Valve guide interferance

[neilca]

I had to weld up one of my exhaust ports since I was a bit over zealous with the porting tool. Now I need to install a new valve guide. The hole in the head measues 0.505" the valve guide is 0.515" . I think 0.010" of interferance is too much, just a gut feel. Anyone have an idea on what kind of interferance should be used?

Thanks,

neilca

[HawgRyder]

Sounds a bit big to me too.
Maybe .005" is closer....you can spin the guide using a drill and sand the OD with paper to reduce it.
Bob

[neilca]

I was thinking of using a 13mm reamer (0.5115") and clean up the hole. That would give me 0.0035" interferance. I have a cylinder head jig and a large mill so I can maintain the vector of the hole. What do you think Bob?

[cgarr]

2 to 3 thou is good. You can get oversize guides and turn them down to the correct interference. Use lube to avoid gulling.

[HawgRyder]

As Craig suggests...you are in the ball park for the sizes.
And by all means...heat the head (wife's oven?....LOL) before pushing in guide.
Bob

[neilca]

Craig,
Good call on the lube, what kind would you suggest, old oil, anti seize etc

Bob,

I usually freeze the guide with dry ice. My Mother's oven had been used inthe past to fit bearings into motorcycle cases. I am not sure I would chance that with my Wife's oven. LOL..then again if she were off shopping.....

[afterburn 549]

dont for get to check your head for sq and flat after the welding.....
Yes to the dry ice Listen to them scream !
yes to oven heat cycle a couple times B4 doing valve job after the guide install
(incase they move after heating up)

[cgarr]

Just a good penetration oil in the bore and the guide works well.