Questions on Oil Clearances

Discussion in 'Small Block Tech' started by OddfireV6, Aug 12, 2018.

  1. Mart

    Mart Gold level member

    Where did you see that 30 lb spec? TA recommends 20 and chassis service manual is 29. Hand tight evenly works well too.
     
  2. alec296

    alec296 i need another buick

    If you cracked aluminum housing at 30 ft lbs, chances are you weren’t on the line up pins correctly. Or cover was not flat on block face.
     
  3. OddfireV6

    OddfireV6 Active Member

    The 30 foot-pound spec was sourced from an original 1977 Pontiac service manual for the Buick 231 engine. My 231 is the original engine for my 1977 Pontiac Ventura. I also have a Motor Manual and a Sun spec sheet, and both give 30 foot-pounds as the spec for the timing cover to block bolts for this year of 231. That sounded rather high to me for such a thin aluminum casting, but I went with it anyway because I'm rather trusting of OE specs on things.

    Sources for the 215 V8 say 20-25 foot-pounds and that seems more appropriate. I don't know why my sources say 30. Maybe the later 231 timing covers were stronger. Obviously it was too much for this cover.

    I lined it up to the block properly, and it was a new TA cover. It should not have been warped.

    The Buick timing cover is a weak design. There are many flaws that make it prone to breakage. I think TA makes the best Buick timing covers of anybody, but there are still design flaws that make it prone to breakage. If I were a Buick engineer or TA engineer I would have addressed those flaws and made it stronger. Perhaps overkill stronger, but stronger none the less. I like overkill and safety margins. I plan to improve my next timing cover's strength by removing some of the casting flashings that create stress risers for cracks to form from, spot facing any bolt holes not perpendicular to the bolt, and using washers under the bolt heads.

    And no, I won't be torqueing my next timing cover to 30 foot-pounds.
     
    Last edited: Oct 16, 2018
  4. MrSony

    MrSony Well-Known Member

    Stuff I Torque:
    intake to head bolts
    head bolts
    main bolts
    rod bolts
    cam gear bolt (loctite)
    flexplate/flywheel to crank bolts (with loctite)


    Stuff I get "tight":
    everything else.

    My idea of tight is this: say you have the timing cover/water pump bolts. You have an extension with a socket on it in your hand. run it down with your hand until your own hand strength physically cannot tighten it anymore, this varies person to person. I then go 1/4 to 1/2 turn past that with a good 1/4 drive ratchet. never had an issue. Maybe you're alignment was off with the dowel pins. Unless you went way above the 30ftlbs and your wrench is off, there's really no way it should crack unless it was already cracked.
     
  5. Mart

    Mart Gold level member

    Great! Sounds like you have it "covered"!:D
     
  6. OddfireV6

    OddfireV6 Active Member

    The cover withstood the initial 30 foot-pounds as I was assembling the engine on the stand. It formed a small crack around the bolt hole that eventually broke off completely, but other than that it seemed to be fine. The gasket seemed fine. The engine ran fine for a day but started leaking coolant from the gasket the next day. The gasket was soaked with coolant and turning to mush and the bolts were barely snug. Either the 30 foot-pounds smashed the gasket and caused the leak or I forgot to tighten some of the bolts when I installed the water pump, but either way the gasket was mushy wet coolant-soaked paper, the bolts were loose, and it was leaking. I tried to tighten the bolts but the gasket just mushed out and that's when one of the bolts cocked over sideways and broke a chunk out of the cover. I think the gasket mushing under the cover is what caused the cover to crack.

    Keep in mind I didn't realize this was happening at the time. I couldn't see the gasket to know what was happening to it. I figured this out later when I took the cover off and discovered the gasket was totally annihilated.

    So....I talked to Mike, the owner of TA Performance about what went wrong and why his cover failed. He told me I should not have tightened it so much and sent me another new cover. After setting up my oil pump again, I installed that new cover with a Fel-Pro paper gasket covered in a THIN layer of silicone and tightened the bolts to 15 foot-pounds. I could see the gasket compressing enough to seal but not so much it would be damaged. 15 feels like a good torque to be at.

    So far it doesn't leak after 100 miles. I'll check the bolts for tightness tomorrow and see how they are doing. I'll go from there.

    I'm going to be honest. I really hate Buick engines now.
     
    Last edited: Oct 20, 2018
  7. MrSony

    MrSony Well-Known Member

    Oh that's no reason to hate them at all. Things like this happen. It's not really anyone's fault. TA covers are made well, you followed factory specs, and it happened to crack. I will say, this is the first time I've ever heard of any issues with a TA cover breaking as described. I have cracked an original cover by not getting it properly seated on the dowel pins, maybe that happened in your case.
     
  8. OddfireV6

    OddfireV6 Active Member

    I was really careful to line up the timing cover and the engine was on a stand with the oil pan off so it was easy to make sure it went right. It didn't crack near the dowel pins so I don't think alignment was a problem.

    I've logged 270 miles on it now since rebuild and the newest timing cover. It runs how an odd-fire 231 runs in a 4000 pound X-body coupe at 7000 feet above sea level...meaning rough and slow. So I guess that's a good sign.

    The timing cover bolts were a little looser than when I first installed the cover so I snugged them up with a 1/4 inch ratchet. Forget the torque wrench. Reasonably snug with a 1/4 inch ratchet seems to be working well. It's not leaking or cracking so I'll just keep it up.
     
  9. MrSony

    MrSony Well-Known Member

    If they keep loosening, to the point of needing snugged again to the previous "tightness", consider lock washers.
     
  10. OddfireV6

    OddfireV6 Active Member

    They're holding torque pretty well now. I think the gasket compresses in the first few hundred miles and then stops. I'll keep checking them but I think everything is good to go.
     
  11. TrunkMonkey

    TrunkMonkey Well-Known Member

    USAF aircraft maintenance career as well as motorsports.

    And a long line of family of aircraft aviation engineers, machinists and engineers who were instrumental in Boeing, Beechcraft, Cessna, Learjet, McDonnell Douglas, Lockheed and several others and drag racing and racing engineering for more than 70 years.

    It's all about torque. More importantly, it is all about torque, properly applied.

    Can one get away with no measured torque? Yes. But if you want consistency, safety, reliability, repeatability and want to win, again and again? Then you need to accept that torque is king, and torque rules. Torque moves the universe.

    It might seem mundane, and bending the wrench until it "smokes" or "feels right" may get you by, but there is more broken dreams and ruined aspirations at the end of an unfettered wrench or breaker bar, than all the junk yards can hold.

    Listen to the experts. They have spent untold hours and dollars so you don't have to throw away yours. Put the wrongful pride (ego) in your back pocket, and let the correct pride (of working together and acknowledging other's innovation) drive you to win and succeed.

    Thus endeth the lecture...

    :)
     
  12. OddfireV6

    OddfireV6 Active Member

    Here's a new one for you.

    I have 40 PSI of oil pressure at a steady 55 MPH, but if I open the throttle to increase speed the pressure drops about 5 PSI until I let off the throttle again and then it comes back up. This happens an most speeds. The pressure drops about 5 PSI when the throttle is opened verses when it is closed.

    How weird is that? Freaky. I can't think of anything in the engine that would cause that. The RPM doesn't change that much. It's an automatic, so if anything the RPM would drop a little when the throttle is released and cause a reduction in oil pressure, but rather I am seeing the opposite. I suspect it's something to do with my electric gauge and sender unit.

    I'm paranoid now. I practically stare at the oil pressure gauge while driving. It makes 15 PSI @ 600 RPM and 40 PSI above 2500 RPM fully warmed up with 10W30 but it still makes me paranoid. I expect it to drop lower at any minute and for the engine to start knocking. I just don't trust it any more.
     
  13. MrSony

    MrSony Well-Known Member

    Get a mechanical gauge.
     

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