Are rod bolts a good idea??
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Are rod bolts a good idea?? ok im doing heads and cam, I tried to search but couldn't really find anything, should I do the rod bolts or just leave the stockers in there?
I don't rev high at all.
I don't rev high at all.
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
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big ends and yet supposedly the Katech ones do not. I've read where
replacing them one at a time and torquing helps to lessen distortion but what
about if the rods are out of the engine ?? I suppose just torque and measure
both before and after right ??
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Verdad Gallardo Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
First, I'm no machinist. Second, I have no dog in this fight. What I have seen, is every rod bolt that clamps harder then stock will distort the rod bore. Also, each distortion is different (for whatever reason), some worse then others. I've seen someone measure with katechs and they distorted the bore also. Will this cause you to spin a bearing? Maybe, you could argue both sides. Have I owned aftermarket rod bolts? Yes I have. That motor threw a rod through the side of the block after about 1200 miles. Will I push aftermarket rod bolts on otherwise stock engines? Nope, not anymore.
Good to know ! I guess I'll do a before and after in the next week or so since
the LS3 rods I recently purchased are getting new bushings and I opted for
Katech bolts as well. The factory bolts with the underhead locating sleeve
just seem a bit funky and not knowing the history of abuse on these rods has
me worried. My guess and hope is that the 260,000 tensile bolts will change
the big end slightly to the point that a few strokes on the resizing machine
will make them perfectly round and give proper bearing crush/concentricity
without having to go to the .002" oversize bore.
the LS3 rods I recently purchased are getting new bushings and I opted for
Katech bolts as well. The factory bolts with the underhead locating sleeve
just seem a bit funky and not knowing the history of abuse on these rods has
me worried. My guess and hope is that the 260,000 tensile bolts will change
the big end slightly to the point that a few strokes on the resizing machine
will make them perfectly round and give proper bearing crush/concentricity
without having to go to the .002" oversize bore.
Clamping harder is not the point, being less prone to stretch is.
Stock bolts stretch then fail at sustained high RPM or frequent high RPM. ARP bolts don't.
I'm not promoting changing the rod bolts only stating the circumstances under which I would change them.
Doing heads & cam is not what I would describe as an otherwise stock motor.
Stock bolts stretch then fail at sustained high RPM or frequent high RPM. ARP bolts don't.
I'm not promoting changing the rod bolts only stating the circumstances under which I would change them.
Doing heads & cam is not what I would describe as an otherwise stock motor.
If you're going to go ahead and get them resized, just get the ARPs. Save $100 and pay it to the machine shop.
However, once you factor the cost of factory rods, ARP or Katech bolts, and machine shop work (plus any balancing you may be doing if you're building up a new bottom end), you'd be better off just getting the Scat I-Beam Rods with 7/16" ARP cap screws. They're like $300 from several vendors on here.
I threw the ARPs in mine as cheap insurance. I figure 7000+ RPM the stock bolts will let go and destroy the motor or I'll spin a bearing with the ARPs and hopefully not damage anything other than the shortblock.
However, once you factor the cost of factory rods, ARP or Katech bolts, and machine shop work (plus any balancing you may be doing if you're building up a new bottom end), you'd be better off just getting the Scat I-Beam Rods with 7/16" ARP cap screws. They're like $300 from several vendors on here.
I threw the ARPs in mine as cheap insurance. I figure 7000+ RPM the stock bolts will let go and destroy the motor or I'll spin a bearing with the ARPs and hopefully not damage anything other than the shortblock.
Clamping harder is not the point, being less prone to stretch is.
Stock bolts stretch then fail at sustained high RPM or frequent high RPM. ARP bolts don't.
I'm not promoting changing the rod bolts only stating the circumstances under which I would change them.
Doing heads & cam is not what I would describe as an otherwise stock motor.
Stock bolts stretch then fail at sustained high RPM or frequent high RPM. ARP bolts don't.
I'm not promoting changing the rod bolts only stating the circumstances under which I would change them.
Doing heads & cam is not what I would describe as an otherwise stock motor.
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
Clamping harder is how you prevent stretch. Stretching a bolt of a given tensile strength will produce a "preload", kind of like a spring. In order to prevent stretching of the bolt during operation, the "preload" force clamping the rod together must be greater than the forces trying to pull it apart.
So, if we know they clamp harder, thus distorting the bore......so we feel more secure at 7k rpms with a stronger bolt but out of round journal, or a weaker bolt and a round journal??? Clearly there is NO real winner in this scenario.
Now don't you go bringing common sense into the discussion!
So, if we know they clamp harder, thus distorting the bore......so we feel more secure at 7k rpms with a stronger bolt but out of round journal, or a weaker bolt and a round journal??? Clearly there is NO real winner in this scenario.
So, if we know they clamp harder, thus distorting the bore......so we feel more secure at 7k rpms with a stronger bolt but out of round journal, or a weaker bolt and a round journal??? Clearly there is NO real winner in this scenario.
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