Large bearing journals on a 455

Discussion in 'Race 400/430/455' started by RonJ, Mar 19, 2015.

  1. RonJ

    RonJ Silver Level contributor

    A good friend of mine who is a Buick racer and a mech. engineer claims that the
    large jernol size is a problem with high rpm in a 455.
    Can any one explain this in some more detail.

    RonJ
     
  2. Racerx88

    Racerx88 Platinum Level Contributor

    Larger diameter means more velocity which it turn makes it harder to keep a good supply at the journal.
    That, combined with the already poor Buick oiling system, can mean problems at higher rpm's.
    Keep it below 5500 rpm's and your relatively safe.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Mains are 3.25" which means very fast bearing speeds. I believe the Buick crank is one of, if not the biggest crank shaft, in any engine. That is why the oil mods coupled with proper bearing clearances and proper oil pump blueprinting is so important. The oil pump is at the front of the engine in the timing cover and there can be a front to rear of the block reduction of oil pressure depending on bearing clearances.

    http://www.v8buick.com/showthread.php?214613-400-430-455-Block-ID-Prep-and-Oiling-mods


    This line also helps by oiling the engine from front and rear.

    http://www.v8buick.com/showthread.php?293955-Oil-Pressure-Equalization-line
     
  4. telriv

    telriv Founders Club Member

    To add to Larry's comment. Fast bearing speeds also create/lead to higher heat.
     
  5. carmantx

    carmantx Never Surrender

    And to further add, you don't need RPM's to produce power with the 455.
     
  6. RonJ

    RonJ Silver Level contributor

    I shift a turbo 400 at 5400 5400 and go through the lights at 6000
    will this work

    RonJ
     
  7. Jim Weise

    Jim Weise EFI/DIS 482

    Yup, no problem.
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Yes, and hopefully you have 70-75 psi oil pressure at the front of the block.
     
  9. RonJ

    RonJ Silver Level contributor

    Got that oil pressure.
     
  10. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    Just a tid-bit, the Pontiac 421,428, and 455s all have the large 3.250 main journals.They too have to deal with similar issues. Larry
     
  11. TA Perf

    TA Perf Member

    Ron,
    Don't loose any sleep over your friends comment. Many of the folks racing the Buick's and Pontiac's turn these engines over 7000 rpm. If you going to do this just make sure you oil pressure is above 80 psi at that rpm. 100 psi is safe.
     
  12. RonJ

    RonJ Silver Level contributor

    Thanks Mike for the reassuring comment.

    Ron J
     
  13. Dubuick

    Dubuick CMDR Racer

    It's fine not the best but works I have none of the oil mods and extra oil lines to the back of the block just have 90 psi oil I shift at 6500 and cross the finish at 7000 for the last 13 years same crank never had a bearing issue I do put bearing in the every 80-125 passes
     
  14. m louk

    m louk Well-Known Member

    Was there any wear showing on the bearings? My only mods were to increase oil pick up and internals to the pump as mine is a 68 block 400 cubes. Motor had some street miles before going race only. Running a solid cam 7500 redline crossed the line anywhere from 7200 to 7600. Engine had fresh oil and filter for next event. Pulled motor after race season checked bearings and no problems. Did this for 3 years no issues with bearings.........Mike
     
  15. gmcgruther

    gmcgruther Well-Known Member

    I hate to bring bad news to folks saying that the "main bearing journal size" is the problem! Please reliterate on that because its not the diameter problem it also includes the width of the bearing and the proper oiling of it. Sonny's Racing engine's, especially the mountain motors, all have the 3.250 main bearing :-O and yes those engine have gone north of 9000 rpm at times and a ton of them are force feed or nitrous feed too and they don't have half the problems of the Buick's 3.250 main bearings ... Again, it's a combination of width and diameter.. There is a ton of information on Reher-Morrison's website under tech talk ;-) Remember the great words of the wise ones "do a search ." Sincerely Gary M.
     
  16. gmcgruther

    gmcgruther Well-Known Member

    Gentleman , don't be fooled on what people say about the Big block buick main bearings. Yes, they are huge but, I contacted to big name engine builders and I was wrong on their main bearing size's but they are big block chevys but narrowed, grooved, lighting lightened, and coated. that includes their 1000+ cubic inch mountain motors. They told me, they spin their engines some times inexcess of 10,000 rpm and their mountain motors have strokes long as 5 to 7 inches long. Proper oiling of the main bearing in high horsepower engine (600-1000+ horsepower ) elminate the six 90 turns and have proper volume and pressure and everything will be ok. That's the words of two of the worlds best engine builders. Reher-Morrison and Sonny's Racing Engine's, if you doubt me ( which some of you will) then grow a pair and call both establishments to confirm this but, it will never happen because of their pride. I erge everyone on here to study their engines and their oiling system and call around because one to two people on here really don't give a dxxn what happens to your engine as long as they can do test with it. Thank God I call very high up people to get better results. By the way, Big Chief off of Street Outlaws has a cast iron gm pontiac block that produced more then 2000 horsepower on 3.250 mains :-O So, some people need to get their facts right before typing , right LarryGS???
     
  17. gmcgruther

    gmcgruther Well-Known Member

    Well, I called TA today on TA's new front cover and the oil pump. Man, let me tell ya, if people would call certain people to get what I got on the new front cover to the scavenger oil pump? I wouldn't had to argue with two people on here. TA's new front cover with their oil pump is good up to about 600-650 horsepower and anything past that, you are gambling and the Scavenger oil pump system is required for anything from about 675 on up. That came from one of the workers at TA Performance Products . This is what I have been trying to tell people, don't always listen to some people that wanna try new stuff but something that is proven and steady. Always make calls because its your engine not theirs .. Sincerely Gary M.
     

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