oil leaks ,pushrod tubes

[n2727d]

I have some irritating oil leaks in the pushrod tube area that I need to fix on a 1952 170 b .Is there a sure cure ? I know there was some discussion on the old site on this subject ,but I have not found it . All input would be appreciated . Thanks Mark

[GAHorn]

The pushrods can leak in two places. At the lower end the rubbers can get dry/damaged and the gaskets at the pushrod-housing can leak.
The upper end of the pushrod tube is "swaged" into the aluminum head at the rocker-box base. If that is where they are leaking it may first appear to be a leaking rocker cover gasket. But if you clean the area up and run it a short while and slip your finger behind that base, around the pushrod tube, you may find that the swaged tube has loosened up and is leaking.
The fix is to obtain the tool, Part No. EL-91 from El Reno (800/521-0333) for $50. This allows you to remove the rocker box cover, pull out the pushrod (after removing the rocker), and insert the tool to re-tighten the swaging. It's a tool that reforms the bead inside the pushrod housing tube.
Or you can find the person who borrowed mine, subsequently moved, and forgot to return it to me. (Hint, Hint, ...in case he's reading this.)

[wa4jr]

The pushrod tubes on the middle two cylinders of my O-300 are leaking as well. Appears to be coming from the rubber seals as I have active drips from the bottom of the compression/retainer clamps with no trace of oil farther up on the tubes near the rocker box. I am going to use the coversion kit that is mentioned earlier in the "Hangar" under the heading of "push rod tubes". I am hopeful this conversion kit will do the job of sealing the leaks while making future MX tasks with the tubes easier in that the cylinder will not have to be separated from the case for tube removal

[wa4jr]

I finally got around to installing the Real Gaskets pushrod tube conversion kit on the middle two cylinders. I found the quality of the kit/components absolutely astounding. Installation was a bit slow at first, starting with the middle cylinder on the right bank. An earlier post mentioned cutting the old pushrod tubes out with a hack saw. HA! No way a hack saw could fit unless the exhaust and induction works are dropped off the engine. I used a Dremel tool with the little cutting wheel to zip through one half of each tube, then grabbed the tube with channel locks and turned it over to cut the other side. Once the tubes were cut on the left middle cylinder, the tubes just fell away from the lifter cover! This shows how poor the seal had become. I replaced the lifter cover gaskets as well since the kit includes nice silicone replacements. I purchased the special spring compression tool sold by Real Gaskets, and it was indeed a lifesaver. I was able to intall kits on both middle cylinders without taking any of the exhuast/intake works down, although one has to be quite a contortionist to get hands and new pushrod tubes and tools all into the same space above the induction spider. I used silicone rocker cover gaskets to tidy things up real nice.

Initial runup and first flight have shown no oil leaks at all from the new components. I only have one leaky rocker to go....or perhaps it is the upper end of a pushrod tube...and my external oil loss should be greatly reduced