[FC] O-ring Replacement

[Ken Hand]

 OK guys and gals,

For all of you out there that have or are going to replace the push tube o-rings there are several ways to do this. There have been several replies already as to how some people do this like loosening the upper nuts as well as taking all the lower stud/nuts loose, one cylinder at a time and most any other way that you can creatively think of doing this.

Personally as a professional that used to do this trying to make a living, time is money. What I do as a total o-ring job is drain the oil since you will be getting debris in there any way. I then remove both rocker covers  and proceed to remove all the rocker arms and place them in the rocker cover, also removing the push rods and spinning them to see if any are bent and also placing them in the rocker cover so the ends sit on one end and will mostly drain out. I then cover the rocker cover so dirt will stay out and place it some place out of the way. I then remove all the lower stud nuts, be sure at this point that you DO NOT turn the engine, there is no need to. Then get a either a 9/16 or a 5/8 socket and tap pretty firmly using the socket on the end of the push rods. After doing this you may be able to gently use pliers or if you have a removal tool it makes for them to come out a lot easier. Once out remove the old remnants of o-rings and clean the push tubes and the oil pan while you are at it. This would be the perfect time to really clean the push tubes and ceramic paint the head end of the tubes to reduce oil heat induced by the exhaust stacks and manifolds. 

OH, I forgot to mention that the exhaust will have to come down as the muffler is in the way to remove the push rods most times. I remove the exhaust as a system leaving the manifolds attached to the pipe and muffler, especially if you have rusty studs and nuts on the manifold. Again, if you are so inclined, remove the manifolds and have them ceramic coated or at least ceramic paint them yourself. This reduces radiated heat significantly.

Back to the o-ring job, clean the head and the block as needed with what you feel is best but I generally use the Wal-Mart brand Super Tech carb cleaner and a brush. Becareful with this as it WILL remove paint. Then install only the outer o-rings on the tubes. You will need to lubricate the o-ring bores, I use a silicone grease, NOT RTV silicone. The dielectric grease works quite well for this and you can get it in small tubes. You only need to lube the lead-in angles and whatever else your finger may touch in the bore. Don't forget to do the block also. Slide in the push tubes and install the other o-rings, there will be a little silicone grease there, leave it. You should then be able to push the tube in place by hand with a little twisting motion. I put a finger on the head side and twist with the other while pushing and generally they slide right in with a push. Install the rocker stud o-rings and with your finger be a little liberal with the grease, yes, some will get on the stud. If needed, clean the stud-nuts, especially the outside that is against the o-ring. You should be able to start them all by hand after this. Once all the rocker studs are all run down get your torque wrench out and starting with the center nuts work in a pattern back and forth till all are tight. Re-torque 3-4 times or until all studs are at the same torque. When you do this you will see why I say this. I generally use 30-33 lbs. ft. of torque for the lower studs.

Here is another controversy. Do you need to keep the same rocker arm on the same valve? NO. Push rods? NO. If you have a very worn rocker arm it need to be replaced anyway. Check the rocker balls, if they have a wear ring on them they need to be replaced also. Once installed run the nuts down to where they are even with the top of the stud then proceed with my rocker adjustment procedure. Notice I didn't say anything about cleaning the rocker arms? If they were covered they should already be oily and clean. If you feel that there is more lube needed use a spray grease of some kind, it goes where needed and stays put. After the valves are adjusted put the rocker cover on, if the valves were adjusted properly you will not take it off again. Do the other side same as the first. With the oil pan clean be sure and pound the bolt holes back while the pan is supported on either side of the hole you are doing. I do use RTV silicone here but you only need a film not the large bead so it squeezes out everywhere. Put all the bolt in the pan and just snug the bolts so they hold the pan firmly in place. All you need for this is a nut driver not a ratchet or power tool. Let things set overnight if you are not in that big of a hurry as you are going to come back and tighten all the pan bolts again this time using your choice of tool. Tighten no more than where you see the gasket crush, just a little, or 20 lbs. in. Put oil in and fire it up. If you read my valve adjusting procedure this is the time you walk away for a while so you don't hear the valves clattering. When you come back all should be quiet.

I know that I have skipped a couple of steps but this is not meant to be a step by step directions. If you think you can handle this then you have the smarts to do what is needed in the right order.

If you are squeamish about taking all the lower studs loose then do just two at a time but it will take you 2-3 times as long. Here is a goal, target, reference for you, My flat rate on labor hrs. was 4 hrs for an average o-ring job and I could do it in less time than that. Painting and ceramic coating added time as does the waiting for the oil pan RTV.

I can't count the number of o-ring jobs I have done over the years and I have never had one come back because of a blown head gasket later.

 

Ken Hand
248-613-8586
www.corvairmechanic.com