I'm curious to know some of your experiences with running hardend valve seats or on the other hand not running them. I've heard the pros and cons for both sides, but I'd like some input from members who have run their cars without them. The car I'll drive will only see "weekend" duty as we like to say, not long trips or towing conditions. Did any wear conditions result etc?. Thanks Glenn. 67 430.
You don't need them on a Buick... Higher nickel content in the Buick iron heads, unlike the cheaper iron heads from say...Chebby. :TU:
I wish I'd never had them put in! The only time they would be needed in a Buick was if there was severe valve recession or excessive amount of valve jobs done. If the valve stem height is excessively high, it would be time to install new seats. I hope I said that correctly...
I disagree with Dan Healy. I usually baby my car, and the last 2 times I dissassembled my heads, I saw valve recession starting on the exhausts. Now I use lead additive....wal mart has it for the cheapest. I'll see how well it worked the next time I take the heads apart (which I hope is at least 10 years from now:grin: )
The more a valve wears into a head (recession) or the more times that the seats are ground, the more the stem height goes up. Installing new seats gives a fresh surface to work from. MUCH harder to grind with regular stones, supposed to use a Serdi-style valve seat cutter, instead.
As the seat gets ground the further up the valve is. Also, when the valves are re-faced, the higher the valves move up. thats why you need valve shims when a head is given a valve job. Most Head shops will grind the tip of the valve down as needed.
I know all buick 400, 430, 455 heads do not need hardened seats due to high nickel content but I think 425 heads would. Unless there are seat problems I would not touch them except for a valve job.
Maybe higher nickel content is why 400-430-455 heads are so prone to cracking? I've never heard of Nailhead cyl. heads doing that but I'm sure anythings possible.:bglasses:
If the nickel content made any difference, GM would not have had to induction harden exhaust seats starting in '71. I guarantee GM would have bypassed that operation if it would have saved five cents a cylinder head. As soon as you wear or grind through the induction hardended metal, (it's not all that thick) you're into the "soft stuff" again. The seats will not last under heavy load. They will last some amount of time under light load. How common were valve jobs in the '60's? I wasn't around then, but I'm thinking there were lots of them done. Seat recession was a problem even with lead in the fuel. Engines now go well over 100,000 miles, and often over 200,000 miles without valve work, in part because of hardened seats. This despite increased operating temperature and general downsizing of engines meaning the engine tends to work harder to push the car around. There is something to be said about non-hardened valve seats that have been ground and then the engine was used for light duty, with lead additive, before going to non-leaded fuel. Those "non-hardened"seats will survive better than fresh-ground seats immediatly placed into service without lead additive: They have work-hardened from use. Any way you slice it, hardened seats are a good plan. As long as the work is done by a competent machinist, it's the only way to fly. Valve recession (even with fresh seats) loweres compression by increasing combustion chamber size, it interferes with the short-turn radius of the port, and so reduces "breathing" ability of the head.
i have them installed, i know the opions on the subject, but it is for my piece of mind, but i DONT USE PRODUCTOIN SHOPS, all my engine and head work is done by shops the due costom work, it cost close to twice as much but it is done right, for example i did all the port work on my iron 455 heads coverted to stage one heads and it still was around $1000 for parts and labor, that was cutting for the larger valves, seats, cutting for dual springs, 3 angle valve job, guides, new stainless S1 valves, dual springs, ect.... if done right i see no reason to take a chance on not installing them. if you are just trying to save $50 bucks, build a chevy there cheap!!ha ha just my 2 cents
When I had my 425 heads done, the machine shop at NAPA told me that there was not enough room for seats without risking cutting into the water jackets. I figure they really didn't know and just didn't want to take a chance.:bglasses:
Re: shops I don't know if you read my thread about Nailhead bearing clearance, but this shop also left my valve guides sticking up 1/4" too high and the cam bearings were too tight. (those I caught before taking it home) The killer was the bearing clearances, .002 on the rods and .003 on the mains.:rant: I would have taken it back and made them do it over, but I wanted to take it to Flint and it wouldn't have been done in time. The pressure is good, but I know it's there and it bugs me. NAPA's machine shop is a good place to take a Chebby or Ford, but not a Buick.:spank:
Hey guys, this valve seat conversation is usally a 50/50 deal right down the line, but I decided not to because the seats that are in the heads now are fairly minty, additives for seat protection are cheap and as mentioned the car is only going to see "spot" use anyway. None the less thanks for the input from all who gave their two-bits. Glenn.
Hey Joe, the next time you need something machined, Get a hold of me. Our shop knows a thing or two about buicks.... We can set you up nice. :beer
Well gang, having just gone through this last year, and after thoroughly discussing it with Jim Weise, here is what the Dr. says: If a shop knows how to do Buick valve seats, then OK. If not, then you run a very good chance of hitting a water jacket when installing the seats. And no amount of sealer will stop the leaks. I had seats done in my Stage1 heads last summer and the job was outstanding. But the shop has to know what they are doing. NAPA wasn't totally wrong, if we're talking 455's. I can't say for sure about the nailhead.
Just an FYI I will not put valves seats in iron heads. I will find different castings. More good reasons not to do it, than to do it. I have heard of more than 1 set of original stage 1 heads that went to the scrap heap after this process, and they were done by a shop that certainly knows Buicks. It's just a hit or miss deal with the water jackets. I have also seen this done sucessfully, but it's a risky proposition, and iron heads do grow on trees.. we have plenty of good cores here. Valve recession?.. Sure, in maybe 100k miles.. on the average Nice weather driven GS, that will take a lifetime at 3-5K a year.. Just a thought.. JW
