This should be of some interest..
Those of us that grew up using stones for seats know the finer things in life are not predetermined by a cutter.
We users of stones are thought of by some as caveman with chisels!
I have always thought cutters were for cookie-cutter shops pumping out the fast work.'
Guess what?
In the porting shops behind the scenes guess what still lurks there?
Yup, the old school way of doing things.
I asked a couple of Porters not too long ago about their religion and all the hype with the new and better ways.
To sum it up they explained, "the big dollar cutters are made for large shops run by people that know how to push the buttons."
The person running it may actually know very little about throat percentages or different seat angles.
In fact, he probably has not ever heard of any other seat besides a 45.
When custom work required, the heads may or might be touched by a great Serdi machine or equivalent, but then the heads are hustled to the backrooms" where the true artist lurks.
Interesting I thought as I have always preferred the stones, slow yes, but much more custom.
They do suit my style.
A shop is not locked into making one cookie cutter seat with a Serdi. Serdi will make a cutter with any combination of angles and radii the user wants. Serdi also makes single angle cutters, single angle with one radius cutters etc. A highly skilled Serdi operator can produce highly concentric seats with a great finish, and accurately repeatable valve heights.
In my shop I have used Neway cutters, stones Sunnen machine and a Serdi. Sunnen is great for speed, but in my experience I get better concentricity with my Serdi.
The shop that does my heavy diesel heads ( non automotive) recently got a Serdi machine very impressive!!!
I bought my Serdi machine in 1998, after years with the stones, and Neway cutters.. For the volume of head work I do, I wouldn't be able to do it with the previous stuff I used. All my cutters are designed by me, and the time it takes to do seats, standard or custom, can be done in a tenth of the time compared to the old way. Easy to equalize installed height, cut custom seats, replace seats, etc. :up:
John
:up: :up:
I have Neways, Stones, and full tooling including angle tilt fixture to do form tool seats on a mill. Then came Serdi. I rarely look back. The mill i could do perfect valve jobs but 4 seats took an hour and major stress. The Serdi takes a third of that or less and since I have designed my own cutters that help too. Better product quality, better productivity, why not.
I suppose if I had lots of heads to do I would consider one?
But to the point, as I think it has been missed-
The stones are still in use behind the scenes.
Archaic art mixed with romancing the seats I suppose.
I have seen guys "F" up heads with stones. They don't true them up often enough, plus the seats are high on one valve, low on the other. The nice thing with a Serdi the seats are all the same, every time. Same height, same diameter, same angle. Sure speeds things up when you do many heads.
Quote from: jsachs1 on February 08, 2021, 01:59:29 PM
I bought my Serdi machine in 1998, after years with the stones, and Neway cutters.. For the volume of head work I do, I wouldn't be able to do it with the previous stuff I used. All my cutters are designed by me, and the time it takes to do seats, standard or custom, can be done in a tenth of the time compared to the old way. Easy to equalize installed height, cut custom seats, replace seats, etc. :up:
John
I bought mine new in 98 as well. Very happy with it. :up:
Anybody that uses stones after cutting seats on a Serdi doesn't know how to cut seats properly. Same with lapping. Learn how to do it right on the Serdi & throw all the other stuff away.
I thought Newen was the way to go. You can program it to cut custom seat any way you want, you don't have to have custom cutter made. It don't matter what you have to cut the seat with you can screw them up.
Not that I use them a lot but the only thing I have used my lapping tools for in ages is to confirm the seat placement on newly cut seats. My wooden suction cup lapping spindle is way older than me and probably closer to 100 yrs old than not. :hyst: Even at that, when I use it, it's only a light touch to show the narrow footprint, not actually lapping. Lapping can ruin the advantage of an interference angle cut to position the narrow seat contact. As PUB says, stones are risky in the wrong hands. There are other ways to do it now for a reason and it's best to take advantage of them.
To check the contact area, I used to use a large black marker, I'd mark the valve face black. You could see the contact area after a few swirls of the valve. The bright steel against the black showed easily.
I have Mechanic's Blue for that. It gives a full circumference footprint. The black marker is a great idea and easy to clean off.
No interference angles used by me or lapping. Seats are checked by vacuum and dykem.
Don, how do you position the valve contact on the seat to be narrow and not full width (or do you)? Do you just reduce the seat face contact available? Maybe your Neway or Serdi is that accurate you can design the seat contact appropriately?
Full face contact, same angles both seat and valve. I have a tool to measure and adjust the form tool where the seat will be placed on the valve. Using an indicator on the machine heights are controlled as well. This is SOP for seat and guide machines just not all work as well as the Serdi if the guy behind the wheel knows what he's doing. The interference angle stuff was a Neway thing and autoshop 101 long ago. 46 and 45 deg. When the seats are concentric and same angle as the other they will seal full pull vacuum. No break in
:up: Thanks. I will take that to mean you don't see carbon damage from full seat contact or the seat width is easy to control and prevent that?
The proper guide to valve clearance is part of the geometry too. No issues.
Absolutely and goes without saying. :up: Thx
From my first crude valve job (about 1970) until now I have not ever ruined a seat with stones.
They are an artform going extinct, I would guess.
Anyway, it is all good for discussion and we all can pretty much elaborate on how fast modern methods are .
But I thought the most interesting point is what was said in the header , -about porters and back rooms
Three head porters replied that they use Serdi.
I guess I for one, wrongly assumed by the "title" it was about valve seats because it was mentioned twice and identified the Great Serdi valve seat machine in particular. The "hustled to the back room" part, the way it's described in the opening post, seems to indicate for hand "porting" work. At least it doesn't say for a secret valve seat trick. Several known excellent trusted and respected porters here have responded to just seat work as did I. I learned something from Don today. It appears to me that speed is one thing, but as stated, repeatable accuracy is a real good reason to continue with the machine work. If not repeatable, the word of mouth would kill these guys. I guess, like the old vintage drive chains discussion, we have to change with what the modern times proves to work best in each situation unless there is a benefit not to. $$$$ play a big part in the DIY build decision making. Results can trump DIY when looking for that little bit that crude work may leave on the table and IMO therefore may be well worth a few bucks.
I guess being porting is part of doing seat work, hand porting is out as CNC porting can be more consistent and faster.
Quote from: Buglet on February 09, 2021, 07:15:31 AM
I thought Newen was the way to go. You can program it to cut custom seat any way you want, you don't have to have custom cutter made. It don't matter what you have to cut the seat with you can screw them up.
Newen sells their Contour machine which can be programmed to single point cut any seat profile you want. Newen also still sells machines that use form cutters like Serdi, Sunnen. TA, etc.
Serdi also sells a programmable single point machine called a Stronik M. Unfortunately they came out long after I bought my Serdi. (New in 2002)
https://www.serdimachines.com/index.php/us/valve-seat-machines/stronik/stronik-m (https://www.serdimachines.com/index.php/us/valve-seat-machines/stronik/stronik-m)
Porting is most definitely part of seat work. Or versa visa .
seat work is part of porting
don't agree on the vice versa