I always hear it takes multiple sets of rods to make one good set.I have 4 sets and want to put a set together to get reconditioned. What should I be looking for? Chris
Buick Big-Block rods are forged steel, but mild steel not high-grade steel, and there's zero intentional heat-treatment aside from how they cool after manufacture. Exactly like Olds, early-'60s Pontiac, and most Chevy rods. Olds rods are considered "Rubber". The ancient Pontiac forged rods don't stand up as well as the later cast-iron rods. Chevy seems to get by OK, though. ALL of these rods were once used by Hot-Rodders before the advent of cheap, bottom-feeder Communist Chinese connecting rods. The stock rods were polished, maybe heat-treated, remachined as needed...and some lived and some broke anyway. 1. Reject any with obvious signs of degradation--rust, bent, dings 'n' chips, non-matching caps, etc. 2. Eliminate the ones with the biggest balance pads. Too much material in the balance pad leaves not enough material where it counts--in the structure of the rod. 3. With MOST rods, you'd want to get a set of eight close enough in weight at the big-end and at the small-end so that with minimal grinding (LATER) on each end, they'd be weight matched on both ends therefore weight-matched for total rod weight. This is REALLY difficult on Buick rods because of the goofy, non-industry-standard "center of mass" balance pads. You can get the total rod weight matched, but not so much all the big-ends and all the small-ends. Because each end of the rod isn't able to be matched, this somewhat sabotages the total engine balance--but what can you do? 4., 5., and 6. Haul the most-likely-to-be-selected rods to a machinist, have them Magnafluxed. Eliminate any with cracks/faults. While they're at the machine shop, have them checked for size on the big and on the small ends. Resize as needed. Resizing often includes upgrading the rod cap fasteners to ARP or other famous-name hardware. Decide BEFORE resizing the rods, whether you want to torque the fasteners, or "stretch" the fasteners. Make sure your machinist does the same when resizing. You don't want him to torque the fasteners, when you plan to stretch them. Grind and polish the balance pads/rod beams (LENGTHWISE) as needed to achieve weight match. Some folks would want to grind and polish before magnaflux, so the ground surfaces can be checked for cracks/flaws. Other folks don't want to waste time grinding rods with flaws, so they want 'em 'fluxed before investing the time to weight-match. What order you choose is your decision. I hate sending money to the people who murdered a million of us with the Plague, but the crazy Buick balance system makes a strong case for buying aftermarket rods if the projected RPM is going to be higher than typical stock performance use. If the RPM is low-to-moderate, the stock rods properly selected and reconditioned, would be fine.
Stay away from titanium rods. Strong and very light weight. But extended strength is worthiness. Ask me how I know.
By the time you sort thru 4 sets of rods to get one set That then MAY be good or NOT, and then have the needed new bolts installed and all 8 of them then you Mag, polish some and then resized you would be better served by getting any new aftermarket set of rods into the motor. Most times with used factory rods that you do not know the history of you have 100% no idea how hard they where beat on in terms of the rpm they had seen and if they where getting hammered by detonation. Used rods may be right on the verge of stretching and there is no testing that can be done to find that out, as not even a mag test will show that, that is other then putting them in a motor and keeping your fingers crossed!
The stock ones are proven....ive taken them to mid 10s and 7krpm..others have gone 9s...with limited usage....not lime we daily driving these turds.....ive never mixed a set either...just used what come out of it or a random set from my pile of them Is a molnar set better in terms of strength....idk..should be...cheaper..not really but close the way labor is now....made in china..of course.....would i still use stockers....hell idk haha
But to answer your question more directly and imo....600hp in 3700lb car with a 6500rpm is the limit.....less weight...get away with more rpm...trans brake..get away with less probably....lightest possible pistons....get away with more..internal balance...more im sure...all relative
I will admit tho....i didn't run my F1c94 procharger setup on the track for one reason.....it had stockrods....was 650hp NA then i strapped on 8lbs of boost...so it was makin a **** ton of power 1k im sure......on stock rods
But then the "new aftermarket set of rods" have to be checked by a machinist to assure that they're made right, because the bottom-feeder Chinese rods can't be trusted to be correct out-of-the-box. If they check good...fine. That's not too expensive. If not, they have to be resized, and/or the pin-end honed, so the cost increases accordingly. RPM on stock rods is going to be determined in part by piston weight...and Buick pistons are unnecessarily heavy due to the <1920s technology full-skirt design. Among the best things (about #3 on the list of mods) you can do to a Buick big-block is to toss the crappy OEM pistons in the scrap bin in favor of something with significantly newer engineering and proper compression height. I don't want to list a number for "safe" rpm. Some guys get by with far higher RPM than I'd be comfortable with; and others spin bearings at what I'd consider moderate speeds.
One thing i can confirm is we only have two budget offshore rod options...Eagle and Molnar....Tom at Molnar is small operation and an ex engineering guy from Oliver..and iirc had his hands in Scat when they started up.....his are machined IN HOUSE to his specifications.....still a china product ultimately tho....eagle....no idea theirs are finished machined here also im pretty sure....given the choice..molnar everyday twice on Sunday
I had a set of stk rods in a 464, iron head ran low 11 to high 10s....turned 6500 ever shift rods never failed. Had about 2000 passes when the block started taking water in. Put a set of molnars in, ran less than 70 pass and lost the rod bolts. On 1 rod.....it made a huge ass mess. I was running it harder 6700-7000.....but the rod it self is twist from where the crank beat it through the block......the other 6 look perfect minus a few dings.......and the other rod bearing could be reused...... So are the better?????? Eagle makes a 6.7 bbc rod set for under 400......the 2 sets I've used on bbc builds have been great.......1 set was the cheaper sir rod one was the fir rods. Me personally if I ever build another it getting good American rods from Crower or Oliver........the 1000 I saved in buying molnar has cost me 5x that to fix the damage. Rpm and use would dictate my choice......a nice 500hp street driver I'd put arp bolts in and have them reworked.......a race motor its pay now or pay later. I ran a stk 50,000 miles 430, right from the junk yard running 11.30s, shifting 6200-6500.....not balanced orginal bearings for over 150 passes b4 problems started.
No question--DECENT aftermarket connecting rods made with CLEAN steel, processed/machined on equipment that's not worn-out, not operated at high feed-speed by high-school-age kids working 70 hours a week, who sleep on a mat in the back room, in a building that has nets on the roof to prevent workers from making a statement by committing suicide on company premises, and not using counterfeit "name brand" rod bolts, are likely going to be better than bottom-feeder Chinese crap, or even Communist forgings "finished" in the USA on worn-out equipment operated at insane feed-speeds. Same holds true for crankshafts, front covers...ANY aftermarket part. There's always a way to make it cheaper, if the decision-makers quit caring about durability, suitability-for-use, warranty claims, etc. IF YOU'RE LUCKY you get what you pay for. Buying cheap imported crap will almost certainly get you cheap imported crap. Paying more for quality may or may not get you quality--ethics in business is getting harder to find.
There is still alot of truth in paying for a name tho....me and my new builder were discussing just this that..showed me 3 LS cranks while i was there and tgey were absolutely identical..in everh single way...even down to smallest detail.....one was a $1600 Callies....other two were a LPC and a Molnar......the Molnar was my brothers for his 408......the molnar was around 1150...the LPC...$875......same crank ..same country of origin.....callies had a nice fancy box tho
Im actually switching to BBC for my performance satisfaction...i dont have the $$ or the patience for the BBB stuff anymore...ive owned close to a dozen sets of TA heads.....have 2 sets sitting in our office now.....but they will be the last for me....ill be a stock oval port BBC guy from here out....got two sets of 781s and ill he getting a US made 4.25 crank here soon ...all US or OE made for me moving forward
I know it's not in the right section, and it's a bit of a thread hijack(sorry original poster) but.... Inline for a set of the TA heads, if you decide to part with them, hugger.
Im not spending any more $ trying to make a Buick fast....ive got a 68 camaro that im gonna do a day two tunnel ram build and a 67 c10 that will be a 496 600hp cruiser.... Ill still have a 500hp GSX...71 aluminum head stage 1 4speed...600hp 70 GS 455 4speed and a 10sec 87 Turbo T ha..so still a buick guy just not fooling with anymore. I sold the 65 Big tire car because i had to...and doin so just put a sour taste in my mouth tbh
