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MG TD TF 1500 - vapor lock

1954 mgtf: Installed B&G heat shield and had jet hot coat the exhaust manifold and the next pipe and still have vapor lock. Can I install both a 10 inch electric fan and a oil cooler in front of the radiator or won't both fit?
Ed Eastman
C. Eastman

Ed,

By Vapor lock, do you mean in traffic or after stopping the engine. I have the Jet Hot manifold, and only have a bit of problem with vapor lock after stopping my car on a hot day. In that case, I simply start with the choke, and in seconds the problem is solved.

I don't know how your car is set up, and how cool it runs, but timing and mixture can affect the running temperature. Also, on some TFs you have to open the RH bonnet to allow the hot air to escape when parked (engine off).

I also think that oil coolers are overrated for keeping an engine cool. They do great on keeping oil cool, but I doubt with 20w-50 they are even necessary, and may be detrimental. A richer mixture does more for keeping an engine cool than cooling the oil, IMHO. Afterall, the head, where most of the heat comes from, sees little of the oil. Oil goes mostly to the bearings and splashes the cylinder walls a bit, but the cylinder walls aren't where the heat is.

As an aside, on aircraft engines, we can open the cowl flaps to increase the airflow around the engine (they are mostly aircooled) or run the mixture up to cool the engine. Guess which is most effective?

warmly,
dave
Dave Braun

Ed,
Have you gone through the carbie set up?? It seems like you might be trying to "bandade" a problem....

SPW
Steve Wincze

Ed , I had a little hot "soak vapor" lock on 100 degree days. The car ran quite warm until I finnally gave up and had the radiator recored with a three row job. I had also added the oil cooler (with a thermostat Dave) and have had zero problems since then. If fact the car runs a little too cool now and I might just add a hotter thermostat.


LaVerne
LED DOWNEY

Ed, I'm also curious- problem when driving, or after hot soak re-start? Makes a difference. Something not right if doing it this time of year. Do I remember in the past this was worse when using more volitle winter blend gasoline? George
George Butz

It vapor locks after running for 20 minutes after starting. I can get to the local grocery but not back.
C. Eastman

Ed - As the others have asked, is the problem when you are driving (true vapor lock) or after having stopped after driving (heat soak)? The former is not a usual problem and if your re experiencing that, it will take some sluthing to find the real problem. A good start is to look at the grill slats on your car. they should be angled such that you get a really good view of the radiator, not the excellent paint job on the slats. The other place to look is the radiator itself, it needs to be free of any internal obstructions and only a good radiator shop can asses that for you. Carburetor set ups (proper mixture adjustment) and especially proper ignition set up, including initial distributor settings and proper advance operation (Jeff Schlemmer at Advanced Distributors http://www.advanceddistributors.com/ ) can help you in this respect.

If the problem is occurring after start up after having been stopped for a short period of time, with the engine shut off after a period of driving. I would like to say (like someone else who responded) that this time of year, this is not a big problem, but if you have an exceptionally nice pre-spring day then sun is out and the temperature has reached the low to mid 60s, the car is particularly vulnerable to this problem due to the winter blend of fuel, which is purposely blended for low temperature vaporization. This becomes a real problem for our cars in the early spring, when the ambient temperatures start going up, but filling stations are still supplying the winter blend of fuel. Dave B has the correct approach to relieving this problem - pull the choke out, even though the engine is completely warmed up and shouldn't need any choking to state. By pulling choke out, the equilibrium in the float bowl to jet passage is upset, allowing the bubble of vapor that has formed to escape. For an in depth discussion of this problem and various remedies (none that are permanent) e-mail me and I will send you a previous discussion of the problem. Cheers - Dave
David DuBois

It vapor locks when driving.
I just had the radiator rebuilt 6 months ago so I can eliminate that.
I installed a rebuilt distributor this past week. I will follow up on that being the source of my problem.

Ed Eastman
C. Eastman

Ed, with all due respect to Dave D. Forget the slats. That is an issue for TD owners and not TF's. What kind of water temp are you showing when driving? Is your fuel pump under the bonnet or by the rear axle? If your water temp is at an acceptable level then I would suspect that your pump isn't up to snuff, particularly if it's under the bonnet.

LaVerne
LED DOWNEY

The fuel pump is by the rear axle. Is it possible to wrap it with something to reflect the heat? If so, what is the source to obtain same?
Ed Eastman
C. Eastman

Water temp?
LED DOWNEY

It may be worthwhile considering factors other than heat as a cause. Fuel pump performance has been already mentioned. Maybe also try running with the fuel cap cracked open to make sure air is getting into the tank. have you checked the condenser in the distributor, also igniton coil issues? Regards, Richard.
R Payne

Likely not vapor lock. Could be spark or fuel. These cars don't "vapor lock" and quit when it is 95 degrees here in the summer. When it quits, have to stop and pull over safely, and carefully remove the top of the float chamber and see if there is any fuel (don't spill on hot exhaust). The float should be bobbing in gas. Or start by checking spark. The coil could be bad also and fail when really hot. Condensor too if not running electronic ignition. Rig up a test plug- take an old plug and open the gap up a little. Place it against the head and have someone turn it over to check for spark. Check the fuel cap venting. Is the fuel pump clicking? Could the screen in the tank be pluged? Lots of things could cause- need to do some detective work. George
George Butz

I would say like George to check the filter in the tank. IF this is plugged it can cause a fuel starvation problem when running. Mine did the same thing until I cleaned out the tank. THis happened when the car would start and idle but once the fuel pump started pumping under a good load stuff would be sucked into the screen and starve the pump for fuel.

Also have had a bad fuel pump that would let the car start and run but when you hit the throttle to go faster it would not keep up thus starving the engine for fuel.
THe only time mine has "vapor Locked" is when it is hot outside, we have had a big run and when you shut down to park or take a rest, it will not start again. Opening the hood on the carb side usually prevents this. I do this as a matter of course on long runs when we stop for a beer or whatever. THe fuel nowdays usually contains alcohol which can cause locking up when allowed to set as it seems to boil out of the line to the carbs.
TRM Maine

Oops - missed the TF part. "The fuel pump is by the rear axle. Is it possible to wrap it with something to reflect the heat? If so, what is the source to obtain same?"

No need to wrap the fuel pump that is mounted at the back of the car. The pumps were moved back there to eliminate the possibility of vapor lock. With the pump mounted at the back of the car, fuel is being delivered to the carburetors under pressure as it travels through the engine compartment. This greatly increases the temperature at which the fuel will vaporize. As TR states, you could have debris in the tank or a pump going flaky. To check for a fuel delivery problem follow the tips in the article, Fuel Delivery Troubleshooting Guide in the SU Fuel Pump Articles on my web site at: http://homepages.donobi.net/sufuelpumps/
Cheers - dave
David DuBois

Hi Ed,

You've had a wide variety of responses covering a no of possibilities. Can I also suggest that you first look at the Archives - lots of psitive ideas there.

Firstly and most importantly are you running the TF on 'standard' TDC static ignition timing? On modern fuels etc this is far too retarded and will inevitably lead to overheating - even Morris Minors in the 1950s were timed 4-5 degrees advanced! I would suggest the same for TDs&TFs this being around 4mm ahead of the existing mark on the crankshaft pulley.

I agree with Dave Brauns reservations re oil coolers on our cars, and don't forget more powerful fans are only effective when the car is stationary, in commute traffic etc - plenty of air goes through the radiator when it's moving.

Heat shields are available that can help - make sure the carb stud insulating spacers are present, but before anything advance your static ignition!

Good luck, John
J C Mitchell

hello, the fellows here have covered most of stuff. i would offer..how did you determine vapor lock? ignition break down when hot happens too, if the engine is running hot, do you have a dragging brake? i have never experienced vapor lock in a car with a rear mounted fuel pump, but that is just my experience. regards, tp
tom peterson

I have run my car in very hot situations, and really have not had a problem with vapor lock. I have had, however, fuel pump issues, when the pump got warm, that have very similar results to what you describe. Also, when the engine would not run, did you check that your coil was putting out and that you were getting a real strong spark? I can't tell you how many times that I have chased problems in my car and found something from (at least I thought)left field!
Steven Tobias

Assuming that Ed's diagnosis of vapor lock is correct, the fuel pump may be the cause. I noted that he has had both the exhaust manifold and the head pipe jet hot coated. I have the coating on my manifold only and noticed that there is more heat transferred to the muffler on my RHD TD. The floor on the drivers side is noticably warmer as a result. Could it be that now there is more heat on Ed's muffler and tailpipe and thereby transferring it to the fuel pump?
Jim Merz

I have found both a faulty rotor arm and condenser which seem to correct after cooling down. The most difficult fault to find on two of my classic cars was due to the hotter burning of modern fuel. I found that the recomended valve clearences insufficient for the hotter burn. The effect was that the valves remained very slightly open after a run, and so made restarting the hot engine very difficult. The simple remedy was to increase the clearances by 1 thou. bingo no more problem.
B Mellem

hello, in regard to valve clearances, my service manual says to set them with the engine HOT. if you set them with the engine HOT how would you end up with no clearance and the valves being open? i'm confused. regards, tp
tom peterson

Perhaps really hot is the key. If you pull into a Fuel station and then try restarting a set of feeler gauges and spanners may do the trick. Otherwise just try it! All the best.
B Mellem

Ed,
Seeing that you live in NJ, is it safe to assume that your car is still put up for the winter, and you can’t really get out and try any of the suggestions offered here until the weather and roads get more tolerable ?? I would hate to see this thread just disappear without solving your problem.. There have been many good suggestions offered by some very knowledgeable people, but I believe they must be "tried on the road" one at a time,,, and the result noted and reported..

SPW
Steve Wincze

Ed,
If you have read the archives, (and it sounds much like you have!)...IMHO check
1: timing issues
2: carb to intake manifold spacers
3: advance problem with dizzy (springs?)
4: did not see this mentioned anywhere...stainless steel fuel hose, not rubber! This was part of the "cure" for mine!
Just for fun ...get a couple of "cold packs" from the drug store and see if packing one carb or the other makes it start up quicker.
Been quite a while since I had this problem but as I recall "chilling" my rear carb made mime start quicker back when I had this problem years ago...turned out I had a bad float in that one.
Best of luck,
Cheers,
David 55TF 1500 #7427
David Sheward

Ed

As crazy as this sounds,it used to work.
Vapor lock could be lessened by placing a couple of old wooden spring type clothespins on the fuel lines.

Safety fast and going slowly crazy

Tom
T. L. Manion Thomas

Can you lead me to a source for stainless steel fuel lines rather than rubber? (1954 mgtf)
Ed Eastman
C. Eastman

"Wooden spring type clothespins on the fuel lines"

Tom,

Do you have any idea as to how this would have any effect on the subject under discussion? You are right about how it sounds. Also,is there any particular location for the pins on the line? Please advise.

George Raham
TD 4224
G. L. Raham

Ed,
IMHO, I think Dave is referring to stainless braided fule lines,, solid stainless lines would not have any flexability in them to deal with the engine movement relative to the body/frame...

SPW
Steve Wincze

I think you are right, that he means stainless steel braided fuel lines. Do you know a source for obtaining them for 1954 mgtf?
Ed Eastman
C. Eastman

George

They seem to act as cooling fins, in the same way that the fins in a radiator help to disperse the heat. Greater cooling surface maybe. Just clip them onto the fuel lines. As I have not had any problem with vapor on my current 1953 TD, (Knocking on wood as I write this), It is about five years since I rebuild the engine. I live in Ohio, where in the summer the temp hit high 90sF. I have the floats set per manual. I run the same SU fuel pump the car came with. The only two things that I think might make this TD different from most is that it does not get stored for the winter. I try to drive it about once a week year round. It sees snow and ice but never road salt. It also benefits from the sound advice of Tom Metcalf from Safety Fast Restorations. Seem to keep everything working .

Safety Fast (but slowly going crazy)

Tom
T. L. Manion Thomas

Thank you Tom For your reply. You are fortunate to be able to run your TD in the winter without the dreaded salt. My TD has only seen snow in two of it's 58 years because I have seen what it does to our car bodies, chassis, suspension etc. When I did it's first and only "body off", I only had to replace one piece of wood at the back. I could have used it as it had only a small area that was suspect. When I see what other owners have to work with, I have nothing but admiration for their dedication.
Thanks again for your explanation, and it still has me scratching my head.

George Raham
TD 4224
G. L. Raham

Ed,
You can get themfrom either Abingdon Spares or Moss..Stock item , nothing special,,,

SPW
Steve Wincze

Ed,
Definitely ..I was referring to braided stainless fuel lines from firewall to carbs. As long ago as I replaced those it would have had to have been from Abingdon Spares or Moss...(only two places I knew where to get parts for these cars then.
Never heard the cloths pin trick ..but can see how that could work as a "heat-sink" as Tom describes.
I just got home from Buffalo and got your email with your # on it. I try to give you a call tomorrow ...I know how frustrating this problem can be.
I do recall from my days as a youngster how much my father hated driving these cars in parades at low speed...but being a small local businessman making a living selling them he came up some interesting ways of keeping a fleet of sports cars moving at slow speed for 4th of July Parade! Early fourth of July morning would find us, bonnets~up with boxes of dry ice, "packing" carbs for the parade...pretty cool idea. He would have loved the "cold-packs" you can buy at most drug stores now...but that is where I got the idea of caring a few of these with me till I got my problems resolved.
Cheers,
David 55 TF 1500 #7427
David Sheward

This thread was discussed between 15/02/2009 and 23/02/2009

MG TD TF 1500 index

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