Pre Heater Hose

[mx71]

I've had the factory Hitachi carb put back on my 85 KC 4x4, and now I'm looking to get the pre heater hose back on. I measured it at 1.6", but I'm not finding one that size. Anyone know what size hose I need to order, or maybe a Dorman part number or something?

[Rjawm]

 

 

https://shop.advanceautoparts.com/p/dorman-help-carburetor-pre-heater-hose-1-9-16-in.-x-21-in.-paper-aluminum-96038/5191637-p?c3ch=PLA&c3nid=5191637-P&c3apidt=25883818074&gclid=EAIaIQobChMIxqa4nP791gIVBwtpCh1NsQOIEAQYASABEgJbRPD_BwE&gclsrc=aw.ds

 

 

 

 

It was a tighter fit but not too bad, plus I figured it would actually stay on better.

[mx71]

Thanks!

[720_Jeff]

The one suggest is fine, looks to be the same dimensions as 

http://www.rockauto.com/en/moreinfo.php?pk=14534

Which was at one time listed as the proper replacement.  I think original was a silver colored hose should anyone want original look on that part.

 

The one thing you don't want is the replacements that are made of foil, basically.  Like this one:

https://www.amazon.com/Dorman-HELP-96020-Preheater-Hose/dp/B000C5E8RY/ref=pd_lpo_vtph_263_lp_tr_img_2?_encoding=UTF8&psc=1&refRID=EZY0Q5ASN3XW4V9V8P5G

 

These are pure crap and fragile as can be

[mx71]

Well, the one posted and that I ordered looks to basically made of cardboard. Why is cardboard and foil so common? Why wouldn't anyone use actual rubber hose?

[datzenmike]

The heat. The air is warmed by 600-900F exhaust manifold. The foil and fiber 'stove pipe' is usually pleated so it's compressible/flexible. It's thin enough to be cooled by the air on the outside. You can try 'rubber' but I think it will just dry it out and shrink/crack. There's probably a good reason why makers use what they use.

 

The ATC (auto temp control) mixes cold outside air with warmed air to feep 100F air to the carb during all seasons. It uses an intake vacuum controlled motor and a sensor. The engine is tuned to run in this 'comfort zone' even when well below zero. It eliminates carb icing also. Under full throttle the intake vacuum drops and the ATC closes off the warmed air and only cooler air from in front of the rad is used for best performance. When the outside temperature rises above the sensor setting of about 100F it closes the exhaust heated air off. 

[mx71]

That makes sense. Thanks! It's really cool how that works. I wish the internet was more popular when I had an 82 Datsun 720 in high school. It would have been cool to find all this out the first time around.

[datzenmike]

What I like is no parasitic draw like a pump. It's totally passive in design and function.

 

 

 

Right now you only need it for a visual pass????

[mx71]

I actually already passed. I just want it for the winter since I park it outside, and I'm obsessive about not leaving things unfixed. Gone are the high school days of removing everything possible.