Firewall cleanup

29fordoor

29fordoor

Member
Hi, I wanted to clean up the firewall a bit where someone had done a rather nasty hole for the heater inlet to the cab and I’d like to make sure I have this right. My plan is to make a nice plate to cover the nasty rat hole and rivet it in after using a chassis punch to make a proper hole. My question is at the hole labeled “1” is the Speedo cable supposed to run through there too? And at the hole labeled “2” what was that for?
1929 Briggs leather back (early ‘29)
Here is the picture
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For reference the GAV rod is between them

Thanks!!
Chris
 
Chris - Hole 1 is completely unnecessary, likely from a poorly-installed manifold heater long ago. Hole 2 is for the speedo cable. The speedo cable fastens to the interior of the firewall just to the right of the "hump" with a clamp, and it screws through the fastener. Ignore my black firewall insulator (and the rust!), but here's what it should look like - more or less (this is a 30/31 firewall).
 

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I made 2 "washers" with a 3/16 hole in the center. Put one on each side then 1 pop rivet holds it together. I didn't bother cleaning up the butcher work on the first hole since it's covered.
 
You can buy plastic plugs in various sizes that will snap into the hole. You might have to use a rattail file to open the large hole up a little. Then paint it to match the firewall color as closely as you can.
Yes, the smaller hole is for the speedo cable. It needs a rubber grommet.
Marhall
 

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Thanks so much for the quick replies!
I actually still have the manifold heater so I’ll clean up the big hole nice and then reroute the Speedo cable back to where it belongs. ( with fastener) and grab the proper grommet. Good idea with the 2 washers too as well as finding some rubber plugs.

The manifold heater is currently off so actually plugging that hole for summer will be nice as even with the heater off, plenty of heat comes through there.
Again, thanks so much!
 
Marshall V. Daut said:
You can buy plastic plugs in various sizes that will snap into the hole. You might have to use a rattail file to open the large hole up a little. Then paint it to match the firewall color as closely as you can.
Yes, the smaller hole is for the speedo cable. It needs a rubber grommet.
Marhall
Click to expand...
Dang, Marshall - all those extra holes, did Bonnie and Clyde own that car before you?
 
I have (had) extra holes from heaters in both my 1930 (under restoration) and in my 1931. For the '30 did it right and welded in patches.

For the '31 (my driver) I took a different tack. My local NAPA has the ability to mix from around 3000 color chips and put the result into a rattle can. I chose the closest one and made up a couple of patches from sheet steel. I then stuck them to the back of my firewall with the clear RTV so the color shows. Not perfect, but a lot better than it was.
 

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"Dang, Marshall - all those extra holes, did Bonnie and Clyde own that car before you?"

Someone had rough-cut holes in the firewall for a hot water heater, which was long gone when the owner brought me his car to straighten out. Those holes in the firewall were the LEAST of this poor car's troubles. You all know the drill...
M.
 
Another firewall cleanup question this is related to the Auto-Lite heater which I now re-installed. I was able to pick up a heater door and install that but since it was not together when I got my A, I am looking at the gap between the heater door assembly and the heater on the engine compartment side and wondering, with the close proximity to the gascolator would this gap allowed hot air to build up and cause issues such as vapor lock? Was there a piece of aeroquip hose that should go there or perhaps another piece?
Again appreciate the help!!

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The gap is there to allow the engine to flex on its front spring-loaded yoke motor mount. The engine doesn't move much, but if the manifold heater top and vent door were tied together, something's going to give when the engine moves up and down on bad roads or over a big bump. The amount of hot air that escapes around the circumference of the opening is minimal and won't affect heating the passenger's compartment. Also, that heat won't damage firewall paint if it's quality paint (not spray can) and the surface was prepared properly for the paint. I have run heaters for years on various Model A's and never noticed any paint blistering or damage in that area.
Marshall
 
Hey Bruce here is the link http://https://www.fordbarn.com/forum/showthread.php?t=356440&highlight=Auto-Lite+heater

Thanks Marshall yes I assumed there needed to be some room for movement but my worry was with no hose or something in there I could get vapor lock from the heat building up by the gascolator.

It’s funny because I expected a loop in the gas line too but stock they did not have one. Of course that big double angle length likely takes up any movement just fine.

Thanks again!
 
Hey Steve,
Not sure but I did not have the the plate or body just the hole and without the heater on quite a bit of heat still came through there so I picked up the plate and housing so I could keep that heat out. Since it’s been getting pretty cool here in the mornings I went ahead and installed the heater right away. I think it works pretty nice imo actually and later in the day I just close the door after the temp outside rises. I don’t know if it would be detrimental to leave the heater on in the warm months and drive around with the door closed but it’s only 2 bolts to remove the heater.
 
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