Fuel loading when hot

[74bigblock]

With the Edelbrock I added some insurance in the form of a 3/8" phenolic spacer (see pic).

I did the same thing when I converted to the Aluminum dual plane intake on the 454. Phenolic spacer... Most autopart stores have them on hand. I got mine at Murray's

 

[67HEAVEN]

The main problem I can see with using a heat shield with spacer, is height.

I'm already extremely close to the underside of the big block hood with the 502 intake and Holley 850. I even cut off a bit of the wing-nut threaded rod as it was kissing the hood.

Hmmmmm. :confused

 

[67HEAVEN]

Does the stumble you get under hard cornering always happen, possible fuel pickup problem?

No. Only on a random basis. The fuel pump is directly below the tank, so getting fuel shouldn't be a problem. It happens when the tank is almost full, as well.

Thankfully, it doesn't happen very often.

 

[Tom Bryant]

Hopefully the heat shield will do the trick by it'self.

 

[67HEAVEN]

Hopefully the heat shield will do the trick by it'self.

Due to the height restrictions I mentioned a few minutes ago, I think the only way to use a spacer is to cut some height off the wire mesh between the base and the lid, seen in this photo. That will drop the lid to give me the required room.

I wonder what effect losing 3/8" of airflow all the way around the neck of the carb will be? Couldn't be good, could it?

 

[Gerry]

I see your problem, so obvious from the picture.

It's that damn power brake booster!

I'm sorry, I just couldn't help myself. I'll try and get help.

Best regards,
Gerry

 

[paul67]

I had not intended to suggest that both be used. The shield protects the Holley bowls from radiant heat by deflecting it away. The spacer gives some heat relief for the carb body itself. Both can of course be used but with the clearance problem you may wish to try the shield first.

 

[motorman]

Due to the height restrictions I mentioned a few minutes ago, I think the only way to use a spacer is to cut some height off the wire mesh between the base and the lid, seen in this photo. That will drop the lid to give me the required room.

http://www.computersupport.ca/Restoration/Induction-06-700.jpg

I wonder what effect losing 3/8" of airflow all the way around the neck of the carb will be? Couldn't be good, could it?

the back of your hood is not cut open where does the outside air get into the carb. if the front of the hood scoop is open you could have a low air pressure area there,even negative. the reason the L-88 hood was open at the rear because that is a high air pressure area on the hood forcing air into the air cleaner.

 

[67HEAVEN]

the back of your hood is not cut open where does the outside air get into the carb. if the front of the hood scoop is open you could have a low air pressure area there,even negative. the reason the L-88 hood was open at the rear because that is a high air pressure area on the hood forcing air into the air cleaner.

Correct. The underhood piece is a Chevy parts counter item from 35-38 years ago. I chose not to open the rear of the hood, at least until a year or two of ironing out various changes made during the project.

Way back in my racing days, I ran a TransAm style hood-mounted electric tach since our cable tachs are so wacky and inaccurate. Then, during the rebuild project, I went back to the cable tach and repaired the hood, but the repair has shrunk enough that under certain lighting, you can see where it was.

Next winter, I may pull the hood, re-do the repair and open the rear for cowl induction. Mind you, I've never been disappointed when the pedal meets the floor.

 

[Viet Nam Vett]

The only prob's I have with my 502 ..is the crappy Holey 850 that came in the package that I'm stuck with.

If I make a hard right or left turn a ..The motor will stumble for a sec..then recover. I guess that's due to float level. But I have not changed the stock setting.

I suffer none of the problems you are incountering as far as hot soak goes. My 502 fires up after a hot soak with no problem. I am running a Carter 7-9 PSI fuel pump straight to pressure gauge and then to and inline filter to the carb. After shut down... there is a slow leak down of fuel pressure..but it returns the moment you crank the motor. I also can prime to carb with a momentary rocker switch I have for the pump.

Were both running the same stock intake manifold So I wonder if in fact it is heat soak causing the problem. Could there be something else your overlooking..???

No problems with fuel flow as the Carter puts out plenty of GPH and GPM flow for the 502 at 7-9 PSI.

 

[67HEAVEN]

I picked one up from a local speed shop.

I'll install the aluminum shield tomorrow to check for improvement. If it's still a problem, I'll add the spacer and leave the cow-catcher off while I test it. If that works, I'll cut the mesh down to make room for the mesh and the lid under the hood.

Thanks for all the input to date. More is always welcome.

 

[Ken Anderson]

I am pretty sure you wil find no help with the "heat shield". I 've never seen one work on a street car. Two things come to mind: First is the gas blend. Down here we have a winter and summer blend and the winter percolates in the summer. Second, you must use OEM Holley .120 needles and seats to keep the fuel from leaking in from the heat. Also make sure your bowl vents are clear and your PV is a "65" and un blown and adjust your tip in acclerator cam. That should cure some of the stumble and other problems.

 

[67HEAVEN]

More symptoms to chew on.

At 2:50pm (Eastern) today, I parked the car outside my personal trainer's, shut the fuel pump down and ran it for about 30 seconds.......then killed the engine. Didn't empty the bowls, but certainly lowered them significantly.

Forty-five minutes later, I flipped the fuel pump switch back on, held the pedal to the floor and cranked it over. It took about 10 seconds until it fired, but I was only able to keep it running for 5 seconds. Held it to the floor again and it started, sputtered, threw some blue smoke out of the side tubes and came to life. Strong fuel smell. It was fine all the way home.

I started thinking about all that fuel in the air and crushed my ceeeegar out on the dash....then drove away listening to my upgraded radio.

It's all true but for the above paragraph.

Thanks for your thoughts, Ken. If the heat shield doesn't help, I'm going inside the carb.

 

[Gerry]

More symptoms to chew on.

At 2:50pm (Eastern) today, I parked the car outside my personal trainer's, shut the fuel pump down and ran it for about 30 seconds.......then killed the engine. Didn't empty the bowls, but certainly lowered them significantly.

Forty-five minutes later, I flipped the fuel pump switch back on, held the pedal to the floor and cranked it over. It took about 10 seconds until it fired, but I was only able to keep it running for 5 seconds. Held it to the floor again and it started, sputtered, threw some blue smoke out of the side tubes and came to life. Strong fuel smell. It was fine all the way home.

How much blue smoke are you seeing? You sure its blue and not black, I am slightly colorblind and could not tell the difference but there certainly is one. I hate to even bring up thoughts connected to blue smoke (oil). Why don't you go and check the plugs and see if that tells you anything?

Best regards,
Gerry

 

[67HEAVEN]

How much blue smoke are you seeing? You sure its blue and not black, I am slightly colorblind and could not tell the difference but there certainly is one. I hate to even bring up thoughts connected to blue smoke (oil). Why don't you go and check the plugs and see if that tells you anything?

Best regards,
Gerry

Gerry,

I may be wrong about the colour. I'll check it more carefully next time.

I plan on installing new header gaskets this week, so it'll be a good time to check the plugs too.

 

[Viet Nam Vett]

Gerry,

I may be wrong about the colour. I'll check it more carefully next time.

I plan on installing new header gaskets this week, so it'll be a good time to check the plugs too.

Header Gaskets........!!!! ...I don't Need No Stinken Header Gaskets...!!!:L

Man..That is so ...60's..

 

[paul67]

I'm out of my league for solutions now. But good luck in finding a resolution to that problem.

 

[67HEAVEN]

Header Gaskets........!!!! ...I don't Need No Stinken Header Gaskets...!!!:L

Man..That is so ...60's..

Crazy glue, Mark? otfl

 

[Viet Nam Vett]

Crazy glue, Mark? otfl

What I'm think-en here....is why after all the miles you have on Heaven...what some over 6000 miles..this heat soak thing shows up now.:crazy

What changed ....?? Weird. You ran Heaven in the heat of last summer last year and did't have this problem.

Riddle me that one Batman..??:confused

 

[67HEAVEN]

What I'm think-en here....is why after all the miles you have on Heaven...what some over 6000 miles..this heat soak thing shows up now.:crazy

What changed ....?? Weird. You ran Heaven in the heat of last summer last year and did't have this problem.

Riddle me that one Batman..??:confused

It's now over 8,000 miles. Actually, the problem turned up (in a severe way) twice on the Bowling Green trip.

Once, just inside Michigan, and the second time in heavy traffic going through Indy. I'll tell you about that at CruiseFest.

Tomorrow is heat shield day.