heat shield

[BobDeSoto]

 I had trouble with vapor lock last summer - 1951 DeSoto

 

Does anyone make a heat shield "kit" or a functional heat shield?

[Plymouthy Adams]

the heat shield that is stock on these engines is so simple to make....many pictures on this forum of them installed.    Like always, I recommend e-bay for a look see or even source to buy if that is what you wish........this is a very good pic.

 

https://www.ebay.com/itm/1949-CHRYSLER-SPITFIRE-FLATHEAD-6-HEAT-SHIELD/254376374193?fits=Year%3A1948|Make%3APlymouth&hash=item3b3a036fb1:g:uZIAAOSwlf9dgY4w

[NickPick'sCrew]

Do you know if you were having issues above or below the manifold or both?

 

There is a nicely done lower heat shield out on eBay now that shields the mechanical pump (PA's post above).  Don't get the black one, you want something that will reflect the heat vs. absorb it.  The reflective silver version will work but would be better if made from tin.  Perhaps black on the pump side and silver on the manifold side would be good, but overthinking it now.

 

My son, Nicholas's build just made his upper shield obsolete.  It was for a 1x1 barrel set up and needs to be cleaned up. It mounts in-between the intake manifold and the carb and requires an extra carb gasket but it shields the carb and upper plumbing from direct manifold heat.    I'm going to help him fashion a 2x1 version for his new setup.  Not too difficult to snip, grind and shape some tin to work.

Edited January 1, 2020 by NickPick'sCrew

[BobDeSoto]

no - I don't know

 

The heat shield on EBay seems to be exactly what I was looking for.

 

Thanks.

[Sam Buchanan]

In case anyone is looking for ideas for a carb shield, here is one I made from 0.025 aluminum....can be made and installed in a few minutes. This one doesn't require disturbing the carb to manifold attachment.

 

[chrysler1941]

29 minutes ago, BobDeSoto said:

no - I don't know

 

The heat shield on EBay seems to be exactly what I was looking for.

 

Thanks.

You also need a special long screw. It's one of the 8 that houses the membrane.

10-32 thread and about 3" long

 

Easiest way to avoid vapor lock is with and electric fuel pump. Mount on near fuel tank in line with original fuel line. Hidden push button to activate pump when starting hot. 

Airtex pumps can be used, they are flow through.

Edited January 1, 2020 by chrysler1941

[BobDeSoto]

I like the electric pump option.

 

Any 6V recommendations?

[chrysler1941]

18 minutes ago, BobDeSoto said:

I like the electric pump option.

 

Any 6V recommendations?

 

http://www.airtexasc.com/product-details?partkey=000759645

 

This a low PSI 6v inline fuel pump I use on all of my cars. It has 2 wires and can be used on positive ground cars. 

Low PSI corresponds with cars original fuel pump so carb's needle won't overflow.

I use it for priming and hot start. Saves battery.

Get it at your favorite parts dealer.

Edited January 1, 2020 by chrysler1941

[BobDeSoto]

Thanks

[Sniper]

Something's wrong somewhere.  I live in west Texas, it's regularly over 100 out here and I have yet to see this problem.  How much ethanol is there in your gas? 

[Sam Buchanan]

2 hours ago, BobDeSoto said:

I like the electric pump option.

 

Any 6V recommendations?

 

Here is the 6v Carter pump that is the only pump on my P15.

 

[Bbdakota]

3 hours ago, Sam Buchanan said:

 

Here is the 6v Carter pump that is the only pump on my P15.

 

I have the same pump but I run mine in series with the mechanical pump. If one fails, the other will not leave me stranded. 

[greg g]

The downloads section of this site has a template to build your own fuel pump heat shield.  If you make one that fits the carb to manifold you will need another gasket to mount it.

 

Make sure that the fuel line from tank to fuel pump inlet has no air leaks. Fuel lines don't like bubbles. Also check the condition of the rubber piece between the hard line and the pump inlet.  They can look good from the outside but be mushy inside restricting low especially when the rubber gets warm.

Edited January 2, 2020 by greg g

[NickPick'sCrew]

Okay, I've been itching to tell this story ever since Nicholas started his project and greg just provided me the context..  

 

Served in the first Gulf War with a forward engineer unit as the mech for 25 5 ton dump trucks and half a dozen HUMVs.  We cleared mine fields, stabilized air fields, and dug in camps for infantry and artillery  The 5Ts came off a floating supply ship and still had old steel fuel lines throughout (the working fleet had already switched to something more forgiving).  Those trucks also had mechanical pumps at the engine. We call these Pull systems  as they pull gas to the engine vs. Push systems which had electrical pumps back at the tank and push gass to the engine.  The lines began to crack and so the pumps just started sucking air.  We had no replacement lines.   The fix.  I asked my drivers to keep the gum from the meals ready to eat (MRE) rations we had and to keep the thick plastic bags that the MRE was packed in as well.  We also had lots of extra zip ties to connect the camouflage netting.  Chew the gum, stick it over the crack, wrap it with plastic and zip tie it in place.  Worked like a charm and we keep the full convoy running till we came home.

 

Only real value in sharing that is, well i think its a cool story.  Also, if you install a secondary electrical pump consider pushing it to the back of your full system (like Chrysler1941 suggests), if you get cracks further up the system it will push the fuel past that and keep the engine running.  Down side is that it will continue to leek -- its a fire hazard. 

Edited January 2, 2020 by NickPick'sCrew

[Merle Coggins]

? So you truly kept our military running with bubble gum and zip ties...

Good story. And thank you for your service.

Edited January 2, 2020 by Merle Coggins

[Greg51T&CWagon]

20 hours ago, Sam Buchanan said:

 

 

Tho it's obvs good enough as it is, it seems to me this heat shield would be even more effective if it were flipped around so that the bit curving down were against the carb base. As it is now that curve would act as a slight air damn pushing the rising hot air toward the carb and fuel bowl. /nit pickin'

[Sam Buchanan]

16 minutes ago, Greg51T&CWagon said:

Tho it's obvs good enough as it is, it seems to me this heat shield would be even more effective if it were flipped around so that the bit curving down were against the carb base. As it is now that curve would act as a slight air damn pushing the rising hot air toward the carb and fuel bowl. /nit pickin'

 

You might be right but without tuft testing who knows how the air moves in the engine compartment. My thinking was the slight curve would direct flow from the radiator toward the carb bowl and reduce stagnation......but that is just a guess....probably doesn't make any difference either way.

Edited January 2, 2020 by Sam Buchanan

[1949 Wraith]

I have the hot start issue with my '51 Dodge truck. She starts right up when cold, but if you stop and have a coffee say 15-20 minutes she will not start on the first crank. Iif you stop for an hour she will start right up she is a 12 volt conversion so she cranks fast. I installed  heat sheild on the fuel pump and installing an switched aux electric fuel pump and that does not change my hot starts when used. Hot starts are improved with some open throttle, hard to do without engaging accelorator pump. So in my case I believe my issue is flooding due to fuel perculation. I have tried setting the fuel level lower in the carb with no noticeable effect. I plan on making a heat shield for the carb this winter and I have been looking for an 3\8" insulated spacer like the GM trucks had.  No luck finding one of those yet.

[Sniper]

Two things, a Holley 1904 will bolt onto a manifold that has a Carter BB on it.  They make an shield isolator for the Scout community that fits the Holley.  It may or may not work here, I don;t know.

 

https://scoutparts.com/1BBL_Carburetor_Base_Gasket_with_Heat_Shield_Isolator_860449R1_Scout_80_Scout_800/p13375

 

Second thing, if you have an automatic choke it will mess with the linkage settings and a 3/8" spacer will mess with it more.  The linkage will be too short at some point. 

[Plymouthy Adams]

heat soak when stopped after a run leads to percolation which is a true existing condition and is made worse it seems by the alcohol blended fuels.  another tip for folks suffering from this could be the lowering of your float to reduce the fuel in the bowl to prevent boil over and subsequent flooding when the fuel expands.  

[Sam Buchanan]

From the For Whatever It's Worth dept:

 

A took another step to hopefully reduce heat-soak when I replumbed the car with the electric fuel pump. The new fuel line was run up and across the firewall, the rational was to keep the line away from the exhaust manifold. Under-hood temps may be higher that far up in the compartment but I speculated that the net result would be the line seeing lower temps. As a bonus the firewall line sure was a lot easier than snaking a new line around and under the front of the frame. Is there a safety issue with having the line above the engine? Don't know, but the line is new, easily inspected and secured with cushioned clamps.

 

 

 

Edited January 2, 2020 by Sam Buchanan

[Merle Coggins]

4 hours ago, 1949 Wraith said:

I have the hot start issue with my '51 Dodge truck. She starts right up when cold, but if you stop and have a coffee say 15-20 minutes she will not start on the first crank. Iif you stop for an hour she will start right up she is a 12 volt conversion so she cranks fast. I installed  heat sheild on the fuel pump and installing an switched aux electric fuel pump and that does not change my hot starts when used. Hot starts are improved with some open throttle, hard to do without engaging accelorator pump. So in my case I believe my issue is flooding due to fuel perculation. I have tried setting the fuel level lower in the carb with no noticeable effect. I plan on making a heat shield for the carb this winter and I have been looking for an 3\8" insulated spacer like the GM trucks had.  No luck finding one of those yet.

 

3 hours ago, Plymouthy Adams said:

heat soak when stopped after a run leads to percolation which is a true existing condition and is made worse it seems by the alcohol blended fuels.  another tip for folks suffering from this could be the lowering of your float to reduce the fuel in the bowl to prevent boil over and subsequent flooding when the fuel expands.  

 

As Tim states, it's a heat soak issue. Fuel expands in the float bowl and tends to flood the intake. I find that holding stepping on the throttle pedal slightly while cranking helps get the Ol' Boy started up after short rest periods. This introduces more air to help lean out the over rich (flooded) condition. 

 

In my truck, with a stomp starter, I've mastered the trick of pressing the starter pedal with my tow while giving a little throttle with my heal. It always fires up that way within a few crank revolutions. Without the throttle input you could crank the battery dead before it'd start.

[Plymouthy Adams]

also with the throttle full open and the low speed of cranking will not draw fuel through the jet as the velocity is not high enough to draft the fuel thus allowing what is already in the induction side to burn off and ultimately lean out enough to fire off as Merle states....secret is....do not continue to grind the starter and cause excess heat in the cable....but at the same time...in-between cranking...do not let up on the gas pedal...if you do and you put your foot back down.....your accelerator pump will induce more fuel to the engine...

[1949 Wraith]

7 hours ago, Sniper said:

Two things, a Holley 1904 will bolt onto a manifold that has a Carter BB on it.  They make an shield isolator for the Scout community that fits the Holley.  It may or may not work here, I don;t know.

 

https://scoutparts.com/1BBL_Carburetor_Base_Gasket_with_Heat_Shield_Isolator_860449R1_Scout_80_Scout_800/p13375

 

Second thing, if you have an automatic choke it will mess with the linkage settings and a 3/8" spacer will mess with it more.  The linkage will be too short at some point. 

Thanks this is is something to consider. I have a manual choke so that is not an issue and I knew I would have to make some linkage  if I went with anything thicker than a plain heat sheild.

 

4 hours ago, Merle Coggins said:

In my truck, with a stomp starter, I've mastered the trick of pressing the starter pedal with my tow while giving a little throttle with my heal. It always fires up that way within a few crank revolutions. Without the throttle input you could crank the battery dead before it'd start.

I have gotten lazy I use the throttle knob on the dash. My throttle peddle had a bend in it from previous owners stompin their heal on it.

[BobDeSoto]

Sniper - we can actually get unleaded with no ethanol - 87 and 91 octane.