Valve guides

[ThomasDodd]

Question for the repar folk.
How are the valve guides attached to the valves on my '76 Olds 3V?
What would it take to change them?

How are nylon guides attached (the DEG contra I'm using has nylon guides)?

Would it be reasonable to put nylon guides on instead of the old brass style?

[Chuck(G)]

My recollection with the O-99's is that they're screwed in just like any other piston valve tuba of the era.

A well-fitted brass valve guide is quiet and lasts a long time. Nylon or delrin can be a bit quieter, but somtimes "fuzz" and slow down.

[Joe Baker]

Lexan is good 'n slippery. Anyone ever try making a valve guide out of it?
______________________________
Joe Baker, who needs to replace an old brass valve guide on his Conn 10J.

[Chuck(G)]

[quote="Joe Baker"]Lexan is good 'n slippery. Anyone ever try making a valve guide out of it?[\quote]

I don't think I've ever seen small hardware made out of Lexan. I wonder if it's a torsional strength issue...

[ThomasDodd]

My recollection with the O-99's is that they're screwed in just like any other piston valve tuba of the era.

So, grab one with some pliers, and turn to the left?

Where might I find replacements then? The have a lot of slop right now. While worn, they don't leak, but rotate and make noise. Fixing that, until I get them replated, would be nice.

I'm trying to get a 4v horn I found. Beat up, bottom bow loose, lead pipe flat, missing valve stems, and missing slide, but a nice looking bell and 4 valves. Should sit right in. So I'm waiting to see how that pans out before doing more to the current horn.

[Chuck(G)]

My recollection with the O-99's is that they're screwed in just like any other piston valve tuba of the era.

So, grab one with some pliers, and turn to the left?

Where might I find replacements then? The have a lot of slop right now. While worn, they don't leak, but rotate and make noise. Fixing that, until I get them replated, would be nice.

I'm trying to get a 4v horn I found. Beat up, bottom bow loose, lead pipe flat, missing valve stems, and missing slide, but a nice looking bell and 4 valves. Should sit right in. So I'm waiting to see how that pans out before doing more to the current horn.

I like to use a very small crescent wrench to unseat valve guides, rather than pliers. That way, yoiu don't chew the guide or piston up if your grip slips.

Ferree's Tools will sell you a whole bunch of guides for cheap (I think they come a dozen to the bag). They look like ultra-wide head screws, complete with a screwdriver slot. You shape them off the horn (Ferree's also sells a cute little holder). It might not be a bad idea to invest in a 3-48 tap and drill, in case you break one of these things off (Ferree's sells that too).

[jlbreyer]

Just to be on the safe side, if you buy a 3-48 tap, you might want to buy more than one. Since I'm clumsy, and the taps are brittle, I find that I often break one or two, even if I'm tapping 1/4 - 20 screw holes. If you are a careful kind of guy, you might get by with only one, but my experience is that I'm happier if I buy them by sixes.

Good luck

AMEN, Brother!

That extra quarter turn will snap it off almost every time.

[Chuck(G)]

When I'm using a small tap, if I can, I clamp the workpiece in the drill press vise and the tap in the drill press chuck and rotate the chuck by hand. The arrangement keeps the tap straight and also limits the amount of force I can apply.

Kerosene or valve oil is a good lubricant for tapping brass, BTW. Steel requires a regular cutting oil, however. I've never had a lot of luck with tapping wax, though.

[Dan Schultz]

A well-fitted brass valve guide is quiet and lasts a long time.

I concur. A well-fitted brass guide that allows for barely more that a film of lubrication is the best way to go. Valve guide noise is caused by the piston being rotated back and forth when the piston moves up and down. The spring will try to make the piston spin one direction on the 'down' stroke and will reverse on the 'up' stroke. Just a slight clearance between the guide and the slot will not allow this rotary action to gain speed and softens the impact. A quick test is to try to twist your pistons back and forth. If you can hear a 'click', chances are your guides are too loose and need to be replaced. Usually just replacing the guides will do the trick. Most of the wear will occur on the guide itself since it has less surface area that the slot. In extreme cases, the slot will be severly worn and may need to be 'straightened up' before fitting the new quides.

[ThomasDodd]

A quick test is to try to twist your pistons back and forth. If you can hear a 'click', chances are your guides are too loose and need to be replaced.

Exactly my symptoms.
They don't stick, or leak (If I move the slides then depress the valve you hear a pop). But do have a lot of rotational play.

Any hints on fitting new guides?
Do you guy use a bench grinder? What size/grit wheel?

What would/should it cost to have this done?
Either a job price, or a number of hours.
I'd rather somone who know what they are doiung do it, but there are no shops near me. Closest I really trust is Memphis, 3 hours away, but there is a place in Meridian, 2 hours.
(both are highway times, so 100 - 140 miles each way)

-Thomas

[Dan Schultz]

Any hints on fitting new guides?
Do you guy use a bench grinder? What size/grit wheel?
What would/should it cost to have this done?

The guides I use come with a round head. Once they are screwed in, they have to be marked and trimmed. I don't use a grinder. A small file will remove material as quickly as you need to.

I don't know how the cost runs in other parts of the World but in my little shop here in Southern Indiana it's usually about $20 per guide. additional work on the guide slot is extry.