Hardened Valve Seats.

38HAULR · January 04, 2008, 05:35:22 PM

Some questions for you guys in the U.S. On our local Mustang forum the question of fuel came up. Many of these vehicles are coming into the country and new owners are asking about valve seat recession,and getting hardened valve seats due to to lead no longer used in our fuel/lead replacement fuel Phased out circa 2005.There are additives you can add of course,and my personal feeling is that VSR is not such a great prob unless you are running high RPM and /or under heavy load.And I generally add some "valvemaster" to my tank when doing a long high speed journey.But for day to day commuting do not bother. Many of these vehicles would have had engine rebuilds, my 66 Stang certainly has. Questions are. Is this a big issue for you guys?do engine rebuilders in the U.S mod the heads as standard practice or on request?. Comments Appreciated.........Frank.

EMSjunkie · January 04, 2008, 05:49:02 PM

Its standard practice at the machine shop I use.
since unleaded gas came into favor here in the states, hardened valve seats are a necessity

surley others with alot more intellegence than I will chime in

Vance

enjenjo · January 04, 2008, 05:51:40 PM

I can't speak fo others, but for me, it has never been a problem. We have had unleaded fuel for over 30 years here in Ohio, and I have run it in most any year car I owned.

When I rebuild an engine, I normally would ask for hardened seats, because the additional cost is minor at that point. But again, some engines had high nickle heads all along, and really don't need hard seats. Cadillac for one.

I guess what I am saying, is don't worry about it until rebuild time.

wayne petty · January 04, 2008, 06:02:40 PM

EMSjunkie · January 04, 2008, 06:13:33 PM

So my Machine Shop guy has been lyin' to me all along :x

Vance

Dave · January 04, 2008, 06:33:51 PM

Quote from: "EMSjunkie"So my Machine Shop guy has been lyin' to me all along :x

Vance

Not really.. Think sprint cars hi rpm and longevity... You are a team member arent you ? Geeze . * its cold here and we are in snow ahole deep! Later im going back to surfing and drinking.
Dave

UGLY OLDS · January 04, 2008, 07:30:07 PM

When I built the "GM corporate" engine,(SBC to you non-"Oldsmobile" fanatic's) , in the Ugly Olds I believed the "induction hardened" valve seat
BS that everybody gave me about Chevy heads...Did the guides & ground the seats...all new valves/springs/retainers/etc....first 2500 miles ..no problem...
Drove the car to Pueblo for the Rocky Mountain Nats , ( Where Car-Nut got his photo's ..Thanks Again ,Car-Nut :!: :!: ) , sucked the #6 exhaust valve almost 3/8" into the head...Why the keepers never released is beyond me..When I pulled the head I could lift the valve spring approx 1/4" off the head surface..Replaced BOTH heads using hardened seats...
The biggest embarrassment was having to trailer the car from Pueblo back to Northern Ill...The ONLY time one of my cars has ever been on a "stretcher" .....I am now a believer in hardened seats....

Bob...

kb426 · January 04, 2008, 07:32:45 PM

I should know better than to join in but I am a team smart member. I only have 2 view points on this: blown alky drag racing and continuous run industrial. Lets start with the easy: the industrial applications need something that doesn't beat out with time. My machinest friend is using some form of powered metal. It works better than most of the other things he's tried. I don't remember the exact alloy and specs. In drag racing, I started out with stainless valves and chromemolly seats. The metal brinnels (sp.) from the seat to the valve so the sealing capacities are destroyed. I fought that deal for years. Other racers tried lots of stuff but none were fool proof. When I went to titanium valves in the alky car, that was the end of the problem. In the dragster, titanium valves were like alum. rods. They have a very definite life span. I found out that titanium valves were on the periodic replacement list with everything else. But, they were compatible with the steel seats and the metal transfer was no longer a problem. What does this have to do with hardened seats? Not alot, but, Vance, those of us old enough to remember when the unleaded gas came on the scene and the resulting head work will be believers in hardened seats of some kind. I don't have a good answer but nothing lasts forever.

wayne petty · January 04, 2008, 09:06:56 PM

whats is important is for most people interested to read the above articals..

exhaust seat contact faces actually melt as the hot exhaust gas passes over them ... this welds to the face of the valve to the seat... then the valve opens and pulls a chunk of seat out... this holds the exhaust valve slightly open making the problem worse..

the tetra ethyl lead previouly used in gasoline..stayed molton on the valve seat and prevented it from welding the contact faces ...

on induction hardened seats.. they only go so deep.. once you have to dress them through the hardness they just dont last...