Engine Bearings?

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by hirevn, Feb 7, 2017.

  1. hirevn

    hirevn New Member

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    I have my first blown alcohol BBC build getting close to assembly and have been trying to figure out what rod/main bearings to put in it. My previous blown race gas 565 used H series bearings with no issues but now we changed it up. Its a 565 with MGP aluminum rods, 11:1 with a 1471 and estimated 1800 hp in a heavy door car.
    Clevite mentioned a national back order on V series bearings but looks like there still available from some places, i was also looking at the King HP series as maybe the best option for my application. Also wondering if its worth getting them coated or running them as is?
    Any advice on this is appreciated.
     
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  2. Bjs344

    Bjs344 Member

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    I got a little Leary of king a couple years ago but didn't find anything better so that's what I run now (~1800 hp BBC with sbc rod journals). I have to change them about 20 passes on average, but have found problems earlier than that. Either flaking, tension loss, or inevitably will squish one or two. I run the softer king, not the trimetals.
    They say trimetals won't work in boosted applications.

    Maybe coatings would help, but I would still suggest regular inspection. I've heard tales of BBCs at this power level going way longer without bearings, but they seem to be the exception and not the norm.
     
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  3. Critical Mass

    Critical Mass Member

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    Hi hirevn,
    I would recommend the Clevites. I have essentially the same set up as you do. I use the Clevite MS-829HXK on the mains and the CB-743HXNDK on the rods. I am assuming your rod caps have dowel pins in them? These bearings are oversize and coated. I got 0.002 on the rods and .003 on the mains with them.
     
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  4. hirevn

    hirevn New Member

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    Yes my rod caps need the dowel pin holes in the bearings. MGP suggests .003-.0035 for clearance on the rods I have.
     
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  5. Comax Racing

    Comax Racing Member

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    .003" to .0035" is minimum on the rods. I use GRP rods in my BBC and they say up to .006" . .002" and you are looking for trouble in my opinion. .0035 on mains 1-4 and I put .004" on the rear main. I use the King bearings and have had no issues.

    Corey
     
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  6. Bjs344

    Bjs344 Member

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    Those clearances are my targets also.

    How much power and how many passes before you change or see squish/tension loss?
     
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  7. Torment

    Torment Member

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    I run the Clevittes in mine as well, uncoated though, door car pushing 3600lbs. I'd estimate 17-1800HP. .003" on the rods, .0035 on the mains. I bet I have over 100 passes on them - plus street miles... lol
     
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  8. hirevn

    hirevn New Member

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    Thanks for the help here guys. I talked with Clevite tech about my application and he recommended using the V series so i am going to try them out. I had to gather them up from two diffrent places to get a full set of STD and X sizes due to the backorder on the V bearings.
     
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  9. Critical Mass

    Critical Mass Member

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    Hi Guys,
    I am trying to get 0.0035 clearance on the Mains of my BBC. My crank has standard clearances. My supplier wants $100 each for XX bearings and he doesn't recommend them for Blown Alky. He also said Clevite is discontinuing the XX bearings? I know the easiest way is to grind the crank so a Std. bearings can be used without using the X bearings.

    That being said, how do you guys get a 0.0035 clearance or larger?
    Thanks for any input. Joe
     
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  10. hirevn

    hirevn New Member

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    I have been wondering the same thing myself, what do you do if an X is not enough? Maybe another manufacture like king or ACL has XX?
    I would guess you just need to have the crank turned down.
     
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    Last edited: Feb 21, 2017
  11. Bjs344

    Bjs344 Member

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    Kings tend to have a 1/2 thou extra oil clearance for the same size bearing. Otherwise, it needs to come off the crank. No big deal at the machine shop I use.
     
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  12. Critical Mass

    Critical Mass Member

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    Turning the crank is not the issue; it's re-nitriding the crank is the pain.
    Joe
     
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  13. Bjs344

    Bjs344 Member

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    I'm no expert, but don't think a .001 cut needs any post hardening??
     
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