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Heat Soak and Flooding

57545754If you're not kickin' up dust, you're collectin' it!
Lately I've been frustrated by the car not wanting to re-start after going for a run and then sitting for an hour or two. The only way to get her going again is to push down the go pedal and crank for 3-5 seconds like she's flooded.

So, I took her to a mechanic who has an excellent reputation with the classic mustang guys in my area and when we shut her off and took of the air filter, fuel was shooting out of the air bleeders and after a while we spotted some dripping out the sides of the carb onto the intake, so she was definitely flooding from all of the heat (the fact that the fuel line is currently routed over the top of the intake and next to the valve cover is probably a contributing factor).

So, here's what we're (well, mostly him, with my wallet playing a supporting role) looking at doing over the next few days ...
1) New braided fuel line with insulating wrap running alongside the gas tank, across the engine bay brace and then up to the carb - I hope this doesn't look ugly, but hey, I'd rather lose a few beauty points and save the engine long-term from cylinder wash
2) Block off the exhaust cross over on the intake to reduce heat under the carb (I've read mixed reviews on this one - I don't drive her in the winter, just the warm days April through November)
3) Install a 1" riser under the carb - and a smaller diameter but taller air filter
4) New fuel pump
5) New plugs - gapped to between .45 and .50

So, are we on the right track here, anything more (or less) we should be doing in this situation?

(not sure if any of this matters, but she has the factory fuel pump just now, a Holley 750 HP Pro double pumper with mechanical secondaries, Edelbrock performer intake, and MSD ignition)

Thanks!
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marlinjackmarlinjackThe Machinist #5723 AMARGOSA MACHINE 'Running on Empty- Middle of Nowhere'
...Some Mechanic!! You Have a Float Problem, a Fuel Pressure Problem, And BAD Needles and SEATS!! And the 'Leaking out of the Sides', indicates Worn Throttle Shaft Bores; which Constitutes a Vacuum Leak! The 1" Riser will Help, After the preceding is Fixed! Make Sure it's Made out of 'Phenelic', NOT Aluminum!

Thank-You!
Pantera 3rd&LastPantera 3rd&LastMember
I am not the mechanical expert here. But others on this forum like Marlin and Mike are. My little bit of knowledge thinks that what you are doing will not solve your problem.

The factory metal line is run over the intake and up to the carb. Also the factory set up had no carb spacer. The heat crossover as Mike said should also not be your problem. All of the things you are talking about doing are great and may even tweak an extra HP or two, but would not combine to have the issue as you describe it.

I am running a Speed Demon on a Performer (with the passage un blocked & no spacer) and do not have your problem. It sounds more like a carburetor that needs re building or replacement.
4nhotrod4nhotrodHe who dies with the most toys is dead
Get a new carb or rebuild that one.
Make sure you install a fuel pressure gauge to see where you're at. My engine builder advised .035 as a gap but I've read many are running .050. I run .035.
Get an air cleaner with the filter on the top as well as the sides for less restriction.
750dp may be a little big for your motor. What are the specs? There are many on-line calculators as well.
Will
57545754If you're not kickin' up dust, you're collectin' it!
My bad - You're all dead on about the Carb, I completely missed that in my post. The first thing he was doing this evening after I left the car was pulling the carb to work on it and doing a rebuild to whatever extent is necessary. He hit most of the items on Marlin's list including the spacer not being aluminum.

I'll talk to him tomorrow about leaving the cross over open, with all of the other changes, if we leave that alone it may be enough to solve the problems without creating new issues.
lf-tp2511lf-tp2511Member
quote:
the fact that the fuel line is currently routed over the top of the intake and next to the valve cover is probably a contributing factor

No, probably it is not. Look at the photo below of the rubber fuel line routing in 2511. I think that is exactly how yours is running, from your description. I have zero hot fuel issues. Like Marlin, I live in Central CA where it is HOT in the summer. If that routing was an issue, it would surely be an issue here.

quote:
New braided fuel line with insulating wrap running alongside the gas tank, across the engine bay brace and then up to the carb - I hope this doesn't look ugly, but hey, I'd rather lose a few beauty points and save the engine long-term from cylinder wash

Yes, it will be ugly. And not necessary.

quote:
Block off the exhaust cross over on the intake

Ford designed the Cleveland with that cross over. They never updated the design as a result of heat problems from it. Blocking it off may lower the carb and fuel temps a bit, but in itself that cross over is not your problem.

quote:
Install a 1" riser under the carb - and a smaller diameter but taller air filter

Yes, but like Marlin said, use anything but a metal riser.

quote:
New fuel pump

Can't hurt. But what you really might benefit from is a fuel pressure regulator. Holley suggests 4.5 to 6.5 psi.

quote:
New plugs - gapped to between .45 and .50

Gap seems large. WHAT plugs? DO NOT use platinum; they foul easily with carbed engines.

Larry

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57545754If you're not kickin' up dust, you're collectin' it!
Here's a shot of my current fuel line routing, yes, very similar to yours Larry.

I have Motorcraft ASF 52C plugs with a gap of .48 just now ... the gap of .45-.50 has been recommended in a number of posts when using MSD systems, it seems to be working fine.

Thanks for the feedback so far guys, sounds like we're doing some good things (focus on the carb and adding the riser), but overkill with some other things (blocking the cross over, and major re-route of the fuel line). She's due fresh plugs, and a fresh fuel pump is good insurance for the long road trip I'm heading on - I'll hang onto the old one as a backup.

... I've resigned myself to losing the engine cover when the riser and new air filter go on ...

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lf-tp2511lf-tp2511Member
quote:
I've resigned myself to losing the engine cover when the riser and new air filter go on ...

Do you have a dropped base for the air cleaner?

With my dropped base, I have room for a 3" tall filter, 14" diameter.

As for the spacer, if retaining the engine cover is important to you (I know it is for me) I would hold off on installing the spacer until after you've run with the reworked carb. I suspect it is a lot, if not most, of your problems.

No sense trying ALL the steps if you can find solution with just some of them.

Larry
57545754If you're not kickin' up dust, you're collectin' it!
quote:
Do you have a dropped base for the air cleaner?


Only the slightest of drops in the base - I'll check into a bigger drop at the local speed & custom shop ... having the engine cover on isn't critical to me, but the option is and, I'd rather see something other than an air cleaner in my rear view mirror.

As for the spacer, I've seen enough positive comments about them that I'm game to try it along with the rework being done on the carb.


quote:
No sense trying ALL the steps if you can find solution with just some of them.


Sage advice I'll nix a couple of the planned items and keep the focus, time, and money on the carb. However, having just discovered the fuel leak and with a big road trip coming up, I need to be sure this is solved in the next couple of days so that I don't glance back and see flames Eeker
pantera1887pantera1887Member
Another thing to consider is new Holley carbs are not that expensive and it might be smarter just to buy a new carb. The 650 cost a bit more than the 750. By the time you pay for a rebuild kit and the mechanic’s time a new one starts looking like a smarter move. Depending on the age of your carb a kit might not fix some of the problems you might have.

It looks like you have a Holley fuel manifold and if that is the case you can turn it around and connect the fuel line from the front of the engine. Take a look at this link http://www.panteraplace.com/page225.htm

Mike
57545754If you're not kickin' up dust, you're collectin' it!
quote:
By the time you pay for a rebuild kit and the mechanic’s time a new one starts looking like a smarter move.


I know what you mean, but to replace this carb-for-carb would be around $900-1K US w tax & shipping (haven't found one at a Canadian vendor yet, still looking), I could go with the 'street' version from Holley and get it for around $600CDN on sale just now. Or the rebuild for $3-400 including some of the above work or a grand including all of the work.

Another option is going with an aluminum Holley 670 Street Avenger for around $530, or an Edelbrock Thunder AVS 650 for $450 (I hope I'm not in danger of starting a debate by mentioning Holley and Edelbrock in the same sentence). If I were to consider one of these carbs, then yes, definitely a better option than a rebuild, but to stay with what I have, the rebuild is more economical - if it doesn't start leaking again for a long time.

... Some folks have asked about the age of the carb, I checked the previous owner's for-sale ad, and he said it was a new carb during his rebuild, based on what I learned while I was buying the car and how long I've owned it, that means the carb could be anywhere from 4-9 years old. However, his resto took 5 years, so I prefer to think he bought the carb at the end of the resto (making it 4 years old) rather than at the beginning and it sat in the box the whole time. So, it would only have 4 years of light use (with about 5-6 months of storage per year each of those years as we both live in northern climates).
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lf-tp2511lf-tp2511Member
quote:
after a while we spotted some dripping out the sides of the carb onto the intake,

You posted that earlier.

Where out the sides?
From the fuel bowl gaskets? Easy fix.

From the throttle plate shaft? Hard fix. That would mean worn metal and only repairable with major repair, involving machining to install some bushings to return things to a proper i.d. for the shaft.

I have run 2511 with the 670 Street Avenger since I bought it. Over 35,000 miles and 7 years. I'm still pleased with the performance.

Larry
57545754If you're not kickin' up dust, you're collectin' it!
Here's a shot of where it's leaking on the driver's side, it seeps out and drips off the spring onto the intake.

I haven't spotted where the leak is on the passenger side yet, I know it's there, there's staining on the intake, may just be a slow seep through a gasket after she's sat flooded for a while.

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57545754If you're not kickin' up dust, you're collectin' it!
I'm going to visit the shop at lunch hour today to see how things are going, I'll bring the camera and get a few shots - maybe the staining on the carb will give some clues as to the source of the leak(s). I'm hopeful that it is just gaskets and a mild rebuild is all she needs along with a few tweaks.
marlinjackmarlinjackThe Machinist #5723 AMARGOSA MACHINE 'Running on Empty- Middle of Nowhere'
...Did I Not already suggest; the Throttle Shaft Bores were Worn?? BUT, They will NOT Leak While the Engine is Running, Because it is the Source of a Vacuum Leak!

One More Thing! I would Not mount that 'Steel Can' Fuel Filter right there, Behind and Between the Heads! Those Heads are 800-900 Degrees F! Perhaps even Higher! Anybody have a IR Thermometer, who can verify this? Shut the Engine off when Hot, right after a LONG Drive; and go back there and try to wrap Your hand around that Can Filter; You'll realize exactly what I mean! It IS a HEATSINK, and it delivers that heat into the Fuel. Think of how many Cubic Inches that can holds! Your Boiling the Gasoline!! I use to Have the Exact same Filter, I mounted it UP in the Decklid Opening, in the Cool Breeze! You should wonder why Racers use a 'Cool Can' to keep the Fuel Cold! To Me; it is Very Important WHERE You Install The Fuel Filter! If I wanted the Fuel Real Cold I would mount that Filter in a Bucket of ICE!! Right now I use -8 AeroQuip Hoses with a Much Smaller 40 Micron Filter, and that thing is Mounted, over the Fuel Tank, on the Pressure Side of Delivery!

I Don't 'Give a Crap' what might look Ugly!! I Want MY Pantera to look as if it Just Came Off the 'Battlefield', Victorious!!

You ARE correct to have the filter on the 'Pressure' side of the fuel delivery! To have put it Before the Pump, on the 'Suction Side' would, without a Doubt in My mind, cause 'Vapor Lock'!!
But You ARE causing that by Boiling the Fuel in that Steel Boiler You have rigged-up!

Thank-You!
Last edited by marlinjack
liv1sliv1sMember
An isulated carb spacer is a greate idea. When I first go my car 27years ago, I had the same issue with hard starting during the summer in San Francisco. After a run, I tried to restart the car after a short rest. At one instance, the primary float stuck open and my engine flooded with fuel coming out of the vents as I tried to crank the engine over. After I rebuilt my carb, I did a test run then tried to restart after a short stop a rest stop off HWY280. Same hard starting problem like it's flooded. I openned the decklid to check what was going on and heard what sounded like percolating coming from the carb. I tried to touch the carb and it was too hot to touch. My friend said our engines don't have the benefit of having enough air rushing through to cool the top like front-engined cars. He suggested putting a heat sink or an insulated carb spacer. After I did that, I have not had this problem.

Good luck with your issue.
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