Valve guides

[drdre]

Hello: I'm having my heads redone (Poly 318) and I got a call from the machine shop tooday about my valve guides (I have bronze guides) he wanted to know about the threaded part of the guide and if it would make contact with the retainer and what it's purpose is. I'm confused considering this is my first time doing this but I'm thinking that this is not a problem. Any information will be greatly appreciated.

[biggerhammer]

let me get this straight, the machine shop called YOU and wanted to know how to install bronze guides?
some machine shop,
there is a set heighth for the guide boss to protrude above the spring seat or it will interfere with the valve spring retainer.
that means the shop will probably not check the valve stem hieght, or spring installed hieght, or anything like that,the threaded part he is most likely refering to is the knurl inside the guide which is there to retain oil for lubricity, by the way, the knurl should stop about a 1/4" from one end of the guide, that end goes toward the combustion chamber.
make sure he finish reams it with a reamer specifically made to ream bronze guides, or you take a chance of seizing a valve at speed and really messing things up

[sanborn]

Your machinist may be asking about the threads on the outside of a solid bronze valve guide. The threads on the outside helps to keep the Teflon type valve seal in place. A lot of local type automotive machinsts don't know much about the solid bronze valve guide.

[drdre]

Thanks biggerhammer and sanborn for the info I'll be going by the machine shop today to see what's really going on, sounds like I may have to find another machine shop. But I've also been told that these guides are for aluminum heads only is this true.

Thanks

Drdre

[biggerhammer]

they don't use a solid bronze, they are actually sintered bronze, have another metal in the alloy, otherwise the bronze wouldn't hold up. as far as the threads on the exterior of the guide, some applications have a teflon seal that fits on tightly and the threads ease installation a little bit

[challenger340]

Some bronze guides have a knurling on the top to help hold the seal as others have mentioned. I have only seen this type of guide in aftermarket heads. I would assume the shop is worried about your retainer to seal clearance. Were they asking you how much lift your cam had so they could check it?