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How to fix Vapor locking from happening

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I would consider the problem perhaps being the coil. If you are moving with RPM down the highway, I would not think vapor lock would be the problem. Coils can be most faulty when the engine is hot or warm.

Steve
 
Thank you both for your responses. I am considering how to do the former, running the fuel line from the pump around the back of the engine. I already tried wrapping the fuel line with insulating foil where it crosses below the thermostat housing. That doesn’t seem to work.

may questions about moving the fuel line to the back are as follows: 1) Did you run it up to the ledge in front of the battery box, or down low behind the block? 2) Did you run it over the top of the intake manifold, or down low (closer to the exhaust manifold)? Seems the former would expose it to less heat, but be exposed to hands tinkering with the carburetor balancing.

Also, what kind of “simple heat shield” did you cobble together? Stainless steel sheathing or some other material? And how did you attach it?

This will be my third attempt to solve this inherent overheating problem. I’ve read that Triumph dealt with it early on by designing a retrofit radiator fiberboard air deflector. That was my second attempt at a solution. The foil insulation wrap was the first. But I am intrigued with the notion that the problem lies elsewhere than vapor lock, given the engine stalled at speed going 50 mph on a 75 degree F day with a 3/4 full fuel tank.
 
You can buy the heat shield from the Big 3...no need to cobble one.

mossmotors.com

Carburetor Heatshields, TR3-4A

Carburetor Heatshields, TR3-4A
mossmotors.com mossmotors.com


When I was into "real" performance, like 700hp+, I would put a 20psi electric pump at the rear fuel tank. Then, a regulator would go in the carb inlet to knock the 20 psi back down to low pressure for the float valve to handle. Early fuel injection was 30psi or less, and often had vapor lock problems. Modern fuel injection is bumped up to 60psi, and it includes valves to route some fuel back to the tank. The high pressure increases the boiling temperature of the fuel, and the return line ensured the fuel was always moving to keep it cool. No stagnation.

My experience with the TR's has been that it has trouble on hot days when stopped for 10-20 minutes. That's enough time to boil the lines, but not long enough to cool the engine (and fuel) back down.

I recommend you try the heat shield before going to the trouble re-routing the fuel line. I bet the shield will be enough.
 
If you have a stock fan, they do not cool well. Sometimes the stock is almost flat. I would have the radiator rodded out or at least flow tested if you have a good old school shop around. Or buy a new aluminum one. I would try a different coil before I did a bunch of modes. The heat shield in hot climates is a good idea. I found a coil to fit a tr3 at the local auto parts store a while back. I think I asked for a coil to fit a 1967 tr4 they are the same kinda (the tr4 might be better)

In addition, I would purchase a 160 sleeved thermostat from one of the suppliers and tropical fan sold by Mazees” (but I am saying their name wrong). That is what I use in PNW.

steve
 
I have mentioned before, but just as a reminder...

It is worth paying for premium fuel from a good station. A higher flash point is one of the many benefits of better fuel.
 
Dear fellow BCF members: I hesitate to write this note after all your good suggestions on how I can eliminate vapor lock. But to bother you again, I’ve come to the conclusion that my problem with stalling may not be vapor lock at all. When this happened a couple times in the past year, it was a hot (90+ F) day and I was in stop n go traffic. The temperature rose to 230 F one time, and about 200 F the other. Both float bowls were empty when it cooled down (off the road), so when I filled them, it started right up and ran me home with the coolant below 190 F.

This time, however, the car lost power driving 50 mph on a relatively cool day (75 F) and the coolant temperature never went over 185 F. Again both float bowls were empty. So I jumped to a conclusion it was fuel vaporization like before. BUT, now I’m thinking it is a deficiency in fuel delivery. I have a new, mechanical pump. But maybe at speed it is not keeping up with fuel consumption. I also have a new fuel tank, which was 3/4 full. So I’m thinking that maybe a spec of dirt got in the fuel and fouled the first float bowl needle valve. I’ll check that out (because it’s easy). I don’t have a fuel filter, and shame on me, I should (and will … in the fuel pump suction from the tank).

You don’t need to waste anymore time on me, but if you will, are there other ideas? I haven’t heard that mechanical fuel pumps on TR3s chronically can’t keep up with fuel demand at speed.

Thank you,
Don
 
Anyone wishing to respond, would you recommend one or the other type of fuel filter here from Moss?
IMG_4443.jpeg
 
Our time is not wasted. I come from a people who find vapor lock and 'the station sold me watery gas' as the cause of all problems. Both are actually rare. Cheap see through plastic fuel filters are the proper choice. The only way to see if the filter is clogged. TR3 fuel pumps are up to the volume required. Try blowing some air backward from the fuel pump supply to the tank.
Bob
 
Thank you very much for this good advice. I will do both: see-through filter and blow out the fuel suction line.

My first TR3A in 1966 to 72 in California never vapor locked or stalled with empty float bowls. I drove it regularly at highway speeds and it ran just fine: Los Angeles to Merced or San Jose, up the steep Grapevine. So you confirm what I thought; the fuel pump should be entirely adequate if the suction/discharge lines are open.

Don
 
None of the Moss filters shown I would recommend. Try your local auto parts store. Again the plastic ones are very good. If you put the filter just before the carbs you need a 1/4" in &out size. If you are going to put it before the fuel pump you need a 5/16" in &out size.
Charley
 
I have a new tank and rebuilt pump, and only use the gauze filter in the stock pump. I cleaned and re-used the steel fuel lines. Every year at tune-up time I will still get a ton of rust crud in the pump filter bowl, presumably from the inside of the old steel fuel lines. That crud has not caused me any problems, but it is possible for it to stick the pump valves, so the pump stops pumping. If crud gets in the carb float valves, it will have the opposite affect of holding the valves open and flooding the bowls so fuel comes out of the carb vents.

I guess I am saying, check your lines for stoppage, and blow out your new pump to clear the valves. The alcohol in our fuel will accelerate corrosion in steel lines, causing a lot of issues with valves and pumps.
 
Okay; these are excellent points. I, too, have a new tank and fuel pump but the original old steel fuel lines from the tank to the pump and carbs. Now alerted to the ongoing corrosion of these steel parts with ethanol containing gas, I will start some maintenance on them.

Thank you both for responding!
Don
 
Looks like you found the problem, good news. I enjoy the forum with questions about cars, so no worries here. I do not have a fuel filter either. The last one I had got plugged up, and I broke down. I trust the one on the fuel pump for what it is worth; the screen on the stock pump is very fine. Plus I believe some of the crap goes out the exhaust. In addition, I have the old H6 with all metal lines that have a screen in the float bowls, so if you have that you might check the first bowl for a plugged screen because the fuel goes through the first bowl then to the second.

The original fuel pump rebuilds easy, and the rebuild seems to last. My understanding is the original fuel pump pushes out 2 psi and pulls about 20 psi from the tank, but that is stuff I have only heard over the years.

In your case, I would rebuild the fuel pump and not install a fuel filter because they plug easy. Then I would blow air back through the line to the tank to make sure the fuel flows well. The fuel should pour out when you undo the line from the tank, so you might not need the air blown through. It is a tr3 simple and strong.

steve
 
I recently had a fuel blockage and had a brand new tank and lines. I also have a fuel filter located prior to the front carb. Because of the clear plastic fuel filter I was quickly able to diagnose that I was getting no fuel to the carbs. Ultimately I was able to determine that during the process of putting the fuel sensor in the top of the tank some sealer dripped into the tank. This floated around for about 800 miles until some of it made its way to the fuel line. Where it plugged the line below the pump.
So just because I had a new clean tank does not mean that it cannot contain a problem.
So as I say live and learn.
Charley
 
Yes I had a new tank once and it had a lot of welding and grinding dust crap from being made. I got it out of Mexico. I was shocked when I looked into the bowls. There was about a ÂĽ inch of fine whatever in there. So yeh you probably need to blow the tank from the pump line back. I regrettably sold that car, so I do not know what more happened.

Steve
 
Thank you both for sharing these experiences. I am amazed at your picking up on my notes so quickly. I would be willing to share stories with others, but I can’t read all notes on all subjects. How are you alerted to messages that you can contribute to? Do you have a list of topics or key words that automatically message you when someone posts a question on your expert topics? I am alerted to your responses to my queries in email from BCF.
Thanks again,
Don
 
Donald1107 said:
Thank you both for sharing these experiences. I am amazed at your picking up on my notes so quickly. I would be willing to share stories with others, but I can’t read all notes on all subjects. How are you alerted to messages that you can contribute to? Do you have a list of topics or key words that automatically message you when someone posts a question on your expert topics? I am alerted to your responses to my queries in email from BCF.
Thanks again,
Don
Click to expand...
Expert?? No
Experienced. Yes.
Whenever one of us contribute to a thread, like you we get a message from the forum that somebody has posted on that thread. But that is all.
I enjoy browsing the forums and see posts where I am interested in learning something or occasionally have experience about the question.
Charley
 
Same here, Charley

As of this morning, there are 1,327 pages of topical posts on this forum. I have been known to randomly pick a page from 5, 6 or 7 years ago and simply scroll through, reading posts where the subject line looks interesting. It is amazing how much you can learn!

Bob
 
I suppose that I could do as you do and just periodically brows forums if interest, responding with my experience or needs for advice when I saw them. Although I have been a member of this BCF for 2+ years now (started when I decided to start getting my 59 TR3 running during the COVID “shut-in”) I do not consider myself an expert on any auto mechanics. I have to say that this forum has been very helpful, along with YouTube videos. But I have had some experiences that I wanted to share but didn’t see a thread where it would be relevant or helpful to someone. A good example was buying replacement chrome stanchions on EBAY: two had to be returned because there is apparently different configurations of bolt holes. I ended up just having my old ones re-chromed.

So my next interest (this winter) will be wheel bearing repacking or replacement. I like doing these projects myself but I have zero experience.

Thanks again to you Star Wars warriors!
Don
 
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