What is the correct fan and pulley for 3.0?

[Jim2]

I'm cleaning up a 3.0 for my car and came to realize I have the wrong ratio pulleys on this engine

The fan, with large holes I think is 901 or 2.7. Is the pulley too large for the needed fan speed on a 3.0?

The crank pulley which was on the engine was this single groove 4.5". I also have this cast iron two groove pulley which measures slightly under 5" or 125mm. Is this the correct diameter?

[Dpmulvan]

Sc’s came with 126mm pulley.

[Dpmulvan]

And I believe that fan is aftermarket.

[boyt911sc]

Originally Posted by Dpmulvan

Sc’s came with 126mm pulley.

‘78~’79 SC’s have the 126-mm diameter fan not pulley.

Tony

Edit:

The fan is 226-mm and incorrectly referred as pulley. My mistake. Thanks for the correction.

[Jim2]

Originally Posted by boyt911sc

‘78~’79 SC’s have the 126-mm diameter fan not pulley.

Tony

Tony, you must mean 226mm fan, not 126. Otherwise my head is going to explode!

This fan I have here in my picture is 245mm, which I believe is the same diameter as 80-83 SC fan. However, based on internet pictures of SC engines I only see fans having the small diameter pulley hub, but I can't really tell if they are the 226mm fan or 245mm fan.

Dpmulvan, it looks like my spare two groove pulley is the correct diameter, only within a mm of measurement error.

[boyt911sc]

Originally Posted by Jim2

Tony, you must mean 226mm fan, not 126. Otherwise my head is going to explode!

This fan I have here in my picture is 245mm, which I believe is the same diameter as 80-83 SC fan. However, based on internet pictures of SC engines I only see fans having the small diameter pulley hub, but I can't really tell if they are the 226mm fan or 245mm fan.

Dpmulvan, it looks like my spare two groove pulley is the correct diameter, only within a mm of measurement error.

My reading compression is getting worse each day. My mistake. Thanks for noticing the blunder. Going 80 in a few months.

Tony

[Flat6pac]

You’re picture is an early fan with the 8 large holes and pulley half to match
The fans changed to small holes and larger crank pulley and 725 mm belt out 76
77 was the 5 blade fan. The 78/79 with smaller fan and large pulley. Factory was using heat to meet emission requirements
1980 the factory went back to larger fan, smaller pulley and 710 belt.
Bruce

[Jim2]

Bruce, could you clarify for me, in 1980 you say they went back to a larger fan but was it with the large holes or small holes?

Thanks for chipping in all of you!

Tony, someone posted a picture of you from one of your engine classes, I'd never have guessed your age. Keep on with what you are doing, it's keeping you young!

[boyt911sc]

Originally Posted by Jim2

Bruce, could you clarify for me, in 1980 you say they went back to a larger fan but was it with the large holes or small holes?

Thanks for chipping in all of you!

Tony, someone posted a picture of you from one of your engine classes, I'd never have guessed your age. Keep on with what you are doing, it's keeping you young!

I am leaving for the tennis court in a few mins. playing against 50 years guys younger than my children. They take longer and more rest time than the oldest player in the group. Stay healthy and be happy.

Tony

[Trackrash]

Several variations over the years. Check this thread for all the details. 993 fan on a Carrera?

BTW, I am running a '71 fan/pulley on my 3.0, ('78). I tried different crank pulleys/fan belts and could not tell a difference in engine cooling.

[thetorch]

I found this useful from another site (914 forum):

fan belt sizes:
1965-75....9.5 x 710
1976-77.....9.5 x 725
1978-79....9.5 x 725
1980-on.... 9.5 x 710

[Jim2]

Man do you guys deliver! Thanks for the link and your feedback Gord. I remembered Bill V had some data but could not find it.

Torch, I'm going to print that chart and keep it among my parts. I think back now and realize I puzzled together random combinations in the past. I've got a 3.2 here which I'll borrow the fan from in order to get the 83mm hub. That chart is exactly what was needed. You mention the chart is from a 914 forum, this 3.0 is going into a 914.

[thetorch]

Originally Posted by Jim2

Man do you guys deliver! Thanks for the link and your feedback Gord. I remembered Bill V had some data but could not find it.

Torch, I'm going to print that chart and keep it among my parts. I think back now and realize I puzzled together random combinations in the past. I've got a 3.2 here which I'll borrow the fan from in order to get the 83mm hub. That chart is exactly what was needed. You mention the chart is from a 914 forum, this 3.0 is going into a 914.

Good to hear. I ended up down this rathole when a powdercoater ruined my fan, which appeared to be original from my '69. But like you I have a 3.0 (with 3.2 crank and top end), and figuring out the correct fan, fan pulley, crank pulley and fan belt combo was a learning adventure.

This post is also informative about how much air is moved.
Question on Pully Size - for increasing cooling

[Trackrash]

BTW, one other detail. You can use the old style upper outer pulley half like in your pic on the new fan, if you want the vintage look.

You can also experiment with different fan belt lengths, which will change the ratio, since a shorter fan belt will ride on a smaller diameter on the upper pulley.

[Mike Andrew]

My 80SC 3.0 fan pulley has 4 sets of 3 small holes. No holes in outer pulley half.