69 400 engine runs smooth, has good even compression on all cylinders but drawing oil by the valve guide on number 3. Has anyone been successful installing oil seals without removing the heads or engine from the car? Thanks

 

Yes, it is a common practice. Put compressed air into the cylinder through the spark plug hole to keep the valve closed, remove the spring, and replace the seals.

 

... Or, if you're a history buff, feed rope into the cylinder until it's full, then turn the crank until the piston pushes the rope against the valves, and proceed to remove the springs.


- Eric

 

Thanks

 

X2, that's worked for me before. Same deal for torquing down crankshaft balancer bolt. Handy trick.

 

... And good in an emergency at the side of the road.

- Eric

 

All good suggestions, but I can't help wondering why the problem exists exclusively on #3. If the rest are similar you may want to change them all.

 

I had planned to replace all of them. Number 8 is gonna be fun with a/c car.

 

When replacing the seals wiggle the valve stems to look for excessive play from a worn guide. Does the spark plug have oil build-up aimed toward the valve in question or is it evenly distributed around the plug?

If the seal does not fix the problem there may be a clogged oil scraper ring on that cylinder that would not show up during a compression test. Try soaking it with solvent through the spark plug hole. Don't crank the engine over with the solvent in the cylinder unless the spark plug is out and the coil is disconnected.

For #8 use a lever/arm type spring compressor.