The International Cessna^® 170 Association

Dear Fellow C-170 Members:

I'm leaking oil, (not enough to register any change in consumption, but enough that it splatters on both the top rear and bottom rear of cowling) and the primary source of the leaks seems to be from the rubber pushrod housing connectors that are located below each cylinder.

My question is, how difficult are these to replace? Do the cylinders need to be pulled to replace these short pieces of rubber tube?

I'm about 500 hours from TBO with all indications that the engine is running strong and I don't want to dig into anything major unless necessary.

Thanks,

Curt
N4288V

For all practical purposes the cylinders at least need to be unbolted and slide away from the case in order to reinstall the new bushing.

So more than likely your going to put up with it and do as I do and call it part of my naturally occurring corrosion treatment.

But you could try a few things. First try simply repositioning the spring clamps to a different place around the bushing. I can hurt and it might seal.

This might be difficult and maybe impossible depending on the condition of the rubber seal. You could remove the springs. Gently with a small screw driver or other suitable blade, break the rubber seal away from the push rod tube. After it's free to slide the bushing up the tube. You probably will need to lubricate the bushing a tube to accomplish this. Next clean the tube and the follower cover where the bushing seats. Put a small dab of high temp silicone around this area and slice the bushing back over it. Reinstall the springs.

Or alternately after removing the springs and cleaning the bushing and tube area with the bushing in place, carefully lift the bushing edge and get some high temp silicone under the bushing to help the seal. Reinstall the springs.

If you've got a little money to spend, check out RealGaskets RG-200PRT-1 PUSHROD TUBE SEAL KIT for $76.50 per cylinder.

http://www.realgaskets.com/files/horizontal.htm

These utilize a spring-loaded push rod tube with a compression seal at each end, a la the "big bore" TCM engines. They install with the cylinder in place on the engine.

Miles

I thought my rubber seals were leaking but it turned out that it was leaking around the top of the push-rod tube (a common problem), running downhill and collecting on the seal. There is a special tool for for seating the push-rod tubes at the top and that did the trick for me.

Forgot about this product. (Real pushrod tubes) After you buy it here is what will have to be done to install it.

Remove the valve cover.
Remove the rocker shaft and rockers
Remove the push rod
Remove the old push rod tube and bushing from the cylinder
Install the new pushrod tube and seals
Reinstall the removed parts in reverse order.
Do the paperwork to include the STC 337 which dictates some IA envelopment.

Not that hard for someone with a little knowledge of the engine and cylinders but not for an engine novice with out help.

Oh and at $76 x 12 for all the pushrod tubes, after all where do you stop, thats $912.

I still like the anti-corrosion program

Bruce, Miles and John: Thank you. All very helpful.

Best regards,

Curt

Bruce, it's $76.50 for a complete cylinder, making it a very affordable $459 for a complete set

I have one that spooges a little too, but it's so minimal that it's just not worth the headache of the installation. I might try the reseat/reseal thing you suggested.

N9149A wrote:.Oh and at $76 x 12 for all the pushrod tubes, after all where do you stop, thats $912.

Actually that's $76.50 per CYLINDER, not per push rod, so it's only half the above amount to do the whole engine.

Miles

First thing I did after buying the 170 was to install the Real gasket Push Rod kit. I installed the kit on my Champ and was pleased with the way it cleaned up the continetal. If you can afford to do it, I recommend it.