seat change

[Brian_e]

I only used the CB seats.

I cut the bores nice and smooth, close as I can get on size. Measure the hole, and then take a skim cut on each seat to get the exact .010” press I like. I heat the head to 350, and freeze the seats in the freezer.

I have a press tool I made that uses a guide pilot to keep it all aligned. I use an air hammer to run them in super quick and easy. I made a counterbore in the top end of the press tool to hold the tip of the air hammer driver.

I think using a press would take to long and be more clumsy. You gotta work quick with the heated head, and chilled seat.

I use .0100” press, and a full smear of high pressure lube. It seems like a lot, but I have had great luck with it. Clyde Berg also mentioned he has always used .0100. Your tiny little 36hp seats could probably be a bit less.

Using a regular style boring head and indicating every guide would work just fine. Just very slow, but if you aren’t doing it to pay the rent, then go for it.

Brian
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[esde]

[modok]

I could probably do the job with whatever tools you already have.
I think you have a lathe and a mill with a nice boring head, right?
So all we need is make an indicator to get the boring head lined up with the guide, and make tool bits of different angles to put in the boring head.


3000$ worth of tools lets you do jobs much faster, and speed costs money, and speed also makes money.
But you can also watch people in india doing this work with a scrap drill press and self made tooling and making it work, possibly very well.
But you know, this thread reminds me of the old mystique when it comes to seats.
With press fit parts you can get all kinds of different results depending on the materials and surface finishes and techniques and the dimensions of the parts.
It's really more about just doing what works, but in order to keep track of what works, you need to understand the materials and dimensions you are working with.


You can find all kinds of advice about how much press fit, but using the same press fit dimension regardless of the material and thickness and diameter of the seat is a load of baloney and is completely useless information but at the same time they don't know any better.
Just basic common sense about a seat ring, the thinner it is and the softer it is, and the less dense it is, the more easily it will squeeze into the hole.
So it's all right, and all wrong at the same time, and the same with how to fit them, and the same with how to machine them.
if you have a thinwall powered metal seat then there would be no real point of shrinking it with dry ice, because you can just slam it in with two or three hits with a hammer. It will squeeze into the hole and the material has natural porosity and lubricity.
But if you had a stout seat made of a very dense and hard material and with a very smooth surface finish then it would be a good idea to freeze it, because that thing is not going to want to go in the hole any other way. it's not going to squeeze smaller much, it's not going to yield, and no lubricant is going to stick to a glass smooth surface.

[Brian_e]

It’s a big first step, but I would just get a Goodson or cylinder head supply ball driver setup if I were to do it all over again. They make counter bore cutters for those as well.

Brian
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www.type-emotorsports.com

[esde]

[Brian_e]

That is a counterbore cutter I made to work with the hex drive from the New 3 Angle driver I use. He also makes the same style now. I made mine years ago when he was just getting started. I will get a couple pics next time I am at the shop.

They are just standard 2 blade cutters, and I built a stand with an indicator to set them with. They work pretty slick, and I have a few of them preset to different seat diameters.

Brian
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www.type-emotorsports.com

[esde]

[nsracing]

Oh come on, Tucker. Are you saying your lathe work is finer than what I can grind on my Landis Cylindrical grinder?

They seats are ground for a reason -to be smooth. Because if they have feed grooves on them they gall the bore as you press them in. If you gall the bores, there goes the press fit that you were expecting to hold.

Also Brian, why are you turning the seats? Can't you measure the stick-out on the boring head? A dial-type boring head will do nicely for this type of work. And just set whatever press-fit you are requiring.

There is nothing like a ground surface. It is fine work that no lathe work can match.

[mark tucker]

if you use a good mandrill and good cutter and the finish is good there is not reazon at all why they wont be good. Ive gotten plenty of custom seats they were lathe cut, and all my berrillium seats are lathe cut., most ground seat Ive seen were crap and chattered because there mass produces spit out so effing fast. all the martin wells seats I got are lathe cut.my cp ,dellwest and more are all made on a lathe not ground.. I do however try to always use the smallest Id seat i can get with the od I can live with. that way the seat can be contoured corectly.not straight shit like factory or most aftermarket vw heads.
of corse after I do all the seat installing&cutting with the cutters I do use stones to finalize the seat finish.so..I gess mine are ground.

[Brian_e]

[modok]

Wow.

[fastone]

No but that's we used in the 80's when I was working here

[modok]

Ok cool. That makes sense. You make those yourself? never seen any for sale, but I understand they were used in the past.

[fastone]

Well you do want it round and a nice finish, do you turn cranks LOL
4130

[modok]

I don't see why.
Perhaps whoever told you that, was... dealing with a materiel that did not machine easily? mandrel too flexy? I can get great results on a crappy lathe with no mandrel. It's not hard. I'd tell you how if you want to know

[fastone]

Seats should be ground on OD.
Why are you turning them after the fact ?, am I missing something here.

[jpaull]

Looks good! Your a brave man lol.
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[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[Brian_e]

[jpaull]

Your always doing the fun stuff!! Limo bus with 2-litre, flow bench fu n, and now installing valve seats
_________________
[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[Brian_e]

Good deal.

I am cutting the bores now, then I will turn the seats for my press, and probably install the seats tomorrow.

Thanks for the guidance!

Brian
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