Hello HAMBland, I, like many of you, have many, many engines and heads lying around. Lately, I've come into for once having lots of time on my hands (my project lost funding at the university and my position was eliminated... sigh). Dave Vizard did an excellent job writing "How to rebuild your SBC", and in it he describes options for refurbishing valve guides. I feel that it would be a good idea for me to learn to do this (since I have so many heads that need it) with thin walled valve guide inserts. There is a page that illustrates the process with great pictures, but more intriguing is the fact that it appears to only require a low speed air drill (and time and patience and some minor machining skills). Of course, that was in the mid seventies... the only tooling I have been able to find online is for dedicated valve guide machines-- much more elaborate and expensive than the drill Vizard was using. My question is: Can any of you provide a source for the reamer he is using to initially oversize the valve guide for the insert? It has a bare pilot with a threaded guide in front of the reaming flutes, which is different than the reamers I see online from Goodson's and Cylinder Head Supply. Also, for installing the liners, Vizard uses an installation mandrel with a brass hammer... the installation tools I see online require an air hammer. Any help would be greatly appreciated-- either a source or even the correct name for the tools. Specifically I am looking for the reamer with shown in the photograph in the top right of the first page. Thanks HAMBsters! acosta Oh, I also plan to invest in Neway cutters so I can do a three angle valve job and put fresh faces on valves... hopefully in the next couple of months I can put up a thread that documents complete refurbishing of sbc heads in a home shop without dedicated equipment.
There are a couple of ways you can go, bronze guide liner kits, or cast iron guides. look on ebay in Ebay motors. type in K-line, or goodson. You can buy bronze guide liner (kits) comes with the reamers and swedge tools. you purchase the size you need, 5/16, 11/32, 3/8. for sbc you need 11/32 (If I remember correctly) you will also need a speed reducer for your drill. You can also purchase the kits in meteric sizes. do an internet search on goodson and K-line for more info. Hope this helps.
I have done a ton of these, but always with a guide and seat machine. Let me explain my process and why I think it will be tough with a machine. On say chevy heads, the original guide are just the cast iron head material. When the guides wear they take on a egg shape. This is because the pressure of the rocker pushing them to one side(exhaust side).When you drill,bore ,ream ,these out to fit the bronzewall guides it's darn near impossible to bore them in the same plane as they were when new. The oblong worn guide draws the boring tool towards the worn part .You have to have a machine with enough spindle strenght to over come this and bore the hole exactly as it was originally. You can make a pilot to fit the seat but it's still difficult to hold the location accurate. Ok if you bore the hole with a hand held drill and it wanders 50 thousands to one side you have trouble. When attempting to use that hole (which would now have a new guide in it) as a pilot for the valve grinding stone,(or carbide cutter)you would need to cut an extra 50 thousands off of one side of the seat to be in line with your guide.In taking this extra off the Seat you will also be lowering the seat. In almost all engines ,sinking the valves further down in the seats is a power loss. Now if your heads have already had replaceable guide installed, and they have not worn thru to the head material ,you can simply take a muffer type gun with a bit machined the same size as the guide and push them out. Installing new ones is just as easy ,just push them in with the same tool. AS long as the original guide was not damaged or worn you are in business. Then you need a reamer the valve stem size and your ready to grind the valves. Now there are different ways to get the job done, if you need or want to replace the valves just buy them with over size stems and then you are out to virgin material in the head and no guides are needed. If you want to do the research you can buy smaller stem valves and then just buy the guides with the correct id for the new valves,but the od for the original guides,therefore no boring is required.I will say if the guides are bored off any tolerance it with be a bitch to get the valve job right. Hope this helps
That was a good bit of info JoeCool. My father in-law has a valve and seat grinder so I just send the heads out for guides then grind the valves at his place. Sounds like a pretty major piece of machinery would be needed to bore an "egged" guide straight. Good to know. Thanks
Joecool, you forgot to mention knurlizing the guides. We use to run a tool down the guide that left a "thread" like trail inside the guide that swells the guide. Then you run the proper size reamer to size it to the valve stem. The tool would guide off the upper portion of the stem and run straight, even if the guide was slightly egg shaped. On a guide that was worn you would just put in a larger roller to make the thread deeper.
Man, I love the HAMB. It's only been a few hours, and already you guys are offering suggestions. Thanks. Joe Cool-- thank you for such a great explanation of why what I am trying to do is difficult (and probably a technique that has been essentially phased out). Also, thanks for walking me through the process you use-- that helped me to see how guide replacement has evolved. It makes sense that a hand held drill increases the possibility of the reaming drifting off the original axis, and, as you explained, having consequences affecting the new position of the seat. You mentioned that the loads on the valve transmitted through the rocker lead to an egg shape... I can see how that leads to the reaming axis drifting-- but how asymmetric is the guide wear along the major axis? That is, how much does the guide resemble a very pointy egg versus an oval? (For those of you with furrowed brows, I am quite the geek-- I know). I am curious because I think the ream design might be able to accommodate this if the wear is more like an oval than an egg. The reamer I am searching for is the one pictured in the top right photograph of the first page. The end of this reamer is purely a guide, followed by a tap, leading into the actual flutes of the reamer. I can visualize that the guide roughly positions the axis of the reamer to match that of the existing guide, while the tap (with its leading cutters being tapered) centers the reamer while pulling it through the guide at a steady rate (depth into the guide per revolution will be constant... perhaps reducing off- axis walking?). If the guide wear is an oval, I think there is a good chance the reaming axis will match the original axis within a few thousandths... while on the other hand, if the guide wear is like an egg (a very point egg), I see that the two axis will be mismatched as you described. My friends find it ironic: I am like a broken record, always insisting it is just easier to go out and get the right tool for the job... and here I am trying to use resurrect a forty year old method. In this case, though, I rely on the fact that these tools I am looking for and the method for using them was good enough to win Dave Vizard's endorsement in the past, so surely they can produce good enough results for getting me around town. The real way to know for sure is for me to find these tools, and use a pair of heads as a test case. Hell. I could even get some "expendable" ones from the Mega U Pull down the street... Again, Thanks for the replies, Joe Cool-- I'm interested to know what you think. acosta
I used to have a setup that looked like a big c-clamp. On the seat side of the guide it had a cone to center on the valve seat, and the other side it used the spring pad. It didn't work very good because you were using worn guides and seats to piolet your core drill and reamer. On the guide and seat machine you can level off a good guide and run right through the all of the guides on the head. And they come out straight. How many guides do you plan on doing? The tools are expensive. The bronze guides cut hard and take a toll on reamers. Some things are just not economical to do at home.
Hi Dyce, I can easily see myself doing the guides on 7 or 8 sets of my own heads... and maybe another 5 or 6 within the next year (for family and dear friends). It's really ridiculous the parts I, just one skinny guy, have managed to amass... but my girlfriend thinks it's cute . I admit that not all of the heads I would do guides on would go right into service (we all love the feeling of having parts ready to go on the shelf, right?), but that's how much practice I could immediately get. Once the tools are acquired, the guides per head are, um, about $10? Maybe a new reamer every 10 or so heads? I am looking at this more along the lines of being 36 and wondering if this is something that I could add to my skill set. And for me, this hobby/affliction (the rust in my veins) is equivalent to other guys watching tv or drinking beer or following a team (none of which I do)-- man, I can't get enough! Over the years I know it would pay off not only with stuff I do for me, but also the other rodders around here. But you are right, if it turns out that the only options is one of those cutting tables, that might be something beyond reason. Still crossing my fingers somebody can lead me to those reamers pictured-- acosta
yeah, you really need a whole setup like jooecool said......you can`t just drill those guides and get them straight.......and if you are gonna do guides you`ll wanna do the seats too.......machine required.....look around, they come up reasonable priced pretty often....
Goodson, a machinest supply place for automotive work, has the kits for thinwall and spiral types.with the long nose reamers. Whether they can do an on-axis job all the way is another thing, and I sure don't know. Vizard, though, is a first class builder.
To be honest sir, you confused the heck out of me.Someone with more knowledge than me will have to jump in. As far as the knurling, a little wheel on a shaft is spun and just literally buggers up the hole. The problem is there is very little metal touching the valve stem when you get done. Very little support ,In my opinion the knurling thing was when engines ran 20,000 miles and then needed rebuilt or used car dealers that were only interested in a quick sale. I spent a lot of time in a machine shop but always managed to remind myself how little I really knew.Valve springs with high pressures will wear guides a lot faster,when the guides get worn the valves have a hard time registering correctly on the the seats. Imagine 5 or 6 thousand rpm how fast they must hit and seal. If you were to have someone bore the guides with the proper machine you could easily do the rest. Maybe that would not be a large cost ,but would satisfy your need to finish the job and save some $$. best of luck.
Amen , not to mention he has a talent for describing technical processes in a very easily understood language. Ron Covell is good at it, too. Ha, Ha, Ha! yeah... unlike Vizard, I am still working on describing technical processes in an easily understood language. If it's worth anything, I understood completely what you wrote and it gave me new insight into the process of preparing guides for inserts. That is an excellent idea... and could be a way around the problem. you're right, I could do the rest, and it would keep my out of pocket reasonably low per head... Thanks. Thanks to everyone sharing their opinion-- it is all very helpful. acosta
Test to see if the lengthy piloting can actually do the job of controlling things as the worn area is cut might be pretty easy...do one, then blue the seat and rotate the valve to see contact. Contact pattern should go to abolute hell in a hurry if the guide cut tilted. I have one of the spiral kits from Goodson, but have never tried it.
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