FJ40 Oil Woes

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Pig could be on to something. The PCV valve is only half of the crankcase vent system. There should be a vent to allow air into the valve cover. Usually a hose from air cleaner to valve cover. If the the vent is capped/plugged on the valve cover and the PCV valve is missing, then there is gonna be a buildup of blowby pressure in the crankcase.
 
The PCV is a good start. How about a test, remove the oil fill cap and start the engine. Using your hand as the cap what kind of pressure do you feel, does it blow your hand off or just mild pressure or vacuum? Do this and rev it a little. Now whats it like.

A picture would help a bunch.
 
A little hijack.
This brings up something I have been wanting to ask the group. Give me one good reason to keep the crankcase vent coming out the side cover if you have one in the valve cover. There are at least 12 holes (pushrods) that run from the side cover chamber to inside the valve cover on top. Give me your best shot. :hhmm:
 
FJforty said:
Give me one good reason to keep the crankcase vent coming out the side cover if you have one in the valve cover.
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There is not a good reason........ Here is one of my set-ups from long ago.......

See the valve in the filler cap?........can you dig it?.......

Cross flow ventilation, Man!.......

If you search around you'll find a thread on valve cover "MAYO"....
FD801011%20%28Custom%29.webp
 
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The factory system is design as a positive flow. Since the PCV is connected below the carburator the vacuum is higher then in the air cleaner. So it pulls any blow-by gas fumes out of the crankcase and replaces it with filtered air from the air cleaner. I would think the earlier system would have worked better since it pulled the fumes right out of the crankcase and the replacement air came from above in the valve train area. Seems to me the later style would short circuit that path. It was from the valve cover and then out the pushrod cover.:hhmm:

PCV: positive crankcase ventilation
 
Living in the Past said:
I would think the earlier system would have worked better since it pulled the fumes right out of the crankcase and the replacement air came from above in the valve train area.
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If it were better Modern Science wouldn't have changed it. :rolleyes:
 
Same reason MODERN SCIENCE advanced forward eliminating the "DOWN DRAFT TUBE"...................:rolleyes:
 
Do a leakdown test for sure. I had the same problem with a Mustang of mine. Fine when tooling around town, but when on the freeway it blew the dipstick out and spewed oil onto the engine. Two of the cylinders were less than half the nearest in compression and the PCV valve and venting it didn't help all that much. Your engine was 'freshly rebuilt' right? I think those 2Fs and Fs used chrome faced, (not chromaly, chromed), compression rings didn't they? I hear those rings are a total bitch to seat properly, perhaps the 'rebuilder' didn't seat them right? Maybe they aren't finished seating at all?
 
justacruiser said:
I hear those rings are a total bitch to seat properly, perhaps the 'rebuilder' didn't seat them right? Maybe they aren't finished seating at all?
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Certainly a possibility. A simple compression test probably would confirm that.
 
AK Chris said:
Well, no pcv valve and the hose was clear, so that can't be it.
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AK Chris said:
Nope....it is missing the grommet and the pcv valve. It has a hose running from the oil fill tube straight to the intake.
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Tell us more about this hose...where in the intake does the other end attach?
My PCV hose attaches just under the carb, on that little spacer/insulator gizmo that has a metal tube coming out the front and angling upwards...does yours do that?
And you say this hose is clear? Is that made out of clear plastic? or clear that you can blow through it? 'Cause if it is clear that you can blow through it AND it's attached to the base of your carb (or anywhere on the intake manifold), you would have a horrendous vacuum leak and you would have posted a question about vacuum leaks instead of oil leaks.
Therefore, the other end of that hose must be closed somehow.
See how a picture would really help here?
 
Fuzzy Logic said:
If it were better Modern Science wouldn't have changed it. :rolleyes:
Click to expand...

grant5127 said:
Same reason MODERN SCIENCE advanced forward eliminating the "DOWN DRAFT TUBE"...................:rolleyes:
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Part of the reason it no longer pulled from the crankcase directly is the fill tube went away after the F145 and the start of the F155 with the 72 model. The only easy stamped steel into the crankcase after that would have been the oil pan itself. Too much splashing oil there. Which it probably why they moved it where they did.

I guess there must have been fumes from the down draft tube on my first FJ25. They ran a rubber hose off the end ran it back to behind the transfer case:meh:
 
If it isn't blowing rain sideways tomorrow I'll take pictures and post them. Just to clarify, when I said the hose running from the oil fill tube to the base of the carb was clear, I meant that I blew through it and it isn't plugged.

Thanks for all the input. I feel more confident that I'll eventually get this solved.....hopefully the pics will clear things up.
 
Okay, we had a brief reprieve in the torrential rains and I took a couple pictures. I also called SOR to ask about a grommet. The gentleman I talked to informed me that 68s don't have a grommet rather the pcv valve actually is screwed into the oil fill tube. I looked at the pic I took and lo and behold that is what is going on. I was looking for the standard pcv valve that was shown in the exploded view I had of the 1F engine. Duh! I will pull it off this weekend and see if it is plugged. Which if it is, explains my problem , but begs the question, where can I find another one since they are no longer made according to SOR? Will I just have to find or make a threaded hose connection and use the 69 "standard" pcv valve? If nothing else, I'm learning a lot more about my cruiser.

Again, I appreciate all the help I've gotten by forum members.
68-left-side-view.webp
68-right-side-view.webp
 
Hose........

That hose you have there connecting the valve to the carb base looks pretty much jik-tak.....

Harmful HCs breakdown innards of common type hose causing a collapse under vacuum conditions cutting-off the needed circulation........

:idea:..........upgrade to proper rated hose.......
 
Those curly cue wires are quite unique.................:eek:
68-left-side-view.webp
 
Living in the Past said:
X2 on the PCV. On the 68 the PCV screws into oil fill tube and runs to the intake just below the carb.
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AK Chris said:
Okay, we had a brief reprieve in the torrential rains and I took a couple pictures. I also called SOR to ask about a grommet. The gentleman I talked to informed me that 68s don't have a grommet rather the pcv valve actually is screwed into the oil fill tube. I looked at the pic I took and lo and behold that is what is going on. I was looking for the standard pcv valve that was shown in the exploded view I had of the 1F engine. Duh! I will pull it off this weekend and see if it is plugged. Which if it is, explains my problem , but begs the question, where can I find another one since they are no longer made according to SOR? Will I just have to find or make a threaded hose connection and use the 69 "standard" pcv valve? If nothing else, I'm learning a lot more about my cruiser.

Again, I appreciate all the help I've gotten by forum members.
Click to expand...


:hhmm:I'm glad SOR was able to help you out with how where the PCV is on a 68. I guess you didn't read my first post.:meh: I agree it's a good idea to replace the hoses with ones that wouldn't collapse under vacuum :cheers:
 
AHAH! So you've found your missing PCV valve! Congtatulations! Aren't pics great?
Sometimes, you can fix a stuck PCV with spray-in carbcleaner, or a soak in a bucket of partsdip. They only have, like, one moving part...

Also, it looks like you have one of those Toyota "Hi-Po" intake manifolds.

Also, I wouldn't worry too much about replacing those hoses...:
1) The PCV to carbbase hose looks very similar to mine. But, my hose goes OVER the valve cover, not in front of the valve cover as yours does. So it avoids running so close to your exhaust manifold. Maybe I'd just feel along the length of the hose, especillly that heated portion, assessing for soft spots. You could perhaps route your hose over your valvecover and trim out that heated portion
B) Your engine will pull, maybe 20 in./Hg at idle, less underway, more on a long downhill but probably not enough vacuum to close that hose off. Plus, any crankase venting will come through under positive pressure and should blow that hose open again. In fact, if the hose WAS closing due to engine vacuum, one would not need a PCV valve at all...the hose itself would act like a flutter-valve, only opening when crankcase pressure would overcome intake vacuum.
III) What the heck kind of carburetor is that? Ain't pics great?
 
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The myth of the hose

AK Chris, it is a very common practice to replace hoses that vent the crankcase with hose that is made for water. This is a BAD practice. Water hose will break down when exposed to oil. The interior of the hose will then start spalling chunks into your intake. If you can, replace those hoses with oil line.
 
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