Grp Rods Pulled Threads

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by SNAPPY, Sep 17, 2006.

  1. SNAPPY

    SNAPPY TAFC

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    Seen Some Pulled Threads On Grp Rods. Bolt Threads Looks Fine. 3 Runs/used Good Torgue Wrench!! Also When You Remove The Cap The Rod Bolt Torque Doesn't Seem As High As When We Installed Them. Will Do Some Torque Checking When We Get Home And Tear Down.
    Nhra Afc

    Any Body Else Seen This. What Rods Are You Guys Running!
    Does Bill Miller Make A Billet Rod For Tafc Screw Blower?
     
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  2. Crew

    Crew Volunteer

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    We have had thread tolerance on the GRP rods get looser, but when we called GRP they told us to stick a junk rod in the vice and use a ratchet or a torque wrench to try and tighten the bolt enough to pull the threads out. They said the bolt would break first. They were right. I broke the bolt and didn't pull any threads. They told me that if your pulling threads on GRP's your hammering the cap off. And this can be done without spinning the bearing.

    Give'em a call. You might want to see if there's another problem.

    C
     
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  3. Nathan Sitko - 625 TAD/TAFC

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    been there...

    Snappy,

    I know you said you are using a good wrench, but even if it is good, when is the last time it was calibrated? We had the same problem for about 2 seasons, chucked the rods through the sides of 3 or 4 motors before we thought, "hey maybe it's something with the wrench???"

    We had a real nice Snap-On, took it to get calibrated because of a hunch, and someone said to get it checked. Turns out it was 25 lbs out...we thought we were torquing to 90lbs, but in reality it was 115...a wee bit too much. Long story short, that wrench went in the garbage, bought a new one and we haven't had a mystery rod failure since.

    I would definetly get the wrenched calibrated if you haven't already. Good luck!
     
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  4. weird science

    weird science New Member

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    wrench calibration

    Have never tried to have a torque wrench calibrated. Who does it? Does anyone have a contact # for them? Thanks for any info.
     
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  5. Randy G.

    Randy G. Top Alcohol

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    What garbage can did you throw the Snap On torque wrench in? Snap On will gladly check and recalibrate them for you.

    Brooks Rods in Anahiem has a machine bolted to the wall that will tell you where your torque wrnech pops. It a simple weighted device that is very accurate.

    I have Snap On torque wrenches, Mac long handle torque wrenches and the cheap click style Craftsman torque wrenches. What to know which one consistantly checks out the most accurate? The cheap Craftsman ones.

    RG
     
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  6. Mike Canter

    Mike Canter Top Dragster

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    You should invest $65 in a No-Go thread checker from Bruce at Childs and Alberts. What Bruce told me was if it screwed into the threads more than 3/4 of a turn then the rod is stretched or if a new rod the threads are cut wrong on the rod. I tested it on a used Top Fuel Brooks rod and got a half turn out of it. Tried it on one of our brand new Brooks rods and got 1/2 a turn out of it. Tried it on a brand new GRP rod and it went all the way in which indicates the threads are cut wrong and it is a No-Go. I just got the checker and I was shocked. I am still going around trying different brand rods to see what else is GO or NO-GO.
     
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  7. Nathan Sitko - 625 TAD/TAFC

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    Lol, by garbage can I meant the bottom tool box in the shop. Can-Torque I believe is the name of the place here in Edmonton. We bought a new torque wrench from him too, as well as got all of our others checked and recalibrated. I think the brand of the new one is CDI, seems to be pretty nice. I don't know who to get ahold of here in Edmonton from Snap-On, I should do some digging and see if they'll replace or fix it.
     
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  8. DQUES

    DQUES Member

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    I bought a set of GRP rods and the threads were so loose I sent them back and they made me a new set . Of course they said to run the rods with the loose threads but I felt much better about the new set . I have never broke a GRP rod although I am only on my second set . Does anybody run the L19 rod bolt option?.
     
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  9. wedge542

    wedge542 New Member

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    snap on can get them recal,we have ours done every 12 mnths,theyll put a stick on stamp on the wrench showing date,person doing the recal,a percentage of accuracy after the recal,location code of recal,we have 1/4,3/8,1/2,3/4,1 drives we have to count on so i take no chances and keep them wrote down in case stamp comes off as reg maint,you might not need yours done that often.
     
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  10. SNAPPY

    SNAPPY TAFC

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    UPDATE NOT A TORQUE WRENCH PROBLEM!!!!! New SNAP-ON TQFR250E (new 4/06) comes with calibration certificate!!!! Trade up every year for a new one...you need it!
    Got home and used a NEW SNAP-ON DIGITAL torque wrench (ATECH3FR250) and checked the remaining rods as we REMOVED them! most had breakaway torque values in the 25-35 ft lb range one was 42 and 2 were mid 80's!!!
    1 run on new rod bearings. Why doesn't the torque stay at or arround 90 ft lbs.??!?!?!?!?
    Also Mike Carter , We noticed the same thing, even with the L19 bolt..... Screw it in 2-4 turns with no cap on the rod and the bolt still wiggles in the rod ! ! ! Cann't be a good fit. Don't like this rod anyy more.
    Anybody run BME(Bill Miller) know he makes some good fuel rods. What about Blown Alcohol TAFC Screw???
     
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  11. secondwindracing

    secondwindracing top alcohol

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    Been running Brooks Rods and never had a rod fail yet!!!!! knockin on wood
     
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  12. SNAPPY

    SNAPPY TAFC

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    Second wind is that with a screw blower and how many runs before you cyle them out. Which material do you use? How much RPM do you turn??? 9400 ?
    We ran brooks with a roots but everybody said not to with a screw.
     
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  13. bruce mullins

    bruce mullins Top Dragster

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    in this class you hear all different opinions on rods. believe me, i have broken them all. currently i am running the b-2 rod in my afc with a screw. i know alot of guys running the b-2's. brooks explained the difference in the 2 different materials and what it comes down to is how well you know your tune-up. the harder material is a stronger rod, and will go more runs, BUT, if your tune up is off the rod will break before it bends. the softer (std b-2) will bend first. i was told 12-16 runs with the std b-2 lightened rod. once again ,my opinion is most rods are all the same. most of them use arp bolts and are made of the same material. grp makes a pretty rod. the external finish is second to none, but pretty get you nothing. some people swear by the grp's and some don't. if you have good luck with one brand , keep using it. just my 2 cents.
     
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  14. The Shoe

    The Shoe New Member

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    It has been my understanding that you are supposed to use a rod bolt stretch gauge to achieve proper specs, as most torque wrenches are not correct.

    Anyone else do this?:confused:
     
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  15. secondwindracing

    secondwindracing top alcohol

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    Bruce is so rite,....as for me we still run the hi helix and for rpm.. 9500 to 9800
     
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  16. Mike Canter

    Mike Canter Top Dragster

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    Yes, a stretch gauge is the way you should do it. You want .006 stretch to achieve the correct clamping force. If you have less stretch you get less clamping force and can stretch the bolt over and over again during a run and at the moment the forces come off the bolt and it shrinks back down it can turn. So after a run it is possible for the bolt to loosen up ever so slightly. If the bolt threads beome loose in the rod threads then the bolt has movement on the threads and gains momentum and will pull the threads out of the rod. This is different from putting a rod in a vice and trying to tighten the bolts and pull the threads out. You have to have loose threads and an impact against the threads. Any movement will allow the bolt to gain momentum and all hell breaks loose. Like not having you seat belt tight in a wreck and allowing your body to move forward at a high rate of speed before you contact the belts. Or not sitting tight in an ejection seat when it fires you out with 20 g's of force.

    During the life cycle of a rod the amount of torque required to get .006" of stretch will increase. I have seen racers plot it out and make a chart to match the amount of runs on a rod. It may take 90 ft lbs to get .006 on a new rod and 95 ft lbs with ten runs on them.
     
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  17. Jeffd

    Jeffd New Member

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    You may not be able to trust your torque reading when removing fasteners. Most clicker type torque wrenches are only calibrated to tighten RH threads. You would need to talk to your supplier. Snap-on and Mac both told me they calibrate for RH tighten only.
     
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  18. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Grp

    Brian at GRP is always a phone call away and will work with you to sort out any problems you have.

    I've ran many sets of GRP's through some high rpm motors. I dont think there are many other rods out there that can take a blown alky motor like they can. 25-30 runs isn't a problem.

    Brian is often in the 'trenches' with teams like Brian Hough and Mike Johnson along with others.

    We run the L19 bolts in our car. Only way to go if you're really going to buzz a motor in my opinion.

    I guess I just have faith in them. Been through alot with GRP's.
     
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  19. afuelfreak

    afuelfreak New Member

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    Amen !!!! William

    HAVE TO AGREE , WITH WILL ON THAT ONE !! we have put those rods thru hell & back , & we run the 3600 pro rods with L-19 bolts have over 60 runs on em , & we check bearings after every pass & re torque rods , never an issue ,
     
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  20. Fuel Cars

    Fuel Cars AA/AM

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    Just a little fyi, the No-Go thread gage needs to be used correctly, and, most thread gages are made to ANSI standards and these are some of the requirements for using the gages:

    All components to be clean and dry, don't oil the gage or the mating part, oil will give a false indication.

    Using only fingertip pressure, screw the gage in until a definite drag is felt, don't force it. The normal method of holding the gage is with the thumb and the middle finger.

    Unscrew the gage keeping count of the revolutions from definite drag to full release of gage, 2 max allowed. The reason for allowing 2 full revolutions is for gage manufacturing and gage wear.

    I wouldn't want a good rod thrown out because of incorrect gage use. Just like every other tool, thread gages need to be used correctly.
     
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