What is the HP/TQ limit of 2 bolt main LT1 shortblock?
09-09-2009, 09:15 PM
#61
TECH Apprentice
The load is actually parallel to the connecting rod, which varies from nearly-vertical to nearly-horizontal depending on rod length and crank angle. However, the register-fit directs this load straight down. Putting bolt tension in any other direction from straight up (directly counteracting the load) will be less effective at keeping the main caps in place. There is another reason to splay the mains, which trades off cap stability for something else.
Try and understand some concepts from Strengths of Materials, Statics, Machine Design, or even how a bolt works (just like a nail, right), then convinced yourself that I'm the one that "can't grasp the concept". When you learn how to plot it on Mohr's circle, calculate bolt stress and stretch, or even draw a "free body diagram", come back and explain it all to me.
But, hey, don't believe me with my measly 900 hp and straight 4-bolt mains. You could always asked George Baxter, who make over 1100 hp on straight 4-bolt mains.
Since I got no satisfactory response from you, I did some digging on my own. It seems they splay the outer bolts simply to tie them into a stiffer part of the casting, which prevents cracking in the block. It has nothing to do with main cap stability, putting the bolt in shear, or nailing wood, after all.
Mike
Try and understand some concepts from Strengths of Materials, Statics, Machine Design, or even how a bolt works (just like a nail, right), then convinced yourself that I'm the one that "can't grasp the concept". When you learn how to plot it on Mohr's circle, calculate bolt stress and stretch, or even draw a "free body diagram", come back and explain it all to me.
But, hey, don't believe me with my measly 900 hp and straight 4-bolt mains. You could always asked George Baxter, who make over 1100 hp on straight 4-bolt mains.
Since I got no satisfactory response from you, I did some digging on my own. It seems they splay the outer bolts simply to tie them into a stiffer part of the casting, which prevents cracking in the block. It has nothing to do with main cap stability, putting the bolt in shear, or nailing wood, after all.
Mike
Last edited by wht97ws6ta; 09-09-2009 at 09:41 PM.
09-10-2009, 06:10 AM
#62
Oh, you mean this?
Well, wht97, I guess we have to just agree to disagree. When you get to the 900+ hp level, perhaps you'll show me how things are done. Until then, I'll continue to use bolts in straight 4-bolt main caps and you use nails in your splayed caps. Let me know how that works out for ya.
Mike
...For LT1 blocks there is less material in the webbing thus a 4-bolt splayed is WEAKER than a 4-bolt straight.
Really tired of making this argument. Too many retard machinists trying to get as much cash as possible from customers have pushed this 4-bolt splayed agenda on LT1 blocks. Again the webbing is weaker on LT1 blocks, thus splaying them only puts the bolts into the weak webbing. The webbing is strongest where the caps register, thus 4-bolt straight conversions are stronger...
Really tired of making this argument. Too many retard machinists trying to get as much cash as possible from customers have pushed this 4-bolt splayed agenda on LT1 blocks. Again the webbing is weaker on LT1 blocks, thus splaying them only puts the bolts into the weak webbing. The webbing is strongest where the caps register, thus 4-bolt straight conversions are stronger...
Mike
09-10-2009, 09:46 AM
#65
Everyone has their own opinions, some guess, some think, some just heard. Of course our engine builder which has been in the business for some 35 years, ONLY builds high end horsepower motors. He has built motors for top pro racers, Outlaw, NHRA, IHRA, WInston Cup ect He has guys working for him that worked for Brodix, Rheer Morrison and other top name companies. He recommended spayed on my LT1 but I'm sure people will come in and say he does not know what he is doing..To each his own...
06-24-2011, 12:24 AM
#66
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Have you ladies ever heard of "guy wires" Oh, you mean this?
Well, wht97, I guess we have to just agree to disagree. When you get to the 900+ hp level, perhaps you'll show me how things are done. Until then, I'll continue to use bolts in straight 4-bolt main caps and you use nails in your splayed caps. Let me know how that works out for ya.
Mike
Well, wht97, I guess we have to just agree to disagree. When you get to the 900+ hp level, perhaps you'll show me how things are done. Until then, I'll continue to use bolts in straight 4-bolt main caps and you use nails in your splayed caps. Let me know how that works out for ya.
Mike
Also,The splayed bolt (on the same bank of the firing piston) is applying a closer to purpendicular clamping pressure on the cap .
My engine has Splayed caps....no brainer. Not because of webbing strength, because of the additional offset pressure the splayed bolts add ( my guy wires).
4 bolt straight only works on one dimension, there are many forces at work when the power stroke happens...imo
06-27-2011, 11:07 AM
#69
08-05-2022, 02:09 PM
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Maybe so, but depending on what you are trying to accomplish, most of the time, it can be done with the 2 bolt set-up for what he is describing. But yes, definitely the splayed mains are superior to straight...do you need them...depends on what you are doing, what supporting parts you have internally in the engine, what revs you want to wind it to for how long, etc. Like you said.
As far as what had what mains, originally, before 4 bolts were as common, they started out in trucks is what I was trying to say. Corvettes have them now, and for a while, but they didn't always.
As far as what had what mains, originally, before 4 bolts were as common, they started out in trucks is what I was trying to say. Corvettes have them now, and for a while, but they didn't always.
