MTFCA Forum

I've got a pretty extensive set of reamers left by a relative years ago.

When taking valves and tappets 0.015 oversized how much larger is the reamer itself compared to the valve or tappet?

If installing a 0.327 stem valve, would you use a .3275 reamer or a .328? Same for the tappets.

Would you use a reamer that is 0.0005 or 0.001 oversized.

Brad

Brad:
I go with .002 clearance on valve guides or tappets in model T ….0005 or even .001 would be too tight and likely seize ,especially on the exhaust valves … hope this helps ...always an optimist...gene french

You need to use a piloted reamer, not a plain reamer.

Agree with Adam. Also use a spiral fluted reamer or dont be surprised if your finish hole is way over size. Seems like I've made every mistske in the book one time or another

Thanks for the info!

Brad

Don’t ever turn the reamer backwards, counter clockwise, as this will dull that puppy almost instantly. Use lots of cutting oil. And while I’m on the pulpit, tell your friends and loved ones how lucky you are to have them in your life.

I agree with Bob on not turning them backwards, plus you want to keep them "cutting" while rotating. If done by hand in the car using long support pilots, use enough pressure on the tap wrench to keep cutting with each rotation. The hole will be to size that way...if casually turned and little material removed, there will be many more revolutions of the cutter than necessary and it will burnish as it goes in and the hole will be slightly larger than intended. Also with Cast Iron, no cutting fluid is called for...the carbon in the metal is sufficient lube for the cutting edges. Pretty much any other metal, then yes, cutting fluid is definitely called for.