The Ford Barn

ventport · 08-02-2023, 01:38 PM

I converted my 56 Bird to a dual master using a 67 Mustang drum drum master. After driving my Bird with the new Mustang dual master I have found that it gets very hot. The dual master is a lot closer to the exhaust manifold that the stock one was, and it gets so hot you don't want to touch it. Also the Midland brake booster mounted in it's stock location but is not hooked up yet, gets so hot you can't touch the band holding the diaphragm together. Any suggestions on how to remedy this? Is this normal?

dmsfrr · 08-02-2023, 06:14 PM

Believe it or not... the distributor may be malfunctioning. Without added timing advance above lower Rpm's the exhaust manifolds get extra hot.
Check the vacuum canisters for a good internal seal, and the points / advance plate for the required movement. Example photos 3 and 4.
https://www.ctci.org/gilsgarage/crac...aust-manifold/

There are heat shields made for the dual bowl master cylinder conversions. Example...
https://www.classictbird.com/Heat-Sh...uctinfo/2137L/

Do you have the correct left / driver side exhaust manifold? It gives a bit more clearance to the master cyl. Photo examples below.
.

ventport · 08-02-2023, 07:07 PM

I believe I have the correct exhaust manifolds, but will check, I have a Mallory Unilite distributor with no vacuum advance, and the 57 intake manifold with a Holley 4bbl carb. I will check the timing, that may be the problem, thanks.

miker98038 · 08-02-2023, 09:43 PM

One of the bird problems is getting the hot air out from under the hood. It’s common to open the hood in a “parade” situation. You can actually feel the heat if you put your hand above the windshield. The boiling point on brake fluid is pretty high, nearly 300 F if it’s old and has some water condensation.

Pretty common to run a Yblock at 10* initial advance instead of the 6 or so in the manual. Most engines won’t “ping” at that. As above, more advance helps, and retarded runs hot. I wouldn’t change it, but a vacuum advance distributor might help if run off manifold vacuum. Above idle, it’ll help even on ported vacuum as that tends to reduce exhaust heat.

It’s surprising how much a heat shield helps, even with minimum clearances. Look at factory turbo installations on modern hp cars.

So you are probably ok, but lowering the temp sure won’t hurt.

dmsfrr · 08-03-2023, 08:06 AM

Quote:

Originally Posted by ventport

I believe I have the correct exhaust manifolds, but will check, I have a Mallory Unilite distributor with no vacuum advance, and the 57 intake manifold with a Holley 4bbl carb. I will check the timing, that may be the problem, thanks.

That distributor should be Much better than the old dual can Loadomatic.
But, it can still have an internal problem that won't let the timing advance much beyond the initial 6 to 10 degrees. (not very likely but still possible)
Double checking the built-in mechanical timing advance is a good idea. IIRC total timing advance is in the 25+ degree neighborhood.

ventport · 08-03-2023, 08:14 AM

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I was looking at a friends 81 Corvette just after he drove over to my house. We opened the hood and his master cylinder was so hot I couldn't keep my hand on it without getting burned. So maybe mine is OK. I will check the timing, and have been thinking about making a heat shield for the drivers side exhaust manifold.

08-02-2023, 01:38 PM	#1
ventport Member Join Date: Feb 2014 Location: St Paul MN Posts: 36	56 T Bird dual Master gets Hot I converted my 56 Bird to a dual master using a 67 Mustang drum drum master. After driving my Bird with the new Mustang dual master I have found that it gets very hot. The dual master is a lot closer to the exhaust manifold that the stock one was, and it gets so hot you don't want to touch it. Also the Midland brake booster mounted in it's stock location but is not hooked up yet, gets so hot you can't touch the band holding the diaphragm together. Any suggestions on how to remedy this? Is this normal?

08-02-2023, 07:07 PM	#3
ventport Member Join Date: Feb 2014 Location: St Paul MN Posts: 36	Re: 56 T Bird dual Master gets Hot I believe I have the correct exhaust manifolds, but will check, I have a Mallory Unilite distributor with no vacuum advance, and the 57 intake manifold with a Holley 4bbl carb. I will check the timing, that may be the problem, thanks.

08-02-2023, 09:43 PM	#4
miker98038 Senior Member Join Date: Mar 2013 Location: Kent, WA. Tucson, AZ Posts: 1,404	Re: 56 T Bird dual Master gets Hot One of the bird problems is getting the hot air out from under the hood. It’s common to open the hood in a “parade” situation. You can actually feel the heat if you put your hand above the windshield. The boiling point on brake fluid is pretty high, nearly 300 F if it’s old and has some water condensation. Pretty common to run a Yblock at 10* initial advance instead of the 6 or so in the manual. Most engines won’t “ping” at that. As above, more advance helps, and retarded runs hot. I wouldn’t change it, but a vacuum advance distributor might help if run off manifold vacuum. Above idle, it’ll help even on ported vacuum as that tends to reduce exhaust heat. It’s surprising how much a heat shield helps, even with minimum clearances. Look at factory turbo installations on modern hp cars. So you are probably ok, but lowering the temp sure won’t hurt.

08-03-2023, 08:14 AM	#6
ventport Member Join Date: Feb 2014 Location: St Paul MN Posts: 36	Re: 56 T Bird dual Master gets Hot Sponsored Links (Register now to hide all advertisements) I was looking at a friends 81 Corvette just after he drove over to my house. We opened the hood and his master cylinder was so hot I couldn't keep my hand on it without getting burned. So maybe mine is OK. I will check the timing, and have been thinking about making a heat shield for the drivers side exhaust manifold.