TR2/3/3A Heat Shield Issues

[DornTRoriginal]

I am working on the installation a recently acquired heat shield that is now causing me new problems.
The heat shield interferes with the movement of the long horizontal rod, I put the spacer/insulator between the carb manifold in order to bring it out far enough to allow the bell crank lever to fit into the gap (forward end) of the heat shield. On the back side of the HS the horizontal rod rubs against the HS when fully pushed to the floor. The Horizontal rod has two threaded connectors, one is a thinner 3/8 nut on one end and a “stockier” 11/32 nut on the other side, is that weird? I put the thinner end to the rear, attached to the Accelerator lever, in order to try to make things fit better, which it does, but it is still not correctly functioning during operation.

Has anyone else had to modify the heat shield to make it fit correctly? I read some old posts which eluded to doing a modification and there was a lot of discussion on the order of installing the gaskets and insulator but was not sure if anyone did a modification and what was done, maybe just a notch taken off the HS?. I followed Randal’s advice; i.e. setting the lever on the front carb so it makes about a 45-degree angle with the first rod, with the throttle closed, set the short rod so the bell crank is at 45 degrees etc. The movement of the whole assembly, at ¾ to full throttle, there’s interference with the HS during operation. Before I start cutting on the HS I thought I’d see what others have done to correct the problem. Should I cut out a notch? Or sell the HS????

 

[TR3driver]

You might want to check out your motor mounts first. My engine sits a good 1/4" farther to the right than yours does, so the rod is nowhere close to rubbing on the heat shield. Maybe even add a shim to the LH mount?

But I did have to modify the HS a bit at the hole for the vacuum line to the front carb. So cutting a notch in the back doesn't seem like a big deal to me.

 

[John_Progess]

I had to modify my heat shield. I slit the heat shield about 1" wide and 1.5" long on the backside and bent it forward so the rod would not rub the backside. I also modified the heat shield so I could remove the bottom section to access the starter and all the stuff behind it without removing the entire heat shield. Have a good day!

John

 

[mrv8q]

ISTR Joe modified the heat shield after the first run of HSs; perhaps you have an early one.

My second HS fit fine with no modification, but I wouldn't hesitate a little dremel modification if you need to.

 

[CJD]

I've gotta ask...

Does the heat shield affect the life expectancy of the starter and generator (or in the case of the pic above, the alternator).

 

[Geo Hahn]

Does the heat shield affect the life expectancy of the starter and generator (or in the case of the pic above, the alternator).

Good question. Alternators in particular may be more sensitive to heat if the use of heat shields specific to them is any indication. Possibly the diodes are vulnerable in a hot location.

Here is the modest heat shield the other Coventry guys used on their cars when they went to alternators:

Since an alternator fan sucks rear-to-front having a manifold on the back side is a hot environment.

For my TR4 I made a carb heat shield out of some roof flashing I had around. Not sure if it helps but it was very affordable.

 

[TR3driver]

With the generator location on a TR3, the air intake is very close to the manifold. So it sucks hot air anyway; I doubt the heat shield is going to change that very much. At any rate, I've not seen any signs of the generator overheating in the 4 years or so that I've been running one of Joe's heat shields.

I did have the bearings go bad in one of the gear drive starters, apparently due to heat cooking the grease out of them. But again, I think that's due more to it's close proximity to the exhaust than any extra heat deflected by the heat shield. I made a cheap "roofing tin" shield for the starter that might help. Really too soon to say, though, the first starter lasted 10 years and I only discovered the bad bearings while I was looking for a different problem (quick connect came loose on the tab leading to the occasional "click-nothing").