all the way" pic! (IMG:style_emoticons/default/lol-2.gif)