LT1_Fireman

iTrader: (12)

I made over 700 to the ground on a 2 bolt main block with no problems...

engineermike

Wouldn't be the first time an expensive fad is marketed well and brought in money.

ElkySS

iTrader: (6)

i think you guys are getting off topic. lets make this easier.

what is the lowest hp you have broke a bone stock shortblock at with a reasonable rev(6500and below)? and im not talking about what happened when your pick up tube fell off. i want 100% from power only.

StangeatinZ28

i'm on a stock 2 bolt shortblock spraying the **** out of it with no problems, and at 135k on the bottom end im guessing i'm somewhere close to 500 on the spray

engineermike

Problem is that symptoms of cap instability include wiped main bearings, broken cranks, and block fretting - not necessarily broken blocks.

97Z28SS

iTrader: (5)

Straight 4 bolt mains are stronger then splayed 4 bolt, then why do Chevrolet and EVERY aftermarket block manufacturer use SPLAYED 4bolt mains on all of their RACE and HP blocks?

RamAir95TA

iTrader: (2)

I think the argument is that there is less material on the LT1 block to secure the outer bolts. The "RACE and HP blocks" you speak of are most likely designed and cast with 4 bolt splays in mind.

96capricemgr

iTrader: (1)

I think a lot of folks are applying what they heard about gen 1 blocks to LT1 blocks which are a different casting.

Lots of blind bench racing going on without any regard to what ACTUALLY WORKS. Which is absolutely perfect because that is all the OP cares about, bench racing.

AChotrod

iTrader: (17)

Ill let you all know when my 2bolt mains break. My car makes good power NA and will be getting a nice big shot of drugs!!
The real question is......
How many licks does it take to get to the center of a tootsie pop??????

7.0 camaro

mine was dynoed right at 400. and then its had a 150 shot on top of that for a few years now. seems like 550 to 600hp is not hard on a 2 bolt. i have eagle crank and rods.

B'klyn9C1

Ben,

Was that 700 HP to the ground done w/NOS or N/A?

Was it done foan extended period of time or distance like over a 1/4 mile on a road course?

7.0 camaro

i believe he has a procharger. he said he had a D2R.

wht97ws6ta

Thats one of the points of going splayed is to get that outer set of bolts into some meat. And Engineermike who in the world told you that splaying the outter bolts does nothing for clamping force????

engineermike

Nobody told me. I figured that out on my own!

wht97ws6ta

Ok im not trying to make a big argument here or tell you that your wrong i see how your looking at this picture. But lets stand back and study this picture for a minute. Ok you are right about having the bolts strait to an extent. Splaying the outter bolts probably will not induce the same amount of direct clamping force in the general area around the bolt, as it would if it were strait in the material. Thats why your inner bolts will always be strait. Having them strait will induce more clamping force in a more concentrated area which is needed in that particular area. But the big question here is... why is it that splaying the outter bolts makes a block stronger? To answer that.. lets just not even think about clamping force for a minute or so here. Ok say you nailed to pieces of wood together with 4 nails and you nailed them strait in the wood. You will find that the 2 pieces can be seperated with minimal effort. Remember we arent talking about clamping force here. There is minimal clamping force induced by nailing 2 pieces of wood together. But lets say you nailed 2 pieces together by placing 2 nails strait in and 2 more at a 15 degree angle to the outside of those bolts. Still you havent increased clamping force any, but youll find that the to pieces take a much greater force or effort to seperate. This is simply because splaying the outter nails spreads the load across a greater span of material when a force has been aplied against the fastners. So its not all about clamping force alone. So if placing the fastner strait in the material concentrates load right around the fastner, then explain to me why you would want to put a bolt strait in the mainbearing saddle where the least amount of material exsist. Just doesnt make sense to me, when splaying the outter bolts gets you away from the bottom of the cyl into some more substantial material. Not only that, you spread the load across more material by splaying the outter bolts. With that said, i am not convinced that splaying the outter bolts will make a block weaker than it would be with strait 4 bolt mains. Your just not seeing the whole picture if you believe that it will be weaker. These aftermarket blocks dont come with splayed mains for no apparent reason. This isnt rocket science, only simple physics. Remember that clamping force is only as strong as the material being clamped to in this case.

engineermike

Putting in nails at an angle (i.e. toe-nailing) is stronger, but not for the reasons you listed. The only thing that holds a nail into wood is friction (sometimes glue, with pneumatic nailers). So, if you put a nail in same direction as load, you just have to overcome friction to pull it out. However, putting them in at an angle puts the nail in sheer. It should be no surprise that the sheer strength of the steel nail is much greater than the friction holding it in the hole.

Main bolts aren't nails, though. Thankfully, 1:1 friction isn't all that holds the bolts in. Plus, when you put steel in sheer (splayed), it's actually weaker than direct tension. Then, if you managed to put the splayed bolts in sheer, something else very bad already happened since there is slack in the holes.

The main bolts prevent the cap from deflecting downward. The register fit prevents the caps from moving side to side. The only direction they are free to move is axially, so some high-hp builds put dowel pins to prevent that.

Again, on my 900+ hp straght 4-bolt conversion, I'm seeing fretting under the caps, but no block cracking at all. If I can't get enough clamping force to make the main caps stay still while not cracking the block, then why bother with the so-called upgrade?

What failure mode, exactly, are you trying to prevent by splaying the mains?

Mike

AChotrod

iTrader: (17)

well fine on my next block Ill do a 6bolt conversion!! 4 straight and 2 splayed bolts! lol!

wht97ws6ta

ok i explained shear strength in an earlier post, to keep the post shorter i didnt want to get into all that because most people can put 2 and 2 together. I realize that you are using the shear strenght of the nail when splayed more so than friction. I used that example because clamping force wasnt the main cause of the added strenght to prove my point. Have you ever thought about your fretting is coming from the lose of clamping load because you are stretching the bolts? Well as i said earlier when you splay the outter bolts you are using tensil and shear strength. The strength of a splayed bolt is going to be directly related to the angle that its placed in the material and the direction the load is applied from. Thats one of the reasons why the angle is not so much of an angle (15-20 deg). If it were in at a 45 deg angle then yea it would make the fastner weaker because shear is weaker than tensil strenght. But when placed at THE right angle you will make the fastner less prone to stretch because the load is shared by tensil and shear strength. Just because your 900 hp small block has survived with your strait 4 bolt mains dont make it the strongest setup.

engineermike

How bout you plot all these theories on Mohr's circle for us.

wht97ws6ta

How bout you prove your theory to me that strait 4 bolt mains are stronger than splayed. You havent proved anything about the theory because you have a 900 HP motor with them in it.