3-angle or more valve job?? worth it on stock motor?

mike mueller · 12-09-2002, 01:03 PM

Just bought all new SS valves and now I need to get the valves and valve seats matched.

Any noticeble gain by doing a fancier job on the valves then supplied by the factory?

Stock Euro spec 2.0

derek_sf · 12-09-2002, 01:14 PM

S-Car-Go did this on my prior euro spec 2.0. the motor did have some extra power, but not sure if that came from the higher compression, balancing, head work, etc.

Brad Roberts · 12-09-2002, 01:21 PM

Do it Mikey. You have nothing to lose and they wont charge you much more for the 3 angle. It does flow better.

Derek, meant to say... S-Car-Go farmed my machine work out and told the place to put a 3 angle valve job on it.. LOL

Rob is now doing general repair. The race support has fallen off.

B

derek_sf · 12-09-2002, 02:16 PM

LOL.

brad you are right, I seem to remember the receipt for that portion was from a machine shop.

they did build the motor though, I swear.

Brad Roberts · 12-09-2002, 02:18 PM

Rob rocks. I have no doubt that he (or somebody in the shop) built your engine.

B

pbanders · pbanders's Garage

One of you guru's enlighten me. I thought the reason to go with a 3-angle job was that it maximized sealing and valve seat contact area, for better heat transfer and lower wear. Is it really for flow?

Mike - I'd go with 3-angle if my reasons are right, especially if you're running SS exhaust instead of sodium-filled. And make really sure you're not running tight on the exhaust once you get the motor together. Getting heat away from that exhaust valve is extremely important, and you will want to maximize the time the valve is seated (or worse yet, if too tight, never seated!!!). I'd check it a few times in the first 1000 miles.

Brad Roberts · 12-09-2002, 02:44 PM

I have always done them for flow.

I used to run a Sioux valve grinder.

You would cut a 45 in the seat and a 45 on the valve (most of them come this way)

I would then cut an angle above the 45 and below it (on the valve and the seat). Tap the valve into the seat and "mark" the valve with paint. This would tell me where the actual valve was touching the seat. I would then grind the other two angles until I had a narrow area for the valve to contact.

This is the best that I can remember (it was 10 years ago) I take apart heads that I have done now, and it appears they are doing the same thing.

I wish I had pics... I could show you.

B

JWest · 12-09-2002, 02:46 PM

AFAIK the 45 degree (or so depending on the machinist's preference) seat remains the same and the interface is the same width (to meat specification - wider on the exhaust than the intake), but in a 3 (or more) angle valve job extra cuts give a transition to and from the 45 degree cut aiding flow.

Brad Roberts · 12-09-2002, 02:58 PM

Bottom line:

it smooths the airflow over the intake valve and the seat with 3 angles.

This is how you do it: per Bentley.

B

mike mueller · 12-09-2002, 03:24 PM

Here is a picture of my new exhaust valve, it only has the one 45° cut on it.

Brad Roberts · 12-09-2002, 03:29 PM

Correct.

Now. Put a 15 leading to the 45 and a 75 on the top.

3 angle valve job.

See that hairy "lip" at the top of the 45 ?? It slows the air down going into the combustion chamber.

B

Brad Roberts · 12-09-2002, 03:35 PM

By the time you get the 15 and the 75 on it, the area for the 45 will become pretty small. Since its easier to replace valves than it is the seats. You cut the valve to match the 3 angles you put on the seat. This requires grinding and testing grinding and testing... blah..blah..blah.. This is why you see people using the blue paint on heads when you get them back from the machine shop.

Why couldnt you leave those fresh heads alone ??

Let me be clear: the 3 angles do not touch. Only the 45 on the seat and the valve actually make contact.

B

mike mueller · 12-09-2002, 03:43 PM

I don't "have" to replace the valves (in fact I have not touched the new heads yet), I guess the thought of using old valves with no known history scares me a little.

Should I just keep them as is and save the new SS valves or sell 'em?

I also bought brand new stock springs and chromoly retainers.

Brad Roberts · 12-09-2002, 03:47 PM

I personally would leave them alone and run them. I have a few core sets of heads we can use those parts on later.

I was thinking of having the guy Randy used do a set of heads for me. The Danish guy in Santa Rosa.

B

mike mueller · 03:57 PM

I can do that....

I'm still waiting to hear from Jon on the white car...not sure if he has that buyer yet or not for the motor. I do have another perfect and running 2.0 that I can borrow from a fellow 914 owner if my motor is not ready when Jon needs to unload his chassis.

This other 2.0 motor that I can borrow was in a nice daily driver that was just recently totalled....(rear-end job on Hwy 13)

The Danish guy, is he the same guy that wasat the SSI swapmeet? He was talking to John and that Joe guy with the factory /6 that was for sale.

Brad Roberts · 12-09-2002, 03:58 PM

I just sent Jon another buyer (Tony Heyer) Tony has been trying to find another engine now for 12 months or so. I know Jon's runs good and I dont have another engine for Tony.

Yep.. same Danish guy. He is dying for my work. He is now closer and probably faster than the Jay guy I used in south bay.

B

pbanders · pbanders's Garage

Quote:

Originally posted by Brad Roberts

Let me be clear: the 3 angles do not touch. Only the 45 on the seat and the valve actually make contact.
B

Thanks, that explains it.

gint · 12-10-2002, 05:49 PM

Mikey,

Where'd ya get that gauge? I assume it's part of a set? Some specialist machinist's joint?

tmp914 · 12-10-2002, 08:33 PM

looks like a nice piece of granite too.

chrisreale · 12-10-2002, 09:51 PM

You can get those gauges at any decent hardware store. They come in handy, thats for sure.