nelsontj

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.

cherokeepeople

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

edzolz

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.

83hurstguy

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.

77403

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.

joe_padavano

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

77403

oops 🤣

CANADIANOLDS

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

joe_padavano

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.

CANADIANOLDS

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?

Loaded68W34

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.

Slick66

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.