[RocktimusPryme]

I just got off the phone with Robb, I think Im going to avoid loading the parts cannon just yet. Im planning on going ahead and upgrading to the 1100, adding a regulator and return line. Im really hoping he opens it and finds a problem, just for vindication sake.

After that if I experience similar issues then I can go from there. Can a fuel pressure gauge pop up on Amazon prime day? That would be nice.

[AG]

I run a Mallory 140 in the race car set at 8 psi, goes down to 6 psi during the run and bounces a little coming off the line. Good enough fuel supply for a 10.0 car.

[78w72]

Originally Posted by RocktimusPryme

I just got off the phone with Robb, I think Im going to avoid loading the parts cannon just yet. Im planning on going ahead and upgrading to the 1100, adding a regulator and return line. Im really hoping he opens it and finds a problem, just for vindication sake.

After that if I experience similar issues then I can go from there. Can a fuel pressure gauge pop up on Amazon prime day? That would be nice.

sounds like a good plan & is the least $$ to start. like you said, maybe theres an issue with the pump so fixing that & upgrading at the same time can't hurt.

if you want to do one part at a time then check results, remember you can run the 1100 pump dialed all the way down to 7psi without a regulator. what regulator are you going to run? robb has a nice unit, i have one & plan to swap out the mallory to see if it helps, robbs has a bigger inlet size & bigger neddle valve than the mallory.

what return line are you going to use? just the vapor return or a real fuel return?

an electric pump is obviously the way to go for cars at this power level & track use, some of us are just being stubborn & trying to make the mechanical work or work better. & since i already own the setup & got it for very cheap, i can keep it all as is & be happy with a great performing mostly street car, or if i want to go faster i am prepared to go electric with a full return.

keep us posted on what you find with the new pump.

[RocktimusPryme]

Originally Posted by 78w72

what return line are you going to use? just the vapor return or a real fuel return?

.

Im going to do it how he says to do it, they are his parts so Ill do it how he says. He said with the 1100 to run his deadhead regulator with a special fitting that allows a vapor return from the regulator, and then leave the mechanical pump only fed with no return.

I know that runs contrary to what some say, about equal feed and return lines. But like I said, its his stuff, Im going to at least try it how he says to do it.

[78w72]

Originally Posted by RocktimusPryme

Im going to do it how he says to do it, they are his parts so Ill do it how he says. He said with the 1100 to run his deadhead regulator with a special fitting that allows a vapor return from the regulator, and then leave the mechanical pump only fed with no return.

I know that runs contrary to what some say, about equal feed and return lines. But like I said, its his stuff, Im going to at least try it how he says to do it.

ok i fiully agree to do it how he says, was just curious if you were doing something else for a real return line... robbmmc doesn't offer a full return system for his mech pumps with equal line size like an electric pump setup uses. just the vapor return diaphram that is supposed to help with vapor lock. i considered the vapor return but with no signs of real vapor lock, i didnt see the need. plus i run a 1970 tank that has no return or vent lines.

[RocktimusPryme]

Question. How much pressure should it take to activate the fuel cap vent? Out of curiosity after work, I took it off and blew through it. You can get air through it, but Im talking red faced, ears popping amount of blowing to get it to push air through the cap. And you have to hold that pressure for a sec before it breaks through. Makes me wonder if most of my problem is a damned fuel cap.

[Formulajones]

Sounds like an aftermarket vented cap to me. The NOS cap I have, as well as another car that still has it's original vented cap, are pretty free, to the point that they even leak fuel when you fill it and take off quickly LOL Which is what these old cars with vented caps used to do back then.

I think the EPA has cracked down on the repop stuff and they are reengineered to not vent so well.

[pokey1]

I ran into a lot of those problems myself and trying different things with my stock tank. Tried different locations for fuel pickup in the tank but unless it was almost full would still have some issues running out of fuel on a full run. Another thing to look at is your stock tank vent, they are sall and if anything is chocking it down it was a problem. I finally went to a new tank (because I went to fuel injection), tank is baffled to prevent to much fuel movement (starvation) and the venting system is huge and in several location. Also return system. Don't depend on the cap at all for venting. Fuel sloshes to the back it will not vent.

[Formulajones]

That's why the originals leak

2 cars here that depends on just the cap venting and are dead headed pumps, no issues at all. Just gotta have a cap that actually "vents"

Like I said the repop stuff sucks.

[RocktimusPryme]

It’s 100% aftermarket. From a local parts store. I’m still sending the pump in for upgrade, since I’ve been brow beaten today on how my fuel system is bad. But man what if 90% of the problem was the stupid fuel cap vent going bad.

I’ll probably just drill a hole in the stupid thing to see if that solves it, the. See about getting a better unit if it does.

[Formulajones]

That's what I did to the cheap store bought cap when I figured it out.

But I agree that might not be the whole problem and I would go ahead with your plans on the Robbmc pump.

[RocktimusPryme]

Originally Posted by Formulajones

That's what I did to the cheap store bought cap when I figured it out.

But I agree that might not be the whole problem and I would go ahead with your plans on the Robbmc pump.

Yeah. I’m just irritated at the wasted weekend. I would really have liked to at least be able to pull hard through the 1/8th mile. Would have been much less embarrassing than a 15 second pass with 500 plus horsepower

[Formulajones]

Originally Posted by RocktimusPryme

Yeah. I’m just irritated at the wasted weekend. I would really have liked to at least be able to pull hard through the 1/8th mile. Would have been much less embarrassing than a 15 second pass with 500 plus horsepower

I hear ya, this stuff can be frustrating sometimes. Something always rears it's ugly head at the track it seems.

[78w72]

Originally Posted by RocktimusPryme

Question. How much pressure should it take to activate the fuel cap vent? Out of curiosity after work, I took it off and blew through it. You can get air through it, but Im talking red faced, ears popping amount of blowing to get it to push air through the cap. And you have to hold that pressure for a sec before it breaks through. Makes me wonder if most of my problem is a damned fuel cap.

i have the cheap auto store metal vented cap & it vents pretty good. it only vents inward, you should be able to suck through it like a straw pretty easily. it doesn't vent outward & is sealed pretty well, i dont have any signs of leaking or wetness at the track.

maybe the cheap ones are hit or miss but mine seams to work pretty good. drilling a hole in them may work too. or what i use since my tank is not vented is a roll over vent from tanks inc that vents the tank very good but has a safety catch to stop fuel spill if a roll over happens.

[Formulajones]

You can tell when those store bought ones don't vent outward, they really build a ton of pressure and when you remove the cap they blow out pretty good, sometimes blowing fuel on you, and I've even seen the tanks deform from pressure. Those caps are engineered on purpose that way these days.

In the past when I raced a car at the track with a real vented cap I would tape a shop rag around the cap to minimize any fuel that may spill. Track officials appreciate that. I generally run with about 3/4 tank so it usually isn't a problem. It's only when I fill it full it may spill some on a spirited take off. I've even had it seep if I park on an incline right after filling it up..

Funny because millennials today freak when they see it. I've even had one follow me about 5 miles after I took off quickly. He just had to tell me fuel spilled out of the tank. When I told him "yeah I just filled it up it's normal" he looked at me like I had 3 eye balls. LOL

[pokey1]

I don't remember you saying you did check the stock vent tube and rubber line to make sure they are clear? I could be wrong and missed it.. I did also have to small of an electric fuel pump the first time around that caused the same issue... just throwing ideas out there.. good luck

[Schurkey]

Originally Posted by 68lemans462

Put a fuel pressure gauge on it

^^^ Winner.

[RocktimusPryme]

Originally Posted by pokey1

I don't remember you saying you did check the stock vent tube and rubber line to make sure they are clear? I could be wrong and missed it.. I did also have to small of an electric fuel pump the first time around that caused the same issue... just throwing ideas out there.. good luck

As far as I know stock 67 tanks only have the cap as a vent point. I would like to add one of those rollover vents mentioned. I just don't have a lot of interest in draining and dropping the tank at the moment to install one. At this point because the pump is off and I cant run the car I would extra be guessing. I bought a gauge, sent in the pump and bought a regulator. When I get it back we will see whats what.

There is another test n tune on the 26th. Im hoping to have it back together by then, but its close.

[AG]

Make sure you do some WOT runs on the street before you go back to the track to verify you have enough fuel supply.

[form74]

RocktimusPryme, was great chatting with you at the Injun Wars, didn't realize till today that was you . As others said get a fuel pressure guage that you can see what is going on like we talked about.