Leaky Pushrod Tubes

[Amskeptic]

I also like to prep the case side holes with some emery cloth to take down any sharp edges from machining the holes. (kinda round over the sharp shoulders), lube with moly and then rotate as the tube is seated. Gives the seals a chance to get in with out being pinched.

Which side is leaking: case or head? Likely case side, that seems to be the most likely place for seal pinching.

May I respectfully scream in panic please.
Do not let emery cloth anywhere near the opened case holes. Nonponononononono, no. Grit can easily score and destroy, and fall down the drain slots in each hole. Just use a paper towel or lintless cloth soaked with GumOut.
Thank-you,
Colin

What about during a rebuild as prep before the case is sealed though? Followed by copious cleaning and rinsing.

I only use razor blades for finish machining around aluminum. Sandpaper products are dangerous. One stupid grain, just one, in the wrong place and it can do serious harm before it gets pulverized or washed away. If it embeds in a soft bearing or gets stuck between two pieces of aluminum/steel, it can wreak havoc for a long time. I will use emery cloth on cranksahft or camshaft journals so long as I know that they will be tanked and pressure washed and GumOut and dishwasher final washed by me.
Colin

[hambone]

I scrubbed the machined areas of my case with one of those green fiber topped scrubber sponges, using soap and water. Granted it was new.
I'll betcha a really fine grain paper with a split case would be ok, more like a polish. I may even go all renegade and do it to piston bores but I sure wouldn't tell Colin. That errant sand grain stuff is scary.

[dhoch14]

I have purchased the new viton seals and permatex pipe thread sealant. Is this the recommended Permatex?

http://www.permatex.com/products/Automo ... h_PTFE.htm

Should I apply this to both sides of the seals or just interior?

-dave

[Westy78]

I have purchased the new viton seals and permatex pipe thread sealant. Is this the recommended Permatex?

http://www.permatex.com/products/Automo ... h_PTFE.htm

Should I apply this to both sides of the seals or just interior?

-dave

Yep, that's the stuff. I put the seals on the tubes and then a semi thin coat of Permatex around them. It lubes and "seals" as you install them.

[Gypsie]

I also like to prep the case side holes with some emery cloth to take down any sharp edges from machining the holes. (kinda round over the sharp shoulders), lube with moly and then rotate as the tube is seated. Gives the seals a chance to get in with out being pinched.

May I respectfully scream in panic please.
Do not let emery cloth anywhere near the opened case holes. Nonponononononono, no. Grit can easily score and destroy, and fall down the drain slots in each hole. Just use a paper towel or lintless cloth soaked with GumOut.
Thank-you,
Colin

Agreed. And duly noted. I was thinking about raw parts that would be cleaned before assembly, but it is a good point that I did not clarify. I think you could still smooth the sharp edges with a razor or another solid scraping type tool while all is assembled and in place, but it is an awkward location to work in.

I think the trick with sharp edges or smoothed edges is to lube and rotate the pushrod tube as you gently push it in. (Go ahead john, do your thing...)

This'll give the seal a chance to slide past any binding spots. If it doesn't slide in gentle like, try again.

[Bleyseng]

I like this stuff the best for sealing/lubing the O rings as its not as thick as the Permetex stuff.
http://www.aircooledtechnology.com/stor ... 354&page=1

[SlowLane]

One thing that no-one has mentioned yet is to be sure that your wire spring pushrod tube retainers are properly installed. That is, the flat parts of the retainer must be bearing on the end of the pushrod tube, not floating inside the bore of the tube.

If a retainer is positioned inside the bore of a tube, two undesirable things can happen: 1) the pushrod tube can work its way out of its seat enough to start leaking, and 2) the retainer can rub on the pushrod itself. Ever pulled a set of pushrods and find a shiny band a couple inches away from the valve end? That would be the sign of an improperly installed retainer.

I found that a pair of needle-nose pliers worked well to pull any improperly seated spring segments into place.

[dhoch14]

Forgot to follow up on this thread:

Last weekend I did this fix via new Viton seals and Permatex. No leaks since.

SlowLane - I was thinking the same thing regarding the retaining springs. One is not 100% perfect and I will adjust via a needle nose pliers on the next valve adjustment.

Case closed.