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Heater box drain flapper

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Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Thanks Eric, I saw the two holes so that made me wonder. So your round tail Spitfire must be the same as my round tail GT6. Understood.

Happy Holidays.

Once I print another flapper, I'll send you one to "test".

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Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Could be as simple as this, snap it into the hole, slide on a piece of flex hose and route it to where ever. For the slotted hole that was originally used to hold the flapper in I'd just make a slot plug for that. It would be made from thermoplastic polyurethane which is tough but is flexible enough to be snapped into the hole. The hole I.D. is 1/2".


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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
I feel that anything that snaps into the hole may allow the water level to rise a little. We want the box as dry as possible to prevent rust.

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Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Very true Tony, on my first design I extended the drain body out about 1/2' and lowered the drain tube down so it was slightly below the existing 1.512" hole. The design looked a little bulky so I sketched up this shorter design. Instead of snapping in, I could attach this plug with a flange but then that would have to be securely attached to the face of the duct, but there are a number of ways to do that. On my GT6---from the base of the 1.512" hole to the deck is very close to 1/4" so there isn't a lot of room to play with.

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
Most cars provide the drain with a hose similar to the one on the battery box.

(cough, Stang, cough)

A lot of LBCs have the heater box mounted to the firewall on the engine side instead of inside the cab.

I would really be tempted if the body was stripped on a rotisserie to plumb for a better drain than stock by blocking the current opening and putting a new one inside the cabin and through the floor with a rubber hose. To get there the heater box needs to be pulled.

Again, it depends on the use of the car. A weekend toy to bug around and cause the kids at the drive-thru on Taco Tuesday to go "WOW!" as opposed to a car parked outside in the employee parking lot in the rain all day (or night).

Mine has had both lives.

It has been noted that parking nose down on a hill helps the rear deck to drain.

Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Makes me wonder why bother, I've owned my GT for 47 years, all of those years in a snow-salt rust belt. (New England) The first few years the GT was my only car and it saw a good share of winters outside and covered with salt. My duct chamber is in excellent condition, Guess we've put this project to bed. On to more needed projects.

Tobydog Avatar
Tobydog Dennis E
Indianapolis, IN, USA   USA
Brian I thought the issue was keeping engine fumes out of the cab.Maybe i missed something?

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Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Personally I never bought into that theory, a flat piece of rubber laying against sheet metal, from an engineering standpoint would not stop gases from passing.
The seal is just not there or possible. You'd need at minimum an O-ring seal gland. I've owned my GT since it was new and after a rain there was always a puddle of water on the shelf below it. If you did seal that hole up, the duct chamber would fill with water up to the level of the heater fan hole and you'd be sucking water into your heater box. So that leaves one other reason for the flapper, to allow water to drain from the duct and cover a l-3/8 hole that looks odd. There is the side effect of keeping critters out of there-to some extent. I'm staying with the flapper. Interesting in our Big Red manual most of us have it is called a "Flapper Valve". Then if you reference the section in this manual, and under the "Dust and water" sealing section, you see the foam seals that are shown that seal the heater box to the firewall. From that I personally deduce that the "flapper valve" is intended to reduce dust from being sucked in yet allowing water to drain from the heater box. Not a perfect solution but at the time a nice cheap attempt.

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
There's positive pressure from the incoming air dam at speed. You only have to avoid an overflow into the squirrel cage fan.

As an aside, if the object is to avoid having water draining from the fresh air intake box through the flap on the firewall from getting on the wire harness than it would seem the best thing to do is to route the wires over the flap rather than under it.

(Yes, I know Word would tag that as a run-on sentence.)

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Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Re-routing the harness would help. I wonder how many of us let our cars get drenched anymore. When my GT was young back in 1970 to 73 , it was my only car and saw lots of rain and snow. But now, neither of my Triumphs see rain except by my stupidity, and never will they be out in snow.

Yellowhawk Valley Avatar
walla walla, WA, USA   USA
1969 Triumph Spitfire "Walla Walla"
1969 Triumph Spitfire "Portland"
1972 Triumph Spitfire MkIV "Spokane"
1975 Triumph Spitfire 1500 "Dayton"    & more
Well, one experiment I tried and proved correct, was that what little leakage may overflow out of that flapper onto the deck area is quickly blown clean and dry with very little continued driving. I just dibbled a puddle onto the deck under the heater box, drove 5 miles at 30 and 40 mph and when I returned it was completely dry. It does not seem to hang around much like brake fluid under the masters.
One of the undocumented stories I heard many years ago was that this normal blow-off and evap was why they changed the type of drain when they changed the heater box design for the Mk3's with the off center dash. It just was not needed except as a block for the various fumes that might sneak into the car.
Dan

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
I inherited a fried harness patch fixed with white extension cord wire.

The DPO removed all of the factory wrap and replaced it with that black plastic split tubing.

At one point I considered replacing the whole harness with an after market one with breakers and relays. Need to add the ARO valve and the PDWA. On mine those wires are getting brittle with age.

Tobydog Avatar
Tobydog Dennis E
Indianapolis, IN, USA   USA
Ok that is it,Im going marine......a 600 gph bilge pump with a float switch!....Hurricane proof !!!

Tobydog Avatar
Tobydog Dennis E
Indianapolis, IN, USA   USA
Brian, i have eliminated the need for the flapper altogether by drilling a 3/4" hole at the bottom of the drain box and i installed a plastic drain fitting with a 90 deg.barbed elbow pointing towards the battery box drain side of the car with a hose attached that runs down along the transmission to drain out just below the frame . The drain fitting is a two piece assembly with an o ring to seal the top portion when the two pieces are fitted into the hole that was drilled.The flapper will be sealed with marine grade silicone for now until i get tired of looking at it. (Im already tired of talking about it ) smiling smiley Or....I might just epoxy my "Indiana Triumph Cars" Medallion over the hole! P.S. This was all very easy to do with the tub off of the chassis,not sure if the hole could be drilled otherwise. I will post pics later as my camera lens was fogging up,when the garage warms up this evening i will try again.

Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
That's a way to approach it.grinning smiley Are you trying to eliminate me from buying my Caribbean Island by taking my profits from "flapper" sales away? eye popping smiley

Brian



Edited 1 time(s). Last edit at 2017-12-27 03:51 PM by Bpt70gt.

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