Another 355 Valve Guide question

Your machinist replacing the guides will know if oversize are needed or not. Typically oversize are only needed if the hole in which the guide is pressed to doesn't have correct offset for press fitting (.0015-.002).

 

Your not getting many responses due to your title, most people on here are tired of being asked what the problem is with valve guides so a thread with a title like yours may get over looked. Since you are actually asking about acquiring the correct valve guides I can point you to a source that will save you a bunch of money. Here you go:
http://www.ferrarichat.com/forum/142820707-post6.html

 

Why are you supplying the machine shop with parts? That's like taking your own steak to the restaurant.

If it is the right machine shop he knows what to get and where to get it.

 

Perhaps he is trying to avoid a markup on parts....

 

who can blame a person right? last I heard Ferrari wanted some $48 per guide?

 

Every business, yours included needs to take in x dollars per day or per job.

Pay it in parts or labor, your choice, Just tell me what column to put it in.

You supply parts and the job goes upside down he says its your parts, you say it's his labor.

He supplies everything he owns it.

My machine shop supplies all the parts. He gets them a lot cheaper than I ever could. He buys thousands of guides and valves a year. He buys them, makes a few buck and I still save money. The guys who make valves and guides care about his business because he is a big customer. They don't give a **** about me or you. We are going to pay their highest price and be put on their longest waiting list.

Any other way is asking for trouble and a false economy.

 

You want to buy the guides from Ferrari go right ahead. I think that is a poor decision too.

 

Speaking of guides, all the 'mill' manufacturers of guides as I now call them (especially Ferrari, who I've never bought guides from anyway) have a product that is made in too big a rush. I notice I have to toss 1 of every 8 or so because the clearance is tapered at the nose with incorrect clearance before any reaming is even taking place. This happens due to the guide being drilled out too quickly on the lathe causing more material to be removed from the nose of the guide than the rest of the guide. Massively frustrating. So from now on, I'm using CHE Precision to make guides. They knocked out a set for me two months ago and each one was perfection and they were still cheaper than whatever ferrari is slinging.

 

Brian, did I say I agree? In my business, we only take customer supplied material on rare occations and if we do, we don't warrenty and scrap responsibility.

 

Misunderstood but I agree with you.

 

Would not guides be made on an automatic screw machine (am I dating myself)?? With computer control it would seem pretty easy to knock these out, regardless of material, with high precision.

 

If the bits aren't sharp, properly cooled, and drilled slowly then clearances will be off, so I'm told anyway. I couldn't make one myself if my life depended on it, but I do know when they're flat wrong.

 

I had a shop that was terrific but so OCD it was hard to ever get them to finish.
As a preface Ferrari heads have often had OE guides made so crooked that the seats were ground off center to align with guide center. In many cases that either left very little seat or too thin a shim when done if conventional run of the mill guide replacement methods were used. He ordered undersized guides, indexed the head in the machine by the existing seat and bored the guide to align with that. Then he could just gently reshape the seat and was done. Very nice but like I said too much trouble getting the job out of the shop.

In Colombo motors the guides were so out of concentric you could see it by eye.

 

I can't speak for Ferrari, but when working at GM, guides (the ones I know of) are powered metal and they are hardened and the outside diameter is ground. Once pressed in the head, the ID needs to be sized.

 

That's a good way to do it and what a lot of the good shops are doing.

 

Not that simple. Fast or slow drilling has nothing to do with it. Proper speeds and feeds, coolant fed drills, the proper drill geometry are all a factor. And guides get heat treated which creates distortion.

 

Now that you mention it. Yes, then need to be reamed once in the head. I knew that, once upon a time, long, long ago.

 

makes sense. kind thanks!

 

Hello John, I am not a machinist nor do I make valve guides, but I run a plant that has 2 CNC twin spindle Swiss turning centers, aka screw machines. One is a Citizen L20 and the other is a Star SR20. Valve guides would be very easy to produce on either machine, and the main advantage would just be the elimination of the second OP setup. As you probably already know, other than the second OP setup, a nice CNC lathe could do the work equally well.

Getting back to the original discussion topic, I'm with Rifledriver on this one. Bringing in your own valve guides to the shop doing the work is a bad idea. Not sure if that is what the OP has in mind since his post did not go into that level of detail, but it seems like that was the intent.

 

Swiss turn machines are not required Greg. Swiss is for long, slendar parts. The second op you mention is the sub spindle. Many lathes has sub spindles and tbey don't need to be swiss turn machines. The main difference of a swiss is that the z axis is the stock being pushed thru the guide bushing instead of the turret moving along the z axis.

But as I mentioned prior, after heat treat, OD grinding is required.

Also, swiss machines are very different than screw machines.

 

LOL Dave, we've been calling them screw machines since we bought them! Probably because we have the thread whirling tools. One of the parts we make on the Swiss machines is a parking brake guide bushing, similar in dimensions to the valve guide being discussed. Just got me thinking that this would be an easy part for us to make. We do OD grinding on small pistons, and heat treat on drive pins. Weird that we do all the OPS required to make a valve guide, just on different parts.