How to Replace the Push Rod Tubes in any Chevy Corvair
Sooner or later, you will have to replace the pushrod tubes and their O-rings. If you don't, the oil from the block and head will drip past the old O-rings (rubber seals) and will fall on the ground or onto the exhaust, creating the famous "Corvair smell": burning oil.
You either do this replacement yourself, or pay someone $600 to do it, if you can find somebody. The parts themselves are not more than $20. The time is usually 3-6 hours for the entire engine (12 push rod tubes).
If you have never done this, or have a fear about working on mechanical things, thinking that you might make matters even worse, be assured, I was the same way. I still am about some things. A good way to get over this is simply to use the steps listed below and have faith in yourself. Another way, which I first did, was to hire a mechanic who came to my home for the repair. The mechanic needs to be experienced with 60s cars in general and hopefully has some experience with Corvairs or VWs, although, it is NOT absolutely necessary.
Show the mechanic your LM Corvair Chassis manual regarding pushrod tubes. If the mechanic is any good, he will know how to proceed. What I did as the mechanic was doing the procedure was to watch him, take notes and ask questions. Treat him as a mentor or instructor because you are paying him!
Step by Step: Changing Pushrod Tubes and O-Rings
Each cylinder has two pushrods from the head (where you took off the valve cover) to the block. When changing the pushrod tubes and O-rings, you can do so on a specific cylinder that needs it, or on all of the cylinders on one side of the engine. If you target only one cylinder, you will need re-adjust the valves for that specific cylinder when done.
1. Make a small box with holes for each cylinder you will change and label them on the box, i.e., Cyl. 1. As you remove the rocker arm and pushrod from a cylinder, keep these together and sorted by the cylinder they were removed from. They will be reinstalled into the same cylinder. Each cylinder will have:
- 2 pushrod tubes (left and right) pushrod tubes,
- 2 pushrods (left and right)
- 2 rocker arms (left and right)
- 2 rocker arm studs
- 1 guideplate
Put the screws you remove into a mug or cup.
2. Remove the Lower Shroud. This has the attached rear door thermostat bellow and is held on by a few screws. This shroud is for air flow and road surface protection. Once dropped, you can either disconnect the attached thermostat or leave it attached. If attached, the shroud will drop partially to the ground. This may be enough for you. If not, disconnect the thermostat and remove it from the work area. You can now see the pushrod tubes.
3. Remove the valve cover. This may be oily, so use a ground cover. When removed, you see the lifter springs, rocker arm studs, and guideplates for the cylinders. You will see three groups of two rocker arm studs for each engine head. Each pair has a guideplate.
4. Remove the two rocker arm studs. As you do, you may notice a stuck small O-Ring. Remove it, it shouldn’t be there. Remove only one pair of studs at a time to prevent any disruption of the Head Gasket. Small O-rings are installed on the inside of each stud, or in the small indentation on the cylinder head.
The long lower head stud is not supposed to come out along with the rocker arm stud, but sometimes it does. If it does, you must (when done) re-install this exactly as it came out.
5. Remove the guideplate.
6. Remove the pushrods by pulling them out by hand. Check them against a flat surface for any bending or damaged ends caused by tapping.
7. Remove a pushrod tube using pliers with a towel wrap to prevent damage. Grip the tube near the engine block and jerk\twist with strength until it dislodges from the block. Some strength is required. You can remove them without removing the exhaust pipe.
8. Remove the O-ring closest to the engine block, using a needle tool like an ice pick or tweezers.
9. Slide the tube out through the head and remove the remaining O-ring from the other end. Look for bad dents or holes in the tube. If found, replace with a new tube. Small dents are OK. Inspect the area where the O-rings are installed. Make sure the area the ring fits into is clean and smooth, with no scratches. Apply some oil or grease around the O-ring.
10. Install a new O-ring on the LONG WIDE end (this goes into the head, where the valve cover is).
11. Insert the tube back into the Head and almost to the Engine block. Now, install another O-ring at the SHORT NARROW end. Apply some oil or grease around the O-ring (this will make it easy to tap into the grooves the O-ring locks into).
12. Position and center the tube on the block. Use a 9\16” deep socket. Place it at the tube opening on the other end (the head), and tap it with a hammer lightly. The tube should easily slide into the block and head hole.
13. Verify that you cannot turn or move the tube at all. The fit should be tight. If not, pull it out again and make sure the O-ring is seated correctly. Use steps 8-13 again on the other pushrod tube.
14. With both tubes correctly installed, install the smaller O-rings into the small indentation on the head or fit it on the inside of the rocker arm stud beneath the guideplate.
15. Position the guideplate over the two open holes that hold the rocker arm studs. Make sure the “U” on the guideplate is visible and not upside down.
16. Install the rocker arm studs one at a time by inserting it through the Guideplate and tightening to the block. Tighten to 30-35lbs.
17. Insert each pushrod through the Guideplate. Make sure the oil hole at one end of the pushrod is visible after inserted (if not, it is inserted backwards). Insert it until there is a snug fit or till there is a slight grab when pulling it out.
18. Install the rocker arms. Make sure the round portion of the pushrod fits into the cavity of the rocker arm. The small oil hole should face the head. It does NOT need to be aimed at the small opening of the rocker arm.
The pushrod spins and spits out oil when the engine is running, providing oil within the head. Many mechanics and others wrongly think that the oil hole must face the gap, but it does not matter, because it spins!
Repeat steps 4-18 if you are doing more than one cylinder, or 7-18 if you have elected to do one side of the engine.
How to Restore Your Corvair
- Corvair for the Not So Mechanically Inclined, by Perry Moore
A Corvair for Dummies book! If you are under 40, odds are you have never heard or seen a Corvair! Learn how to repair the most common restoration issues for the Chevrolet Corvair, 1965-69.