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TR2/3/3A Fuel line heat shield

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Bob, I don't believe you need a heat shield on the TR3's as long as the fuel line is not in contact with the block. I haven't had a problem with that even here in Kansas where it gets pretty hot. Those shield's were pretty pricy.
 
I hav.e not had vapour lock problems however I used some scrap exhaust manifold wrap left over from wrapping aftermarket downpipes just in case.
 
I have been thinking about a fuel line heat shield as well, so I was very interested in your post.

However, my main fuel line heat concern is the short run of steel tubing sandwiched between the valve cover & right behind the thermostat housing ( on my car anyway). A secondary concern would be over the exhaust manifold.

i was looking a little more on the cheap side at:

https://www.amazon.com/Heatshield-P...sbs_263_2?ie=UTF8&refRID=18KRNP86N0QTEZ6VVWXJ

or a little more attractive alternative w/a stainless steel braided jacket FL:

https://www.minimania.com/ss/FUEL_SYSTEMS,FU_FUEL_HOSES
 
GTP1960 said:
However, my main fuel line heat concern is the short run of steel tubing sandwiched between the valve cover & right behind the thermostat housing ( on my car anyway).
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I believe it is supposed to routed around in front of the tstat housing on all TR2-3B; with a clip to the lower stud on the tstat cover.

The section from the fuel pump to the float valves is where it is least likely to boil, because the fuel is under pressure (which raises the boiling point). And even if it did boil in that section, it would cause relatively little problem. The vapor produced would just escape through the float valve and vent; while the heat absorbed by the boiling process would cool the line and tend to stop the boiling. "Vapor lock" involves the fuel boiling before it gets to the pump (the pump does not handle vapor very well), while "percolation" happens in the jets.

The main problem, IMO, is keeping the float bowls and jets cool, as they are hanging out where the radiant heat from the exhaust manifold 'shines' on them. Installing one of the A.R.E. heat shields made a noticeable improvement for me.
 
I believe it is supposed to routed around in front of the tstat housing on all TR2-3B; with a clip to the lower stud on the tstat cover.
Click to expand...

i was thinking mine didn't look right, compared to the diagrams I've seen.
the back of that thermo housing routinely gets above 195 ( in my car)
does the vacuum line pass in front of the housing as well?

Thx
 

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The clip to the stud secures both lines pretty well; keeps them away from the belt & pulley. Early cars have a simple twisted metal bracket, while later cars use a clip with a rubber insert.
 
Not obvious in the angle of that pic, but the lines are actually just ahead if the pulley.
 
I wanted easy access to the rubber fuel line so I could splice in a pump (in an emergency). I routed my fuel line behind the motor. It required swapping front and rear float lids. Not original, but it works for me.
Russ
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I installed the ARE heat shield and put two layers of ThermoTec self adhesive heat shield on the back side of it before installation. That did help a lot, but I still seem to be getting hesitation to start when the engine is hot, and a bit of rough running while at stop lights when it is really hot out. I have an override switch on my 14 inch electric fan and I use that all the time at stop lights even though when I stop the gauge is not reading over normal. As I set at the stop light in 95/100 degree heat, the temperature gauge rises quite rapidly even with the fan running and takes quite a while to go back down after moving, if it even does go down before the next stoplight. (I seem to hit them all on red cycle). That is when it starts to run rough. If I can keep moving even when the temperature outside is hot, the air dam I fabricated keeps the temperature gauge at normal without the electric fan on, and it runs smooth. So that is why I was thinking it might be fuel line heat since the fuel line runs right along side the engine and the ARE heat shield does not protect the fuel line when it comes over the manifold going to the fuel bowls. (BTW, I put a small cable tie around the fuel line and vacuum line and the bracket coming off the thermostat housing to ensure they don't fall down into the water pump pulley).

Also on 6-Pack they were talking about gas line heat shields to help with vapor lock and percolation. I have not had a problem on my TR250, but in the back of my mind I was thinking of putting fuel line heat shield on it as well just to be sure.

Regards,
Bob
 
I wanted easy access to the rubber fuel line so I could splice in a pump (in an emergency). I routed my fuel line behind the motor. It required swapping front and rear float lids. Not original, but it works for me.
Click to expand...

Russ,

that's an interesting configuration.
can you show some pics from the other side?
my rear float bowl is mounted "inboard" and is angled forward.
So did you swap the entire float bowls?
i assume you could not swap the entire front carb because of the vacuum line connection?

also where did you get paper paneled air filters?
ive been looking to replace the rock catchers (as Randall calls them)��

thx.

Guy
 
Possibly this is too obvious, but JIC : Note that Russ is running HS6 carbs, as used on later TR4A. Although still SU, they aren't the same as the stock H6 carbs on TR3 through early TR4. An improved design that eliminates many of the common H6 problems, but a bit expensive to buy new.

The air filters are the stock TR4A units, readily available from the usual suspects. They will bolt up to H6, but interfere with the fuel line linking the two carbs and the stock bowl vents. I'm using them, by using a long rubber tube for the vent (hanging down instead of directed into the filter), and angling the bowl lids.
 
TR3driver said:
Possibly this is too obvious, but JIC : Russ is running HS6 carbs, as used on later TR4A. Although still SU, they aren't the same as the stock H6 carbs on TR3 through early TR4. QUOTE]

Never knew. PO did replace the carbs. Thanks for the info.
Click to expand...
 
Possibly this is too obvious, but JIC : Note that Russ is running HS6 carbs, as used on later TR4A. Although still SU, they aren't the same as the stock H6 carbs on TR3 through early TR4. An improved design that eliminates many of the common H6 problems, but a bit expensive to buy new.
Click to expand...

i appreciate you pointing that out.
i knew Russ's were different from mine, but I didn't know why or how.
Do you think it feasible to route the fuel line to the back of the engine compartment on H6 's
( just by swapping the bowl tops?)
also, my heat shield is different from his( kind of triangular with a shelf) & my overflows has no hose at all, just the 1/4" ID connector.
i guess I need to address the overflow ASAP.

Thx again.
 
I think it would take more than just swapping the bowl tops, because the later H6 lids have two fuel connections on the front carb, which are on opposite sides of the lid. But I'm sure it could be done. Perhaps by capping off one of the fuel connections and using an external tee.

The vent line is not so important, the engine will run fine with it just left open. But we get a lot of very abrasive dust where I live, and I wanted to try to keep it from getting into the engine. Eventually, I would like to make a filter housing that would accept TR6 elements, and supply filtered air to the bowls. Might even hook it up to get cool air somehow.

I'm not positive, but the heat shield differences may be due to the HS6 carbs. For example, those holes right behind the throttle cranks look like clearance for the crank. H6 don't need them (and my shield from ARE doesn't have them).
 
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