BTL FED

iTrader: (9)

I had an engine builder say he could offset grind the the stock crank to 3.82, which would make the rod journals 1.888 <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> , he says they cryo treat and nitrate (sp?) all there cranks <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> , What do you think this would do to the strength of the crank? would a 1.888 rod journal be able to hold up to very much abuse <img border="0" alt="[evil]" title="" src="graemlins/gr_devil.gif" /> , the stock is 2.100 I believe?
Thanks

<small>[ February 08, 2003, 05:48 PM: Message edited by: 00REDZ28 ]</small>

-Joseph-

iTrader: (12)

We're waiting on the pistons to try that out. The crank is cut to 3.825" stroke and the 6.125" rods are here. The crankshaft probably won't last unless the balancing is right on.
We found out that some Nascar engines run the 1.88" rod bearing size in our research.

Miles in Michigan

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 00REDZ28:
<strong> I had an engine builder say he could offset grind the the stock crank to 3.82, which would make the rod journals 1.888 <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> , he says they cryo treat and nitrate (sp?) all there cranks <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> , What do you think this would do to the strength of the crank? would a 1.888 rod journal be able to hold up to very much abuse <img border="0" alt="[evil]" title="" src="graemlins/gr_devil.gif" /> , the stock is 2.100 I believe?
Thanks </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The formula for max torque allowable in a solid cylinder under a torque is:
torque = max_shear * (pi * r^3)
, where max_shear is the maximum shear strength of the material.

1.888 is about 90% of 2.1, and 0.90^3 is 73%, so a crank shaft 90% of the size of the original will be able to handle 73% of the torque, assuming the machining doesn't change the material properties, and ignoring the effects of cryo-treating.

That's how strong it ought to be, anyway. What's more important is if the engine builder will buy you a new engine if the cranks snaps. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Can you use stock rods and pistons with an offset-ground crank? I imagine you'd have to change one if not both, to keep the same deck height.

What I'm even more curious about is how much cost an offset ground crank will add to the price of an all-bore motor. JPR's got 382 all-bore short blocks for only $4200 (stock crank and rods). If you could add a 3.82" offset-ground crank for $500, you'd be at 404ci, and still under $5000. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

J-Rod

I brought this topic up a few months ago. Shirl Dickey built a motor for someone based upon the post I made on this subject. 1.888 is an Accura/Oldmobile Alero V8 bearing size. They are using it in NASCAR. If you have it done, make sure they put plenty of radius on the filet. but, yes, it is an easy way to stroke a motor.

Formulation

He is referring to me doing this for him. The crank may be actually be stronger than stock after we're done with it. We put a really nice radius on the fillet and after it's cryo'ed and ion nitrided it's definitly stronger than stock, let me know if you wanted to get it done, with the 6.0L block bored .060 over you get that 396 cu in, the cheapest way possible. It will run $500 plus a good core and that's cryo and ion treated!!!

BTL FED

iTrader: (9)

Yes this is who I was asking about. He is a really nice guy and really seems to know his stuff. Just asking around if anybody else has run a combo like this. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

RyanJ

i wouldnt call that possiblity very small. NASCAR uses a 1.88" journal for a reason. I have been thinking of this for a while. only problem is that it forces you to buy new rods...which is against my budget rules.

Fly By

I wouldnt do it. They do it because they have the money to tear the motor down every race, and if they blow it, oh well!

Can it take it? on a cast, stock crank, I wouldnt tell ya. Sure it will on a forged crank, but then again, its not going to last as long as the 2.100 jrnl. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

J-Rod

Here is my original post on this...

https://ls1tech.com/ubb/ultimatebb.p...c;f=1;t=008409

In case anyone was wondering who makes 1.888 rods, Carillo has a nice selection. Sets used by NASCAR teams for one race, or one dyno pull can be purchased from jrmotorsports for $550.
http://www.jrmotorsports.net/
look under products then select connecting rods. There are about 100 sets for sale...

Ackattack

There is also potential (though very small) gains from the reduced contact area of the crank to the bearings. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Formulation

I've spoken with my crank grinder whom has been doing racing crank work for 30 years and for top names/teams and has personnally done at least a dozen LS1 cranks both stock and forged Lunati's for me. I spoke with him about this exact setup recently and there is NO loss in stength going to a 1.888 rod journal if the crank is done properly. I feel very confident to sell anyone who wants 1 this setup with the matching rods. Bang for the buck you can't beat using a stock block and crank to make 396 ci's. We are using the Carrillo rods that new go for $2,200, hell the rod bolts alone are $500 on these and that's what I pay for the whole set of these rods--- amazing deal!!! We can get 3.822 out of a good crank without any spun journals of course. You have to allow 10-15 thou of clean up. So the total differnce in bearing size assuming STD bearing sizes is .212 - 12 thou cleanup will net around .200 of clean stroke increase. Also you can get a little more if you go with a 10-20 under bearing. But I would rather do a STD bearing so if you ever need to regrind it undersized it's still usable. Hope this helps, Thanks dave

Aircooled

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Formulation:
<strong> It will run $500 plus a good core and that's cryo and ion treated!!! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">How much does it cost to get one of these 0.2" offset strokers ballanced? I would imiagine that it would take quite a bit of Mallory Metal ($$) to ballance.

Steve

jleews6

iTrader: (2)

formulation I think this is a great idea.Someone needs to offer this with rods and pistons as a package.A complete rotating assembly for $2200 would have people knocking down the door." i would think"

I think the reason the nascar guys run small journals is because of such high rpm's.

Formulation

I think the Lunati cranks probably take more work to balance, I'm working out the final prices to put these together in the range you referred to!!

jleews6

iTrader: (2)

<img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

jleews6

iTrader: (2)

TTT

Jason 98 TA

iTrader: (4)

I just installed our prototype offset ground stroker in my 99 Vette. She should start tonight if we get everything bolted on <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> We will be strength testing her with a large shot of n2o to make sure they are worthy of selling to the public. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

CHRISPY

what type rod are you forced to use with this setup?
Would you sell complete balanced assemblies?
Say with a 4.030 piston?
Cheers,
Chris

Formulation'98

Chris, with a 4.030 bore some shelf pistons will work making it even cheaper, I am using a Carrillo 6.200 X 1.888 rods everything is off the shelf and just needs a good balancing job, can't beat that bang for the buck! Hit me up at indacalinc@attbi.com Thanks Dave

yobabiesdaddy2001

iTrader: (20)

how did this turn out?