push rod tubes

[dpowell]

After looking back thru some old threads, I need to ask, did the fix of cutting the pushrod rubbers and gluing them back together work out ok? Is that still current procedure or has someone come up with a better fix for leaking tubes? Thanks for allowing me to beat a (probably) dead horse.

[Bruce Fenstermacher]

No that procedure looked very promising. So promising it was let out of the bag before it's time. But it didn't actually pan out in practice. The problem is the rubbers are stretched over the pushrod tubes. There is no way to stretch the cut rubber and hold it in place till the glue cures. Then of course the glue would have to prove it could hold under the pull of the stretch. It was close but no cigar.

[170C]

i was really interested in the procedure to cut the rubber, install it and glue it back together, but as Bruce said, no one seemed to think glue would hold the severed rubber together with the stress it would have been subjected. I did find some glue which I tested on an old rubber and found it to be exceedingly strong. Strong enough that I could not pull it apart. However we never did come up with a way to squeeze the rubber back together and secure it until the glue cured. Thus, I still have 2-3 that leak Someone suggested moving the clamps off the rubbers and rotating them 180 degrees, then reinstalling the clamps to see if that might stop the leaks. I have not done so and am somewhat concerned that it might make the leaks worse Sure wish our cylinders had come with the spring push rod tubes like Richard and others have installed or have come that way from the factory as do the larger Continentals.

[marathonrunner]

NOt sure what the problem is but you could try loctite 515, the purple stuff used to put the engines together on sealing surfaces. It does work on the Continental style pushrod rubbers that also leak on occasion

[dpowell]

Strange thing is that we just finished the annual. Prior to the annual I had very little oil leakage. Just a small amount thru the alternator seal( i think). BTW this is an 0300D. IA removed the rocker covers as this was his first time looking at this a/c. Replaced with new gaskets. Removed alt and checked brushes and replaced seal and gasket. New plugs etc. Found the timing to be set at 20' btdc on both mags. Reset to 28/26 btdc. Compressions are great all 75 or better. I saw some seepage on the rod tube rubbers and moved the clamps a bit to see if that would help. Well it is leaking oilway more than ever before. 30-40 min flight and there were probably 20 or 30 drip spots on the right side and bottom of cowling. Could the clamp adjustment do this much in you guys opinion? Does the timing adjustment have anything to do with it? Are the rubbers replaceable by sliding the jugs back or do you guys know do the jugs have to come off to replace the seal at the bottom of the jug?

[dpowell]

Thanks Aryana,

It looks like that is the way to go for leaks. Do you (or anyone) know are these direct replacements or require a stc? If they require stc, does that come with the kit? Thanks

[dpowell]

Will do. Thanks

[170C]

Aryana, does the installation of these spring push rod tubes require any modification of the upper cylinders in order for them to properly fit? You mentioned that they are coming out with stronger springs. Does this mean that the current springs have failed, in some cases, to stop leaks? Is that price of $87.98 per cylinder or is it $175.96 per cylinder?

Thanks

[Bruce Fenstermacher]

I saw some seepage on the rod tube rubbers and moved the clamps a bit to see if that would help. Well it is leaking oilway more than ever before. 30-40 min flight and there were probably 20 or 30 drip spots on the right side and bottom of cowling. Could the clamp adjustment do this much in you guys opinion? Does the timing adjustment have anything to do with it? Are the rubbers replaceable by sliding the jugs back or do you guys know do the jugs have to come off to replace the seal at the bottom of the jug?

Yes moving the clamp can open a flood gate. I suggest putting it back.

Timing the engine can have nothing to do with a pushrod tube leak.

Yes you can replace the rubbers by sliding the jugs back and not removing the piston from the cylinder but you must also remove the push rod as well which adds extra complexity to the job which is not trivial to begin with. Having said that, if you know how to properly move the cylinder back, and reinstall it, you should have the know how to remove and reinstall the pushrod.

[dpowell]

Got the real gasket tubes installed and have a few leaking. Used a very small amount of rtv on the outboard end as called for. Maybe should have used a more liberal amount and covered the entire gasket surface?? Anywho, found that I also have quite a bit of leakage around the jug to case flange. Are these actually packings as called for in the IPM or have they been upgraded to o-rings and does the jug need to come completely off to replace or are packings cut (at the top), will o-rings stretch over the jug etc. Thoughts/wisdom anyone. Thanks

[Bruce Fenstermacher]

The o-ring is the packing. Never saw anything else. Yes the jugg must come off but off course you don't have to pull the piston from the cylinder. Only far enough to remove the pin.

Sometimes we get way to fanatical about having a completely dry engine. Then we are mad because the hardware rusts.

It would have to be dripping quarts of oil before I pulled the cylinder for just this.

[dpowell]

It appears that way,but, will know more tomorrow. Just cleaned it up and will run up tomorrow. It is not a severe leak,however after a 4 hr flight on saturday the inside lower surface of the cowling was completely covered,there was not a noticeable amount gone from the dip stick. I despise oil leaks on anything, but, it does keep the bottom from rusting! Did I mention that some of the oil appears to be coming from around some of the hold-down bolts and nuts. I think that I read somewhere that the real gaskets are reusable. Anyone had experience with using them after having been torqued down. It has 4 .5 hrs since installation.

[GAHorn]

Engine oil leaks are like Blood and spilled-gasoline.....a smidgeon looks like gallons.

The REAL silicone gaskets are reuseable.

[dpowell]

Thanks all. About to do the run-up.

[n3833v]

I have been told if a Continental doesn't leak oil, there is none in it.
I also don't like leaks.
John