47-59 fuel pump wrap

[nvrdone]

As I posted earlier, my electric fuel pump over heated causing a vapor lock / no start condition.
I'm at the point of doing a heat wrap on the pump and wondering should I use an exhaust heat wrap or something like dynamat ?

[mr48chev]

I don't think I would wrap it but fab up a heat shield on the side facing the exhaust with a bit of clearance between the shield and the pump. You still want air flow across the pump to help cool the motor in it.

[leegreen]

I agree, don't wrap up the pump itself. The guts of it are probably a plastic vane pump and possible a second stage with eccentric steel rollers, not stuff that is forgiving of running dry.

move the pump to a cooler location, run a regulator and return line, put the pump inside the tank were all good suggestions in the previous thread.

if they wont work I'd weld a heat shield to the exhaust and put another heatshield between pump and exhaust, but leave as much airflow as possible for the pump itself

[nvrdone]

I appreciate all the feed back. The plan now is to to route the pipes out under the running boards with a heat shield on the pipe and over the fuel pump. I'd like to run the pipes out the back but I dont see that there is enough room.
I've never had this problem before and since I have another parade June 16th with my grandson, I want to get this fixed asap.

[Hcb3200]

I put in a heat shield between exhaust and my external pump and it really helped keep it cool with good airflow.

Since your running a external electric pump. And you said this just seemed to happen.
Confirm the check valve is doing its job if it has one.

Since pressure raises the boiling point. If the pressure is bleeding off before the heat of the parts around it cool then it could be boiling faster than expected.

I had a pump that had a good check valve and it did its job and keep good pressure on the lines long after shutdown (I run LS but principle is the same)
By the time it bleeds down the engine, pump and parts all around and fuel is cool enough.
That check valve went bad and I had a real hard time starting that engine after a shutdown a few minutes before. And a hell of a time troubleshooting that one. Once i replaced the check valve it really helped on keeping the fuel pressure up therefore the boiling point.

[nvrdone]

Well, after visiting 2 exhaust shops, I've learned a lot. First I have about 16" clearance between the end of the pipe and where the pump is mounted. Both shops don't think it is a heat issue. One shop asked when I last changed the fuel filter. I can't remember. So tomorrow I will get a new filter and just for grins & giggles I will add a heat shield over the pump and filter. I will also run a pressure check on the line at the carb.

[dsraven]

personally i boubt if it is a filter issue since it only happened that one time. does it get up and go without any issues when the hammer is put down? if so, I would still be looking for the heat issue. there can be lots of heat built up under the vehicle on a hot day when not really moving. your engine may be staying within heat limits but thats because the fan is coming on to cool the rad. if you had the a/c on then add that extra heat from the rad area too. that hot air usually goes under the truck, right? add the exhaust heat that also dumps under the truck, the heat from the trans (I assume auto trans) thats building in the torque converter from sitting in drive, the heat off the asphalt, the warm air in the area from all the other vehicles ahead of you. suffice to say it gets hot under a vehicle in a parade. thats when it quit, right? no problems before or after? I would still go with the heat issue if it were me looking. in tank pump may help, especially with a full tank of fuel on a hot day (full tank takes longer to heat up). exhaust dumped outside the vehicle perimeter would help, anything you can do to lessen the heat under the truck would probably help your pump survive. curious what you have for clearance under the truck to allow for air flow? got a recent pic of your truck on a flat surface at ride height, like when in the parade?

[nvrdone]

OK, well I got into the fuel pump overheat issue. First, the fuel pressure at the carb was varying between 2 & 6 psi. Not a good sign. There is no a/c or auto trans to cause excess heat. If you look at 2025 American reflections car show photos elsewhere on this forum my truck is the first one shown.
Anyway, I pulled the pump & filter and just for fun, I put air pressure to both of them. You should have seen the crap that came out. So I replaced both. Now I have 6.5 psi at the carb. Much better. I did build a heat shield over the pump and filter. Next week the truck goes to the muffler shop to have the pipes run out under the running boards infornt of the rear tires. I'd like to run the pipes out the back if possible. We will see.

[nvrdone]

A follow up. Today I drove the truck to a local show. When I got home, just for grins I checked the exhaust temp at the end of the pipes. The left one was 131 deg, the right one was 168 deg. Wonder why the difference.

[dsraven]

there are a lot of factors to consider there but i would check pipe temps at the manifold exit for a more precise indicator.

[leegreen]

if your using stock manifolds, check the exhaust flap is free

[nvrdone]

stock manifolds, no flap. Will check temps at the manifold exit. thanks for the ideas. Also, the temp at the pump cover was 103 deg. its on the right side about 9 " from the end of the pipe.

[mr48chev]

That big of a difference side to side might mean that the the mixture on the carb isn't even.

Normally I'd go with the heat riser thing though. Or something else causing a restriction on one side more than the other.

[leegreen]

With dual exhaust and turn downs under the bed it may be loud enough to mask an exhaust leak before the turn down?

check at the manifolds, if they are different then also check each manifold runner adjacent to the head to see if there is a lazy cylinder -this may be more apparent before engine is fully heat soaked.

[nvrdone]

OK, today I had some time to play with the truck. Here's what I found on the heat issue.
Left head center of exhaust manifold was 790 deg. cyl 1 was 177 deg, cyl 3 was 436 deg,cyl 5 was 252 deg, cyl 7 was 195 deg.
On the exhaust, muffler in was 380 deg, out was 248, tip was 147.
On the right head, exhaust manifold was 775 deg, cyl 2 was 240 deg, cyl 4 was 663 deg, cyl 6 was 394, cyl 8 was 180.
The exhaust was muffler in 404 deg, out was 246 deg, tip was 217 deg.
the thermostat is a 180 & the housing was 217 deg.
my big concern is the variation between cyl 3 & 4.
My next check will to be to adjust the valves and the carb.
Am I being concerned about nothing

[leegreen]

how does it run in general?

That does not seem excessively hot, fully warmed up you should see that across the board. but the imbalance... hmmm.
Center cylinders usually get more mixture and run colder, what is your intake setup?

Maybe a 60 second 10 and 30 minute drive check temps for each, maybe it is not so much of a problem

some ideas
Try closing the choke a bit and see if the temps equalize with a richer mixture.
look at the plugs and compare gap on the hot cylinders to others, check the inside of distributor cap, compare the terminals. shove a borescope in and compare how the tops of pistons look

[nvrdone]

Great ideas. A friend suggested that because I am running an aluminum radiator and an iron block, there may be some corrosion build up. His idea was to remove the water pump and see if there is any corrosion build up where the pump and block meet. then also flush the cooling system.
It's a nerve ending game with these old vehicles. Just like us.

[nvrdone]

Further update. First compression on all cylinders are 90 - 109 psi. That may be normal for a 52 year old engine.
Second temps on left center exhaust manifold went from 790 to 705 deg. Right center exhaust manifold went from 775 to 665 deg. Those numbers seem high but more balanced. I did richen up the carb 1/4 turn on the mixture screws.
Tomorrow I will flush the cooling system and see what happens. The saga continues.