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MG TD TF 1500 - Fuel line heatshield

Having suffered with what I have diagnosed as vapour lock on my TF1500 recently whilst touring in France has anyone experience with the Heatshield Products -
https://www.heatshieldproducts.com/blog/tech/keep-fuel-rails-cooler-and-make-more-power-with-fr-shields
for insulating fuel lines. I already have a stainless heatshield between the inlet manifold and carbs.
JK Mazgaj

Living in the south of France I had some vapor lock symptoms on my TD on hot days.

I made a heatshield for carburetors with insulated fabrics on both sides. 2 insulating spacers between carbs and intake manifold.
I then added an insulated sheath on copper lines, , an insulated strap on the exhaust downpipe.

Also I take care of my fuel choice (98 summer fuel from a good french brand).

I had no problem during 2 seasons.

To get more margin. I had insulated hoses made from a small company who works for aircrafts.
I also built a fresh air scoop and a heat shield between exhaust and fuel pump (a rear one).
Few weeks ago, I drove a long day with many stops. 97°F ambiant, Engine at 185°F and no problem at all.
So yes it's efficient but you need to identify the weak point or to shield many things.

Note also that the scoop, just above front cross member, is of great benefit for driving comfort. Legs are definitely cooler.

Laurent.



LC Laurent31

Different car but this 1990 Jaguar XJ6 also suffered from the rear mounted high pressure underfloor fuel pump cavitation. I wrapped all the accessible exhaust system that was near the fuel pump and lines with this insulating tape.





John Quilter (TD8986)

Does your TF have fuel pump(s) in the rear or up on the firewall?

If the pump is on the firewall, and it starts chattering like a chipmunk instead of slowly ticking, the problem is vapor lock in the line below the pump. It can't suck up vapors as it just keeps boiling in a vacuum until the temp drops way down.
The fuel line is behind the exhaust and I've measured as high as 250F with a thermocouple. One cheap little preventive measure is to snap a corrugated wire loom around the fuel line for some insulation.

The ideal location for the pump is down low near the gas tank as it easily primes and pushes fuel to the carbs.
JIM N

Thank you Laurent, Jim and John for the thoughts/advice. Isolating the location of the problem will be the first issue. Pump (Facet)is located at the rear near the fuel/gas tank and the exhaust manifold is ceramic coated.
JK Mazgaj

As Laurent, I am in the south of France. I have always had vapor lock on hot days, this gave poor restarting after a long run. This was not too much of a problem as the solution was to pull the choke out for about 30 seconds when restarting, this always solved the issue.
Last winter I needed to change the water pump as it was leaking. I decided to replace it with a 6 vane pump. It seems to have made some difference but cannot be certain until I take the car on my "test route", the highest mountain pass in Provence (col de la Bonette)
I am planning to do this before it closes for the winter.
I don't have any form of insulation in the engine bay.

John
J Scragg

I have owned my TD since 2000. I have driven it in stop and go urban traffic with the temperature 96F. The traffic back up lasted over 2 hours. The drive in those temps was 1 1/2hrs. So the engine and compartment was at full operating temperature. I have an original radiator and run a standard Midwest, United States antifreeze blend. I have never, and I mean NEVER experienced vapor lock while the engine is running. The ONLY time I experience vapor lock is if, after a drive, I stop for more that :15 minutes. The entire engine compartment heat soaks and I have vapor lock. No heat shield can prevent this. If I experience vapor lock after a stop, regardless of the outside temperature, I apply choke, the car starts right up and I drive off. By the time I reach the street out of the parking lot I take off the choke and run normally. I have a standard tune car. I cannot speak for anyone running a supercharger or a higher tune configuration.

This has been my experience over 21 years of ownership in temps in the low 100’s, and stop and go traffic in the upper 90’s.

Make sure your cars are properly tuned and timed and your brakes are not dragging.

Regards, Tom
tm peterson

My car is stage 2.

You can find many interesting things on this topic at https://classicenginesmodernfuel.org.uk/Default.aspx?dyn_menu_mainmenu=1000001.
Among others, you will learn how to stop the engine to avoid hot restart issues. This worked great for me. I never had a hot restart problem.
I would also recommend to buy this excellent book.

Laurent.
LC Laurent31

I lived in west central Florida for over 50 years.I restored British cars for my living. During thos years I had a TC/TD and two TF's. I drove them all over the eastern part of USA and I have never had fuel starvation other than With my MGB Coupe the fuel pump failed completely.
The 1955 TF 1500 I drove over 60,000 miles with one breakdown. The rear frost plug popped out late one night in the middle of nowhere. Fortunately my friend was behind me and towed me the last twenty miles.
Sanders

Viewing the new submissions it must just be me. I'll keep analysing until I solve my problem. Today finished rebuilding and fitting the carbs. Started up straight away with a steady purr. However bit of throttle and the rear carb backfired so a bit of adjustment required but stopped for the day. Have ordered some "Heatshield Thermaflect sleeve" velcro tape for fuel lines. Can't hopefully do any harm. With a planned 2000 mile journey in France and over the Alps in a couple of months I've got to sort it even if only for my wifes' sake!!! One question the fuel pump located above the rear axle on the chassis is a Facet continuously running one should I question its location with regards to the silencer.
JK Mazgaj

In my opinion, this is not the weakest point for fuel heating. This could be an aditional improvement if every thing else is already cool.
Your manifold is ceramic coated : good point.
I would then install insulated tape on the downpipe.
Muffler is way cooler than the downpipe.

I eventually added a shield between muffler and rear pump but just to gain more margin.

Laurent.
LC Laurent31

This thread was discussed between 04/07/2022 and 06/07/2022

MG TD TF 1500 index

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