rod bolt stretch Saturday, 23-Sep-00 18:33:02 209.198.4.187 writes: When I ordered my rods from CB Performance my old catalog said they came with ARP 2000 bolts. When I got them they had the 8740 bolts and CB told me you have to upgrade to the 2000 bolts now. They let me pay a small diiference and get the stronger bolts, but told me they couldn't accept the 8740 bolts back because they were pre-torqued and not reusable. I remember reading somewhere that you should tighten/loosen/tighten/loosen/tighten your bolts to pre-stretch them so they don't stretch and get loose once the motor is assembled. Does anyone know the proper procedure for this? Is there any truth to what CB was telling me? I have to take the bolts out to assemble the engine, so they would be re-used, so it doesn't make sense to me that they can only be torqued once. Do you guys have any secrets concerning bolt stretch/ pre-torqueing, etc.? Thanks, scott s scott s

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Replies:

try this address .............. (bergboy) (23-Sep-00 19:49:59)

hi scott, could you please tell me what the torque specs and stretch measurements are that are on your rod chart? the arp website does not have that info, i even called arp and they don't know... i'm building a motor with bugpack h-beam rods and arp2000 bolts... MORE (dan) (24-Sep-00 00:56:29)

I didn't get a rod card with mine. I have CB perf. H-beam rods(Bugpack copy)too. I'm wanting to make sure I do everything right the FIRST time! (n/t) (scott s) (24-Sep-00 10:25:30)

The ARP 2000 bolts should stretch .0056" this equates to about 30 ft lbs on MY torque wrench,this reading may vary from wrench to wrench but don't take chances,use the bolt stretch method. (n/t) (Paul) (24-Sep-00 08:52:12)

thanks for the info, paul! i agree, bolt stretch is the most accurate way... now i gotta figure out what to use for a bolt stretch gauge, something that doesn't cost a small fortune! :-( (n/t) (dan) (24-Sep-00 16:35:17)

I use a micrometer with ball end attachments and a very long handled 10mm ring wrench. (n/t) (Paul) (24-Sep-00 17:45:29)

Speedway in Nebraska (look at any street rod magazine) has a rod bolt stretch dial instrument for about $90. (n/t) (Randy) (25-Sep-00 12:50:19)

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hi scott, could you please tell me what the torque specs and stretch measurements are that are on your rod chart? the arp website does not have that info, i even called arp and they don't know... i'm building a motor with bugpack h-beam rods and arp2000 bolts... MORE

Sunday, 24-Sep-00 00:56:29

63.207.140.44 writes:

i had a long conversation with arp on the telephone friday, they make a lot of rod bolts that are not listed in their catalog.

however, their catalog is a downloadable .pdf file that answers all your questions about bolt stretch, and why you have to tighten down the rod bolts multiple times before the final torquing.

rimco tightened down my arp2000's to 45 lbs. before reworking them, but i think that is too tight.

they also lost my rod card, so any info anyone can give would be appreciated... i'll put it on my website... here is the arp website url:

http://www.arp-bolts.com

dan

http://www.oceanstreetvideo.com

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