which rod for a bracket motor

i'm upgrading my combo, time to ditch the old rods & step up to something newer & stronger. I'm looking for a set of 6.535 rods to suit my stroker, HP is around 900, reving to 8k. what do you guys feel would be a good reliable rod to fit this combo?

http://www.dragracecarparts.co/oliver-billet-i-beam-connecting-rods-bb-chevy-6-535-length-c6535bb8/

If cost is no object here they are. Callies Ultra would also be there, as would Crower or Carillo.

But realistically you could probably run Scat or Eagle H-beams or Molnar or Compstar or K1 or 440Source, no problem.

The real question is your rpm is 8000, what is your stroke and how much does the piston/pin weigh? The inertia loading at the top of the exhaust stroke is what kills rods, that and detonation.

R.

I've been very happy with Molnar. Call Tom and give him your stroke, piston/pin/ring weight, and desired RPM level. He'll give you an honest answer. Mine were $579 shipped. The weight was light, tolerances were with-in .0001"
Doug

I've got a set of GRP rods mated to a set of Ross pistons that lived @ 8200 rpm, in a 408 cu.in 440-1C headed motor, injected on alcohol.

GRP here

To be honest, I cant see myself using Scat, Eagle & definately not 440 Source rods in a 900 HP engine. I'm also leaning toward Steel rods so GRP's are out too. Never seen Molnar rods so i'm not sure how strong they are, i know theyre lighter but are they as strong as Compstars?
My pistons are custom Ross pieces @ 4.400 dia. with their generic pins running at 12.5 compression running on on gas, no spray.
i remember a few years back someone did a comparrission test of the different rods, anybody have a link to that?

questions about Molnar rods? Call Tom himself.

Oliver make good rods also

Had real good luck with compstar rods.

The molnars come with ARP2000 bolts as well. The machining is very nice and for the price I think they are a bargain.

Local racer around here has an 8 second w8 barracuda. He broke a molnar Rod in it

Lol. Some guys can break anything and lots of issues can too. High rpm, bad engine building technics, oiling issues, and MANY more. Some guys shift at 8000 rpm without ever trying 7000 rpm

Im sure someone some where in the world has broke a Oliver rod as well. Just sayin

Most of the broken rods I see are from spun bearings (from tight oil clearance), or locked wrist pins, same issue, too tight.

Or people that think because an engine block coming from a machine shop LOOKS clean, it is clean.

Valid point
Engine assembly is like brain surgery, it is absolutely freaking impossible to keep it to clean

the thing about asking the seller is sometimes they'll just tell you want you want to hear, bit like car salesmen. Hence this is why i'm asking here so i can get some real world experiances on the different brands. Unfortunately you have to weed thru the folk that know what theyre talking about & those who only have an opinion because they have that brand & they consider it to be the bomb, even if theyre not using it to the capacity i want to be. maybe i should have done a post on 900HP engines & asked what rods they used & for how long they've run them?

The more info you provide in your post the better replies you will get back. Garbage in, garbage out

Crower or Carrillo.

your possibly right Pittsburgh, but i thought 900 HP & 8k rpm limit might have reduced the possible options for good answers. i guess i need to be more specific even with that info.
so looking for...
6.535 length STEEL H beam rods
900HP power output
8000 rpm limit
565grm Custom Ross Pistons
No spray
4.250 stroke
am i missing anything?

Honestly there aren't a lot of 900 horesepower 8000 rpm engines on this site. Then subtract the dyno queens, show cars, and cruisers or many can give you good info. Asking for total passes instead of years is the only way you will get good feedback. Forty years plus of racing for me an I hope to have my first 900 horsepower engine next year

There was a good exchange of this same topic somewhere over on the Bullet. But for steel, at that power lever/CID and well above, the Ultra was pretty highly regarded. RMRE uses Manley in there builds which exceed your limits. If you are on the margin of using a 'cheap' crank you may want to consider aluminum however. The comparison post only gave you a reference of cross-sections. The entire process of manufacturing gives one strength over another which goes beyond mere cross-section and weight comparisons. Processes that minimize inclusions etc.

I brought up the molnar Rod itself breaking because it did. The guy who had that failure is a veteran racer most around these parts know well.

Regards compstar, I ran them for years in a motor that saw 7500 every pass, current owner still has them in the motor.
I ran them on the advice of Chuck at Best Machine, who built that motor. He had high praise for them in that price segment.
Just relaying my experiences. Those wise asses who cast stones always do.

this is the kind of stuff i want to hear about. Just as someone mentioned 440 Source, i've physicly seen the aftermath of their rods breaking at only 7000 rpm & high 600 HP & it was rod failure, nothing else. I am seriously thinking Compstar but just thought i'd test the waters & see what others might suggest. Thank you for your input.

Give Best Machine a call and see what those guys recommend. They have never steered me wrong, and always been top shelf in both knowledge and skill.

Power really doesn't factor into it. That being said mine has a 7500 rpm limit, 4.5 stroke, 157 gram pin, 630 gram piston. If it's a bracket motor the aluminum rods might be out do to number of passes. I ran my BME 300 passes w/o issue before I swapped to Molnar (7.100/2.200/.990). Motor's never been on the dyno but will run 9.0-9.1@146-148 depending on weather at 3350lbs.
Doug

I wouldn't run an h beam in this app. steel billet I beam would be my choice... Crower. That being said the few 900
+hp 8200+rpm engines I have personally touched had BME aluminum rods.

My

Another thing that is more troublesome than cheap rods, are cheap cranks. I've seen many eagle crank and rod combos hang in there at and above 900 when properly machined. Meaning get the crank turned .01, redo the housing bore, and pin fit on the rod, and go for .0035+ for oil so it can deal with the flex. Much above that, and it looks to me like crank flex is what starts the downfall.

My crank seems to be strong enough to handle the duties but after checking a friends engine that was running less power than I run, I thought it would be a good move to upgrade before we experience the same failings as him. These rods have done 5 seasons n the hardware was changed at last rebuild. The hardware was fine but the rod failed badly

definitely this I run Oliver I beam in all my motors. I would not use an h-beam rod in anything over 800 horsepower..

My $.02 is I haven't been able to get any rod through my machinist's inspection. I bought some Manley Hemi I-beam rods off a SS Hemi racer. They were new in the box. The rod bolts were galled on the threads and under the bolt heads and cap. I paid $1300 for the rods and then another $1000 to get them fixed - new rod bolts, ring dowels, remachine the big ends and touch up the rod bolt seating areas, etc.

I've taken a set of 440 K1 rods and some Manley 440 I-beams to him. The Manleys checked out dimensionally, but the rods were in the mid-20s on the HRC scale, so basically in the annealed or normalized condition for 4340. The K1s were in the mid-30s HRC, but had some ovality in the pin and big end bores.

My machinist likes the Crowers and Carrillos and the CARR bolts. I'm thinking that is the way to go on an all out race engine. Why spend money ($600or so) on new rods, and then have to spend more fixing them? CARR bolts are about $50 each, so that's $800 for rod bolts alone. For the money I got in those Hemi rods, I would have been better off buying Carrillos with better bolts.

Hard to tell from the picture, but it looks like it grabbed the bearing first, with the heat discoloration the picture shows. Were you able to find the bearings from that rod?

The bearings were almost perfect n the rod journal was mint apart from a gouge where the rod bounced off it prior to snapping. At the break we found signs of stress cracking. This is a rod failure nothing else. OIL pressure on this motor had been excellent the week before as I was involved in prepping this motor for racing.

A lot of opinions here. Some from experience on a personal level (Me) some from someone who has done many, many engine builds (DT Hemi), others just quoting what they might have heard. I read a lot. I talk to many people I feel have a good handle on the subject. From what I've gathered gram for gram a H beam will be stronger if the same material is used. The material can be placed in the higher stressed areas with out adding unneeded mass. I suggest talking to Tom Molnar personally. He designed rods at Oliver for many years. My bet is he knows more about rods than most. I agree with DTHemi. Most rod failures have either grabbed a bearing or broke a bolt. I also run extra bearing clearance to combat flex. So far zero rod/bearing failures with my builds.
Doug

Doug how many runs on the molnar rods so far?

Right around 100 runs. This was my first year with them. I spent a fair amount of time researching for rods for my motor. Although the BME's worked excellent I felt 300 passes was a good number for replacement. I had absolutely no issues with them. Unfortunately my budget is hard pressed to purchase a $1200 set of rods every 300 runs. I have a Mega-Block and do not want to hurt it. I felt the Molnar's were a good compromise, time will tell. Also anyone interested in Aluminum rods to talk to Bill Miller. Both Bill and Tom spent time teaching me about the benifits of their style rods. Both good guys in my book.
Doug

My first build with aluminum rods going in my 1000 plus horsepower build for next year

Hate to say it but I would venture over to the bow tie forums, got to go where the knowledge is on high hp-rpm small blocks, plenty of professional 1000+ hp small blocks built that turn 8000 to 11,000. I'm sure they have found what works and don't. Happy hunting.

I sent Tom an email n after an exchange of information he considers his rods to be up to the task. You think he's being on the level with me?

I have used Tom's rods, run them for 8 years with 1500+ hp, no problems. They were checked for cracks two years ago and one had some because it had been hurt in a lifter failure, but never broke.

just checking what i'm reading here, you say you used the same set of rods for 8 years & at 1500HP? How many runs would you say you did with these rods over the 8 years?

Yes

I have steel billet Oliver rods in my hemi. Somewhere around 850 hp on motor plus another 225 hp or so of nitrous.
Been beating on it since 2006. Had nitrous on it since 2014.

RB 528, 8.80 to 9.00 at 3050 weight, 4.15 stroke, 2432 bob weight, 910 grams for 6.965 Manley H beams with ARP 2000 bolts, 7450 rpm shifts, 7800 limiter, (been there too much in the burnout box!) over 300 runs, no issues.

Whoa....don't know how I should take that.

I'll vouch for Jyrki. His turbo C body is a legend.

I have GRP in my turbo car. That is why I recommend them. I also have GRP in my Valiant. Valiant is same HP as you and turbo car is 1500HP

Just a thought if this is a race engine you're building. An aluminum rod will be easier on your crank, block, and way nicer to your piston skirts. Also will allow your engine to accelerate faster.

Im taking apart a 482 hemi right now that has been together 4 years, and made 915hp@7800 when it went together. 4.15 stroke, going 8200 in the traps in a heavy car. I cannot say the number of runs, but the owner goes most weekends weather permitting. He is never kind to anything,and blasts this motor around on the street too. this motor has worn out 3 sets of springs. I've never broken an aluminum rod, from anything the fault of the rod.

Just a thought.

nice ....what rods are in it?

The rods in the 482 are GRP pro material 5500 series if I recall correctly. 1.032 pin BBC journal, Chrysler width.