Rocker Bushings and Oil Flow. (Long) (1 Viewer)

[Steamer]

I have poor oil flow out of my rocker holes. I get barely an ooze from valve side rocker hole and practically noting out of the smaller push rod side hole. Rocker shaft and bushings were replaced new in 2000 and still look in very good shape. There is no slop at all in the bushings, but the rockers slide and spin freely on the shaft. The rocker assembly was disassembled and thoroughly cleaned with every orifice checked. I get good flow out of oil hole in head that feeds up to the #4 pedestal although when spinning the oil pump with a drill, I can stop the flow with a fair amount of pressure of my thumb closing the hole. I don’t know what the pressure should be delivered up to the top and wonder if anyone knows or has ever checked it. I have fittings on order and will check this but won’t have anything to compare it to.



I was able to get a tight fit with an air blow gun into the #4 pedestal and deliver 140 psi to the shaft. Very little air escapes from anywhere in the assembly until I rotate a rocker (one by one) so that one of the rocker holes lines up with one of the two holes in the shaft and then the air shoots out like a blow gun sending rags flying. However, the shaft holes are top, and bottom and the rocker hole are to the sides so the holes never line up in normal operation. It seems that the bushings are fitting too well, and air or oil can’t get out. I assume those inner grooves in the bushings are to pass oil to the holes, but they are not elongated enough and won’t line up with a shaft hole in the normal arc travel of the rocker. I think if there was a way to elongate those bushing grooves full circle, it would solve the issue but don’t know if that’s feasible.

 

[Steamer]

Do my bushings need to be reamed? I’ve heard something about that long ago but can’t find any info on it now. When I replaced the shaft and bushings in 2000, I had great oil flow and could see the oil spiraling down the push rods as they rotated. Now the rods are staying almost dry.

My oil pressure runs 45 to 60 between cold startup and hot idle. I thought maybe the cam bearings are worn enough to not get enough pressure up top and into the bushings but after the air test it seems I would need more pressure than even a new engine could deliver.

 

[bj70bc]

interesting
What engine?
Is it possible the center tube is misaligned 90 deg?

 

[Steamer]

interesting
What engine?
Is it possible the center tube is misaligned 90 deg?

F.5 one piece shaft.
Grooves in the side of shaft match up with pedestal mounting bolts. If it is not rotated properly, the pedestal bolts won't go in. The shaft can only be rotated to its proper position. The only one possible other way to mount it would be to flip it end for end. But then the main oil feed hole would be on the wrong #3 pedestal and looking up.

 

[Steamer]

I blocked off the oil hole in the head that feeds the rocker assembly and added a gauge to the oil galley plug hole where I previously tapped it for a 1/16” NPT plug. Spinning the drill at low-speed setting, I get similar pressure on the dash gauge when engine is I running at start up cold. 70*-90*F. ambient.

I thought for sure I’d get low pressure up top and maybe indicating worn cam bearings but not the case.

So, I’m even more puzzled why I’m not getting flow out of my rockers.

 

[bj70bc]

i wonder if the rockers are a half mismatched assembly from another f series engine where the oil slots and holes are just a bit different

per wiki

In September 1973 the F engine was updated, to a model sometimes referred to as "F and a half" or F.5. This remains a 3.9-liter, 75/93 kW (105/125 hp), carburated gasoline engine capable of 261/289 N·m (189/209 lb·ft) of torque at 2000 rpm; the major difference between the F and the F.5 is the oiling system. The F.5 uses the same oiling set-up and configuration as its 2F successor.

	The second version of the engine, called the 2F, was introduced in 1975. There are a few differences between the F and 2F, i.e., a larger bore in the 2F, removing one oil ring and forcing the oil to travel through the oil filter before the engine.

 

[Steamer]

i wonder if the rockers are a half mismatched assembly from another f series engine where the oil slots and holes are just a bit different

per wiki

In September 1973 the F engine was updated, to a model sometimes referred to as "F and a half" or F.5. This remains a 3.9-liter, 75/93 kW (105/125 hp), carburated gasoline engine capable of 261/289 N·m (189/209 lb·ft) of torque at 2000 rpm; the major difference between the F and the F.5 is the oiling system. The F.5 uses the same oiling set-up and configuration as its 2F successor.

	The second version of the engine, called the 2F, was introduced in 1975. There are a few differences between the F and 2F, i.e., a larger bore in the 2F, removing one oil ring and forcing the oil to travel through the oil filter before the engine.

Yes I have the F.5. I had good oil flow for 23 years. I'm confident the rockers are original and oriented properly.

 

[Steamer]

Another flow test just to make sure I’m getting flow right to the rocker holes in the shaft.

 

[Steamer]

So, I have figured this out.
When viewing from the front, it is when the rockers rotate clockwise that the grooves in the bushing move closer to a shaft hole. The valve side bushing groove moves towards the bottom shaft hole, while the pushrod side bushing groove moves towards the top shaft hole. It appears my rockers do not rotate enough for the grooves to reach their shaft holes and I don’t know if they are supposed to rotate that far. But it made sense to me that the closer the grooves get to the shaft holes; the more flow would occur. So, if the rockers don’t rotate clockwise enough, maybe the shaft could rotate counterclockwise. I know that sounds impractical, but then I discovered "THIS".

 

[bj70bc]

so whats the fix? drill the holes over a bit? pin the shaft where its supposed to sit?

 

[Malleus]

Do my bushings need to be reamed? I’ve heard something about that long ago but can’t find any info on it now. When I replaced the shaft and bushings in 2000, I had great oil flow and could see the oil spiraling down the push rods as they rotated. Now the rods are staying almost dry.

My oil pressure runs 45 to 60 between cold startup and hot idle. I thought maybe the cam bearings are worn enough to not get enough pressure up top and into the bushings but after the air test it seems I would need more pressure than even a new engine could deliver.

I'm confused. Are you saying that for 23 years the oiling system worked fine and now it doesn't? Or has something happened/been changed recently?

 

[Steamer]

I'm confused. Are you saying that for 23 years the oiling system worked fine and now it doesn't?

Exactly!

has something happened/been changed recently?

Head was recently re-built. When I re-installed the rocker assembly, I just had the shaft rotated properly so the shaft grooves would line up with the pedestal studs which allow the rocker assembly to slide on & down all the way. I never was aware about any rotational slop in the fit between the pedestal studs and the shaft grooves. I think the shaft may have been rotated clockwise in that slop range which would rotate the shaft holes away from the bushing grooves.

Also, the valve seats were not replaced during the re-build. Shop said they were good and just needed “Dressing Up”. If they were cut deeper, the valves would ride higher which would make the rockers rotate a bit counterclockwise which would move the bushing grooves away from the shaft holes. This amount would be slight but still would add to the problem.

 

[Steamer]

so whats the fix? drill the holes over a bit? pin the shaft where its supposed to sit?

The fix is, rotate the shaft counterclockwise within the slop when installing. This direction moves the bushing grooves closer towards the shaft holes. Plus, in my case, I went ahead and did a little grind work on the alignment grooves to rotate it a little more in my favor. I also chamfered the oil feed hole so the hole-to-hole line up wouldn’t get hindered.

I used a 7/64” extra long drill bit to rotate the shaft as shown in the vid. With the pedestal bolts just snug, the shaft can rotate but when torqued down it doesn’t move.

 

[Steamer]

And today in between downpours, I got it back together, adjusted the valves and fired it up. I’m now getting oil flow out of the rocker holes. I’m guessing I got about 5 degrees more rotation with the groove grind. I might just go for a little more. I can always back it off if I get too much flow.

The oil squirts from testing got on the exhaust manifold so the video is very smokey. I’ll try again once it’s burned off.

But who’d of thought. The oil flow out of the rockers is adjustable.

I know this all sounds odd but, I went from hardly any flow to good flow.

 

[Steamer]

So, I’m wondering if my first noticed rotational slop (before the groove grind) is unique or is it common on all vehicles. Has anyone ever noticed or checked for it when installing the rocker assembly? If so, has anyone realized that counterclockwise rotation of the shaft will increase flow to the rocker holes?

I would recommend when installing a rocker assembly, one should check for slop and if it’s present, rotate it counterclockwise.

 

[EWheeler]

And today in between downpours, I got it back together, adjusted the valves and fired it up. I’m now getting oil flow out of the rocker holes. I’m guessing I got about 5 degrees more rotation with the groove grind. I might just go for a little more. I can always back it off if I get too much flow.

The oil squirts from testing got on the exhaust manifold so the video is very smokey. I’ll try again once it’s burned off.

But who’d of thought. The oil flow out of the rockers is adjustable.

I know this all sounds odd but, I went from hardly any flow to good flow.

Ive never change the bushings in the rocker arms, so im asking from a point of no experience - could the busing be removed and reinstalled for better alingment? Or in another way of asking, could one install the bushings such that you have zero chance of proper flow ?

Thanks for posting this. I enjoy your threads and always learn something.

For visual reference:

RL1041 F/2F ROCKER ARM OILER BUSHING

Replaces the discontinued Toyota part number 90999-73043 (Bush, BIMETAL Formed), for F-Series Land Cruiser engines. You will need 12 - Sold as a set of 12.

redlinelandcruisers.com

 

[bj70bc]

im due for my second valve adjustment since re doing my head, im going to check this as i replaced my exhaust rockers and reassembled

 

[Steamer]

could the busing be removed and reinstalled for better alingment?

Technically yes. If the holes in the bushings are bigger than the holes in the rocker arm. You could rotate the bushing a tad without covering the rocker arm hole. But I believe that amount would really be slight. I believe the bushing holes are bigger simply to give you a little wiggle room when installing. I think it would be easier to rotate the shaft holes towards the bushing holes rather than the bushing holes towards the shaft holes. I would first check to see if there is any rotational slop already there. I did have that slop, but I added a little more.

 

[Steamer]

im due for my second valve adjustment since re doing my head, im going to check this as i replaced my exhaust rockers and reassembled

You probably will have to loosen the pedestal bolts to check this. With mine being finger tight, I could rotate the shaft with the drill bit as shown in the video. When I torqued down the pedestal bolts & nuts, the shaft couldn't be moved.
I believe this occurs due the a slight amount of play between the pedestal bolt holes and the bolts or studs themselves and a very slight misalignment occurs when torqued down. I don't think this hurts anything but actually is a benefit . If I could have rotated the shaft when torqued, I had planned to add a lock set screw by drilling and tapping down the center of one of the pedestals. Turns out it wasn't required.