Rod bolts, main caps, and what not.
 

Since we got a little derailed, and generally out of control last night :picard1:, I wouldn't mind getting back into where we were going, without the drama.

The majority of guys today are probably using some brand of H beam rod here. Curious as to what rod bolt is favored, and at what level is the upgrade necessary.

We have the standard 8740, ARP2000, and L19 lets say. There is talk about the L19's being affected by moisture, and hydrogen embrittlement. Is that a real concern, or is it simply internet hype? I know alot of guys have had scenerios of water in the oil, from maybe reversion, a leaky intake gasket, or things of that nature. I can only go off what I've read on ARP's site, about those bolts. I personally have never used them in anything.

At what level should one consider upgrading from the 8740 bolts, and which bolt is preferred? Mainly talking about your average marine BBC staying well below 7k RPM.

Yes but what about in a 4.25 stroke application like yours? As far as the power level, would a engine that makes 900hp with a roots blower, be seeing more stress than a N/A or turbo engine since the roots blower is probably consuming 100hp to turn ?

I`m a just a dumb hvac guy
 

I don`t know so Ill just keep out of this.

I'm obviously no expert, but i think you have to make a judgement call on stroke, weight of the piston/rod assembly, crank stroke, and max operating RPM. Most of us who are running a max of 6K or so are just fine with the 8740's.

I'm running 8740's and Eagle I-beams in my 489, but it won't see more than 6K RPM (probably a lot less than that), and the smaller bore probably results in a lighter piston assembly.

For the record, I have heard some talk that there are some Chinese knock-off 8740 rod bolts floating around out there, so make sure you get any replacement bolts from a reputable source.

Personally, unless I was building an absolute max effort large displacement engine that was going to be spun regularly above 6500, I would avoid running the L19's, because I would always have the worry of some moisture from condensation or a leak somewhere causing problems. Seems to me like moisture could get to them even over the winter if condensation were to occur inside an oil pan on a rod bolt. Perhaps that won't happen since it is inside the oil pan, but I would still be concerned about moisture.

Hopefully some of the pro's will comment, but after the mods had to break out the Ebola-grade disinfectant last night for the oil pump thread, I can see where everyone might be a little gun shy. :eek:

Probably a wise decision. Now go fix a furnace - somebody's freezing their azz off up there in the frozen tundra of Chicago! :D

The most murderous action placed on rod bolts is when the rod stops and then starts and continues to accelerate back down from TDC on the exhaust /intake stroke. IE:overlap.

No compressive forces helping to keep the piston + such pushed towards the rod cap.

So, its not really horsepower, it's rpm's vs piston/ring/pin/ good part of the connecting rod itself weights that's trying to seperate from the connecting rod's cap.

All my IMHO of course.

Lets say we have two 540's, with identical rotating assemblies. One is 700hp NA, and the other is 1100hp with 10#'s boost. They both turn 6000rpm. Would the boosted motor require stronger rod bolts then the NA version? If so, why?

Neither do I but that's why I'm asking. :cartman:

I'd like to say yes, because of the higher cylinder pressures. But ....is the peak cylinder pressure actually higher in the blown engine, or is it simply the same pressure just carried out longer during the stroke?

The main issue with the L19 bolt is when it is manufactured. Yes, stress corrosion can in extreme cases weaken it, however, as confirmed by Callies, it's not something that materializes in the real world. I will call them again Monday morning and provide their findings on the L19 so we have some data.

Budman- Think about an oils polarity regarding metal surfaces, and you soon realize it would take a decent amount of moisture to disrupt the balance. Just food for thought.

I go to bed way to early and miss all the fun...I now have a headache from 2 hours of reading the other thread.

I am currently working with Bob on (2) 572 builds, they are fuel injected, Dart big M's, AFR, dry sump with a goal of 850+ at just over 6000 RPM. The rods are Callies Ultra's they use a AMS 6487 modified tool steel bolts marked as "ULTRA 180 (or 160 hard to tell) ARP 14D (or 140 again hard to tell even with my 250's on) where do these fall in the line of rod bolts to use or not. I am no engineer but more of a hands on builder with some good tools, my wife is beautiful even at 53 years old and I also was a firefighter in my youth.

It's probable that the S/C motor has heavier piston, pins, and connecting rods....so I say yes...I better bolt would be required than the N/A, unless of course the N/A version is equipped with same weight items for some reason.

Also, (thinking out loud) I would think that the S/C engine would be more likely to have higher spikes in rpm if the prop leaves the water, coupler or drive breaks, or etc. I may be wrong on that one....but seems more probable to me. I don't leave the water much.....so no real experience there. This is where offshore racers could tell us.

A non loaded engine spiking high in rpm has to be murder on rod bolts.

That's what I'm led to believe also.

Now that's a build I'd like to follow. Sounds very cool. I know last time I spoke with Bob he was very excited about it as well.

Although I have never done the research and got down to the nitty gritty of rod bolts I have always been under the assumption that as the rpm's go up so does the quality of the rod bolt. It has nothing to do with horsepower. Also, for what it worth my builder said the L19's are junk and doesn't use them in anything. I didn't ask him why cause I really didn't care to know. Myself I don't like h-beam rods I-beams give a little more protection when you are dealing with detonation.

Wouldn't the n/a motor be pulling harder on the intake stroke than the forced induction? On the upstroke the crank and mains are bearing the load with the caps along for the ride? No?

No it's just getting filled with compressed air.

boost tends to want to rip the **** out of rod bolts, rods, wrist pins, pistons...we use K1 Billet rods with ARP bolts on my Turbo LS Drag Car...just all depends on the boost level..we run 25+, but only 6 with the procharger in the boat..Alex can tell you at length whats going on with boost....

the higher horsepower rod bolts need to be stronger.rpm is rpm,,but the combustion pressure is what accelerates the crank back down.

what afr's are you planning to run?
also,,what size throttlebody?

tell that to the guy that owns team envy he is pretty successful for an "hvac guy" lol

L-19 especially I have been taught not to handle them with your bare hands because of the acids from your skin can promote corrosion. FWIW

You can have the strongest rod bolt made but it still requires the importance of proper stretch / torque.

I always thought for rod bolts as the crankshaft rotates the big end of the connecting rod becomes almost oval shaped that's mainly what causes rod bolts to bend. So I always believed rpm had a lot to do with it more so as the rod bolts is the main supporter for all the tension loads caused by each rotation of the crankshaft..

Stupid truck driver.
 

This is the dumbest truck driver I know. Jus sayin.
http://sharkeyimages.zenfolio.com/im...26457788-2.jpg

Speaking of rod bolts, I don't keep my boat in a heated garage mahal. That said, all those spring days that the dew is on your windshield, your engine is sweating on the inside. I don't start my engine everyday and bring it to operating temp everyday. It takes some run time to boil all the water out. That's why short trips in the car are worse than highway miles. L19 sounds like a bad idea anywhere besides a desert. I guess a super stocker or a dragster you are running a filled block with would be ok, but those are easier to put in a temperature controlled garage.

Of course I've never built an engine or been to college for that kind of thing. I've never sat and talked with any drag racers or engine builders. Never met anybody who engineered the 426 hemi or street raced the silver bullet in the 60's. I'm a dodge driver. It would be awesome.

That's what I thought. And it's a real killer when the motor free-revs with no load. That really oblongs the rod. But I guess when you are filling a cylinder with compressed air it is more detrimental than rpm is.

Where does the "CARR" rod bolt that Carillo uses fall in the spectrum?

Big money. High Rpm

Who makes them for Carillo? I'm assuming that "CARR" is short for carillo.

Any down side to using them? I have carillo rods and those are the bolts I have.

Thanks, rob

They use there own bolts. Everything they make is top notch. Ever see there diesel rods? I don't know what they make them out of but it's almost impossible to machine the weights on the end of the rod. They make some bad as stuff. To expensive for my wallet.

My experience comes from drag racing and circle jerks. That being said, I've had great success with ARP 2000's.Myself and a group of drag racer's making 1000hp at the wheels on boosted engines with no failures. To me the question should be who installed a ARP 2000 or (insert aftermarket option) and had a failure??? What horsepower and RPM did it happen??? All the engine failures I've seen are normally from something else. I. e dropped valve, lose of oil pressure (yes possibly from rod stretch) and leanouts.

How long before this thread goes completely off topic? lol

I give it 5 more posts...

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Marine engines are not car engines. Crazy that no one understands this. A strong bottom end is crucial in either hobby. Cams seem to be the major factor between the two. I'm talking 600hp big Chevys. Since when did the blocks change? Never did. You can add Merlin, worlds, brodix, dart, ect to any marine engine. The cam gives the engine it's personality.

And was your point to derail this? Thanks for the recap and your Marine engine wisdom genius! FYI, we're talking lower ends, NOT cams.

*FYI, an outlaw car that is locked in gear, entering and exiting corner, lifting (dragging the lower end) and hammering the throttle, at much higher RPM is very abusive to the lower end. Tolerances are critical since the bearing sees loads on all sides. Marine engines, sees this only when the prop is moving air. BOTH are abusive environments and alot can be learned by both. Let's keep an open mind.

Carr bolts where made by SPS. They are non magnetic and I think they add another 500. to the cost of the rods. And you don't have to replace them non serviceable.

Would it be safe to say that in a sub-6000 rpm marine engine, proper machine work and proper clearances outweigh the bolt selection? In other words, will we commonly see failures in 600 hp, 6000 rpm BBC marine engines with proper setup and using the base ARP offering?

Arp 2000 6700rpmand less. 6700rpm and above needs a "custom bolt"

Oh God , someone didn't have their lanyard on . Safety police post #32 please......lol :helmet:
Humor is good !

I think I'm gonna name my next dog Rod Bolt.

That will give new meaning to "popping a rod" lol