push rod tubes

[sharky914]

Hello,

I need to change my push rod tubes and the seals cause oil is leaking from there and falling on the exchange manifolds.

Is it possible to remove the pushrod tubes without removing the engine?????

Thanks in advance!!!!

[jmcleod]

yes, you can replace the tubes with the engine in the car. in fact, i have to do it again. if anyone reads this post, i need to know the "stuff" you use to seal the o-rings. RTV sealer ???? the first time i replaced the o-rings, i put them back in dry but they still leak but i think its due to the "hole" being bigger like it was ground out bigger. my other type 4 had a tighter fit and no leaks. what i did was to bring the piston up to TDC, so the valves will be closed and there should be the valve adjust "gap" (unless of course you have hydraulic lifters). then you can take off the wire, the rocker arm shaft, remove the pushrod, and remove the push rod tube. i used a plastic cable tie to keep the rocker shaft assembly together by threading it though the bolt holes. installation is the reverse. you can help the pushrod tube back into the head with a gentle tapping on the tube with a socket and extension. try not to catch/pinch/cut the o-rings between the tube and the head. do each cylinder in turn. hopefully, someone will tell the name of the sealant. enjoy!

[JP Noonan]

Sound's good, there is a slightly more detailed article on the 914 fans web site.

I did this on my 72 1.7L (whith the motor out) but to add...

I took out each lifter, ONE AT A TIME, DO NOT MIX THEM UP, to inspect them. Then I pluged the hole with a small peice of a blue paper shop towel. I don't like the cloth ones because peices can come off and don't disolve like the paper kind. With the lifter bore pluged I used a "Scotch Brite" pad to clean the O-ring bore of all RTV and burnt oil. I did the same on the cylinder head side. Clean all the little bits of Scotch Brite and dirt out of the head and block. I then used the "Vitron" seals with oil as a lube and installed the tubes. No RTV, and NO leaks for two years. I've been told the RTV dosen't work because the bloack and heads expand so much the pushrod tubes actually have to move (Bob Hoover, and Tom Wilson). I've also been told that there is a "new" type of selant, some aircraft stuff that works better than anthing else, and works for many years on high HP motors (FATS Performance. Ask John Rogers, I think they just built a motor for him (lucky dog) and he knows how to aquire some of this magic glue.

One more thing, if you have anything other than the German made, and/or "VITRON" seals throw them away!!! My experience with Brazilian Type4 seals is about as bad as it gets. The push-rods tubes leak and the main oil seals fall out of the bore!!! The good ones are about a buck each, but to save 16 dollars do you really want to do this job again?

Oh, and one more thing, DO NOT USE BRAZILIAN SEALS!!!! Seriously it's worth statig twice

[oredith]

i forgot where i read this.. so take it at face value..
what i read amounted to something in the line of "don't put any sealant on the o-rings" the o-rings were designed to have some play in order to accomidate the expansion and contraction between the case and head due to heat..
that said.. i don't know hwo to prevent leaks if the hole is bigger than what the o-ring was orininally intended to fill..

good luck,

Jeff

[John Rogers]

Make sure you get the hi temp vitron or what ever they are and that you get the spring clips back in correctly. You shouldn't need any sealant. I use AmsOil 2000 synthetic grease on the ones in the race car since I have not clamping springs and they get a better seal that way. You could use some synthetic grease to coat them if you want.

[BenI]

The tubes are steel, and the jugs are steel, so they expand and contract together, so the o-rings dont slip, right? Ive used the red RTV with great success. Vitron is the material you want, because it doesnt degrade with heat, but may be hard to come by at local hardware stores. Even my local o-ring dealer said he couldnt get metric sized vitron o-rings. SInce the job is not much fun, I think its worth ordering the right ones from Pelican or someone.

[oredith]

beni said: "The tubes are steel, and the jugs are steel, so they expand and contract together, so the o-rings dont slip, right?"

i don't know if that's true.. it'd be true if they were the exact same piece, but the difference in the size, shape, exposure to cooling air, etc. can effect expansion rate, i think..

Jeff

[michel richard]

I think that the jugs are cast iron. In addition, I would think there might be a difference in temperature between the jugs, the heads and the tubes.

They're all close to each other, but may see different air flows and the tubes, especially, may be somewhat insulated from the other parts by those seals we are discussing.

In addition, I was at industrial supply shop a couple of years ago and was amazed to see that the kinds of seals we are talking about come in all sizes and shapes and materials for industrial applications. I remember seeing specs for some of the materials that mentionned operating temperatures far above what our engines could produce. Teflon and viton (which are the smae thing, I believe) were not the highest spec materials.

All of this to say that it might be possible to simply find rings there. You might even find some that are slightly thicker (same i.d. larger o.d.) and would take care of the bored out holes.

HTH