vbls

iTrader: (17)

ok im doing heads and cam, I tried to search but couldn't really find anything, should I do the rod bolts or just leave the stockers in there?

I don't rev high at all.

01ssreda4

iTrader: (96)

Leave the bottom end alone.

KCS

iTrader: (20)

I agree.

vbls

iTrader: (17)

that's what I was thinking too

ss performance

iTrader: (17)

If you are going to be spending much time at high RPM or if you are increasing you RPM range you might want to change them for some ARP's.

WS6ICK2k

Leave them alone don't turn it to the moon pick a cam that peaks in a safe rpm. When you need a short block in the future make sure to upgrade.

01ssreda4

iTrader: (96)

You gonna replace his rod bearings when them being out of round causes one to spin? Doubt it.

A.R. Shale Targa

iTrader: (2)

Just asking here...how is it that the ARPs apparently change the shape of the
big ends and yet supposedly the Katech ones do not. I've read where
replacing them one at a time and torquing helps to lessen distortion but what
about if the rods are out of the engine ?? I suppose just torque and measure
both before and after right ??

01ssreda4

iTrader: (96)

First, I'm no machinist. Second, I have no dog in this fight. What I have seen, is every rod bolt that clamps harder then stock will distort the rod bore. Also, each distortion is different (for whatever reason), some worse then others. I've seen someone measure with katechs and they distorted the bore also. Will this cause you to spin a bearing? Maybe, you could argue both sides. Have I owned aftermarket rod bolts? Yes I have. That motor threw a rod through the side of the block after about 1200 miles. Will I push aftermarket rod bolts on otherwise stock engines? Nope, not anymore.

A.R. Shale Targa

iTrader: (2)

Good to know ! I guess I'll do a before and after in the next week or so since
the LS3 rods I recently purchased are getting new bushings and I opted for
Katech bolts as well. The factory bolts with the underhead locating sleeve
just seem a bit funky and not knowing the history of abuse on these rods has
me worried. My guess and hope is that the 260,000 tensile bolts will change
the big end slightly to the point that a few strokes on the resizing machine
will make them perfectly round and give proper bearing crush/concentricity
without having to go to the .002" oversize bore.

01ssreda4

iTrader: (96)

And for those that missed the memo, katechs are being discontinued due to supplier issues. Remaining stock is all that's left.

ss performance

iTrader: (17)

Clamping harder is not the point, being less prone to stretch is.

Stock bolts stretch then fail at sustained high RPM or frequent high RPM. ARP bolts don't.

I'm not promoting changing the rod bolts only stating the circumstances under which I would change them.

Doing heads & cam is not what I would describe as an otherwise stock motor.

Rise of the Phoenix

iTrader: (27)

I've got rod bolts with my setup and I'm glad I do. When you spin it high it's good insurance.

JakeFusion

iTrader: (7)

If you're going to go ahead and get them resized, just get the ARPs. Save $100 and pay it to the machine shop.

However, once you factor the cost of factory rods, ARP or Katech bolts, and machine shop work (plus any balancing you may be doing if you're building up a new bottom end), you'd be better off just getting the Scat I-Beam Rods with 7/16" ARP cap screws. They're like $300 from several vendors on here.

I threw the ARPs in mine as cheap insurance. I figure 7000+ RPM the stock bolts will let go and destroy the motor or I'll spin a bearing with the ARPs and hopefully not damage anything other than the shortblock.

high impact

iTrader: (5)

Agreed^^^^ leave it alone until you decide to forge the bottom end with pistons and rods.

KCS

iTrader: (20)

Clamping harder is how you prevent stretch. Stretching a bolt of a given tensile strength will produce a "preload", kind of like a spring. In order to prevent stretching of the bolt during operation, the "preload" force clamping the rod together must be greater than the forces trying to pull it apart.

01ssreda4

iTrader: (96)

Now don't you go bringing common sense into the discussion!

So, if we know they clamp harder, thus distorting the bore......so we feel more secure at 7k rpms with a stronger bolt but out of round journal, or a weaker bolt and a round journal??? Clearly there is NO real winner in this scenario.

Exidous

iTrader: (11)

There is a winner. ARP bolts and a hone to fix OoR. :-p

KCS

iTrader: (20)

I agree. Best thing to do is follow ARP's instructions and resize the rods IMO.

ez2cdave

I suggest picking up a set of "budget" 4340 Forged rods. By the time you spend the extra money at the machine shop, you might as well step up on rod strength.

Scroll down till you hit your "budget" . . .

http://www.summitracing.com/search/d...SortOrder=Desc