Quick background, I bought a used LS2 short block that wound up having a spun rod bearing. Before that the original plan was to throw on a pair of 243 heads with AI’s 226cc porting package that I already have sitting in the garage and then swap the engine in to a ’84 K5 Blazer with a 4l80e and use it as a daily driver in the summer and a camping/hunting rig in the fall.

Now the question, the crank has a pretty deep groove where the rod spun and I don’t think a machine shop is going to be able to salvage it so I’m looking at other crank options and wanted to see what you guys thought would be the best route. I could try to pick up a used crank from a junkyard/recycler for around $100 and then have it cleaned and polished at the machine shop for another $40-150 (price depends on if it needs to be ground or just cleaned). The other option would be going with a reman crank from ATK or Crankshaft Rebuilders (sold at Autozone, O’Rileys, etc) either one being around $300. Of those two, Crankshaft Rebuilders looks pretty tempting since it comes micro-polished and includes either Clevite, Federal Mogul, Sealed Power, or King rod and main bearings for the same price as ATK’s crank by itself. Either way I go I would re-use the stock rods (already have ARP bolts) and get everything balanced after I figure out what pistons I’m going to use. Which way would you guys go if you were on a relatively tight budget and wanted to get the car back on the street sometime this year?

PS. I know a lot of guys automatically think “go stroker” whenever the crank needs to be replaced, and that was my first thought as well, but a couple things are holding me back. The first being the initial cost of less than $900 (for a reman crank, stock rods, and Mahle or Wiseco pistons) versus over $2000 for a stroker rotating assembly from one of the sponsors. The second thing being the heads since I don’t have the funds to buy another set, especially if I’m going to pay the extra $ for a 402. I know the AI 226cc heads kick *** but I’ve seen a ton of people on here say they won’t breathe enough for a 402 and you won’t get the full benefit of the extra cubes…

 

Did the ARP rod bolts come from the engine with the spun rod bearings?

 

Yeah the previous owner had installed ARP rod bolts and main studs. Why do you ask?

 

Just popping in the ARP bolts (usually) distorts the big end rod bore which likely led to it eating the bearing material and ultimately spinning the shell
That particular rod should be junked, specially if there is blackening from the excessive heat it endured.
Also R.A. sells DNJ hyper pistons in .020"(.5mm) or .040"(1mm) oversize with rings for under 3 bills since a daily truck app doesn't NEED forged stuff
From my experience, the big end of LS rods ALWAYS(even re-using factory bolts) need a few licks on a sunnen rod hone to true up the bore shape AND create a crosshatch which helps grab the bearing shell when it's crushed
Unfortunately the best bolts available are the now discontinued Katech ones which only distorted the big end about .0003".......so as mentioned, few strokes and mine came right in and were still within spec. Did NOT need to go .002" over or anything.

 

You're probably going to need the crank balanced too.

I'd just pick up a used crank and have it cleaned, balanced, and polished.

 

Because if I had a dollar for every person that put ARP rod bolts in their stock rods and then spun a bearing, id be a rich MFer.

 

Thanks for the replies guys. I had read about the ARP bolts distorting the rods on here but for whatever reason I never put 2+2 together about that being why the previous owner spun a bearing...

A.R. Shale Targa - I've never heard of those DNJ pistons before do you know who carries them? When I tried to look them up on Google I could only find a couple of import race shops that carried them... I know Summit carries Speed-Pro flat top pistons in 4.020" for around $250 and Sealed Power moly rings for another $85 that I was originally looking at. Would the DNJ's be any better than those?

KCS - I'll definitely be getting everything balanced. Just trying to work out all the details so I can have all of the parts ready before I take everything in to the machine shop.

 

R.A.........rock auto..........(sorry Kent....plz don't hollar @ me/non sponsor)
look up 2006 vette LS2......they have the thinner 1.2/1.5/2.5 rings instead of the 1.5/2.0/3.0 rings of the LQ stuff
They have coated skirts and floating pin locks as well; plenty of pics in my (Goofy Combo 368) build thread
My LS2 block needed a .015" deck cut to achieve zero deck height but the iron blocks are .010" shorter than the aluminum stuff (according to what I've read)
so just a light clean up cut should have you in business
Just looked and it appears that they only have Engine Tech brand now....hmmmm weird
Perhaps Amazon or some one else.....looked at the DNJ website and the 3170 pistons/3169 rings are still valid numbers

 

Hi, MY method could save your crankshaft.

I use Castillo to "offset" grind the throws in your case.
OBSERVE the wear marks, you WILL find them on the BEST SIDE to "stroke" the crankshaft, just .015", with "30" undersize bearings.

The money you SAVE for a No Deck machine will almost pay for the Crank Grind ($150.00)

You could buy my Forged Rods, on sale now, for less than ARP stock reworks.

Would you like my help ?

Lance

 

Castillo knows his stuff. I used to send them my cranks for offset grinding and nitriding a long time ago.

 

A.R. - Thanks, I was able to find the pistons and rings on Amazon for around $250 once you posted the part numbers. I'm waiting for the seller to confirm the over bore size but so far they looks like a solid way to go.

Pantera EFI - Sent you a PM for more info.

 

Out of curiosity, what's the difference/advantage of the thinner rings vs the LQ stuff? I looked at a couple of Mahle, Diamond, and DSS piston sets and they all come with the 1.5/1.5/3.0 rings...

 

Less weight and friction means more power. Usually not very much though.

 

Hi Anthony, STOP your piston order.

The FIRST item is to "finish bore/hone" your block.

The Hone to 4.003" vs Bore to ??? could save you $150.00.

The cost of a Forged Piston (4.003") would be lower than your CAST/BORE cost.

GM states their LS AL blocks NOT TO BE Bored.

Lance