[T3] Serpentine Belt on a Type 3 Motor

[John Jaranson]

I did a write up on the Samba about the modifications I made to Jill’s Type 34 Karmann Ghia in order to run a serpentine belt for the alternator for the electric A/C.  Thought I would share it here also.  If you were at the Ticonderoga Invasion last year, you saw the system in person.

Time for a little update....even if it is back dated a little.  

Back before that last Invasion, I wanted to switch to a serpentine belt system to help with the belt slip issues we were having driving the 150 amp alternator (now 95 Amp) for the electric A/C.  Of course there are no kits for this conversion like there are for the upright Beetle motors....so more custom work.  The Type 3 motor also poses the additional challenge in that the crank pulley is also a fan that i necessary for the cooling system.

I started out by turning a stock pulley in my lathe to remove the v-belt groove and the lobes around the outside.  I did leave a flange on the inside edge of the pulley to give me something to mate the new aluminum multi-groove ring to.

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_2.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_3.jpg

Then I got sleeve of aluminum and turned the inside diameter to be a few thousandths interference fit to the modified stock pulley and cleaned up the outside diameter to make sure everything was concentric.

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_4.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_5.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_6.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_7.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_8.jpg

Then I parted off the appropriate length and end up with two parts that now needed to be shrink fit together...

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_9.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_10.jpg

I made a simple wooden fixture to hold the pulley, through it in the freeze and the outer ring in the oven for an hour or so.  Dropped the frozen pulley into the fixture.  Dropped the hot ring over the pulley and clamped it all together to let it come back to ambient and lock together.  Worked great!

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_14.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_15.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_16.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_17.jpg

Next, I had to make a cutting tool that matched the profile of the grooves for the serpentine belt.

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_18.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_19.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_20.jpg

Then I machined the profiles into the ring and cleaned it all up.  I transfered the timing marks to the outer diameter of the pulley (this is one thing I still need to improve by transfer the marks to the outside edge of the pulley so you can see them easier through the timing hole).  The pulley mods were done.  Not just need assembly...

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_21.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_22.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_23.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_24.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_26.jpg

I did have one other mod I had to make.  The idler pulley for the serpentine belt had larger ID than the old v-belt idler, so I turned a bronze bushing to make up the gap.

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_29.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_31.jpg

Assembled onto the motor with all the tin in place.

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_33.jpg

https://www.carartbyjohn.com/JillsGhia/Ghia_Serpentine_Belt_34.jpg

The system works great.  I might try finding and fitting a sprung belt tensioner idler pulley, but for now the static tension adjustment at the alternator brackets seems to be just fine.

We now have well over 6000 miles on this version of he system after the 4500 miles we just put on going to Las Vegas and back.  We have had no issues with belt slippage or the pulley mods.  The A/C system still blows plenty of cold air.  We used it for 4 hours straight one day on the drive out to Vegas and it kept the Ghia nice and cool and comfortable.  It was so much nicer driving with the windows up where Jill and I could actually have a normal conversation in the car.

John