78'Bu-88SS said:
o0o0o0o0o0o00o i was ordering some stuff from summit as we speak but im going to hold off untill i hear from you. How much use does the powertrax have and which one is it?
i have 26's
rod bolt torque- oil vs. vasoline
- Thread starter Horsepwraddict
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o0o0o0o0o0o00o i was ordering some stuff from summit as we speak but im going to hold off untill i hear from you. How much use does the powertrax have and which one is it?
i have 26's
rod stretch
I have done a bunch of testing on this subject and i can tell you that with aftermarket bolts the only way to be 100% sure that you are right is with a stretch gauge....
I don't have time to typ the entire R& D session but i can tell you that the torque wrench is not the way to do it.. I spent maybe 16 hours os so looking at all the different rod bolts, lubes, etc.... As one example i was testing the stretch vs torque on a 11/32 rod bolt. I pulled it up to the rated torque value and only got .003" stretch. I noticed the finish on the cap where the nut seated was reall rough, so i set it up on my mill and re-spot faced the cap. I then re-tested It,,, this time i got .005 stretch with the same torque value....Changing nothing else....
Again this is all about aftermarket bolts.... With the stock bolts i just make sure eveything is clean, lubed with oil, and the finishes are good,and i use the standard torque values for them....
Also i have found that new ARP bolts will usually stretch .0005" or so on the first hit and then settle into that length....
Keith
I have done a bunch of testing on this subject and i can tell you that with aftermarket bolts the only way to be 100% sure that you are right is with a stretch gauge....
I don't have time to typ the entire R& D session but i can tell you that the torque wrench is not the way to do it.. I spent maybe 16 hours os so looking at all the different rod bolts, lubes, etc.... As one example i was testing the stretch vs torque on a 11/32 rod bolt. I pulled it up to the rated torque value and only got .003" stretch. I noticed the finish on the cap where the nut seated was reall rough, so i set it up on my mill and re-spot faced the cap. I then re-tested It,,, this time i got .005 stretch with the same torque value....Changing nothing else....
Again this is all about aftermarket bolts.... With the stock bolts i just make sure eveything is clean, lubed with oil, and the finishes are good,and i use the standard torque values for them....
Also i have found that new ARP bolts will usually stretch .0005" or so on the first hit and then settle into that length....
Keith
Keith I think I remember you stating that before, I think thats where I heard it. When using new fasteners I always torque and loosen them a few times to stretch them to their final length. Good stuff
i believe ARP says to cycle the rod bolts at least three times before torquing them down for final installation, and i remember they gave specs for the bolts dry, with 30wt, and with the lube they supplied in the package...
the instructions that came with my main studs say to torque em down 3 time as it "polishis" the treads and seats the fastners. and the give a spec for ARP moly lube and a spec for 30wt oil wich is 15 ft lbs more.
1 question, what about main studs and head stud. you obviusly cant mesure stretch on them so??? i understand that rods are the most streesd part in the motor, but what is that main studs dont need strech and rods do. also a few rod muncfactures only include a torque spec with there rods
1 question, what about main studs and head stud. you obviusly cant mesure stretch on them so??? i understand that rods are the most streesd part in the motor, but what is that main studs dont need strech and rods do. also a few rod muncfactures only include a torque spec with there rods
A product called CMD high pressure lube #3 is THE stuff to use! CMD stands for chicago manufactuoring distribution (even tho' it is made in Grand Rapids, MI. - go figure!). If you can't find it elsewhere, Jesel sells it. It is far superior to the ARP moly lube.
You just can't do anything but torque method on the main studs and other blind end fasteners.
Rod bolt clamp force is most critical because it also affects the final shape of the journals......make sure you and your machinist are on the same page when you have your rods re-conditioned.
All block and rod machining operations are done properly with all fasteners and caps at full final torque values. Same reasons you should torque plate the final hone operation.
Rod bolt clamp force is most critical because it also affects the final shape of the journals......make sure you and your machinist are on the same page when you have your rods re-conditioned.
All block and rod machining operations are done properly with all fasteners and caps at full final torque values. Same reasons you should torque plate the final hone operation.
If you don't have a stretch gauge ARP will tell you to torque with there lube 4 to 5 times to set the threads. I bet thee's something on there website.
We broke a rods in one of the mud bogger engines a couple of years ago it had 3/8 ARP wavelock bolts in the rods. After tearing the engine down to see if there was anything worth saving. I put one of the rods in the bench vise just to see how for the bolts would go just over 100lbs the threads stripped out, the bolts never broke.
From ARP'S WEB SITE
If the stretch method cannot be used in a particular installation, and the fasteners must be installed by torque alone, there are certain factors that should be taken into account. ARP research has verified the following “rules” pertaining to use of a torque wrench:
1. The friction factor changes from one application to the next. That is, the friction is at its highest value when the fastener is first tightened. Each additional time the fastener is torqued and loosened, this value gets smaller. Eventually the friction levels out and becomes constant for all following repetitions. Therefore, new fasteners should be tightened and loosened through several cycles before applying final torque. The number of times depends on the lubricant. For all situations where ARP lubricants are used, five cycles are required before final torquing.
2. The lubricant used is the main factor in determining friction, and therefore, the torque for a particular installation. Motor oil is a commonly used lubricant because of it’s ready availability. If less friction is desired in order to install the fasteners with less torque, special low friction lubricants are available. With special lubes, the required torque can be reduced as much as 20 to 30 percent. It is important to keep in mind that the reverse is also true. If the torque value has been specified for a particular fastener on the basis of low friction lube, installing the fastener with motor oil will result in insufficient preload; the torque has to be increased to compensate for the extra friction caused by the motor oil.
3. Surface finish is also important. For example, black oxide behaves differently than a polished fastener. It is therefore important to observe the torque recommendations supplied with each fastener.
NOTE: It is possible for even the most expensive of torque wrenches to lose accuracy. We have seen fluctuations of as much as ten (10) foot pounds of torque from wrench to wrench. Please have your torque wrench checked periodically for accuracy.
We broke a rods in one of the mud bogger engines a couple of years ago it had 3/8 ARP wavelock bolts in the rods. After tearing the engine down to see if there was anything worth saving. I put one of the rods in the bench vise just to see how for the bolts would go just over 100lbs the threads stripped out, the bolts never broke.
From ARP'S WEB SITE
If the stretch method cannot be used in a particular installation, and the fasteners must be installed by torque alone, there are certain factors that should be taken into account. ARP research has verified the following “rules” pertaining to use of a torque wrench:
1. The friction factor changes from one application to the next. That is, the friction is at its highest value when the fastener is first tightened. Each additional time the fastener is torqued and loosened, this value gets smaller. Eventually the friction levels out and becomes constant for all following repetitions. Therefore, new fasteners should be tightened and loosened through several cycles before applying final torque. The number of times depends on the lubricant. For all situations where ARP lubricants are used, five cycles are required before final torquing.
2. The lubricant used is the main factor in determining friction, and therefore, the torque for a particular installation. Motor oil is a commonly used lubricant because of it’s ready availability. If less friction is desired in order to install the fasteners with less torque, special low friction lubricants are available. With special lubes, the required torque can be reduced as much as 20 to 30 percent. It is important to keep in mind that the reverse is also true. If the torque value has been specified for a particular fastener on the basis of low friction lube, installing the fastener with motor oil will result in insufficient preload; the torque has to be increased to compensate for the extra friction caused by the motor oil.
3. Surface finish is also important. For example, black oxide behaves differently than a polished fastener. It is therefore important to observe the torque recommendations supplied with each fastener.
NOTE: It is possible for even the most expensive of torque wrenches to lose accuracy. We have seen fluctuations of as much as ten (10) foot pounds of torque from wrench to wrench. Please have your torque wrench checked periodically for accuracy.
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