"How To" on Replacing Pushrod Tube Seals?

[73ess]

I searched the archive and don't see a good thread or how to for replacing pushrod tube seals. I'm a newbie and need a step by step. Can someone walk me through the procedure? Thanks!

[david c.]

check out the shoptalkforum for T4 motors. You'll find lots of info on engine issues like this. If you're pulling the heads to do the seals, there are lots of other things you may as well replace, too. Better to get a sense of all that you can do to save yourself time 'while you're in there,' as they say.

[Bleyseng]

step 1- jack up car onto jackstands, drain oil etc......
2.- pop off valve covers
3.-carefully remove rockerarms and wire retainin bail, note the order in which they go so you install them back the same
4. remove pushrods again noting their exact placement in which lifter bore
5. remove pushrod tubes and clean the heck out of them, replacing any that are dented on the ends.
6. Clean the bores where the tube O rings seals really well
7. install O rings on the tubes
8. before you install each tube, lightly coat with Permagasket teflon thread sealant , then install so they seat properly
9 re-install pushrods back, rocker arms etc.
10. Do a valve adjustment
11. install valve covers
12. add new oil filter and new oil.

[73ess]

Thanks Bleyseng. So the heads DON'T have to be pulled to replace the pushrod seals?

[NOTASIX]

NO, they do not...

I have several posts on the STF about this and a few tricks to keep them leak free for a long time..

[david c.]

I didn't mean to suggest you had to pull the heads off. Sorry if you got that. But, like I said, Jake and the other T4 gurus have lots of tips on the STF, including which seals to buy and which is the preferred goop to keep them from leaking again.

[Dave at Pelican Parts]

I suggest doing one cylinder's worth at a time, and setting that cylinder to TDC before starting the replacement. I have found that you get really badly skewed torque results if one of the valves is open when you try to torque the rocker shaft retaining nuts. And you do want to use a torque wrench, as these are spec'ed at 10 lb-ft! That's not much, but the heads can't take much in that area...

I have found that some of my pushrods do not like to stay in the "cup" in their lifter. Sometimes it takes patience, and several tries, to get the pushrods to seat while getting the rocker arms and rocker shaft in place correctly.

--DD

[jurhip]

While you are in there, take a close look at your valve adjustment screws. These should be softer than the valve and therefore may show quite a bit of wear. Engines with high miles may show a wear groove on these screws and will result in an inaccurate valve clearance measurement. These are cheap too, just get the high quality ones with proper hardness. (or if you are in a hurry, you can re-profile these with a file and some fine grade emory cloth)

If you can pinpoint your leaking pushrod tube, I recommend replacing the seals on that one only. It is personal preference, but oil and dirt tends to accumulate around the opening in the block, especially with an oil leak. It is a hard area to get to with the engine in the car. You want to minimize the chance of dirt contaminating the seal (or getting in the engine). If a seal is not leaking and the tube is good, I see no reason to disturb it.

[73ess]

Thanks for the advice everyone. It wasn't mentioned, but I'm assuming that the oil should be drained prior to pulling out the pushrod tubes? Also, I'm assuming you hold the middle of the tube and push it out through the head, correct?

Oh, not sure of this, but I may have seen one of the tubes bent at it's mid point. What's the procedure for removal of the tube, if that is the case? I'd guess the head must be pulled in that case, correct?

[Dave at Pelican Parts]

You don't have to drain the oil, no more than you would have to for a valve adjust. There may be a little oil left in the tubes and heads, but they should be above the oil level in the crankcase so very little oil should be there.

Correct, you grab the middle of the tube and pull it outwards. You can just let it "hang" by the middle on the hole through the head--the suspension will definitely get in the way of pulling several of them straight out!

You do not need to remove the heads to deal with the pushrod tubes. Once you pull them out of the hole in the case, you can lower the inboard end and pull them toward the center of the car. They'll come out of the head with only a little argument--if you prefer, you can pull the outer O-ring off before you do this, so it should go through easier.

Some of the tubes, however, can come straight out.

--DD

[73ess]

Got it. Thanks much Dave!

[SGB]

I realize this thread is a week old, but for future searches, I want to point out that in some cases (mine, at least) the #2 intake pushrod tube will not come out all the way unless the engine is lowered about 1.5 inches. I changed the seals on that one with the tube halfway out, but still through the head. I started to try to persuade it, but could see scratches inside the head where the seal rides from where someone (prolly me) had tried too hard before to remove the tube. It worked ok. I used the captive tube as a sleeve to wrap 1000 grit sandpaper around to reduce those gouges. Unfortunately, the leak is not gone, only reduced. Which is another lesson- before you do a valve adjust, make sure you won't be removing the assembly again...

[bd1308]

when installing the tubes, twist as you push in.

This reduces the chance of having some grit slice your seal.

b

[Amphicar770]

Originally Posted by Dave at Pelican Parts

I suggest doing one cylinder's worth at a time, and setting that cylinder to TDC before starting the replacement. I have found that you get really badly skewed torque results if one of the valves is open when you try to torque the rocker shaft retaining nuts. And you do want to use a torque wrench, as these are spec'ed at 10 lb-ft! That's not much, but the heads can't take much in that area...

I have found that some of my pushrods do not like to stay in the "cup" in their lifter. Sometimes it takes patience, and several tries, to get the pushrods to seat while getting the rocker arms and rocker shaft in place correctly.

--DD

Dave,

Thanks for the tips. I have engine out and am about to tackle this. Mine are not leaking but want to get to the tins underneath and also figure I will powder coat the tubes. A couple of dumb questions.

TDC for setting valves is based on flywheel mark and / or rotor position. How do you determine TDC for the other three cylinders as you tackle each one?

Is there one retaining wire per cylinder or is it one per head? If the later, I presume you install both rocker shafts loosely so that you get the wire positioned properly before tightening?

Thanks.

[beatnavy]

Originally Posted by Amphicar770

Dave,
TDC for setting valves is based on flywheel mark and / or rotor position. How do you determine TDC for the other three cylinders as you tackle each one?

If I understand your question, then same way you do the valves (why would it be different?). 1 and 3 have the same TDC mark. 2 and 4 have the same (and it's 180 degrees out from 1 and 3). Best to make a mark on the flywheel as a "2/4 TDC" so you know (in conjunction with rotor position, as you pointed out).

Originally Posted by Amphicar770

Dave,
Is there one retaining wire per cylinder or is it one per head? If the later, I presume you install both rocker shafts loosely so that you get the wire positioned properly before tightening?

One per head. Yes, that would make sense, IIRC.

I've only done this once, and others will probably have better info. I didn't bother setting the cylinder to TDC when I attempted to put the rockers back on (bad idea) and I ended up having the spring washer fly off. It temporarily went to that other dimension things go when you lose them on the garage floor. It reappeared after hours of searching on top of the heat exchanger.

[TheCabinetmaker]

all good ideas. for best life use only Viton material Orings they last the longest. get a bright flash light and inspection mirror and examine each new install very carefully all around the circumference of the exterior of the tubes.
if the ring came out of the groove and got pinched it will leak and it is easy for them to get pinched. as others suggested install with a gentle twist motion and lube the rings and bores with oil to help them not get pinched. this is important. look under the motor with a light and mirror and examine all around the push rod tubes ends for signs of the oring being pinched. you can see this from the exterior of the tubes, but you need a small mirror to see the top of the tubes cause the motor is in the way. do this inspection before putting the rockers back in. also besure the bores in case and heads are spotless clean.

good luck

[avocadotom]

Do I have to put the pushrods into the tubes before fully installing them?

I'm having problems getting the pushrods go into the intake tubes on the 3/4 of my 1972 914.

I have it up on jack stands, but it doesn't necessarily look like the position of the engine will change substantially in relationship to the frame/suspension if I lower it. Then again, I could easily be wrong in that regard...

[RSOHC]

Please be advised that there are several sizes of push rod tube seals and that if you install the wrong seal the push rod tubes will continue to leak. The parts listing a automobile atlanta shows (1) a part number 021109349 for a seal that is red in color and has a dimension of 23.5 mm., (2) a part number of 021109349B for a seal that is green in color and has a dimension of 25.1 mm,(3) a part number of B021109349B for a seal that is black in color and is a large and made of viton.

Lauran

[Dave at Pelican Parts]

Originally Posted by avocadotom

Do I have to put the pushrods into the tubes before fully installing them?

I'm having problems getting the pushrods go into the intake tubes on the 3/4 of my 1972 914.

If you are doing this with the engine in the car, it will be impossible to get a couple of the pushrods in once the tubes are in place. The easiest thing to do would be to pull the tube back out of its location, then tilt the inboard end down until you can slide the pushrod up into it. Then swing it back into position and re-install.

Failing that, you can unhook all of the wiring and hoses and control cables and such, and unbolt and lower the engine down until you get a straight shot at putting the pushrod in. The up side there is that you have a lot more access to the area for anything else you were going to do at that point.

Originally Posted by RSOHC

Please be advised that there are several sizes of push rod tube seals and that if you install the wrong seal the push rod tubes will continue to leak.

Sort of. The inboard and outboard seals are different sizes. They are the same for almost all 914 engines. The exception is that some very early 1.7 engines have smaller outboard (I think) holes in the head, and therefore tubes with a smaller diameter, and therefore seals with a smaller diameter. Most of us don't have to worry about that, fortunately.


--DD

[RSOHC]

What is meant by "posts on the STF" in comment #5