bbc Is changing to hardened seats that important? - Chevelle Tech
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post #1 of 19 (permalink) Old Jul 23rd, 19, 8:52 PM Thread Starter
Brian
 
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bbc Is changing to hardened seats that important?

My local machine shop talked me out of hardened seats IN THE 402. Said the 063s will last a long long time in my mild build with new valves/springs. Engine hasn't been assembled yet,,it'll be street driven and probably tuned around 87-89 octane...anyone done it?
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post #2 of 19 (permalink) Old Jul 23rd, 19, 9:03 PM
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Mr Bill
 
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Re: bbc Is changing to hardened seats that important?

I agree. About the only time I have seen seriously receeded seats on a Big Block has been on trucks that pull a lot of load. To be honest with you in 32 years of doing this I have only seen a handful of heads with a problem. I think it is very over rated. I have however seen a few heads ruined when guys tried to put hardened exhaust seat in and hit water

Go with what your machine shop said
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post #3 of 19 (permalink) Old Jul 23rd, 19, 9:24 PM
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Re: bbc Is changing to hardened seats that important?

I've actually never seen seats sunk in a car or truck head. Irrigation engines are bad about it because there's nothing in natural gas to cushion or lubricate.

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post #4 of 19 (permalink) Old Jul 23rd, 19, 9:57 PM
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Re: bbc Is changing to hardened seats that important?

I love those irrigation 454's.

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post #5 of 19 (permalink) Old Jul 24th, 19, 6:31 AM
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Re: bbc Is changing to hardened seats that important?

I've never seen it to be an issue especially on a car that isn't a daily driver.
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post #6 of 19 (permalink) Old Jul 24th, 19, 8:16 AM
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Re: bbc Is changing to hardened seats that important?

Quote:
Originally Posted by Stokerboats View Post
I love those irrigation 454's.

I have several stacked.


The only issues I have had were a couple that the exhaust valves beat the seats so far down that the locks came off and the valves dropped, destroying everything. I managed to get 'em cheap enough that I didn't get hurt too bad, though.
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post #7 of 19 (permalink) Old Jul 24th, 19, 8:32 AM
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Re: bbc Is changing to hardened seats that important?

I had a ‘67 Jeep with the V6 (Buick mfg) that had the snot beat out of the exhaust seats. It was 50 years old when I got it. Worst I have ever witnessed. But it had been ‘rode hard and put up wet’.

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post #8 of 19 (permalink) Old Jul 24th, 19, 12:10 PM
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Re: bbc Is changing to hardened seats that important?

Quote:
Originally Posted by Busted Knuckles View Post
I have several stacked.


The only issues I have had were a couple that the exhaust valves beat the seats so far down that the locks came off and the valves dropped, destroying everything. I managed to get 'em cheap enough that I didn't get hurt too bad, though.
My 500 incher is one of those blocks. It had "Hi Perf" large oval port heads with small valves in it. The valves and seats were beat to death when I picked it up. Block. crank and rods were like new.

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post #9 of 19 (permalink) Old Jul 24th, 19, 12:24 PM
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Re: bbc Is changing to hardened seats that important?

i had some 60s small blocks where the exh seat was so recessed the valves would barely open. i would only worry about it if you planned to drive it for 50k or more. not an issue on most street cars
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post #10 of 19 (permalink) Old Jul 24th, 19, 5:44 PM
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Re: bbc Is changing to hardened seats that important?

What's different in the irrigation engines? I wonder if they did what ford did with their stationary equipment propane 460's? Good seats and probably not much else, ordinary 4 bbl intake manifold and 2 bolt blocks...

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post #11 of 19 (permalink) Old Jul 24th, 19, 6:05 PM
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Re: bbc Is changing to hardened seats that important?

My machinist said that there was a greater risk of ruining the head by cutting for the seats than there would be by not adding them. He suggested a cam that didn't need high spring pressures as well. Having said that, I do know of one case where the seats were not done and they receded. The guy was using the car for a long cross country trip and it ate them up.
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post #12 of 19 (permalink) Old Jul 24th, 19, 6:10 PM
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Re: bbc Is changing to hardened seats that important?

I wonder if he had it running lean?

'71 chevelle, 468, TH400, 12 bolt posi w/3.08's, drinks a lot of 87 octane.
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post #13 of 19 (permalink) Old Jul 24th, 19, 7:11 PM
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Re: bbc Is changing to hardened seats that important?

Casting# on my irrigigation engine is #959 which I've never read on any casting nu,bers listing.
OP, sorry for getting off track in your thread. I'd just pick up another set of heads if yours are bad. Factory seats are induction hardened.

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post #14 of 19 (permalink) Old Jul 24th, 19, 7:47 PM
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Re: bbc Is changing to hardened seats that important?

Almost all the Mark IV irrigation engines I've torn down have been tall deck 427's. They went to 454s around here while we still had water, now it's down to electric submersibles.

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post #15 of 19 (permalink) Old Jul 25th, 19, 12:09 PM
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Re: bbc Is changing to hardened seats that important?

My 468 in my 70 has over 39.000 miles on the stock org. type valve seats. The engine builder for a street driven, cruiser the stock stuff is just fine.
Building a Elephant Motor for racing..... Thats another kind of engine!( bring lotsa money)
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