Eagle 5.967 vs 6.300 rod with 3.625 crankshaft

Discussion in 'Engine Tech' started by 434nova, Nov 14, 2017.

  1. 434nova

    434nova
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    I am looking to do a stroker, has anyone run into problems with using eagle 5.967 rods with 3.625 stroke? I am wondering if i should go with the longer rod eagle has which is the 6.300. How does the eagle rods hold up with the 3/8 rod bolts? I know other companies rods have 7/16. Im thinking the 3/8 rod bolts would give more clearence? What seems to work better in the stroker motors long or shorter rods. Im looking to turn the motor around 6500 rpm.
     
  2. dank GN

    dank GN
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    I would go with the 6.3 rod . I’m currently runing a 3.625 Crank with a 6.5 rod in my stage motor which has given me a zero deck . This decision really depends on your blocks deck height truthfully . If your block is all squared up and good to go I would deffintly go with the longer rod . There is many good things the come from it IMO . You also know that it doesn’t just drop in correct ? You will have some clearanceing to do on the block and the rods to clear the cam and block .
     
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  3. BEATAV8

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  4. marleyskater420

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    What bolt type does the rod with the 3/8" bolt have? If it is an ARP 8740 bolt, I wouldn't run it if you plan on making power over 650-700hp.

    There is a reason that stronger rod bolts cost extra. They do make a difference.

    If you're looking for a stroker kit, I would suggest to check the Advertiser's Specials section..this one company run by a bunch of hooligans is having a sale on a bunch of different types of stroker and stock stroke rotating assemblies... but I'd be careful, I heard they're all a bunch of scallywags (how often do you get to use that word in conversation, really?).
     
  5. Steve V

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    Here's a little tidbit if using GN1 long rod stroker kit. The bolts that come with it are chinese junk, must replace with ARP 200-6006 . The rings are moly coated not AP steel rings, with a serious motor I would only use the AP steel rings.

    The rods will need to be clearenced for the cam lobes and it's possible the oil galley will need to be clearenced as well. Lots of extra work goes into a stroker build.
     
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  6. BEATAV8

    BEATAV8
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    Research a bit on Molnar rods.
     
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  7. marleyskater420

    marleyskater420
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    The rods come with those bolts because they're cheap-o pieces that are made to a .05" tolerance, which is why they typically require a lot of machining to get right.

    Molnar's forged rods are the strongest forged offering for the Buicks that are available, in my opinion. For what it's worth, we worked with Molnar to design our "RPS / Molnar" billet 4340 rod that was specifically designed to be as strong as Crower rods, if not stronger! Molnar has helped start 3 separate companies (Oliver, K1, and now Molnar Tech.) and has over 35 years of experience designing rods..if there is anyone you want to be creating that product for your car, it is him!


    Shameless plug- One of our Black Friday deals has a rotating assembly that uses Molnar rods and has custom Racetec pistons that come in ANY compression ratio you want, and also come with steel rings....we try to sell products that we would run in our own cars.
     
  8. forcefed3.8's

    forcefed3.8's
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    Get Molnar rods. Dont skimp, dont use 3/8 bolts.
     
  9. Nick Micale

    Nick Micale
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    The discussion of long rod vs. short rod has been beat around on this board for years.

    Lots of tech articles and opinions have been discussed, but the info has been from all-out racers with obscene high HP, big displacement V-8's, which does not actually pertain to our puny V-6 turbo engines.

    I have had the fortunate experience to work with Ken Duttweiller on many of his V--6 builds, and respect his extensive engine building skills.

    A few years ago an article of his was published in a popular magazine was to the effect "that it makes no difference in power with a stock length rod or a 6.50" rod with the Buick V-6"!

    I know other engine builders in the race engine arena, and when building a large displacement V-8 with a long rod will increase 40-50 HP at high RPM.

    In all our Buick v-6 engine builds, we use a Molner stock length rod unless the customer demands a different rod,

    As far a rod bolt breaking or giving up, never seen that happen with stock or aftermarket one, but a rod can get destroyed with pre-ignition!

    engine.jpg
     
  10. 434nova

    434nova
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    The eagle rod uses arp 2000 series bolts. But i was wondering on the 3/8 bolts strength compared to the 7/16 bolt.
     
  11. MCH86GN

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    Ouch!!!
     
  12. Boost231

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    Got to love alumimum. That block was fixed..

    Sent from my SM-G935T using Tapatalk
     
  13. MCH86GN

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    No kidding. That's cool for the owner.
     
  14. ek02

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    Molner rods have more cam clearance than any other H beam rod on a stroker build. Rod to cam clearance still needs to be checked, but very little if any material needs to be removed. The side clearance is a little too tight with Molnars, about .004 depending on the crank, which is stock clearance. That's easy to fix if needed. Go with Molners for the best quality IMO.
     
  15. vboosted6

    vboosted6
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    If I was to do it again l would use shorter rod with a custom piston.Side wall pressure on cylinder wall be minimal.Making the block live longer and able to run longer duration cam.
     
  16. 434nova

    434nova
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    Does anyone have pictures of where the block needs to br clearenced? Specifically oil tube. Do the 4.1 blocks need to be clearenced in the same spots as the 3.8?
     
  17. Pronto

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    Do a search, there's plenty of pics and info. Btw, you asked the same question in 2013.
     
  18. ek02

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    The 4.1 and 3.8 both need to be clearanced where the rod bolt meets the oil passage. Mock up the crank, piston, and rod and grind where the rod bolt meets the passage. I grind a small amount off the rod bolt head and leave plenty of material to get a socket on it. I grind it until I get .060 clearance between the bolt and block. The passage will be about .125 thick after grinding. If you break into the passage you can use a piece of tubing in the passage to seal it off. I have never broken through on 4 blocks done this way. Go slow.
     
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  19. TURBOELKY

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    Long rod will result in less side loading on the side walls.
     
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  20. ~JM~

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