Hello Engine Building Sages;


When I Bought The k1/Weisco Combination for Ruster's Race Engine I initially used the Torque angle method for Setting Rod bolt torque.

This Time around I sprung for the Stretch Gauge as per K1's Directions.
Will the Stretch Method Provide a more accurate and Consistent Torque load measurement?


Also Can ARP Assembly Lube be a substitute for the Extreme pressure Lube #3 Supplied with the k1 Rods?


Thanks,


Greg

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http://www.youtube.com/hyperpack

Greg

think of a bolt as a rubber band,,
The bolt actually stretches, gets longer when tightened,, that is called elongation.

The torque and angle is calculated to provide the bolt stretch required to develop a given clamp load.

As there is always some variation in bolt thread quality and metalurgical properties, the torque and angle specification assumes the bolt properties are at some nominal point.

When you measure bolt stretch, you are measuring what it takes to get to the required clamp load directly., regardless of thread and metalurgical quality,,

When the load is removed from the bolt, it will relax back to its pre tightened length, as long as bolt was not taken into yield and permanent enlongation.

If I had access to both bolt stretch and torque and angle,, what I would do is use torque and angle to tighten the bolt, then measure bolt stretch to verify that the expected bolt elongation occured.

With stretch,, you will be measuring bolt length down to the .001
watch for marking on the bolt head or uneven spots on the bolt tail that can affect the before and after measurements.

I would like to see the gauge you got?

I find it very funny that at the banquet last week I spoke one of the best racers we have and he never used an angle or bolt stretch gauge in his life on his ARP fasteners. He just torques them and goes! Seems like that is the way it should be to me. Just talkin out loud.
Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

the bolts / rods and slant six motors in general, are so beefy as long as you hit the minimum torque and don't go way out of bounds on the high side, the joint will live. If we were working with high end, very light weight modern parts that would not be true.

that being said, with parts from any source, there is always the possibility that the bolt material cound have gotten mixed or heatreated incorrectly and as a result, may have properties that do not match the requirement. Using fastners from a known source like ARP minimizes the possibility of bolt material errors, but anything is possible. If one were to measure bolt stretch of ARB bolts after assembly, the information would be additional data to confirm or dismiss the possibility of material or assembly error. There would still be error remaining, associated to the bolt stretch measurement gauge and technique.

Torque and angle when calculated correctly should result in a more uniform clamp load as it is a two stage process, as well it provids notice when some error is present that prevented the desired clamp load from being attained.
For example, I can run a two inch long bolt into a one inch deep threaded hole,, where the threads match properly, and hit a torque of 35 ft lbs, without the head of the bolt contacting the work piece,, remember this is a two inch long bolt going into a one inch deep hole,, zero clamp load at the bolt head.
On that same example, I could not reach a torque of 33.5 lbs and 180 degree of angle,, the bolt would bottom in the hole at 33.5 torque,, and when pushed to move another 180 degrees, either would lock up short of 180 or the head would twist off. This is an extreme example,, but shows how torque alone does not guarantee that the clamp load was achieved.
Using torque and angle gives more confidence,, is it required,, no.
Measuring bolt stretch gives additional confidence.

Thanks for the nice perspectives, DadTruck. I will keep that in mind for when I build a 7000+ RPM 225 with uber parts.

Up to now, I have been totally shade-tree. I overtorque (using a beam-type wrench) all of my internal engine fasteners by 5-20% and have never had a problem. I would guess that the K1/ARP setup is already overkill for 6500 RPM, and a standard beam wrench with a mild overtorque is what I did on mine. YMMV...

Lou

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Home of Slant6-powered fun machines since 1988

this is the one I got Rick,

http://www.summitracing.com/parts/lun-98401/overview/

Greg

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http://www.youtube.com/hyperpack

yeah, I guess that works for some people...

but never for me... if I don't do everything by the book, and triple check stuff it breaks and then I have no fun.



also I don't think I would take rod bolt tightening advice from a dude whose race engine windowed a block due to some kind of suspected rod cap/ bolt failure!

team Covalt will overcome all obstacles however, always have, always will!


thanks for the input all.. also thanks John, I do understand all of the points you make.

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http://www.youtube.com/hyperpack

does anyone have any info on this assembly lube substitution?

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different thread lubes will give different resuts,

http://benmlee.com/4Runner/threads/threads.htm

I would agree that a light oil will provide the most uniform results as the thread coverage with a liguid will be more uniform than a paste. The key thought here is use the lube, or type of lube that is recommended by the bolt / joint manufacturer. I also agree that Anti-Sieze thread lubes are not the same as moly based thread lubes.

Greg, concerning your specific question,,, if both products are a heavy paste, probably moly based, they can be interchanged,, if one is a light liquid oil and the other a paste, probably not. But by measuring bolt stretch you will know positively if the bolt load and effective torque was affected

By the way,, here is another interesting article on fastners and load

http://www.designworldonline.com/elimin ... r-failure/

Thanks for the reminder!!!

I was just reading the instructions that came with my new rods thinking about which way I should do mine on my next motor.

Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6