70 Stage 1 Head Damage - OK or scrap?

Discussion in 'Street/strip 400/430/455' started by 2nd Gen Buick Fan, May 31, 2020.

  1. 2nd Gen Buick Fan

    2nd Gen Buick Fan Platinum Level Contributor

    Would some of you more experienced folks look at these pictures and weigh in on the damage? Engine is a 1970 Stage 1 with stock heads. A valve spring broke on the #8 cylinder and it pounded away for a bit before I shut it off. The casting on the bottom of the head where the valve stem enters the area above the valve seat has some damage. Is this no big deal / repairable / scrap?

    20200531_154626_resized.jpg 20200531_154631_resized.jpg
     
  2. hugger

    hugger Well-Known Member

    It's fine just dress it up and go
     
  3. johnriv67

    johnriv67 Well-Known Member

    That valve seat looks awful, maybe its just the light. Since the head is already off, you probably should do a valve job.
     
  4. Bens99gtp

    Bens99gtp Well-Known Member

    I dont see any reason to scrap that head, but if they are junk to you I will take them
     
  5. Stevem

    Stevem Well-Known Member

    I new guide will get that back to good!
    What happened, did a valve break?
    If so can you wipe out and clean up that chamber and post up a few more pictures?
     
  6. 2nd Gen Buick Fan

    2nd Gen Buick Fan Platinum Level Contributor

    It looks like the spring broke first which allowed the valve to drop into the cylinder. I'll pull the rest of the motor this weekend.
     
  7. 2nd Gen Buick Fan

    2nd Gen Buick Fan Platinum Level Contributor

    LOL
     
  8. Schurkey

    Schurkey Silver Level contributor

    Clean the head(s), test for cracks.

    The seat looks horrible; but not unfixable. The guide would be easy--dress the damage if the guide is still unworn, or cram in a thinwall insert if the guide-to-valve clearance is loose.

    "I" would want hardened exhaust inserts anyway if they need to be reground or recut, MAYBE you need an insert on this intake. Others will disagree, and some will talk about "high nickle content" which is all rumor and no truth.

    Optical illusion? The exhaust valve looks like it's very low in the seat.
     
    2nd Gen Buick Fan likes this.
  9. 65Larkin

    65Larkin Well-Known Member

    Id be looking real hard at the rest of the chambers especially #5 to see what shrapnel went bouncing around. I'm thinking the crown of your piston won't be pretty.
     
    GS464 and 2nd Gen Buick Fan like this.
  10. Jim Weise

    Jim Weise EFI/DIS 482

    One thing I can assure you is that installing even thinwall hardened exhaust seats, even by someone very experienced with the Buick head, is Russian roulette with the water jacket on these heads. You either go into water, or the area under around the seat gets so thin, they crack when you pound the seat in. Years ago we tried everthing imaginable to achieve a 100% success rate with this job, and came to conclusion it is a hit or miss situation at best.

    There is no reason not to replace that head, with a better copy of it... no unique stage 1 part numbers. Keep the head and show it to a potential owner if there is any "collectablity" issues.. often having a trophy like that is a bonus for those guys.

    -----------------------------

    I can also tell you that Buick used high nickel content iron, that has less valve recession issues.. and if you don't believe that, the only reason is that you have never done a hone job on a block.

    After 71, the exhaust seats were also induction hardened, and for that reason, Buick valve jobs on iron heads that were in service, and not sitting around rusting, or damaged, are typically just a skim cut. While it is true we cut most of that hardened material away, as the induction hardening is only a few thousandths thick, 30 years of doing this has taught us that there is no great concern about unleaded fuel and exhaust valve resession in these motors.

    Had you done that work in any volume, there would be no argument that these blocks/heads are not made of the "grey iron" that was often used by other makes. This change was required when Buick went to the thin wall casting technology.

    I had Cliff Studaker, the guy who designed the motor, sit across from my desk and tell me that..

    That was the answer I got when I directly asked him about the material used.. he spit out the actual material specs, but I did not write them down, and don't recall it. I will have to look at my copy of the factory block blueprints, I bet it calls out the material used..


    But hey believe what you want, but don't expect that I will not correct you when your wrong.

    JW
     
    Last edited: Jun 2, 2020
    Smartin likes this.
  11. telriv

    telriv Founders Club Member

    As far as I know Buick started the thin wall casting process in 1957 with the NailHead.
     
  12. Jim Weise

    Jim Weise EFI/DIS 482

    Could be Tomas I, I know thin wall casting tech was the reason.. he was not specific about a time frame, now that you mention it. Having done exactly 1 425, I am not at all knowledgeable about those kinds of specifics on the nailhead. I will ask Ron next time I see him if that one honed like the later motors do. He would remember, as it is a PITA.

    JW
     
  13. 2nd Gen Buick Fan

    2nd Gen Buick Fan Platinum Level Contributor

    I'll pull the rest of the motor this weekend and disassemble. I haven't found the stem of the valve yet!
     
  14. telriv

    telriv Founders Club Member

    Yeah Jim they do hone out like the later engines proof positive that it started earlier.
    They look sooooo much better than when you hone most other type of engines.

    Tom T.
     
  15. 2nd Gen Buick Fan

    2nd Gen Buick Fan Platinum Level Contributor

    Definitely a valve job in my future! Still checking the rest of the engine for damage though.
     
  16. 2nd Gen Buick Fan

    2nd Gen Buick Fan Platinum Level Contributor

    Thanks for the detailed response! I'll be pricing out new heads vs repairing and rebuilding the old ones. I'm kind of a sucker for the "stock" look, but money and reliability play a factor. My son is moving to Medina for a job. I may have to come see him and TSP in the future.
     
  17. Schurkey

    Schurkey Silver Level contributor

    I don't know what honing a block has to do with valve recession. The process is totally different.

    Every one of the GM divisions EXCEPT Chevy, and perhaps some Fords, seem to have gotten "better" iron for the cylinder blocks. Bore wear on Chevy small-blocks was way worse than Pontiac/Olds/Buick/Cadillac. About the same--or even worse--on Ford 221--351W. I don't know about 429/460, Mother Mopar, AMC, Toyota, Mercedes, etc. And I'm not saying the iron alloy didn't change as the years went by. None of the former problems with bore wear seem to be a current issue; I've thanked Feedback Fuel Injection and overdrive transmissions for most of that improvement (but I suppose GM could be pouring better iron into the SBC molds.)

    The issue is not that the iron making up the bore walls is "better" or "harder" than same-model-year typical Small Block Chevy. The issue is whether NICKEL is the reason for the difference.

    There's no guarantee that the heads were cast from the same material as the block. I've never had a machinist tell me that BOP valve seats seemed harder to machine than Chevy valve seats, or that the guides were tougher to ream because the iron was harder. Maybe they are...maybe not. I'm not about to fund a metallurgical analysis to find out. GM felt the need to induction-harden Chevy--Pontiac--Olds--Buick--Cadillac valve seats; clearly the GM engineers weren't convinced that the parent metal was good enough without the extra hardening process. GM is not known for performing extra processes or adding extra parts/materials when the vehicle can get through warranty period without.

    Suspicion: What gives acceptable service life in limited-use, hobby-car applications might not give acceptable service life if the car was still a "daily-all-purpose" driver.

    "Thin Wall" casting is not a "technology" or a single process. All it means is that the casting walls are "thinner than they used to be" because the casting process has improved. What was "thin wall casting" in 1970 would not be considered "thin wall" now. But I don't doubt that changes in casting processes go hand-in-hand with changes to the iron alloy, or aluminum alloy, or whatever material is being poured into the mold.

    I have ZERO problem with that. You do have far more experience with engine building than me. For the record, it's "you're", not "your".
     
    Last edited: Jun 2, 2020
  18. Bens99gtp

    Bens99gtp Well-Known Member

    I had a shop do a valve job on a set of 430 heads.......they proceeded to put exhaust seats in.........which they didnt tell me or put on the bill.......and they did such a shitty job that the seats fell out ofvthe head within 100 miles of me sending the car home.........the shop refused to replace the heads, said it ass the only thing they could do to save the heads.......funny it was running well b4 rebuild just had some bottom end issues......but no lreal leakage issue.

    They managed to turn good head into boat anchors
     
  19. Jim Weise

    Jim Weise EFI/DIS 482

    A valid p0int..

    But again, because this is what I do, and I am not try to be an expert on every make out there, I do have extensive experience to base my opinion on.

    In this case..

    I had a 76 Chev 3/4 ton pickup with a 455 Buick in it, that I towed a 10k+ lbs race car trailer with for more than a decade.. about 65-70K miles..

    It had everything going against it, when it comes to exhaust valve recession..

    • Pre-induction hardened seat material (heads were 1970 vintage, induction process started mid year 71)
    • HP cam and increased valve spring pressures
    • Steady diet of unleaded fuel
    • Constant heavy engine loads
    • often high ambient heat and elevated engine temp
    When the engine was disassembled to utilize the head cores in another project, NO VALVE RECESSION existed. I expected to see some evidence of it, but none was seen.

    That closed the book on the need for hardened exhaust seats on these heads, as far as I was concerned.

    As you said, limited use, hobby car applications are often not subjected to the rigors of daily driver use.. Which lessens the issue even more.

    ----

    I can assure you that the heads were cast of the same material, in the same foundry, at the same time ... there was no "head" iron, vs block Iron.. The block honing process is where the material harness is most evident, that is why it's relevant. And over the years, several of my guys have mentioned that getting a good finish on the seats is harder with the Buick stuff.. because the iron cuts harder. But no where near the difficulty one will experience achieving a proper cylinder wall finish.


    As far as the grammar.. give it a rest, you understood what I meant. You're being petulant now.

    JW
     
    PGSS likes this.
  20. Bens99gtp

    Bens99gtp Well-Known Member

    There is a word one doesnt hear used to much
     

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