Vipergtrs

Hi

When my 66 427 temp get to about 170+ it's starts to stutter and I'm pretty sure it's a fuel issue

Two things, will a plate under the carb help

Or, should I just wrap the fuel line that sits in the V? or both

Any recommendation for the type of heat plate and where to obtain one

Very much appreciate your help

Bluestripe67

I would start by verifying the engine temp against the gauge. You could be running hotter than what the gauge is showing. Then check and make sure your vacuum advance is working. If not, that contributes to higher engine heat at idle. The heat shield should help, and wraping the fuel line. Fuel today can contribute to the problem. Heat shields are available on line at Jeg's, Summit etc. If difficult to get over there in GB, make your own. Template with cardboard, then aluminum sheet stock from a hardware/building supply place. Dennis

Vipergtrs

Thanks
Vacuum is working and for some reason when I bought the car it had a separate gauge wired up to a sender that wasn't working so I got a new sender and both gauges read the same.

It doesn't get dangerously hot but hot enough to affect the fuel

Modern fuel is no good and as you say I'm sure it affects the temps too

Tiros

This is what I use:

https://www.summitracing.com/parts/hly-108-70

I put the aluminum shield on the manifold, then the spacer. One respected member here says it belongs on the carb side, but I disagree. Connecting the plate to the carb, allows all the radiant heat from the engine and to be conducted directly to the carb base. Putting the spacer on top of the plate IMHO, insulates the carb more completely from the engine heat, as the carb is resting on the phenolic heat separator, not a hot aluminum shield.

dkleather

What would be good to use to wrap the fuel line? Is there something available specifically for that purpose? Dave

leif.anderson93

This has been recommended in the past...

https://www.summitracing.com/parts/d...FQMPaQodaxkP5Q

warrenmj

If I'm reading your profile correctly, you're from Great Britain. You must have some pretty crappy "petrol" if it causes problems when the engine reaches 170. That is barely warmed up! Hopefully the carb spacer and fuel line insulators solve your problem.

Vipergtrs

There's a lot of ethanol in our fuel, not sure if that changes things

GTOguy

Yes, ethanol changes things for the worse. We have it in California, too, and all my old cars are much less content with it on hot days. Ethanol also leans out the mixture, so the car will ping or detonate easier unless the carburetor is re-jetted to richen it up a bit. I need to do this to both my GTO's and my Corvette.

63split63

Could be plug wires or too much plug gap ?
Bill

Faslane

got a feeling it has nothing to do with gas, coil getting hot and breaking down?????

6T5RUSH

Here is the "order of battle" I used in assembling the heat shield to my 327:



CARB HEAT SHIELD ASSEMBLY ORDER



ENGINE TEMP AT THERMOSTAT HOUSING



PRIMARY FUEL BOWL TEMP

That's a 60* drop in temp...still on there today.



Jim
In God We Trust!

lawdawg

Two things:
1. The rush has the order above
2. Get some DEI fuel line wrap. You can get it at any local advance. Auto parts , summit ....., put it on the line startin g at the carb, going backwards, all the way past the fuel pump under the floor boards and body is ok to get away from the heat. You can get it sown solid like a sock, or Velcro. Take your pick.

4. Yeah, I left off three, blow ME! Get all the ethanol out of the tank, siphon if you need to. Only use pure gasoline, even if it is low test. The boil off is much lower on straight gas even if low octane.

Do this and your problems will be minimized. After all this, if your prob is not fixed, you are going to need to increase octane to 100ll.

I am assuming you have addressed full advance

lawdawg

Don't mess w the timing yet if you haven't already!

Frankie the Fink

That's amazing....I've fought this problem on 3-4 cars and even with my best efforts and spacer combos I considered a 20* drop a big success

Vipergtrs

I like your thinking..


Thanks Chaps, very useful

My shield and line wrap has arrived. Tomorrows job

Birdball

I 100% agree here. I battled fuel boil with my 427 even in moderate weather. I installed the fuel line wrap and still had the issue, then the heat shield minus the rubber spacer and still no help, then finally added the rubber spacer on top of the shield this summer and now no issues even in 100 degree outside heat. I also have the b28 vacuum can plumbed to manifold vacuum for good advance at idle and it's now a real pleasure to drive even in traffic.

Good luck!
Matt

Vipergtrs

Chaps, can I resurrect this issue that I'm still struggling with.

You guys are mustard, a great help

This is where I'm at

Car starts and drives beautifully on a cool day but on a hottish day once ive been for a run I switch car off and when I come back to it 5,10,15 minutes later its starts fine.

I get 50 meters down the road and it splutters and cuts out.

Now, I feel it has to be vapourisation even though the engine isn't running hot but..

I've got the Carb plate and spacer
I've wrapped all fuel lines
I've just fitted a new pump
Fuel bowls are fine plus the vapourisation isn't this close or it wouldn't run for 50 meters.
It also has this issue f I'm sitting in traffic
Running 5% ethanol as it's the best I can get here in the UK 98Ron

I am at my wits end with this problem. What am I missing

Bear in mind it's perfect in cool weather

Frankie the Fink

Your radiator temperature is not a big factor....fuel can boil a little over 140* and your radiator runs 180* plus - it could boil fuel all day long. Have you taken an I/R temp gun and 'shot' the fuel bowls when this happens to get the only temp that matters ?

Proper diagnosis is a lot cheaper than throwing more do-dads on your motor. If the bowl temps are north of 140*, you hear boiling or see fuel dribbling from the primary squirters its percolation (NOT vapor lock so be careful with your term). If you can hold your foot on the floor and get the car started again its percolation as you're basically starting a flooded engine...

Vapor lock is fuel vaporizing prior to the fuel pump and the pump can't pump vapor; that can occur just running down a straight road on a hot day. Percolation is most prevalent on a hot day after the car sits 20 min or so after a run; 'heat soak' raises underhood temps to the fuel's boiling point.

You may indeed have vapor lock as the hot car starts and runs a bit with the fuel in the bowls and then chokes when the pump encounters vapor. See if you have any fuel lines close to hot surfaces as a first check. Less volatile fuel can help too. Other permanent fixes are an electric pump conversion, fuel return line, or, a booster pump.

It would help if you can tell the difference in operation of a car running terribly rich (perc) or a car running out of gas (vapor lock) that's the best diagnostic tool. One other thing to check is that the gas cap is venting; either run without one briefly, replace it or do a blow/suck check (but this can fool you sometimes if the thing is failing hot).

Tiros

My problem is that your car starts fine after the hot soak. My experience with hot soak is trouble on re start. ie: The fuel has all boiled out of the bowls. Since this doesn't seem to be your case, I don't think you are hot enough for this to be the root cause.

What about the carb? Is the needle sticking? When was last rebuild? Sounds like you are getting just as far as whats in the bowls. For some reason they are not being refilled.

Other things:
How long can you idle after the re start? Does a long idle period help? I mean if you idle long enough before you go again will it still sputter/cut out?
What sort of choke setup do you have?
How do the plugs look?
It sounds like fuel but are you sure its not an electrical problem?
After the sputter cut out, how difficult to restart? What happens next?

FWIW I am confident an electric pump wont fix this.