sn95

iTrader: (2)

For those of us that never have enough tools or aren't satisfied until we can spend twice the money and 10 times the time just to say "I did it myself"...here's one old boy's explanation of how he does his own 3 angle valve jobs

BJ: Old School Valve Grinding is Still Cool - One Dirt Forums

Now, if only I can find a cheap Sioux setup on Craigslist......

NA6C-Guy

iTrader: (1)

For the price of a 3 angle job from a machine/head shop, I would MUCH rather pay for something like that. Some things I can see doing yourself, but that isn't one I would mess with. Cool for him though if he can do it and have good results.

Braineack

iTrader: (62)

A valve job in my area is $200-250. I'll stick with the pro.

cueball1

iTrader: (13)

Have you looked at the Neway kits? Use a cutter instead of a grinder. Supposed to leave a finished surface vs. the grinding wheels rough surface.

sn95

iTrader: (2)

I posted up the Sioux link as a tongue-in-cheek follow-up to an earlier discussion on DIY valve grinding in another thread where Serdi micro vs. Sioux vs. real Serdi valve seat refacing equipment was being debated. If you want a good multi-angle-valve job, pay an experienced machinist with a Serdi floating air cushion setup to do it. You can probably get that same machinist to open up the diameter of the port right below the seat for a nominal upcharge over the multi-angle valve job.

The Serdi micro and Neway are both lightweight, low mass tools using carbide or tungsten carbide cutters on hardened seats. They also require using a pilot to center the cutter on the seat; if the valve guide isn't perfectly concentric, if the pilot doesn't fit the valve guide perfectly or if the valve seat isn't perfectly centered around the guide, quality of the seat finish is impacted.

BTW, the Neway claim that their cutters leave a smoother finish than a grinding stone is only true if the valves are NOT lapped after grinding. Anyone doing high performance seats (vs production work) with grinding stones always laps the seats!

gospeed81

iTrader: (51)

DIYvasectomy.com

cueball1

iTrader: (13)

Corrected.

webby459

iTrader: (8)

Ouch. I'm butt-hurt.

Duckie_uk

iTrader: (1)

This guy is almost as old-school as patsmx5. He spent ages grinding his seats to a radius by hand (what he called bowl blending) whilst not touching the existing 45* contact margin!

I just picked up a set of over 20 of those Neway cutters and pilots/tips galore from a shop that was shutting down in the area. I'm going to use them to do a 3 angle on my head fairly shortly so I'll let you know how I get on.

sn95

iTrader: (2)

Bowl blending is done to the port below the valve seat and is a separate operation from cutting the seat angles. Standard 3 angle valve job consists of top exit angle, a middle 45 degree angle "face" that the valve face seats on and a lower lead in angle which guides the flow in from the port throat. A lot of porters will do the majority of the bowl blending on a port before doing the valve job. If you do the valve job first you can ding the new seat doing the bowl blend and have to re-do it.

Duckie_uk

iTrader: (1)

I know what bowl blending is lol (been doing rather a lot of it recently ). Just saying what pat does (and what he calls bowl blending. His argument was "If 3 angles is good and 5 is better then why not 50 or 100? In fact wouldn't that look like a radius?"

He used to swear by it every time someone asked the benefits of a 3 angle job.

Here's a thread over on m.net where its discussed post #17

http://forum.miata.net/vb/showthread.php?t=343947

sn95

iTrader: (2)

Got the link. If you read through it completely you'll see that Pat differentiates between a 3 or 5 angle valve job and what he describes as the optimal setup which is a multi angle valve job combined with bowl blending. He also correctly describes the most critical part of bowl blending to be smoothing the transition from the bottom of the valve seat into the throat entry.

gospeed81

iTrader: (51)

I miss Pat.

sn95

iTrader: (2)

Is he totally gone from this site?? Anyone who can grind a perfect radius on an upper and lower valve seat (freehand with a cartridge roll no less!) without whacking the 45 degree middle surface is pretty damn good!

NA6C-Guy

iTrader: (1)

Maybe he still lurks under another name... Really, I don't know. As far as I know he is gone. Bring him back!!!