My X-mas Idea for all. A new way to seal rocker shafts

[HKZ Bob]

Dear all,

I would like to hear opinion of my new cheap robust way of sealing rocker shaft
with 18mm cylinder head drain plugs pushed in the opposite side with curil green.


Here my pictures.

This will never leak again and only 10 cent a piece. What a saver for Christmas.

BR
bob

[KTL]

If the shafts are properly positioned, you can only put the plugs on one side of the shaft. The shaft is supposed to sit flush against the "thin" rocker support. So that leaves no room to insert a plug, yes?

Good idea nonetheless. How do you propose to remove them? You could tack weld a tiny nut on them before installing. Then you could thread in a short bolt and use a pair of pliers and hammer to tap them out, kind of like a crude slide hammer.

[HKZ Bob]

No the rocker is centered and I put them on both sides in the opposite direction, which gives sufficient overlap to the rocker bore.


Actually I don't want to remove them anymore.

build to last forvever

[HKZ Bob]

Here he pictures of the other side.

[brads911sc]

As KTL stated, the rockers properly installed are not centered. perhaps this is why it was leaking in the first place... Always better to install them correctly rather than rigging to cover your error.

[Walt Fricke]

HKZ - is this an early engine with the short early shafts? These are not centered on the housing, but when properly installed both ends are in some from the end, though one is rather farther in. Thus the shaft is centered on the rocker. The factory procedure involving using a feeler gauge between the rock and the housing to "feel" where the rocker shaft slot is, so it can be moved just outboard of where the rocker is, is important with these early shafts.

The later shafts, which just about everyone is using, are longer. One end of the shaft is flush with the housing, and the other end is in. There is no need to fuss with feeler gauges, as getting the (proper) end flush means that the shaft is centered on the rocker. You can see this relationship by holding the shaft on the outside of the housing and centered on the rocker space. It is obvious that there is a long and a short part of the housing, so the shaft is flush with the short housing, and indented on the long one.

If shafts are not centered on the rocker, tightening them will cause the end which is in too far to expand into the rocker. Things won't work well with a bunch of friction introduced in this way.

Hope you have short shafts, though these have fallen out of favor because I think the pinch bolt was of a smaller diameter (as well as being shorter), which did not allow it to squeeze the expanding ends of the shaft as much as proved needed to keep them in place.

[cgarr]

When mine stops leaking I know to add oil....

[HKZ Bob]

Dear All,

I evenly positioned the rocker arm prior I put the caps on.

As you see by the picture the cap fits perfect over the clamp nut on both sides.
So I used all the room for a good interference.

Yes this is an early 72 Cam tower, and I think it could be also a good field fix on early 911 without taking the engine apart to fix a leak.

How can I identify what shafts I have by dimension ?

I will not have a problem with this design proposal that a shaft will float. The will be aligned and hold in place by the caps.

[brads911sc]

Not sure what the advantage is over properly installing the shaft with RSR seals. I applaud your ingenuity but your fixing a problem that doesnt exist if the shafts are installed properly.

[HKZ Bob]

Originally Posted by brads911sc

Not sure what the advantage is over properly installing the shaft with RSR seals. I applaud your ingenuity but your fixing a problem that doesnt exist if the shafts are installed properly.

Several Advantages.

On the RSR seals I may have wear due to age temperature.

This fix can be applied without removing the rocker. (field fix)

This solution won´t allow the rocker to float inside.

BR
Bob

[KTL]

Bob,

How tight is the plug fit? I would think a light press fit with Curil would be pushed out by a walking rocker shaft rather easily? There's a good bit of force on the rocker and that would translate into a fair amount of force on the shaft to make it move out of the housing bores. Or am I way off, and the walking shaft is a result of its loose fit and rattle when the rocker is relieved of the cam lobe (at base circle)?

[brads911sc]

Nice fix. I do like the idea. Sorry for being critical.

Originally Posted by HKZ Bob

Several Advantages.

On the RSR seals I may have wear due to age temperature.

This fix can be applied without removing the rocker. (field fix)

This solution won´t allow the rocker to float inside.

BR
Bob

[HKZ Bob]

Originally Posted by KTL

Bob,

How tight is the plug fit? I would think a light press fit with Curil would be pushed out by a walking rocker shaft rather easily? There's a good bit of force on the rocker and that would translate into a fair amount of force on the shaft to make it move out of the housing bores. Or am I way off, and the walking shaft is a result of its loose fit and rattle when the rocker is relieved of the cam lobe (at base circle)?

It would be more worried about to get them out.
The fit is a tight as you are pressing in a water freeze plug into a block.
There is no way that it will get loose.

I used a hammer do press them in.

BR
Bob

[Tippy]

I thought of using a big 'ol glob of RTV to make like a plug.

You would simply stick screwdriver in it and pop it out.

It was my shadetree side coming out.

[KTL]

Originally Posted by HKZ Bob

It would be more worried about to get them out.
The fit is a tight as you are pressing in a water freeze plug into a block.
There is no way that it will get loose.

I used a hammer do press them in.

BR
Bob

That was my thought. I know you don't intend to take them out regularly. But at some point they have to come out to service the rockers or cams. I suspect some heat from a heat gun would help expand the cam tower. However the alloy tower is such a good heat sink that it may prove to be ineffective. I really think a small nut on the cap would be wise to do, in order to have a means of "grabbing" the plug. Otherwise a right angle drill (very small) and self-tapping machine screw would be the next idea i'd have in my head to try 'n get those buggers out.

I thought of using a big 'ol glob of RTV to make like a plug.

You would simply stick screwdriver in it and pop it out.

It was my shadetree side coming out.

Oooooh man don't do that. RTV never unplugs clean. Makes a real mess of remnant residue and will make you (or the next guy) curse from the shaft being more resistant to be pushing out of the bore. I had a few shafts recently that were bears to move out of the bores. They'd also been treated to something similar- non hardening paste instead of RTV goop. On one I resorted to a split piece of fuel hose to protect the shaft from the vise grips. Then whacked on the vise grip handle with my hammer.

[CaptainCalf]

Nice engine-nuity Bob

[HKZ Bob]

Oooooh man don't do that. RTV never unplugs clean.

I thought Curil T stays soft?

[KTL]

Curil T remains the same as it came out of the tube- sticky liquid paste. RTV hardens to rubber and is a real mess to clean off surfaces. I'd gladly clean up some Curil T residue without complaint. I'd swear like a truckdriver if I had to clean up RTV.....

RTV = Room Temperature Vulcanizing, which implies a liquid paste sealant that turns into a firm rubbery non-tacky material. Real pain to remove because it deflects scraping and most solvents don't break it down. It's designed to be resistant to all but the most nasty solvents.

[Walt Fricke]

I am no fan of the RSR seals. They cost way way too much for what they are. Half of mine have a bit shaved off when I install the shafts. And that area of the cam carrier is always all grimey when I pull things off, calling for a fair amount of clean up work. The grime doesn't hurt anything, though, until you go to put a motor back together - you don't want to work with dirty parts, and the cleaning is the part I like least about the job.

However, HKZ, in order to install the short side plug you had to install the rocker shaft too far in. Your '72 has the long rocker shafts, same as succeeding 911s until the 993s. I think the short ones ended maybe in '67 or back then, in the 2.0 liter era.

A rocker shaft installed by the book will not have any of the shaft hole exposed on the short end for a cap to fit into. To do so, you had to cheat the shaft in a bit farther, moving the groove closer to the rocker itself. That could be a problem.

[Ken911]

turbo kraft has rocker arm locks to prevent them from moving. some cam towers get opened up over time if the motor has been apart several times(especially turbo motors). I have a set on the way.