924Board.org

[RC]

Decided to start this thread here since another one in the for sale section is growing but will eventually vanish into obscurity.

After sussing out other blower drives decided to mount mine forward of the alternator and water pump drive. And just for fun chose to also convert the V belt to a flat polyrib PK section belt.

Heres a few pics of my progress so far:





This shows both sides of the crank pulley and the high tensile M16 x 65mm (2 1/2") bolt and hardened steel washer I made to secure the gear pulley. Stock bolt is only 50mm (2") long. Also the locating dowel on the crank has been increased from the standard 4mm to a 5mm hardened steel one.



Alternator pulley:




The water pump pulley has been shown elsewhere so wont bother posting it again. This pic was taken before I had finished the alternator one, painted the fan and installed it properly. Gives an idea though and will update it soon when its complete.



Roger

[Rich H]

Loving your work
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

[endwrench]

WOW!! Thats all I can say.

Are you a hobby machinest or do\did you do it for a living? Very nice work. Wish I could do stuff that nice.

Todd
_________________
'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

[Martijnus]

combine that with a built in 36-1 triggerwheel and I'll buy a kit
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

[RC]

Thanks for the compliments guys.

Not much of a hobby machinist as I dont have a lathe but I used to and played around with it a bit.. I`m an electronics tech so this is not my line of work. Just took it slow and careful to try avoiding mistakes.

To be fair these were made on a new 14 grand lathe with a digital readout at a mates small machine shop. We do some mutual back scratching and he kindly lets me use his equipment when theyre not being used.

To start with I ground a piece of 1/4" tool steel to a 40° angle to cut the Vs. After determining a starting point the digital readout made it easy to index the 0.140" or 3.56mm rib centres. The hairyest part was using the boring bar to get the bores spot on. After that it was just some enjoyable carving as the dimensions were not critical except for the end face to rib measurement.

To get the holes right on the crank pulley i used an old timing gear, located in the 29.98mm (tight 30) bore and a 17/64" drill that was a tight fit. After centralizing it was clamped in a mill drill, checked again for a free up/down movement and then drilled through. Used a handful of 17/64 drills, placing them in the drilled holes to tightly locate the gear while setting up for the next hole. Once I had all 6 holes I would locate the centres, clamp it tight and then changed to an 8mm drill and opened them up. Repeat this 5 times.

Then the pulley was flipped over and the same slow but accurate procedure was used to centralize the 14mm holes for the cap screw heads. I took this down around 15mm visually by looking at the depth gauge. With the pulley still clamped I changed to a 14mm slot drill I think theyre called, like a mill cutter with a square end face. The stop was set at 16mm and drilled. A slight deburr with a countersink and the job was done.

The whole thing was a learning experience for me but I am really happy with the result. Thats why Im wanted to show them off here.

Well guess what Martijnus, I wont be making any more. Am happy to post my drawings if you want to have a go. Dont you work at a machine shop?

Did actually give a lot of thought to incorporating a toothed wheel as Im also running a MS. However decided against it for a few reasons. With no intention to get into an OT debate about ignition systems will say that EDIS is good for a stock system using a VR pickup and some basic digital electronics to process the signal that was used up to about 10 years ago. It is now outdated and I am confident that in the short term can achieve an equivalent result (correctly timed spark of desired duration and intensity) using a modded distributor, MS and a high energy ignition that I already have.

In the near future when MS hardware and software allow full sequential injection and COP ignition a cam wheel will be required anyway. So I chose to remain using the dizzy short term and then just doing another change for the better later and fit a cam wheel.

Roger