Heater Tap Mod

[jonclancy]

Hi All,

After splurging my new coolant on the drive, and searching here, I have noticed that my car has never used the heater tap mod! I'm going to order the tee and hose this weekend. Just wondering who has connected where. There seems to be a choice of expansion tank, rad return hose, etc. I don't have a swirl pot.

Your wisdom greatly appreciated! Pics more so!

Ta!

[bobwhittaker]

Sourced a top hose - Thermostat housing to radiator - with a half inch " T " moulded in and made
a simple two bolt flange with a half inch 90 degree bend welded on to bolt over the heater tap outlet
adjacent number 4 cylinder , then a piece of hose from that to the " T " in the top hose .
For 90 % of my open road running the temperature shows 175 - 180 without the electric fan ( No direct fan )
which I have on manual so I know it doesn't run and the engine hasn't boiled since build five years ago .

Mind you I am using the " Old fashioned " top to bottom brass radiator without expansion tank

[Westfield 129]

I tapped the heater outlet hole in the cylinder head (1/2 or 3/8" Pipe tap, Don't remember which...), installed a fitting (Pipe to AN-6 or what ever works for your return line) and ran the line to the header tank. No welding, no plate, no leaks...

Install a couple of small bolts (I use stainless steel) into the holes for the plate/valve with some Hondabond or similar sealer.

The fitting can be a push on hose, no clamp (the cooling system wont exceed your radiator cap pressure, usually less than 16 psi).

You can also run this line to the radiator, or the coolant return line to the radiator using a push through fitting in the top hose itself.
I like the top hose with the molded in T.

You will likely drop 15F of temperature.

My LHD car doesn't have the mod yet. I do have the parts around somewhere.
I was waiting to make a new swirl pot or do a header tank installation.
But I could run it to the plugged radiator bleed... Maybe I need to finish this, if only for the pictures.

[jonclancy]

Great stuff. Thanks guys!

I have the heater tap in place. Easiest route is to get some more half inch hose and a tee-moulded thermostat to rad hose.

I'll update when the deed is done.

Cheers

Jon

[jonclancy]

I have the 1/2" heater hose on the way. Looking for a top hose with 1/2" spigot, and it looks like the Midget Crossflow bottom hose could be the one. GRH510. Just wanted to check before ordering. Is that what you used, please Bob?

A 1/2" brass joining union is also easy to find. But a 3/4" to 1/2" reducing tee looks like it's available from only the US or China!

[Westfield 129]

Half inch is really big for this application. You can use 3/8" (AN-6), and you can get a 3/8" through the hose fitting (curved to match the hose, with a seal and a "B" nut to hold it in place). I have used these fittings and have found that they are reliable.

Also, you can use the side vent on your radiator if you have one that is capped off.
Or... If you have the brass screw in cap, you can tap that for a fitting as well.

You can also drill and tap the thermostat housing for a -6 push on hose fitting (no clamps needed)...
Lots of possibilities other than having to find a new, perhaps hard to source or replace, hose.

My car has a cross flow rad with a bleed hose (now capped off) for the header tank. I will be using this for my own cylinder head bleed hose.

[jonclancy]

Thanks Jan. As you say, lots of options.

The hose is readily available here and Stateside. I'm a bit tied up at the moment, but will order one, and get it plumbed in. An easy, reversible, solution.

Or, I might fit a heater matrix!

[jonclancy]

That was a joke, but I can tell you Mooch and I would have paid handsomely for one a few years ago on a cold night-drive back from Goodwood a few years ago!

[Westfield 129]

Just convert to LHD and you will be toasty warm all year around.
Nothing like having your feet just a couple of inches from the exhaust header to keep you warm on a cold night.
Extra heating available if you don't cover the pedal quadrant...

[jonclancy]

Time for a quick update, as this little mod is yet to be installed. I've been swanning around on my hols, y'see?

I have received my 1/2" hose, GRH510 bottom hose and new jubilee clips.

The main point to note with GRH510 is that the spigot is mounded to the outside of the main bend. As water flows down the radiator and up the engine, I want to plumb into the radiator return, just downstream of the thermostat. This will slightly slow the engine warm up time, I guess, but promote slightly cooler running in my set up.

A quick ratchet around in my gasket collection turned up a fresh heater tap gasket. I'll spin the tap to point nearside, and run the hose on the hot side of the engine. Some new, stainless and rubber, 20mm P Clips will hold the hose away from the manifolds and run it down to join the GRH510. Finally, a brass 1/2" joiner will complete the job.

All in theory! I'll post some pics when the job is done this week...