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Post by cline48 on Sept 6, 2022 4:43:18 GMT -5
Well I know now that my fuel system was substandard. First the in let brass fitting was loose on the fuel pump. Who wants to go one more turn but it needed it. Second I had a fresh rebuilt pump but the cork gasket didn’t fit the glass bowl very well. The pump was a rebuildable pump but time had its way with the seat area. It was corroded and full of creators. Between the cork gasket and the poor matting surface it allowed tiny air bubbles to enter the pump. The cross over hose wasn’t factory but was made with quality fittings. I believe that they didn’t leak other my have a different opinion. On prior trips I always waited to buy gas when I got to the last town before going to the mountains. Tried to buy 85 or 87 octane gas with no corn in it. This time I was using 93 octane premium no corn from Omaha. I have done some research and gasoline is formulated for different part of the country. Rocky Mountain fuel is formulated different than mid west fuel. I think that the fuel was the biggest problem with my vapor lock problem. Due to it boiling point with the increased altitude.Then with the poor. Fuel delivery system compounded the issue. I never had a vapor lock problem before using the the same fuel system but was using different gas and the problem showed up at high altitude. Here at 1000’ I have no problems with vapor lock no matters how hot it got this summer.
Lee is going to retest the fuel pump that I lapped the bowl seat on the pump that gave me problems. He will do that at the Fall Colors Tour.
The 1/4” fuel line wasn’t a problem until the changes in the fuel formula for modern engines.
BW has a stock fuel system using Gas purchased in Colorado and had no problems. I feel that there is something to that. Oilleaker didn’t you say that when you got home the the boiling stoped in your pump?
The other Five Jeeps had good tight fuel systems and didn’t have vapor lock problems no matter what fuel used. A leaking system gave the problem. Even boiling gas in a tight system didn’t Vapor Lock. That should answer all the questions.
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oilleaker1
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Post by oilleaker1 on Sept 6, 2022 5:17:30 GMT -5
Shack worked at making sure the fuel line had no air leaks. All except the glass bowl sealing surface. Altitude will show problems you did not have at low elevations. Air leaks in the fuel supply will not leak liquid fuel but will suck air. Watching cold water take a empty pump and not only fill the pump glass, but also put fuel in the glass bowl at the inlet of the carburator is crazy. This is with the engine not running.
I believe the answer was already proven. The problem is the fuel pump itself. The check valves are weak.
I did put clamps on my rubber push on barbed flex hose ends, but yes it quit boiling in the glass bowl.
The boiling point is a good observation. I opened a metal 5 gallon can in camp and the altitude difference had pressured it up. It came out like a air compressor and sprayed my leg. (I had a manley scent). What I saw once the screw cap was off surprised me. The fuel was sitting there boiling like a caldron. Never have seen that before.
That could be part of it, but the Car Quest pump seems to point the best at the answer.
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Post by cline48 on Sept 6, 2022 5:27:03 GMT -5
Shack worked at making sure the fuel line had no air leaks. All except the glass bowl sealing surface. Altitude will show problems you did not have at low elevations. Air leaks in the fuel supply will not leak liquid fuel but will suck air. Watching cold water take a empty pump and not only fill the pump glass, but also put fuel in the glass bowl at the inlet of the carburator is crazy. This is with the engine not running. I believe the answer was already proven. The problem is the fuel pump itself. The check valves are weak. The air on my pump was coming in around the glass bowl. The air enhanced the vapor lock problem that others didn't experience and Higher the altitude lowers boiling temperature of the fuel. I feel the pump are good other than the bowl seats. Both of my pumps were leaking around the bowl. Both pumps were corroded about the same. But we will find out in a couple week if lapping the seat worked.
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Post by m38mike on Sept 6, 2022 7:48:40 GMT -5
I do agree that the fuel itself is a huge contributing factor. But another question. Perhaps the size of the fuel line might also play into this? As well as metal vs. rubber? Or perhaps a combination of the two? I'm wondering the same thing. We need to do surgery on Shack's Jeep at 1100 feet. Replace the 1/4" steel line with a 5/16 or 3/8 rubber line and see what difference it makes. I've got spare rubber fuel line in both sizes here at TDR. Shack, or Grumpy, Come on out for FCT and let's experiment. Or show up for the week after and we'll focus just on your Jeep. I'd bet a case of beer that a continuous rubber line of either 5/16 or 3/8 diameter would eliminate the vaporlock problem if it's connected tank to pump.
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Lee
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Post by Lee on Sept 6, 2022 7:57:21 GMT -5
I do agree that the fuel itself is a huge contributing factor. But another question. Perhaps the size of the fuel line might also play into this? As well as metal vs. rubber? Or perhaps a combination of the two? Ok, so what’s the fix ?…. If we use the stock outlet your going to have to bush down the larger line to 1/4” anyway, the resistance of that on the opposite end of the fuel pump would be the same as a 1/4” line, am I wrong ?… IMO ditch the stock outlet, and use the tank drain, solder a short stand pipe into the 1/4” pipe elbow so your not drawing fuel right off the bottom, then run a 3/8” steel line from that point to the fuel pump, and you will have an ample supply of fuel under any situation, also perhaps a fuel pressure regulator between the pump/carb to return (or loop fuel) to the tank, this would eliminate excessive pressure in the pressurized fuel line due to under hood heat after the engine is hit down as well and circulate cool fuel through the pump. Lee😉
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Post by m38mike on Sept 6, 2022 23:44:16 GMT -5
I do agree that the fuel itself is a huge contributing factor. But another question. Perhaps the size of the fuel line might also play into this? As well as metal vs. rubber? Or perhaps a combination of the two? Ok, so what’s the fix ?…. If we use the stock outlet your going to have to bush down the larger line to 1/4” anyway, the resistance of that on the opposite end of the fuel pump would be the same as a 1/4” line, am I wrong ?… IMO ditch the stock outlet, and use the tank drain, solder a short stand pipe into the 1/4” pipe elbow so your not drawing fuel right off the bottom, then run a 3/8” steel line from that point to the fuel pump, and you will have an ample supply of fuel under any situation, also perhaps a fuel pressure regulator between the pump/carb to return (or loop fuel) to the tank, this would eliminate excessive pressure in the pressurized fuel line due to under hood heat after the engine is hit down as well and circulate cool fuel through the pump. Lee😉 Lee, as fluid line diameter increases, resistance to fluid movement decreases. The friction loss in flow rate is reduced significantly with an increase in pipe diameter. Some of the parameters within the system affect the fluid properties like density, velocity, and viscosity which affect the fluid flow in the piping system. -Like the temperature change will change the viscosity and density of the fluid. -The length and the inner diameter of pipes. In the case of turbulent flow the internal roughness of the Pipes. -Position of supply and discharge containers relative to pump position. -Addition of rises and falls within the pipe layout. -The number and different types of bends in the system. -The number of valves and other pipe fittings in the system. -Entrance and exit conditions of the pipework. This was borrowed from "What is Piping - A Blog for Piping Engineers" I think the bottom line here is that if we increase the size of the supply line between tank and pump, we'll reduce the suction needed to move the required volume of fuel. That should reduce the opportunity to draw air into the system. I think that even with 1/4" fittings at both ends of the fuel line, If we increase the size of the line itself, we make it easier for the pump to draw fuel. If it's easier for the pump to draw fuel, it's less likely to suck in air. Is this making sense to everyone?
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Post by Scoutpilot on Sept 7, 2022 3:42:35 GMT -5
That's why I normally recommend 5/16" over 1/4" for our motors. The rebuilds with up to .060-over especially.
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oilleaker1
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Post by oilleaker1 on Sept 7, 2022 5:43:51 GMT -5
Do like Carol Shelby's race team did. They were limited to fuel capacity by the rules panel. So, they never said anything about fuel line size . He installed one inch fuel line. Got some extra capacity and another lap.
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Lee
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Post by Lee on Sept 7, 2022 10:25:04 GMT -5
Mike Said,
This was borrowed from "What is Piping - A Blog for Piping Engineers" I think the bottom line here is that if we increase the size of the supply line between tank and pump, we'll reduce the suction needed to move the required volume of fuel. That should reduce the opportunity to draw air into the system. I think that even with 1/4" fittings at both ends of the fuel line, If we increase the size of the line itself, we make it easier for the pump to draw fuel. If it's easier for the pump to draw fuel, it's less likely to suck in air. Is this making sense to everyone?
It is indeed making sense to me and I was thinking the same, BUT why not eliminate the 1/4” bottleneck at the tank, even more so if we are unsure of the condition of the pickup tube built into the tank… ?…. I still think a 3/8” tube plumbed to the tank drain (solder in a short stand pipe to not suck fuel from the bottom) would be the way to go, yes it would still be bushed down to 1/8” pipe at the pump inlet fitting but at that point you would have an unrestricted volume of fuel at that point… 35 years in construction feild service has given me a volume of experience with fuel issues that I’m looking back on and if your going to upsize do it right. Dads Jeep has never left me stranded on a mountain trail (knocking on wood) and I’m not going to allow that to happen after this jeep season, it will get re-plumbed as I described above, I’m all for keeping things as engineered but the fuel company’s have not held up there end of that.
Lee😉
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Post by m38mike on Sept 8, 2022 2:22:43 GMT -5
Using the drain opening instead of the intended fuel opening would allow for a larger sized connector, one with a short pipe added. How long would you make the pipe? 1/2" above bottom of the tank? The purpose being to keep water or solids from being sucked into the fuel line? My thought would be to just use the drain outlet and put a filter inline shortly afterwards. The filter does not limit your fuel capacity when on level ground like an added pipe would. The filter will trap the water or solids that are sloshing around inside the tank. that will help to clean your tank as you drive. I have this arrangement in the Blue Mule. I am amazed at all the sediment that filter traps from the fuel on the way to my throttle body injectors. And when I'm bouncing down a rough trail at different angles of tilt, I don't doubt that many of those small solids will get suspended in the fuel within the tank. That short added pipe is not going to stop those small solids from going down the fuel line.
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Lee
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Post by Lee on Sept 8, 2022 6:57:57 GMT -5
Using the drain opening instead of the intended fuel opening would allow for a larger sized connector, one with a short pipe added. How long would you make the pipe? 1/2" above bottom of the tank? The purpose being to keep water or solids from being sucked into the fuel line? My thought would be to just use the drain outlet and put a filter inline shortly afterwards. The filter does not limit your fuel capacity when on level ground like an added pipe would. The filter will trap the water or solids that are sloshing around inside the tank. that will help to clean your tank as you drive. I have this arrangement in the Blue Mule. I am amazed at all the sediment that filter traps from the fuel on the way to my throttle body injectors. And when I'm bouncing down a rough trail at different angles of tilt, I don't doubt that many of those small solids will get suspended in the fuel within the tank. That short added pipe is not going to stop those small solids from going down the fuel line. Nothing wrong with that plan Mike, I personally would rather have a stand pipe soldered in place and no need for an excessive length, perhaps 1/4”-3/8” above the bottom of the tank would be more than adequate. I would run a filter before the fuel pump as it’s much easier to replace leaning over the fender from above than laying under the Jeep with gas dripping 😬 Lee😉
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oilleaker1
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Post by oilleaker1 on Sept 8, 2022 11:59:47 GMT -5
Gas dripping down your arm and chemical burning your armpit you mean? ??
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Lee
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Post by Lee on Sept 8, 2022 21:41:16 GMT -5
Gas dripping down your arm and chemical burning your armpit you mean? ?? Pretty much sums it up! 🤔😬
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