Replacing Valve Guides

by Scott Suhring

While rebuilding my ’59 TR3A engine, the machine shop that boiled and tested the head for straightness recommended that the exhaust valve guides be replaced. Reading the manual, it instructs you to lay the head on your bench, gasket side down, and using an appropriate drift, drive the guide down through the head. Well, this does not work well for an engine that is over 40 years old and the guides are quite set in their sleeves. Sitting and thinking about this for a while, I came to the conclusion that I needed a way to apply a good amount of force to the sleeve while maintaining the vertical alignment so as not to break the top of the sleeve that is exposed above the head (don’t ask how I know).

The solution was the purchase of 2 bolts: one that was the same size as the inner diameter of the sleeve and the other with the same or near to same outer diameter of the sleeve (in my case, 3/8" and 1/2"). The length of the bolt is not critical, but I used 4" bolts. Next, cut off the threaded part of the bolt so you only have the smooth shaft. I would recommend filing the end so that it is level for the bolt used for tapping down the outer diameter. Use these steps:

  1. Drop the inner diameter bolt into the sleeve and using a hammer, drive the sleeve down until the top is flush with the head.
  2. Then use the outer diameter bolt to drive the sleeve the rest of the way out of the head. What was nice about this is that using the head of the bolt as the point of driving down the sleeve with the shaft of the bolt inside the sleeve assured that the blows were true and forced the sleeve downward without any movement right or left. The head casing provided the same support when finishing the job using the outer diameter bolt, with the head of the bolt providing a good striking surface.
  3. Installing the new valve sleeve was just as easy, using the inner diameter bolt to drive down the sleeve into the head (be sure to measure the distance the sleeve protrudes from the spring seat face so that the new sleeve is the same distance).

Worked like a charm!


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