Odd engine behavior after first shutdown of the day

[spdbrake]

Originally Posted by Unique427

Use non-oxygenated fuel.
There's a VP Racing Fuel location
in Long Beach. Buy some 260 GTX
98 octane non-oxy race fuel for testing.
If that solves your issue
go to this website to find
Ethanol free fuel near you:

Pure-gas.org

I had thought same thing. Cali is tough though and barely anyplace sells it. VP doesn't make the Sunoco 260GTX.
The VP available in Longbeach is 5 gal cans only and the Gulf fuel in Downey ( 25 miles away) has 5 gal can 55 gal drums.
https://www.pure-gas.org/index.jsp?stateprov=CA Be prepared. race gas is over $80 per 5 gl cans.

[1795]

The cheapest I have ever paid for race gas is $8.45 per gallon and I have paid up to $11.50 per gallon. Just remember that some race gas comes with lead in it and it will not be good for any pollution mitigation systems that your car may have, other than a pcv valve.

[Unique427]

Originally Posted by spdbrake

I had thought same thing. Cali is tough though and barely anyplace sells it. VP doesn't make the Sunoco 260GTX.
The VP available in Longbeach is 5 gal cans only and the Gulf fuel in Downey ( 25 miles away) has 5 gal can 55 gal drums.
https://www.pure-gas.org/index.jsp?stateprov=CA Be prepared. race gas is over $80 per 5 gl cans.

Oops...you are right 260GTX is Sunoco.
It is indeed expensive but maybe worth the stretch for
a few gallons just to see if it resolves your issue.

I didn't see any place that sold recreational fuel where you
could reduce the cost by doing a 50/50 blend with race gas
and some 91 octane unleaded non-ethanol.
I'm guessing pesky Cali law does not allow the sale of it.

VP unleaded non-ethanol available here:

Chevron
16103 Sherman Way, Van Nuys, CA;
818-780-2938;
ethanol-free VP RACING 100

Socal Nitrous & Race Fuels
7052 Garden Grove Blvd, Garden Grove, CA;
714-622-5093;
ethanol-free VP RACING 96 100 105

Vp Racing Of Long Beach
3605 E 7th St., Long Beach,
CA; 562-434-2500;
ethanol-free VP RACING

[eschaider]

OK guys, here's one of those Dick and Jane word problems from grade school that we so fondly loved.


Exam Question #1

How many tanks of $10/gal race gas does Dick have to buy before Jane starts yelling at him?


Bonus Question (5 points)

How many tanks of $10/gallon race gas does Dick have to buy before an EFI system that uses $3/gallon 91/93 octane gas (less for you guys outside of CA) begins to make financial sense to Jane and she stops yelling at Dick?


Extra added attraction, optional at no extra cost:

Dick's Cobra now starts, idles and accelerates beautifully in all weather, at all altitudes, gets unbelievable mileage (and reduced fuel costs) with his new EFI and Jane no longer hates the Cobra, she actually likes to ride in the Cobra with Dick again (but still yells at him from time to time — just because ...).


Ed

[Sledge]

SkipJ: the link worked, it is on its way. I'll try it out. Cheaper than race gas or EFI if it works for me as well as it worked for you.

MaSnaka: You may have something there. Looking down at the butterflies I can see where they appear to contact the side of the bore. This could explain why the "return to idle" issue improves as everything gets up to temperature on my engine. Now, to find a long 3/32 allen wrench without a ball end to loosen the butterflies...

Thanks for all the help locating race gas dealers, amigos

[NROTOXIN]

"Now, to find a long 3/32 allen wrench without a ball end to loosen the butterflies..."

EKLIND 51906 3/32 Inch Cushion Grip Hex T-Handle T-Key allen wrench. Sorry for the long link

https://www.amazon.com/EKLIND-51906-...&tag=hydsma-20

[MaSnaka]

Sledge,
The screws have an interference fit...Someone on the FE forum mentioned they are peened (not sure what that means). I assume so they don't vibrate loose and get sucked in and processed through the combustion magic. Only loosen maybe 1/4 turn, set idle adjustment as low as it will go. Tighten and readjust the idle position screw. I was getting a weird hang up with the engine running, but with the engine off no hang up. Maybe vacuum was pulling the butterfly plates closed where the friction occurred. I hope it helps you.

John

[Skip J.]

Good deal Sledge and hope it works as well for you as it did for us.

[Sledge]

Skip: plate is in, I should get a test drive in today.

John: I can't break the butterfly screws loose with my new 3/32 allen key. They would rather round out than loosen.

Thanks everyone for your help!

[Sledge]

Skip: the cool plate assy was just too tall, insufficient underhood clearance.

And the reason my 3/32 allen did not loosend the butterfly screws is because they are actually T10 Torx. Duh. Still, I am unable to break them loose to adjust butterfly clearance. They're really in there!

eschaider: I'm not ignoring you. When budget allows it will be EFI'd.

Cheers

[eschaider]

Originally Posted by Sledge

...eschaider: I'm not ignoring you. When budget allows it will be EFI'd.

Cheers

Not a problem, Bill. I didn't think you were, The Dick and Jane stuff just popped into my head for some reason and I had to use it partly for comic relief and partly because it did shed some light on the important considerations in the decision process.


Ed

[cycleguy55]

Originally Posted by MaSnaka

Sledge,
The screws have an interference fit...Someone on the FE forum mentioned they are peened (not sure what that means). I assume so they don't vibrate loose and get sucked in and processed through the combustion magic. Only loosen maybe 1/4 turn, set idle adjustment as low as it will go. Tighten and readjust the idle position screw. I was getting a weird hang up with the engine running, but with the engine off no hang up. Maybe vacuum was pulling the butterfly plates closed where the friction occurred. I hope it helps you.

John

'Peened' in this context means the protruding threaded end of the machine screw is hammered into a bit of a mushroom shape against the throttle shaft so it physically prevents the screw from loosening.

[patrickt]

Originally Posted by cycleguy55

'Peened' in this context means the protruding threaded end of the machine screw is hammered into a bit of a mushroom shape against the throttle shaft so it physically prevents the screw from loosening.

In other words, you just take a big-ass hammer and whack the crap out of the fastener until it's so mashed up that it won't come apart by itself. Yep, done that many a time.

[Skip J.]

Sure sorry to hear that Sledge because as mentioned, we had great success with the cool plate.

[patty442]

You must defeat the peen before you have any chance of removing the throttle blade screws. Take the carb off the manifold, invert it on the bench and take a Dremel tool and CAREFULLY grind the peened portion of the screws before attempting to unscrew them. Unless someone before you has messed with the screws and blades in the past, your problem is unlikely blade sealing. There is a compound used by GM/Rochester division to improve sealing of throttle blades on end Tripower carbs in the late fifties and early sixties. It has worked wonders on big Hilborn blades and Lucas timing injection blades that have been beaten up by heavy handed engine builders and tuners. Please make sure you really want to mess with the blades before you start grinding.

[Gaz64]

Originally Posted by Sledge

Skip: the cool plate assy was just too tall, insufficient underhood clearance.

And the reason my 3/32 allen did not loosend the butterfly screws is because they are actually T10 Torx. Duh. Still, I am unable to break them loose to adjust butterfly clearance. They're really in there!

eschaider: I'm not ignoring you. When budget allows it will be EFI'd.

Cheers

If you have T10 Torx button head screws, they are unlikely to be peened over.
They can be tight, but a GOOD quality bit will loosen them.
How about some pics of what throttle body blades and screws you have?

[jhv48]

I tried everything that’s been suggested here. Even swapped out the baseplate of the carb (it contains the butterflies) to no avail. You’ll chase your tail for years trying to eliminate the vaporizing (Boiling)but the only way to get rid of it is to move to a state that doesn’t mess with the boiling point of its gas or swap to pressurized fuel injection.
Now you know why you always see the hoods open when cobras stop for lunch.

[cycleguy55]

Originally Posted by Gaz64

If you have T10 Torx button head screws, they are unlikely to be peened over.
They can be tight, but a GOOD quality bit will loosen them.

Perhaps, but if they have Loctite on them they may need a bit of heat to loosen.

[Sledge]

Gents: after a closer look, the butterflies were not hanging up in the base plate. After ensuring the fast idle screw was off the fast idle cam, the throttle would come right back to idle. I'm not sure what else I did that might have affected the return to idle issue but it is acting normally now.

As for the crap California gas, I've built a short hood hold-open rod to allow the heat to escape, and have wrapped the fuel lines at and near the carburetor with heat shielding. Not pretty but appears to be effective. Yes a pain in the neck but better than dealing with the fuel vapor. I also obtained two small battery powered fans that I can aim at the carb and fuel lines on hotter days to help move the hot air out.

Not ideal but it works. The only investment was in the fans. The other stuff was in my pile of accumulated but unused or repurposed cobra stuff.

[cycleguy55]

Originally Posted by Sledge

Gents: after a closer look, the butterflies were not hanging up in the base plate. After ensuring the fast idle screw was off the fast idle cam, the throttle would come right back to idle. I'm not sure what else I did that might have affected the return to idle issue but it is acting normally now.

As for the crap California gas, I've built a short hood hold-open rod to allow the heat to escape, and have wrapped the fuel lines at and near the carburetor with heat shielding. Not pretty but appears to be effective. Yes a pain in the neck but better than dealing with the fuel vapor. I also obtained two small battery powered fans that I can aim at the carb and fuel lines on hotter days to help move the hot air out.

Not ideal but it works. The only investment was in the fans. The other stuff was in my pile of accumulated but unused or repurposed cobra stuff.

Good to hear things are back to normal. Hope it stays that way.