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ARP head and connection rod studs?

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R

recordsj

Jedi Warrior
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rebuilding my 1500 midget engine
I am going from 7.5:1 to 9:1 compression on the engine, will I need to use ARP brand head studs or are stock OK? No other performance changes to the engine is being made.
 
You don't necessarly need ARP rod bolts and head studs, but they are really nice hardware.
 
I trust ARP quality. Standard "spec" ones may suffice, but what company name is standing behind them guaranteeing that they meet the "spec"?
 
I bought my ARP rod bolts and head studs from Jegs.com and found them (at the time) to be less expensive than "stock" hardware from the usual sources.

The really cool thing about the ARP head studs is that they have an allen wrench head cut into the top of the stud, so if you ever have the head off again the studs are very easy to remove.
 
kellysguy said:
Aren't the 1500 rod bolts one time use items?
Click to expand...

No, ARP 2000 rod bolts have a 12 torque cycle life, so for street engine, you could reuse them in a couple of rebuilds, you'll use about 5-6 torque cycles in the first rebuild, ARP has you torque cycle them 3 time upon installation, so by the time you assemble you're at 5-6 torque cycles, and with say a rebuild or refresh you may use up a couple of more. On race engine I normally reuse them for 1 -2 engine refreshes and at that point we toss them and get a new set, now who knows how important this is, but when you dealing with race motor full of high dollar components, you don't want to risk it, but keep in mind they are getting much more the work out on race engine vs street engine.

Here's something I strongly beleive in, if you are replacing rod bolts that should be aprt of connecting rod big end resizing job, I do not recommend just installing new rod bolt and not resizing the the big ends.
 
Hap Waldrop said:
kellysguy said:
Aren't the 1500 rod bolts one time use items?
Click to expand...


Here's something I strongly beleive in, if you are replacing rod bolts that should be aprt of connecting rod big end resizing job, I do not recommend just installing new rod bolt and not resizing the the big ends.
Click to expand...

why do you say this? what do you mean by resizing the big ends?
 
The holes of the big end will not be perfectly round when clamped under different forces. So the idea is to clamp it with the same force that will be used in final assembly and then machine the holes back to perfectly round. This will help ensure the bearings do not have a tight spot.
 
Adding to Hap, ARP is great for racing and especially for performance street applications. If you’re going to use ARP on your rods and your block, resizing is mandatory, the rods and block will be out of round if you don’t. If you’re running very close tolerances with deck height you will find that those deck heights will decrease by a few thousandths with rod resizing and will increase a few thousandths with honing your block or line boring your block, I prefer honing but ether will work... so be carefull their. Or you could step up to the very big bucks and buy the Carr hardware, but way-way over kill for street use!!!
 
Adding to Hap, ARP is great for racing and especially for performance street applications. If you’re going to use ARP on your rods and your block, resizing is mandatory, the rods and block will be out of round if you don’t. If you’re running very close tolerances with deck height you will find that those deck heights will decrease by a few thousandths with rod resizing and will increase a few thousandths with honing your block or line boring your block, I prefer honing but ether will work... so be carefull their. Or you could step up to the very big bucks and buy the Carr hardware, but way-way over kill for street use!!!

Correction: Resizing the Rod will make the rod shorter so deck height will increase. Line honing or line boring decreases deck height because crank is deeper in the block making the piston closer to the top of the deck. Sorry for the confusion.
 
What those guys said, I pretty much use ARP in everything, but that's me, as for rod big end resizing, I do it on every rebuild, did alot of study and checking on this years ago, never saw a set of rods come out of used engine that didn't need sizing on the big end , over time they tend to grow clearence at the parting line, I consider connecting rod big end sizing part of engine rebuild of any sort, this probably more than anything causes rod bearing failure, when a housing bore is out of spec, bigger, it no longer holds the bearing correctly.
 
Trevor Jessie said:
The holes of the big end will not be perfectly round when clamped under different forces. So the idea is to clamp it with the same force that will be used in final assembly and then machine the holes back to perfectly round. This will help ensure the bearings do not have a tight spot.
Click to expand...

what do you mean by "different force"? How can there be different forces?
 
Different bolts require different amounts of stretching to maintain tension and thus exert different amounts of clamping force.
 
In essence... yes.
 
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