My E heads from a 1970 442 are going to the machine shop to be resurfaced for new head gaskets. Should I have the valve seats hardened? or is that a myth that the unleaded gas will cause valve seat damage? There is 48K on the engine.

 

i have heard from a couple good shops that stainless valves is all you need.and if i remember right just the exhausts.

 

I do not know of any way to harden the valve seats other than replacing them with hardened seats. Unless your machine shop is familiar with doing this to Olds heads, do not do it. I ran a 67 400 for over 75K miles, both intown and highway miles and had no valve recession.

 

If the seats haven't recessed, they likely aren't going to, unless you are planning on installing it in a motorhome or tow a trailer with it.

I would not replace the seats. As mentioned, that's the only way you harden them. The old ones get milled out, the new ones get pressed in.

 

Yes you need hardened exhaust seats or run lead substitute which isn’t great. I ran my 455 without hard exhaust seats and beat the valves back into the head in 15,000 miles. If you are going to have any fun at all with your car at all. I am not talking racing

But make sure whom you have put the seats in is familiar with Oldsmobile heads or if possible done it before. The water jacket is very close. If they cut into it you will have boat anchors instead of heads. I had my small combustion chamber heads ported polished and exhaust seats done. You maybe money ahead to just get some new aftermarket heads😀 do not I repeat do not just use the soft seats. Unless you are put put put around driver. And even if you are they will still fail at some point.

 

After eight years I hope the OP got that car back together.

 

oops 🤣

 

This is a perfect example of why a post SHOULD be revived.

the info given out here is total bs. Olds heads do not need hard seat in virtually all cases. Even when using Titanium valves in an all out race app with big spring pressures..they can be cut oversize and survive.

usually the only reason for a seat insert is if they can’t be recut for the stock size valves without sinking them or there is a minor crack in the seat area.

Both my jet boat and my motorhome have heads without seat inserts. If your afr and timing is what it should be, there should be no reason to burn an ex valve…which is what burns, not the seat in the head. a stainless ex valve would be the only upgrade, if any.

if you are worried about burning an ex valve..keep the seat 30deg and extra wide to help pull heat out of the valve head with factory rotators

 

Had it not been revived, no one would have paid any attention to it. Should we go back and correct every bit of incorrect info in every old thread, just in case? I do agree with you as far as the need for seats is concerned.
As I've said before, the issue isn't reviving a threat that's relevant. The problem is that invariably someone revives a long-dead thread with a question that usually isn't even related to the title of the thread, and people start responding to the original question and not the new one, which usually results in even more incorrect answers.

 

I agree on all that…

here in this case though the op never responded after his initial question..so nobody knows what he ended up doing, so reviving it should help someone decide. It’s a short one so you don’t need to read through pages of responses.

another thing is how do you use the search to find good info that isn’t mired in fifty pages worth of responses in posts that have gone off the rails?

blocking or locking out old posts that have dreadfully inaccurate info don’t seem right…especially where that info can still be seen and taken as legit when using the search function….like if someone specifically revives it to ask..hey, is this correct?

 

I would simply like to point out that the info in the original thread was not really a problem. In posts 3 and 4 members explained that original valve seats cannot be "hardened" they need to be machined out with new seats pressed in, but everyone pretty much stated that is not necessary and did not recommend it. Post 5 where it was stated that valve seats need to be hardened was posted today and is the post that revived the thread. Maybe I am mistaken, but I thought you were saying the post should be revived so the info posted 8 years ago could be corrected and not seen as fact. Had the post not been revived, the assertion saying seats need to be hardened never would have been made. BTW, I agree and have never had a problem with "unhardened" seats in any motor (BBC, SBC, BBO, SBO, BBP) even with 10% ethanol.

 

Well I'm sure glad I came across this one. I was thinking of having hardened valve seats installed and now I'm thinking it doesn't really make any sense at all unless you had no other choice. Even then if the heads couldn't be saved unless you had to press a seat in, I think you would be better off replacing the head. A joint is a weakness and it doesn't take an engineer to figure that out. What about two metals of different compounds and the way they respond differently the expansion and contraction of heat? I haven't taken my heads off yet but will very soon. Its good to see discussions like this.

 

You do not need to harden seats or put in inserts for 99% of applications and the other 1% is debatable. Used heads have probably work hardened anyway.

 

Yeah I think its just a simpler matter that depending on the conditions, valve seats may get damaged period. Lead is extremely soft. How do we know that the lead theory didn't originate as a marketing ploy. Lead helps with pinging. Heat and friction causes metal damage. I dont see a dusting of lead being enough to offset that.

 

I would only do it as part of a rebuild or if you were planning on doing extensive headwork anyway.

 

It's not elemental lead, it's tetraethyl lead which is a liquid, or, at least, a suspension. It lubricated the valves and seats and eliminated hotspots and kept it running cleaner.

 

I see, I would just love to see the exact scientific data on this because it would seem to me that the benefits the lead does yield to proper combustion (which has been scientifically proven and documented I'm sure you know) could in itself be then linked to overall internal temperatures and then excesses of friction. Which then in turn could be applied to the actual rate of wear. I've searched intensively for the data on the actual contact of the lead to the valve seat and what benefits this would yield but I haven't yet found an acclaimed study. Needless to say I've never seen these two studies then compared against eachother. Obviously driving habits and maintenance would be massive variables here. I'd be willing to bet though that there are many people whose valve seats have worn, all of these factors apply to some degree, and harder metal is one solution but a whole head that is of a harder compound has to be incomparably better than just only a hardened seat. To the point that the only logic here would be a last resort to save the head that is not otherwise salvageable, that the posesser of that head has an attachment to. If you want to keep your head and the seat can just be ground and that will get you another 90k out of that particular seat on modern fuel than thats what it is. Is this line of thinking correct?

 

It also was an octane booster. Probably its main application.

 

Can you translate this to simpler language ? Read this about Tetraethyl lead.....
https://en.wikipedia.org/wiki/Tetraethyllead

X 2

 

Yes sorry I'll do my best to simplify this. The engineers designed the engine to be run off of what today would be something like 120 octane. The design of the combustion chamber, all parts associated, the materials used, and the timing are all part of a precise mathematical equation. Lowering the octane alone with or without the lead and running the car long term that way, even if timing has been adjusted may not be enough of an alteration to restore every single aspect of the combustion process back to behaving exactly the way the engineers had intended. So weather this form of lead in the gas truly has any lubrication properties or not, the smashing of the valve seat is the END result, not the root of the problem. The valve is being warped because the combustion process has been altered by removing the lead and the valve is then damaging the seat. (And the valve may only be warping temporarily) If your seat is getting hammered like that, then you will just hammer your new hardened valve seat and maybe that stronger metal can take the abuse, but the metal it is pressed into is still less durable and still feeling the impact. If you really think about this, you would have every reason to belive that the hardened valve seat would eventually fall out. Also if the metal is harder, then the actual head metal will definitely expand and contract at greater rates than that seat and since it contracts faster than the hardened seat, the head would eventually crack. Especially since its pressed in which creates its own permanent stress. In my view at this time I would say that this procedure is a compromise and not an actual improvement. I would be very curious to see while using unleaded gasoline, if hardened valve seats last any longer than undamaged replacement heads before other serious damages would occur. Maybe someone does have the answer to that. PS if the weaker explosion is causing drag overall, that increases friction, which increases heat. Sorry this is so long.

 

Also with the lead in the gas, how many miles does a factory valve seat commonly last?

 

My heads had hardened seats installed back in 1990 or thereabouts. I haven't experienced any issues.

 

Ok thank you, how many miles. I assume alot?

 

this is exactly what I’m talking about. if this old thread wasn’t revived, this guy could have done something totally unnecessary. not only that, he could have the heads destroyed by incompetent machining.

 

Not only that but It caused me to look into any other machining of the heads like port and polish and all that. I see no benefit in modifying heads at all unless absolutely necessary but this does pertain to a daily driver not a racecar.

 

The problem is in the mobile app or on your phone, CO automatically put "related threads" at the bottom of the current thread and often people don't realize they are not replying to a current thread.....

 

I would like to add that before I joined every time I Googled a specific Olds question this site came up which is ultimately why I joined. ALOT of the info I was looking for I found in your oldest theads. It actually doesn't matter if people are responding to the wrong threads or not. If you Google a question it pulls you to the answer. It doesn't care what the original question was, it's pulling you to the keywords you're typing in. I should say its not the only thing that matters, of course you want to keep things organized.

 

By the way my heads are now off. The seats don't appear to have any visible damage. I ran the car for 3000 miles 93 octane 10%ethanol. Looks like one exhaust valve is burned . I keep trying to download a pic but it won't right now.