ARP Rod Bolts - REALLY essential?
#21
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I've swapped them without resizing, but I don't torque to ARP settings. Keep the clamping force as close to stock as possible, and your chances of keeping the rod journal round are a little better.
#23
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Yes, but you only see the extra clamping force if you torque it harder. You can recalculate the torque to match factory clamping force, but use loctite if you do
#24
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Fasteners have the best fatigue properties at the highest possible torque. This is why torque to yield fasteners are used - but they can only be used once.
ARP uses a much more exotic material for their bolts that allow for a higher torque value without plastically deforming the bolts - improving performance and allowing for repeated use (not infinite, but at least a few installations).
Installing ARP bolts at a lower torque value might very well have worse properties than the stock TTY bolt.
ARP uses a much more exotic material for their bolts that allow for a higher torque value without plastically deforming the bolts - improving performance and allowing for repeated use (not infinite, but at least a few installations).
Installing ARP bolts at a lower torque value might very well have worse properties than the stock TTY bolt.
#25
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That exactly the point why I brought back this thread. I started to think about the cost to resizing ,arp rod bolts ,time and gas plus the risk of having the job done right from the machine shop. At the end I questioned my self if it worth the trouble and decided to ask for opinions.
#26
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That exactly the point why I brought back this thread. I started to think about the cost to resizing ,arp rod bolts ,time and gas plus the risk of having the job done right from the machine shop. At the end I questioned my self if it worth the trouble and decided to ask for opinions.
You said you only plan on spinning it to 6800 rpm. DO NOT do rod bolts in that case. Anytime you can leave the OEM bottom end alone, do just that.
#27
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If stock rod bolts on a Gen 4 are good to 7k+, if the engine won't see more than that and normally shifts at say 6500 - at what power point would you change rods?
#28
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Some people have done dumb enough things to toss rods at stock power, and it's not always dumb, mistakes happen. But in a perfect environment the gen 4 rods held up fine at nearly 1600 in a 6.0, but that's a few pulls in a controlled environment on an engine dyno.
It's gonna be a matter of personal preference, you could change them at low power (600 ish) to be super safe (I personally think that would be a massive waste), change them if you're gonna go over say 800 at the tires to be reasonably safe or you could go full on send and go for 1200 or so to the tires. At some point I think a consideration needs to be do I want to toss a rod and put oil under the tires, if that doesn't concern you go hard and go for around 1k to the tires.
With everything perfect they hold incredible amounts of power, but betting on things always being perfect isn't a good plan. On the flip side, some of those unforseen things can also take out a forged rod.
So the answer keeps getting further from a definite one.
But how you treat it, maintain it, tune it etc will all play into staying together or not.
I think I personally would judge it more by the car. If I had a low buck build with a cage at the track. I'd probably try to do 1100-1200 or so before getting concerned with it. If it was a fancy *** fairly new vette. I'd probably build the motor. But then again, if you can ever keep from touching the bottom end bearings the better usually the better off you are.
#29
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I still say it has more to do with rpm than power.
#30
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Rods or rod bolts? I've been saying through the thread rod bolts are about RPM. Power has zero effect on them.
The dude above asked about rods and power so I tried to answer it but it's real hard to answer. I think of limits on parts far different than most, I'm not for built motors, but I don't want to advocate my personal way to everyone so I tried to make a blanket answer about rods and power.
The dude above asked about rods and power so I tried to answer it but it's real hard to answer. I think of limits on parts far different than most, I'm not for built motors, but I don't want to advocate my personal way to everyone so I tried to make a blanket answer about rods and power.
#31
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Damn I didn't read that post correctly.
#32
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High POWER = compression load on the rod, most often concentrated in the beam area.
High RPM = tension load on the rod bolts, big end cap and small end "strap" above the wrist pin.
I'd say stock bolts are good for the capabilities of a stock rod. If you think the stock rod isn't enough, then bolts aren't going to help you out much from there.
Given the nature of the "cracked cap" design of the rod, I don't know why they even make an aftermarket rod bolt for them when the oversize OD bearing shells aren't offered in many "performance" grades.
High RPM = tension load on the rod bolts, big end cap and small end "strap" above the wrist pin.
I'd say stock bolts are good for the capabilities of a stock rod. If you think the stock rod isn't enough, then bolts aren't going to help you out much from there.
Given the nature of the "cracked cap" design of the rod, I don't know why they even make an aftermarket rod bolt for them when the oversize OD bearing shells aren't offered in many "performance" grades.
#34
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Call Katech and ask them.
#36
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High POWER = compression load on the rod, most often concentrated in the beam area.
High RPM = tension load on the rod bolts, big end cap and small end "strap" above the wrist pin.
I'd say stock bolts are good for the capabilities of a stock rod. If you think the stock rod isn't enough, then bolts aren't going to help you out much from there.
Given the nature of the "cracked cap" design of the rod, I don't know why they even make an aftermarket rod bolt for them when the oversize OD bearing shells aren't offered in many "performance" grades.
High RPM = tension load on the rod bolts, big end cap and small end "strap" above the wrist pin.
I'd say stock bolts are good for the capabilities of a stock rod. If you think the stock rod isn't enough, then bolts aren't going to help you out much from there.
Given the nature of the "cracked cap" design of the rod, I don't know why they even make an aftermarket rod bolt for them when the oversize OD bearing shells aren't offered in many "performance" grades.
#37
Years ago..
99 ls1 aussie holden sedan.. 3700lb race weight. SBE ls1 .. with absolute speed cnc'd stg2.5 5.3's / futral 230 .. 7200 rpm shifts.
That SBE 99 ls1 did 70,000 street miles while street racing and over 100x passes at the track in different guises.. unopened, cam only, then heads/cam.
IT copped an insane amount of abuse and the stock GM rod bolts are the last thing that worried me. I never broke it.. I later returned it all to standard and sold the car. The new owner had no clue to what it had gone through.
If staying with stock rods I don't mess with the bolts. I'm now turning my current 'cam-only' sbe ls1 in sig to 7400rpm often. It's quicker when I carry the rpm that high, it must be that 114 lsa made for boost camshaft I have in it, idk.
99 ls1 aussie holden sedan.. 3700lb race weight. SBE ls1 .. with absolute speed cnc'd stg2.5 5.3's / futral 230 .. 7200 rpm shifts.
That SBE 99 ls1 did 70,000 street miles while street racing and over 100x passes at the track in different guises.. unopened, cam only, then heads/cam.
IT copped an insane amount of abuse and the stock GM rod bolts are the last thing that worried me. I never broke it.. I later returned it all to standard and sold the car. The new owner had no clue to what it had gone through.
If staying with stock rods I don't mess with the bolts. I'm now turning my current 'cam-only' sbe ls1 in sig to 7400rpm often. It's quicker when I carry the rpm that high, it must be that 114 lsa made for boost camshaft I have in it, idk.