Rocker arms bushings!....when to replace them!

[AUSTmike]

Hi guys!..I just did a oil change and adjusted the valves..when doing the valve adjustment i noticed some of the rockers had a bit of play from side to side.

here is a video on what i mean
courtesy from RCPD
https://youtu.be/2kfM0LkDcSY

Can this be a worn rocker bushes?..my engine is fine and don't get tappet noise on cold start..its when the engine is warmed up and up to operating temp that i get the ticking of the tappets

[Winter911]

Originally Posted by AUSTmike

Hi guys!..I just did a oil change and adjusted the valves!..when doing the valve adjustment i noticed some of the rockers had a bit of play from side to side!

here is a video on what i mean!
courtesy from RCPD
https://youtu.be/2kfM0LkDcSY

Can this be a worn rocker bushes?..my engine is fine and don't get tappet noise on cold start!..its when the engine is warmed up and up to operating temp that i get the ticking of the tappets!

That's my video. I'm still looking for a solution as well.
I had a fellow pelican tell me that side-to-side movement on a rocker arm should not make noise since the rocker arm moves up-and-down. Can anyone confirm?

[pampadori]

@winter911 have you considered moving the rocker and shaft from cyl 3 with one from the other bank to see if your noise follows it? I'm not sure how "married" the rockers become to the cam lobe and valve they interact with but if the two look pretty similar I wouldn't think it would be too risky to try.

[AUSTmike]

Winter..I hope it was ok to use your video it was that i have this same issue as well with some of my rockers i did message you a few days ago to ask you if i could do this..
im pretty sure though that its the bushings..the older style bushings are brass and thats a soft metal...the newer bushings are steel like bushing and last alot longer.

With my motor the engine sounds good on start up but once the motor is warmed up i get the tappet noise or ticking of the rockers..and i also get the side by side rocker movement

I'm waiting for a quote from my local shop to replace the bushings but it does point after a lot of investigates on the top end that i do need to replace the bushings..

[fanaudical]

How much side-to-side play do you have? You should be able to measure the gap between the side of the rocker arm and the housing with the arm push all the way to one side.

[David Inc.]

This thread says 0.5mm (last post): Rocker side to side play?

I just installed some rebuilt shafts and rockers with new bushings, they all had some axial play.

[AUSTmike]

Thanks Guys..your input is very interesting..When i adjusted my valves i did over 4 rotations of the settings adjusting each valve with rockers 4 times over till i was satisfied

but i did the back side gauge method which is more easier for me..but in the end much more satisfying for me

After doing this though i still didn't make any progress with the ticking noise..after warm up..i mean the return oil tubes are hot.

I am thinking now that the rocker bushings are due for new ones...hmmmm that's what may be the next service
I get the same here in winter911 video
https://youtu.be/2kfM0LkDcSY

[AUSTmike]

David Inc. what was your situation..was you getting tappet noise after your engine was warmed up.

why did you replace the bushings and shafts..were they worn and do you notice a difference in the tappets afterwards..did the tappet noise go away once you replaced the shafts and bushings.

[David Inc.]

Originally Posted by AUSTmike

David Inc. what was your situation!..was you getting tappet noise after your engine was warmed up!

why did you replace the bushings and shafts!..were they worn and do you notice a difference in the tappets afterwards!..did the tappet noise go away once you replaced the shafts and bushings!

A previous rebuild improperly installed my rocker shafts and it wore out the cams. No engine noise but since I was regrinding the cams I had the rockers and bushings cleaned up by Dougherty Camshafts.

I think axial play is not what would produce noise, but wear in the bushing or rocker shaft allowing the rocker to rattle on the shaft.

[AUSTmike]

I agree i think my rocker bushings are due for new bushings..David did you go the steel bushings..and what did you see on the cams to know they were wearing.

[Winter911]

AUST,

Any updates on the rockers? My noise is still there.
Car pulls hard so I don’t think it is affecting performance.
I did a leak down and all cylinders were under 5%, which tells me the motor has been rebuilt..

[PeteKz]

Late on this thread, but let me toss in my observations. Side-to-side play does not cause valve noise, unless it's really excessive. If it's really excessive, that's because the side surfaces in the head are worn, not the rockers (rockers are iron, head is aluminum).

The indication that your rocker bushings are worn is a wobble on the rocker shaft. IIRC, the clearance is around .002', which is just enough to feel with your fingers. If you can visibly wobble the rocker on the shaft, then the rocker bushings need to be replaced. If in doubt, try to stuff a .002" feeler gauge in there, or take the parts to a shop that can measure them accurately.

Everyone wants a quiet engine, but as a general rule, valve clearances that are a little loose are better than those that are a little tight. The spec is .004", but I set mine to .005". I don't get noticeable valve noise at that setting. If you hear a significant valve tick, check the clearances. If you have a valve that the clearance is increasing on a regular basis, then you probably have a cam/rocker wear problem. When everything is setup and working correctly, 911 rocker clearances don't change much between service checks.

[pampadori]

What Pete said.
@Winter911 did you ever move your rocker shaft to another location to see if the noise you had moved with it?

[Winter911]

Originally Posted by pampadori

What Pete said.
@Winter911 did you ever move your rocker shaft to another location to see if the noise you had moved with it?

Pete thanks for that info. I’ll check for that wobble.

I haven’t had a chance to mess with it. I’m in the middle of moving and the car has been under a cover. I’m moving the car to the new house tmr so I should be able to get to it soon. I’ll keep you posted.

Any tips if the rocker shaft doesnt want to come out? There’s a little corrosion on mine. I’ll try pb blaster and all that but I can’t fit a punch to hammer it out since the motor is in the car

[grb008]

Did you loosen the 5mm allen screw while holding the 8mm. I just was doing my valves also with the snap gap. Whoever worked on the car power torqued all the nuts and even had some non standard nuts on them. I had to PB blaster and slight heat on the rocker shaft nut. Clean out the allen head screw and the 8mm compression nut with a pick before using tool on it. I used my bicycle toque wrench which is a low NM 1/4 inch and eventually got the bolt out and the shaft slide right out ready for replacement.

[lateapex911]

I have sawed off an Allen Key and used an box end wrench because of the tight clearances. Def soak that think in PB over night.Once the thing is loose and it's reluctant to slide out, Use a socket and flat pry bar and mallet. Think it through, sometimes it comes out one way easier than the other.

I'd also vacuum out as much crap as possible out of every nook and crannie near your working area.

[proporsche]

Originally Posted by Winter911

AUST,

Any updates on the rockers? My noise is still there.
Car pulls hard so I don’t think it is affecting performance.
I did a leak down and all cylinders were under 5%, which tells me the motor has been rebuilt..

can you make a video of your noise? I s the noise there from the start or only when warm?
There is a possibility that you have a broken one of the 2 springs

ivan

[proporsche]

When everything is setup and working correctly, 911 rocker clearances don't change much between service checks.[/QUOTE]

Pete, this is the point.
I have done in my 911 live maybe zillion valve adjustments on 911 as full 10k miles
service.I have to say a lot of times the valve were noise...do not remember any time or place 911 with tight valve adjustment.
Personally i like it quite..here is an example how it should sound....(my911) warm or cold
https://www.youtube.com/watch?v=Out_PKGkYYY

[PeteKz]

Ivan, thanks for that good info on valve clearances opening up to make more noise, instead of tightening up. You have adjusted more 911 valves than I ever want to! I'll go back to .004" on my next adjustment, although I gotta say, I've not noticed that .005" makes noticeably more noise than .004" Thanks.

[Walt Fricke]

Winter
One of the main issues with rocker shafts is leaking oil. That grody shaft and housing in your photo looks wonderfully dry. I'd hesitate to take it out short of as part of a top end rebuild.

If rocker (or shaft) wear is the cause of the noise you are determined to eradicate, you should easily enough measure it when you have the shaft out. A caliper for the shaft, and a snap gauge (not expensive) and your caliper for the bushing. You'd want to take a number of readings at different points, though it is obvious from looking where the most wear on a bushing is - the bottom of the bushing when the valve is full open. Same as on the shaft, though that can be dealt with a time or two by rotating the shaft.

In one of his helpful practical posts, John Walker noted that you should always remove a rocker shaft from the short side. That way you are less likely to score the aluminum bore, which can lead to leaks eventually. You can't do that for this shaft without some further disassembly. Cleaning that particular exposed bore looks to be difficult.