1970-W30

I'm having a set of #5 SBO heads rebuilt and the rebuilder strongly recommends hardened exhaust valve seats. I'm on a budget (aren't we all)
and the cost will be an extra $216 for labor, new seats and ex valves. The current exhaust valves and seats are just in need of slight grind, the reason is just that the rebuilder is worried about the valve eventually recessing into the head. I was under the impression that for street use 5000 miles a year or less it would not be a problem. What do you guys think, should I decline the extra cost?
I'm already looking at $529 for a 5 angle grind, new valve guide liners, head resurface, grinding out the air injection bumps in the ex ports, drilling head bolt holes to 1/2" and 1.995" new intake valves. Heads are going on a rebuilt 403. With new valve springs, I'm looking at a total of close to $600 all in,
Does this sound about right? It's been decades since I've done these kind of projects and these prices now a days kind scare me........
Harold, the oldtimer

J-(Chicago)

I have an in depth article about this. I will try and find you the link.

One thing I can attest to with olds heads, when you beat the crap out of them in stock form, the valves will lose the boxing match vs the seats 99% of the time. Once you run a cutter into them, and use harder valves all bets are off however.

edzolz

Evidently your rebuilder does not know Oldsmobile engines very well. If he insists on putting hardened seats in your heads, more than likely they will be junk when you get them back. I would pull everything I had in his shop as soon as I could and find a good Oldsmobile machinist. I ran a 67 442 without hardened seats for over 65,000 miles on unleaded gas without any valve recession at all. Hardened seats are needed only if you are going to run sustained high RPM. Around town and short highway trips and you will never see any problems.

krooser

What he said....

DoubleV

What about drag racing or a street car that just sees the track a few times a year ( but plenty of WOT street blasts )?

I was told by some of the top Olds engine builders that hardend seats aren't needed in Olds heads, but there's no harm putting them in, it's just going to cost you to do it. I always looked at it as extra insurance.

chadman

Not needed on an Oldsmobile. You are more likely to have problems with the seat falling out that they put in because 90% of them use the wrong seats.

edzolz

Why don't you believe the top Olds engine builders? It is not extra insurance. It is only a good way to scrap your Olds heads. Putting hardened seats in Olds heads sometimes hit water when they cut the head for the seats. Why take the chance when it isn't necessary in the first place. WOT open blasts are not the same as sustained high RPM runs. By high RPM I mean over 3000 for HOURS at a time.

krooser

I have run many different vintage engines without having hard seats installed. My daily driver and hauler for three years was a '48 F-1 Ford with a Buick nailhead and never had any problems.

While hard seats are "the norm" I really doubt many engines really need them.

joe_padavano

I ran an E-block 400 with B heads and stock seats for years on unleaded pump gas. No issues whatsoever. The reality is that for a daily driver, not using hardened seats might mean that you'll have to do the valves in 80,000 miles instead of 100,000 miles.

If you DO get seats installed, be sure the shop uses OLDSMOBILE seats and not Chevy seats. The latter are too tall and the shop will hit water if they machine the heads to fit them.

Oldsmaniac

I am sure back in the day some had run their cars on an exclusive diet of American/Amoco gold premium which was unleaded. I never heard of any detriment... Back then a lot of people were brand specific with their gasoline choice.

1970-W30

Thanks for the replies guys, I think i'll save the $216 for something else besides hardened seats...
Harold

1969w3155

I had the heads done on my W31, by an "Olds guy" who races a '70 W31 in NHRA, I put in stainless valves, and when I questioned him on hardened valve seats, he stated "not needed with stainless valves", if you are going with the stock ones, I would heed the advice given here.

DoubleV

You may want to re-read what I posted. I said there were some top Olds builders ( ones I have actualy talked to ) that stated you don't NEED hardend exhaust seats but there is certainly no harm installing them, and of course that means installing them correctly. So putting them in, while not really needed, would be 'extra insurance' you'd probably never of had to worry about 'cashing in' on anyway. The cost was always quoted to me as being only about $100.

My question to you about drag racing was just me asking you your opinion on it since you didn't mention it.

D. Yaros

Slightly off topic, but please educate me -

I keep running across the acronyms of BB/BBO and SB/SBO, usually in relation to heads. What to the terms stand for, I wonder?

TripDeuces

Big Block/Big Block Olds and Small Block/Small Block Olds

joe_padavano

You're probably more familiar with the terms SBC and BBC for Small Block Cookie-cutter and Big Block Cookie-cutter.

joe_padavano

Actually, I should point out that Dave has a 394-powered 62, so the BBO and SBO in the common usage don't really apply to his car, despite the fact that the first gen Olds V8s came in THREE different deck heights.

brownbomber77

My machinist said he's only seen valve seat failure and sink in Chevy heads...

Rickman48

Yeah - pre '70 heads with 300,000 plus miles on 'em!

Greg Rogers

Boy, Wish I had seen this discussion before I had seats put in my #7 71 Olds heads earlier. I broke a valve spring and decided to do it all even though I had no problem w/valve recession. I live around Lansing and know some of the guys who worked at the engine plants who said Olds blocks and heads were high nickel content which I believe because they have such good durability. Anyway Joe Mondello really recommended having seats installed. I drove my Olds 30-40,000 miles w/no problems untill a original 42 year old spring broke- should have replaced them all earlier. Well now I have hardened seats and all seems ok. I sure hope it didn't ruin the heads or they will come out,etc.

joe_padavano

Just out of curiosity, how many NON-Chevy heads has he seen, period?