How about "peace of mind."
Fuel in Oil Problemo! Need help troubleshooting. (1 Viewer)
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How about "peace of mind."
FishTacos
Full Globetard
Doh.
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- #23
Hm that's interesting. Hopefully it is just oil. I am currently looking at the carb as the next culprit!
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- #24
I am currently uncertain of what the "PCV" stands for or is but I am looking into that right now. I imagine it might be drawing into the crankcase just below the carb but I am not sure. All I know is that when I changed the oil there was fuel mixed in it at the oil pan. Is there a way to find that answer (about the crankcase) pretty simply?
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- #25
Wow. Yeah I definitely don't want that to happen! Thanks. I'll be taking a close look at the carb.
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- #26
It was running, thankfully. I got the engine to start before I changed the oil. I never let it run for more than 60 seconds at a time. Once we changed the oil, that's when we discovered the problem.
I'm an amateur when it comes to automotive work so seeing that I rebuilt the carb myself leaves a pretty substantial amount of reason to believe that I might have the screws way off. I have tried adjusting the screws and have them set back I believe around 2 1/2 turns from fully tightened...I think.
I have a double barrel Holley carb btw. I'll definitely look into the lean-drop method and I'll try to remove that hose and take a look at whether or not it's pushing gas into the crankcase.
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- #27
Right on!
Positive crankcase ventilation. Basically there is a vacuum source at the intake and a hose going to a check valve then into the crankcase. The vacuum from the intake draws air from the crankcase through the combustion chambers to burn. This process evacuates hydro carbon buildups
from gas that leaks past the rings into the crankcase. Hydrocarbons break down engine oil. On the Cruiser, many times the vacuum hose is located directly below the carb. It passes over the back of the valve cover to the pcv valve which goes sits atop a steel elbow coming from the back of the pushrod cover on the passenger side of engine
typical pcv valve operation
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- #29
Hey thank you so much! This has been a huge help in getting me going in the right direction concerning the PCV Circuit and how to troubleshoot it.
I'll be doing some work on the Cruiser tonight and throughout the week and I'll let you know what I come up with as I go along.
How obvious will it be, or how do I identify rather, whether or not it is indeed pushing fuel into my crankcase from the PCV circuit?
It will most likely still be a carb issue. Perhaps a fuel buildup below the carb after the motor is shut off. While running , there is a vacuum at the pcv port below the carb so fuel shouldn't travel against the vacuum...but anything is possible if you watch enough star trek. Aside from the diaphragm in the pump, fuel draining past the rings , and the pcv circuit, there shouldn't be any other pathways I can think of that fuel could
normally mix with oil. The second option, the cylinders, would suggest both a flooding of the carb and bad rings, the fuel pooling at the piston tops after shutdown. The pvc would suggest a flooding after shutdown ,fuel pooling in the base and draining down the pcv tube. It would be hard to travel up hill over the valve cover but maybe during start up something odd occurs.
If this is something that just occurred when the weather warmed up it could be a post shut off vapor lock, in which case you may want to route
a return line from the carb as close to the carb as possible using an adjustable pressure regulator with return. The firewall directly behind the carb is a good place. Az summer have always been a challenge for carburetors too.
Vapor lock in the line from the pump to the carb can push fuel past the needle and seat. When I went to a Weber on my 60, the return had to be moved to the firewall the same manner. I had more vapor lock issues while running . After the change the difference was dramatic. Before, the feed line to the carb when the engine was hot was also hot when running. When I moved return about 8~10" behind the firewall and the lines were cool to touch even with the motor running. It was even better using a high volume electric pump . The fuel circulated so fast the lines felt
almost cold while the engine ran
normally mix with oil. The second option, the cylinders, would suggest both a flooding of the carb and bad rings, the fuel pooling at the piston tops after shutdown. The pvc would suggest a flooding after shutdown ,fuel pooling in the base and draining down the pcv tube. It would be hard to travel up hill over the valve cover but maybe during start up something odd occurs.
If this is something that just occurred when the weather warmed up it could be a post shut off vapor lock, in which case you may want to route
a return line from the carb as close to the carb as possible using an adjustable pressure regulator with return. The firewall directly behind the carb is a good place. Az summer have always been a challenge for carburetors too.
Vapor lock in the line from the pump to the carb can push fuel past the needle and seat. When I went to a Weber on my 60, the return had to be moved to the firewall the same manner. I had more vapor lock issues while running . After the change the difference was dramatic. Before, the feed line to the carb when the engine was hot was also hot when running. When I moved return about 8~10" behind the firewall and the lines were cool to touch even with the motor running. It was even better using a high volume electric pump . The fuel circulated so fast the lines felt
almost cold while the engine ran
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- #31
Thank you for taking the time to share that info with me. You have been a huge help so far. I intend to search out each of those options and troubleshoot them one at a time. For now, I think it's safe to rule out the fuel pump as an issue as far as potential leaks in the diaphragm are concerned.
I also believe that I have found my PCV Circuit, here are some pics. This is the elbow on the passenger side.
Here's the connection point at the carb.
Lastly I snapped a shot of the carb overflow tube (forgot the term for it) that's pictured in the center there, where I'm assuming I would set up a return line and an adjustable pressure regulator that would dump unused fuel back into the tank...?
I found a Holley Adjustable Fuel Pressure Regulator that I think might work for my 2 Barrel Holley Carb, but I don't think it comes with a return line, but I should be able to use any ol fuel hose and route it back to the tank from the regulator right?
Here's the link to the regulator.
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- #32
Well I'll go ahead and correct myself, just watched a video on installing an AFPR and realized that if it has 1 port in and 2 ports out then then it hooks up with the fuel pump going in, and continues to the carb through one of the two out ports, and finally the last out port is the return port that runs back to the tank.
FishTacos
Full Globetard
I think the general consensus here is that a 2f is best served by an OEM (aisan) carburetor. Trollholes Cruisers sells a new version:
New F & 2F carbs
Holley replacement carbs do not get high marks.
New F & 2F carbs
Holley replacement carbs do not get high marks.
I find it hard to believe this is a carb issue. Even if the carb were dumping excessive fuel into the engine, it would be vaporized and burned in the cylinders-you would also notice a very rough engine(with the resultant black soot in the exhaust pipe)
If the fuel is dumping from the carb, it will simply sit in the intake mani--unless you have some sort of pressure system that is blowing the fuel in there(do you have an electric fuel pump)--when the engine shuts off, the vac goes away. If the fuel is indeed getting into the cylinders from the carb/intake circuit-it has to go past the piston rings to get to the crankcase-not likely, plus you would be seeing oil burning when the engine is running(from the washed cylinders)
On the gurgling sound--you potentially may have excessive heat developed by the exhaust mani causing the fuel in the carb float bowl to "boil"--{gurgle}(my 77 used to do this all the time when I shut it off after an hour's running--headers fixed the heat prob), but a carb cooling fan was installed by Toyota to help with this prob.
My vote is the fuel pump for sure--the diaphragm is cracked and allowing fuel to enter the crankcase(the pump block gasket really has no impact on this--it would just leak oil)----my .02
If the fuel is dumping from the carb, it will simply sit in the intake mani--unless you have some sort of pressure system that is blowing the fuel in there(do you have an electric fuel pump)--when the engine shuts off, the vac goes away. If the fuel is indeed getting into the cylinders from the carb/intake circuit-it has to go past the piston rings to get to the crankcase-not likely, plus you would be seeing oil burning when the engine is running(from the washed cylinders)
On the gurgling sound--you potentially may have excessive heat developed by the exhaust mani causing the fuel in the carb float bowl to "boil"--{gurgle}(my 77 used to do this all the time when I shut it off after an hour's running--headers fixed the heat prob), but a carb cooling fan was installed by Toyota to help with this prob.
My vote is the fuel pump for sure--the diaphragm is cracked and allowing fuel to enter the crankcase(the pump block gasket really has no impact on this--it would just leak oil)----my .02
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- #36
Right but I don't know if it's entirely necessary to go OEM at this point if I can troubleshoot the issue with an AFPR and a bit of tuning up. At least not yet. Eventually I'd like to go OEM, but currently those fine looking carbs are a pretty penny that would be a stretch for my budget.
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- #37
Well, I haven't run the engine long enough to notice any black soot for one thing. The engine does run rough, and has died on me a couple times after maybe 30 seconds of running. It also has to be choked and I typically have to play around with the choke in order to get her to start...
I do not have an electric fuel pump. It is mechanical.
I think you could be right about it leaking through the pump diaphragm but I can't really tell if that crack is through and through...I'll take a closer look at it. I was hoping to rule that out as a problem for several reasons, some being the fact that new pumps can be a bit pricey and mainly the fact that I cannot find a fuel pump rebuild kit anywhere.
FishTacos
Full Globetard
I hear that. Used OEM is another (read: less expensive) option. They come up in classifieds regularly. I think you can use a carb from 75-87 on your engine with only minor modification to the vacuum circuits. You will want to verify that though.
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- #39
Ok that's good to know! Thanks man!
