Rebuilding 240Z heater/vent system PICS

[bjhines]

There is one point to this that I have not tested... And I likely won't get to test for a long time...

Will the original heater resistors and wiring handle the higher current draw???...

If they will... what about the switch and the harness wires...???

The Fuse that powers the relay high current side is 20amps (that one inline behind the control panel... Oddly enough the circuit for the blower in the fuse panel had a 20amp fuse as well... though all it runs is the relay coil side(0.5amp)...

It would seem to me that I could leave the fuse panel wiring alone and only rewire the high current side of the relay (20amps currently)...

but that would still leave the original switch and resistors in the high current circuit..

I would need to source another set of resistors and another higher current switch in order to really improve the system wiring... That is a large task.. I think I will install this blower into one of my operational 240Zs to make sure it works without serious electrical modifications...

Another thought is that the original switch could be used if it were only operating a bank of relays that provided for 3 fan speeds... the only problem there is sheer complexity and added weight...

[hls30.com]

Ohm out an original motor and the Honda replacement,and the difference will tell you-if you also ohm out the circuits(all closedswitch settings) they are going into. Using ohms law with the results will paint very clear picture!

Will

[bjhines]

OK... just got done testing resistance of the motors...

I used DC and turned the fan to dozens of positions and found this...

Original 240Z datsun fan::::::::::::::::::::::::::::::::

30% of the tries I got 0.7 OHMs

60% of the tries I got 0.6 OHMs

The Datsun motor showed variations(0.8, 0.9) at some points that would indicate wear and age... I tossed these out of the data...

Newer Honda 88-92 fan motor:::::::::::::::::::::::::::

90% of the tries I got 0.5 OHMs

5% of the tries I got 0.6 OHMs

5% of the tries I got 0.4 OHMs

... You might see a 25% increase in power usage... A 20 AMP fuse might not be enough when it ages and begins to stick... I think it will work fine though...

[GreenZZZ]

Variation of this inspiring thread...

Painted with POR. For padding, I used black headliner material, some thick closed cell foam for the actuator arm seal, and regular 1 1/4 inch AC gasket foam. Didn't use vinyl like a should have, but love the results. Took me almost a whole day to cut and glue the pads into place. I used 3M Hi-Tack 76 spray adhesive so I blew a bunch of time masking glue areas. A good brush on adhesive would have been a better choice.

The heater core in the photo is total B.S. It's too wide making the fit a stretch (literally) and tall preventing the flap actuator from moving. Fortunately my stock core was rebuildable as it didn't have much rust. Click the link for higher res shots.

http://www.classiczcars.com/photopost/showphoto.php?photo=33852&ppuser=14083

http://www.classiczcars.com/photopost/showphoto.php?photo=33851&ppuser=14083

[gnosez]

Great post and I'm saving this for next year's project list since I also need to replace my heater core.

One quick question - Why do you need heat (and added weight) in a race car?

[a7dz]

I had the same problem with the replacement heater core. I too had the original rebuilt.

[bpilati]

Super job, looks great.

[GreenZZZ]

One quick question - Why do you need heat (and added weight) in a race car?

BJHines hasn't posted in a few years, so this will probably go unanswered, (this is a very old thread), but having more air in the **** pit with the Honda blower upgrade can't be a bad thing. Nascar guys have a box of ice and run the air to their helmets through it. The guy who basted my shell does the same thing with his respirator. Creature comforts, and the weight associated with it, can get you better performance I imagine.

Lee