Vintage heater piping

[zanman]

Could use some help as I am working on installing my vintage heater/defroster. I cannot identify with certainty where to connect the in and out fluid lines. I have a forte 427 and am posting a pic of my bypass line and other open manifold piping that came installed on the engine from Mike. I can’t find any good pics of other vintage installs to see what I should be doing here. Advice and installed pics would help a ton.

Thanks!

[rich grsc]

All hoses that connect to the water pump are return flow, any connected to the manifold or thermostat housing are output flow.

[phileas_fogg]

As Rich said, you need a port on your manifold or thermostat housing to feed the heater, and a port on your water pump for the return. On my 302, I used the port behind the thermostat housing for the feed (the sensor in the t-stat housing is for the temperature gauge on the dash). A lot of builders don't like the gauge sensor in the t-stat housing, and use a tee connector in the port on the manifold to connect both the heater feed & sensor so that it's "upstream" of the t-stat. I used the port at the bottom of my water pump for the return. Due to some interference between the screw-on heater hose connections and the valve covers, I cut the screw-on connectors off and beaded the copper with this tool: https://www.amazon.com/gp/product/B000A8FTIU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1. I used 90* hoses from Napa (https://www.napaonline.com/en/p/NBH10071) and 90* elbow connectors (https://www.napaonline.com/en/p/NBH9924) to route the bulk of the hoses along the 3/4" member at the top of the framing. I didn't install a heater bypass, so hot coolant goes through the core at all times; one day I'll probably install a bypass (https://www.oldairproducts.com/product/25-1018-bypass-heater-valve) to minimize the heat behind the dash. The hoses pretty much disappear when the body is on. I don't remember if the heater core is directional, or if you use either hose fitting for the inlet, but I feel like it's the latter.

Hopefully these pictures will help, and give you some ideas on what to do for your big block.


John

https://thefactoryfiveforum.com/attachment.php?attachmentid=189115&d=1692562468

https://thefactoryfiveforum.com/attachment.php?attachmentid=189116&d=1692562468

https://thefactoryfiveforum.com/attachment.php?attachmentid=189117&d=1692562468

https://thefactoryfiveforum.com/attachment.php?attachmentid=189112&d=1692562356

https://thefactoryfiveforum.com/attachment.php?attachmentid=189111&d=1692562356

https://thefactoryfiveforum.com/attachment.php?attachmentid=189113&d=1692562356

https://thefactoryfiveforum.com/attachment.php?attachmentid=189114&d=1692562356

[cc2Arider]

I've been wondering about this, too, since I also have a Forte 427. Got it: manifold or just before the thermostat is outflow and the small tube near the water pump is inflow.

Thanks

Craig C

[zanman]

John - thanks those pics and your write up are super helpful!! I actually used that port for my water temp sensor. The port closer to the pump I used for the thermostat sensor for radiator fan. I guess I may have to rethink it. Thanks again.

[zanman]

So i checked again and looks like I have another free port on the manifold. Can you guys checkout this pic. Any reason I can’t use the port I have circled in yellow? This would be perfect as it’s actually right near the heater intake tube.

Also John I noticed on the url to the Napa 90’s you sent they are 5/8 by 3/4. I’m assuming you had to upsize the piping? My manifold ports appear to be 5/8 so I’m thinking I can just stay 5/8 whole way? Thanks again guys.

[zanman]

Sorry it didn’t attach the pic.

[Norm B]

With the mod I made to move the heater forward to facilitate a glove box, I too had to shorten the heater tubes. I cut them off and soldered a 90 degree npt adapter to them. I found the heater tubing to be very thin and slightly less than 1/2 inch in diameter. Here’s a picture of my hose routing. I followed the path used on Mustangs for years. A Tee in the port behind the thermostat housing allowed for the ECT sensor for the Sniper.

Norm

[zanman]

That looks very nice Norm. What’s the block break in the piping sitting over the manifold?

Any idea if the port I circled in my pic towards back on manifold would be suitable instead of putting a T in on the port you used? I already wired up the sensor in that port and would prefer not to take it apart.

[Norm B]

The block in the heater lines is a bypass. It allows a small amount of coolant to flow through the Tee and back to the water pump when the heater is not in use. This was required to get an accurate reading of the engine temperature. A bypass heater control would have accomplished the same thing but, they are much larger than the unit supplied with the heater and wouldn’t work with my hose routing.
I can’t give you an answer on the rear cross over port you have circled as I don’t know enough about the coolant flow requirements for your engine. I would call Mike Forte and ask him.

HTH

Norm

[phileas_fogg]

So i checked again and looks like I have another free port on the manifold. Can you guys checkout this pic. Any reason I can’t use the port I have circled in yellow? This would be perfect as it’s actually right near the heater intake tube.

Also John I noticed on the url to the Napa 90’s you sent they are 5/8 by 3/4. I’m assuming you had to upsize the piping? My manifold ports appear to be 5/8 so I’m thinking I can just stay 5/8 whole way? Thanks again guys.

I've forgotten the specifics, but I may have used the 5/8 by 3/4 elbows to I could later match the return on the water pump. Or maybe it was to match the 3/4" hose provided by Vintage Air. Or maybe the inlet & outlet of the core are 3/4". I know there was a size difference somewhere, but just don't have it at my fingertips.

Whatever it was, measure your specific components! :)


John

[zanman]

I finally got a chance to re assess the piping per this thread. The manifold port I wanted to use in the rear of the engine wont work it’s a smaller 1/2” port. So looks like I need to install a T on the forward port I currently have the water temp sensor installed in. I’m having a heck of a time finding a T fitting for this. I know some of you heard of others with this setup anyone know where I can find one of this fitting? Would need to be 3/4 male into manifold, then “T” with 5/8 barb on one end and 3/4 female thread on other. Thanks again.

[Norm B]

Breeze automotive used to sell a Tee fitting for that purpose. I would contact him first. If that fails go to the hardware store or to the link below and get the appropriately sized street tee to fit your port. You may need a combination of reducers and a barbed pipe nipple to make everything fit.
https://www.amazon.com/s?k=Street+tee+fitting&crid=1AYOAS2J9UUNY&sprefix=street+tee+fitting%2Caps%2C96&ref=nb_sb_noss_2

HTH

Norm