Pushrod tube seal replacement, You guys help me out Options

[bd1308]

I pay over $600 at the "Porsche" place to get them replaced...perfect. I take them to the VW guy to get them replaced, $20 labor and parts and nada....i know the guy is cheap, this is why "I"want to do them myself. Somebody PLEASE tell me how to clean the ports up (where the seals go) cause the VW guy says that's what is needed and he can't do them real well.

[dmenche914]

To answer your question.

You need to clean the areas that seal, and also have the surrounding area very spotless also (this is just as important as the seal area)

You want to be sure the O-ring, which is pre-attached to the push rod tube does not pick up any dirt during installation.

You can have a lot of grit up under the cylinders, and tucked up in the upper nocks and crannies that are hidden above the tubes on both the case, and head ends.

For staters, before pulling the tubes from the motor, give the bottom of the motor a good cleaning with degreaser and hose it off, next using brushes and paint thinner and some spray carb cleaner, remove as much grit and dirt from all around the tube ends, get up between the tube and engine with the brush,

Once all is pretty clean pull the rockers. Be sure to mark rockers, and all other parts to assure they go back in the original location, do not mix them up. Like wise with the push rods, number them with a little masking tape "flag" wrapped around, and write on it, also identify which end goes to the lifters, make sure you put them back in the same location AND direction.

The tubes caan now be removed, some gental twisting with pliers on the outside usually works, but do not dent them if you intend to reuse them. If already dented, you might need to replace them, as a dent might cause rubbing inside on the push rod, it will leave marks if it does. So examin the push rods for wear marks, and see if it corresponds to a dent (a prior owner might have replaced a dented tube, but the wear mark on the rod will still be there, so confirm the dent matches the rods wear location before condemming the tube.)

Now you'll need to do the final cleaning, first stuff the lifter bores with paper towels to keep out dirt, carefully brush off, away from the bore any loose grit that may be near the bore that the paper towel might drag on into the bore when you put the towel in the bore. Cleanliness is very important, you do not want even one bit of grit in that bore!

Once the bores are sealed, clean with spray carb cleaner, and a brush / rag untill the entire area near the lifter bore, and the head are clean. Also you might have gotten some dirt in the rocker area in the head as you pulled out the tube, so inspect and clean it also.

Clean the old tubes if re-using and install the O-rings, Use Viton, else you will be doing this again much sooner. Viton resists the temperature, and engine chemicals much better than about any other rubber material.

Oil them O-rings with engine oil before putting them on the tubes, also oil the the tube ends. This will help prevent O-ring twisting or tearing.

Oil the O-ring surfaces on the lifter bores, and head end holes, and install the tubes, Since the lifter bore hole engages the bottom end of the O-ring last, you can get at it, and you will generally find you need to gently poke at the oiled O-ring to coach it in without it catching and tearing on the bore lip. A popsicle stick or other non-pointed stick can be used to help push the o-ring in. Make sure the O-ring does not get twisted.

Only after the o-ring is fully engages in the lifter bore end, can you gently tap with a soft hammer the tube from the head side, it should be pushed in until it stops, all the way. As the O-ring on the head side starts to engage the head, make sure it does not catch and tear.

Now re-assemble, putting parts back in the original location, and use a torque wrench on the nuts, with new lock washers. Now is also a very good time to inspect the adjuster tops for wear. If the adjuster tops are mushed flat, they need to be replaced. They should have a shallow dome shape, and they also need to hit the valve stem slightly off center. The dome shape, and the slightly off center contact give the valve a very slight rotation on each hit. This valve rotation reduces valve seat leakage, as it is sort of self lapping each time it rotates. Changing spacers on the rocker shaft allows adjustment to rocker spacing to get the adjuster screw slightly off dead center of the valve stem.

Do not use any sealants or glues on the O-ring seals, and remeber a twisted or torn Oring will likely leak. Viton costs a little more, but it is far superior, and with the labor to replace, well, you do the math. Cleanleness is important, you got the guts of the engine opened up to an area that tends to get road dirt and grit built up, and you will be bumping this tube thru the spaces and cannot allow any grit to ruin the seal, or worse the lifter bores.

So $600 or so might be worth it to some folks, depends on how much time you have, and desire to do this, it is dirty (the clean up part), you need a good place to work, have the right tools. You can shop around for a lower price, and I am sure their are places where it can be done cheaper, but you might end up without someone taking the time to do it right, so besure the shop or person you pick to do the work understands how to do it right, verses slapping it together fast and dirty. I have on several engines, upon dissassembly found torn or twisted O-rings, which could have only happened with a sloppy installation, I have seen big dents on top or side of the push rod tube, that had really rubbed down the push rod, since the dents where up where road debries could not have done them, I figure they were used, and re-installed with big dents rather than dented in use, again a sloppy job.