Valve guide replacement

JRV,
I've got to replace the valve guides on a pair of Daytona heads. Any tips or suggestions other than local heat and driving them out?

Hi Bill,

I was taught to drill the guide itself with a step drill 75% of the lenght of the guide (basically 90% boss depth) first leaving only about .20 -.30 thousanths wall thickness left. Then heat, and press or drive out with a drift. The drift sits on the internal ledge left by the under drilling.

By drilling all the center material out of the guides it releases the compression fit and prevents the guide from expanding the boss on it's way out. It is important to drill striaght to prevent going into the boss material.

The best type drill bits for this operation have a stepped tip to aid in alignment and to keep things centered to avoid going thru the guide wall as the cut coes deeper. It's nice to start on the seat side so the guide is removed out the way they go in. But sometimes on well worn guides the drill bit won't center well enogh for the long cut.

If you need a better explanation of the procedure we can talk on the phone.

Regards, JRV

JRV,
Very good idea. We'll give it a try. I appreciate the info.
Bill

would like information on valve guide wear on early 355s have 95 355 with one low cylinder

Richard, welcome.

what would you like to know?

valve guide problems on 355's are a common problem.

the 'fix' is to pull the head on the side with the low cylinder and determine cause...if it's a guide issue then the update to sintered steel guides is in order. It's prudent to do both heads at the same time to avoid a costly second trip inside the engine later on.