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TR4/4A Tr4a, alternator heat shield

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R

Rrbbeerrttoo

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I replaced generator with GM alternator with larger diameter housing that overheats ( hot to the skin )from #1 exhaust pipe. I made up a temporary metal shield that works, but looks atrocious in a beautifull TR.
Has anyone had a similar problem and can share the solution. Metal is ok but maybe asbestos wrapping is better, if this material can be found legally.
Thanks for any comments.

Robert
66' Tr4a irs
CTC 53788 L
 
I have a smaller mitsubishi alternator. My original conversion used a big GM alternator. How in the world did you ever get enough belt adjustment? Did you go to smaller pulleys or what?

Dan B.
So. Chas, WV
 
Besides a heat shield, what about some kind of duct to help ensure the air being sucked into the alternator is cool, rather than the hot air around the exhaust manifold?
 
Thanks for the comments.

1. PeterK, I will look into the wrap material, perhaps look for a piece at a car shop to keep cost down.
2. Darrell, The heat is radiated to the alt. housing only , to the side/rear corner that parallels the block, not to the back. Do not know if it would eventually have overheated the internal electronics as I caught it on time. I thought the Alt. fan brings air from the front, thru its rotor and out the back.
3. DanB, I have just enough belt adjustment w/o hitting body parts. I could not stretch the new belt over the pulley with the Alt already mounted so I unmounted and manuvered the Alt to get the belt on, then remounted it w/o problem. Everything is still original: similar wide/thick belt but different ( TR28400 ); same big pulley; same generator mount, although with slight change to the bolts ; and cut off Alt. boss as written in other posts. Only bad thing , maybe , is the Alt is too close to the block, mostly exhaust pipe heat.

Robert
tr4a irs
CTC 53788 L
 
Rrbbeerrttoo said:
2. Darrell, The heat is radiated to the alt. housing only , to the side/rear corner that parallels the block, not to the back. Do not know if it would eventually have overheated the internal electronics as I caught it on time. I thought the Alt. fan brings air from the front, thru its rotor and out the back.
Click to expand...

No, most alternator fans pull air through the housing, back to front.

It is actually a centrifugal blower, similar to how the water pump works.

-Darrell
 
Darrell,

You are correct. To confirm I looked up my alt. data sheet.
However, I do not feel any hot air at the intake proper, just the radiated heat from the manifold against the outer shell. Agree, maybe a 45 degree duct as intake might do it, as alternative , but may look worst than my metal shield.
Thanks you for your feedback!

Robert
 
It would seem that your issue is at idle. Once underway the air flow inside the engine compartment would tend to cool the exhaust manifold as well as the alternator case. I have run a GM alternator in my TR4A for years with no issues related to heat. I do use one of Joe Alexander's carb heat shields but that would have little protection for the alternator. It does wonders for the carb's however.

I wrapped my exhaust manifold with the fiberglass wrap before the getting the heat shield. The only success I had with that was to eventually crack the manifold and throw it away. I learned the hard way that you should not wrap a cast iron manifold.

Having said all of this I'm sure that doing something to reduce heat getting to the alternator is a good idea but be careful that the fix does not create another problem.
 
Another thought, ceramic coating, besides looking nice, is supposed to help with keeping heat inside the exhaust system.
 
I have been running an alternator since about 1982, at first the big GM one, now the mitsu. I still use the wide belt too, and it sounds like your conversion is pretty much like my first one. Eventually the belt will start to slip and you won't have enough adjustment. Changing to the smaller alternator provides more adjustment and allowed me to go back to the original belt, with some mods to the mounting brackets, upper mostly. I got the alternator from a junkyard, off of a wrecked Geo, and that has been 10 years ago or so. Much better small alternators are available now.

I never have had an issue with heat affecting the alternator either way though.
 
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