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What con-rods would you buy?

PostPosted: December 18th, 2008, 2:41 pm
by bvlahov
I just bought a set of used Carrillos with 7/16 Carr bolts.
Those should be as good as you can buy. For $264 I just
didn't want to pass on that. New ones are $2100+.

I'll have them inspected when they arrive, install
new bushings, have them resized if necessary and I think
that I should be more than safe
for my goals (550-600chp/7500rpm).

It's allready over now but I'd like to know what would you buy
and why?! Did I make a mistake when I bought used rods?
Lets say that this would be 7500 rpm, 550-600 crank hp engine.
I'm talking about 4340 forged 6" H-beam rods.

1. Brand new Manley rods that are somewhere in $600 range.

2. Brand new Eagle rods - $520 range

3. Used Carillo rods for $600 ($2000 for new)

4. Something else? (manufacturer and price?)

5. New Callies Compstar rods - $550

6. New K1 (by Carillo) billet H-beam - $400 or $465 (with ARP 2000 bolts)

Re: What con-rods would you buy?

PostPosted: December 18th, 2008, 4:29 pm
by grumpyvette
If you got a set of those rods in good shape at that price you, probably got a GREAT DEAL even if they are used rods, naturally youll need to have them checked by a good machine shop before re-use.

The better 4340 connecting rods from most manufacturers themselves rarely fail, its the bolts that stretch or the valve train,control ,lubrication,and clearance issues or detonation, that causes the problems that get mistakenly listed as rod failures.


ALL make nice and lower cost /affordable connecting rods

Now obviously when selecting a connecting rod, the stress and rpm limits and the matched components must be considered,

the best connecting rod on the planets not going to survive a constant repeat high speed impact with or be expected too successfully try too compress busted chunks of pistons or valves that failed for one reason or another against a cylinder head where its expected to survive the impact stress with whats left of a piston or the head of a valve that busted off ,or that comes apart due to detonation or valve float issues.

Its been my experience that almost any rotating assembly with 4340 forged connecting rods (with 7/16" ARP bolts (L19) OR (ARP2000)if possible) are strong enough , if the clearances are correct and they were assembled according to the instructions with a rod mic, stretch gauge
Image ... toview=sku

or even the correctly used torque wrench, for most if not all street strip or even the full time race engines most guys commonly build that produce under 4500fpm in piston speeds and under 750 hp.

Almost without any exception the busted / bent/damaged connecting rods and the damage they got blamed for was the RESULT of,and not the CAUSE of,a piston or valve train failure, due too a lack of valve control, or detonation , or clearance or lubrication issues , and NOT a rod failure.

I like CAP SCREW equipped connecting rods with 7/16" (L19)or (ARP2000) rod bolts in EITHER (I)beam or (H)beam designs MATCHED to an INTERNALLY BALANCED ROTATING ASSEMBLY with reasonably long rods, 2618 forged pistons and tool steel piston pins in the bushed rods in a full floating and balanced assembly with a well designed lube system


strength, obviously it depends on materials, design, care in manufacturing and which connecting rods are being compared properly prepared LS7 or L88 big block rods are a whole lot stronger than the stock 3/8" rod bolts big block rods, but many of the better aftermarket rods are significantly stronger that even the l88 rods
I beam rods typically have a balance pad and thats a good feature, typical H beam rods are SUPPOSED TO BE nearly identical in weight, as they are usually machined not castings (obviously they too occasionally need to be balanced)






better aftermarket

Re: What con-rods would you buy?

PostPosted: December 19th, 2008, 7:58 am
by bvlahov
Thank you very much for such detailed post.

I've bought these rods because in my opinion (and I may be wrong),
it's better to use high quality components (even used if they're
checked to be good) than lower quality.
I have also bought Callies Dragonslayer crank (used), and I could've
bought new forged Eagle for even less money.
But when i did research on crank or rod failures, it's almost impossible to
find broked Callies crank or Carrillo rod.
With Eagle, that's not the case.
I'm not saying that Eagle is junk, but in my opinion, used Callies will
allways be on top of the list over new Eagle.
Same goes for the rods.
A lot of people have different opinion, but this is my opinion.

Re: What con-rods would you buy?

PostPosted: December 19th, 2008, 8:14 am
by grumpyvette
youll seldom have problems with that theory, as most parts failures I see are with the components purchased with LOW PRICE rather than QUALITY being the prime factor in thier sellection.
decent 4340 forged components that are correctly clearanced, ballanced and lubricated rarely just FAIL.
detonation, and loss of valve train control issues probably account for most problems, and lack of proper lubrication and cooling most of the rest if the basic configuration was properly assembled, clearances were checked and assembly ballanced and operated within reasonable limits on piston speeds. try to stay under 4500 feet per minute in piston speeds with forged components and well within the valve trains designed stability limits in rpm.


BTW heres an article with a TON of good basic info, its slanted toward PONTIAC, but about 80% or more of the info applies to most american V8 combos

Re: What con-rods would you buy?

PostPosted: December 19th, 2008, 11:44 am
by bvlahov
Thank you, great infos!

Re: What con-rods would you buy?

PostPosted: December 19th, 2008, 12:03 pm
by grumpyvette
these threads help almost everyone that takes the time and effort to read thru the info in the threads and sub links

BTW ON my LAST BBC build I discussed, connecting rods with the guy I was building it for, he wanted to reuse stock rods untill I pointed out the cost vs strength issues
"the 7/16" ARP connecting rod bolts are about 18% larger in cross sectional area than the 3/8" bolts and the better L19 or ARP 2000 bolts are a MINIMUM of 150% stronger than stock bolts even in the smaller 3/8" size,, the larger 7/16" is at least 200% stronger than the stock bolts in the rods.
but ID strongly resist the urge to just drill out and install 7/16" ARP rod bolts in rods designed for the 3/8" rod bolts, theres a very good chance youll have removed enought material from around the bolt to effect its strength.
the amazing thing is that the total out the door cost of even the moderate aftermarket forged 4340 cap screw rods, is similar or even cheaper than the ,machine shop cost of the arp bolts and reworking the stock connecting rods.

example ... cts_id=519 ... cts_id=243

YEAH! maybe.. IM paranoid but I generally spend the extra $90 for the upgraded rod bolts...and we bought the H beams above with the better bolts installed for his 427 bbc, hes been running thru the lights at 7200rpm and never had a problem

ITS ALMOST ALWAYS A BETTER IDEA to buy a matched ballanced kit with all components supplied from a single source
heres a few IVE used with good results ... 5f1f37f9e5 ... ath=71_231

INTERNALLY BALLANCED (SCAT, or LUNATI, or CROWER) 4340 steel FORGED KITS WITH 7/16" ARP rod bolts and clevite (H) bearings, and forged pistons are prefered in most cases, the scat 9000 cast steel cranks work ok for mild performance applications but INSIST on 7/16" ARP ROD BOLT RODS and ID strongly suggest INTERNAL BALLANCING

Re: What con-rods would you buy?

PostPosted: December 19th, 2008, 12:53 pm
by bvlahov
This is definately best site for somebody who is looking for
some technical help and infos.

You did really great job with organizing this site.

Re: What con-rods would you buy?

PostPosted: December 19th, 2008, 1:05 pm
by grumpyvette
thanks! as I get time to transfer data this site should easily quaduraple in size/info at the least, if you or anyone else has a few buddies you can get to join the site, please ask them to join as the more questions, info and input the better.

Re: What con-rods would you buy?

PostPosted: December 23rd, 2008, 5:30 pm
by grumpyvette





more info you might need

forged components are generally stronger
(IE will take abuse longer and at greater stress levels) and forged pistons are slightly more heat resistant than hypereutectic or cast
as a general rule if your going to exceed 100hp shot of nitrous or have the rotating assembly spin at near 4000 feet per minute in piston speed forged components tend to be a good investment