WTF!? rod bolt snapped!! Thursday, 22-Jun-2000 20:03:17 Message: 208.247.198.178 writes: Hey guys, Well this has turned out to be one bad day for me. I decided I was going to start to assemble my engine for the last time. (final assembly) I lubed up the connecting rod bearings, and started to torque them down. I have Scat I beam rods. with 3/8 ARP bolts (forget the number, but they are not the 2000 series.) Anyway the card that came with my connecting rods says to torque them to 40 ft/lbs. I used the ARP lube, and started to torque. All was good untill I hit about 35 ft lbs. Then they were never tight. Stupid me just kept tightening and tightening..waiting for that magic click of 40 ft lbs. Well needless to say, I never got it. Bolt snapped. I tried the rest, and all seemed to do the same. WTF is going on here? I even bought a torque wrench just for my engine rebuild. I really doubt that the torque wrench is bad but who knows? Any ideas? Thanks Jay Boudreau Jay Boudreau

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Replies:

Don't they have... (Tom H.) (22-Jun-2000 22:49:25) Read your istruction sheet again....My Scat rods call for 22ft-lb's with ARP lube. .0045-.005" stretch. I think you over torqued them..... (n/t) (Ohio Tom) (23-Jun-2000 00:39:45) I have the same rods. Here's some theories. (Mike Fritz) (23-Jun-2000 01:00:55) Re: WTF!? rod bolt snapped!! (Muffler Mike) (23-Jun-2000 01:22:30) My rod card is missing! (Oliver) (23-Jun-2000 02:44:39)

Re: My rod card is missing! (Muffler Mike) (23-Jun-2000 12:18:10)

Re: WTF!? rod bolt snapped!! (Jay Boudreau) (23-Jun-2000 09:16:54)

Re: Re: WTF!? rod bolt snapped!! (Muffler Mike) (23-Jun-2000 12:10:19)

two arp web sites (Muffler Mike) (23-Jun-2000 12:13:34)

torque math... (John Connolly) (23-Jun-2000 13:09:40)

John, are you saying the Scat specs are incorrect as I notated in my post above? (n/t) (Mike Fritz) (23-Jun-2000 14:07:15)

I was just throwing them out off the top of my head. I do know there is around a 20lb/ft difference depending on WHICH lube you choose to use. Moly is so slickery it's TIGHT as hell at 25lbs/ft. You are just stretching the bolt since there is almost no friction on the fastener. (n/t) (John Connolly) (23-Jun-2000

YOU READ THE CARD WRONG!! the high torq is for the BIG bolts[7/16] i think .. the smaller ones get less torq.. time to buy a new set of bolts. fred (n/t) (fred stanki ) (23-Jun-2000 23:08:09)

JEZZUS!!! there aint NO WAY a 3/8 bolt is gonna take 45 # !!! what the hell are you thinking!! (n/t) (dennis/valley) (23-Jun-2000 23:12:53)

Pauter AA rods, 3/8 bolts, 50 ft.-lb. torque, no problems. (n/t) (24-Jun-2000 08:38:56)

Re: NO I didn't read the card wrong. 40 ft lbs for a 3/8 ARP 8740 bolt. Check out ARP's website if you wanna see for yourself. (n/t) (Jay Boudreau) (24-Jun-2000 10:31:08)

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Don't they have... Thursday, 22-Jun-2000 22:49:25 12.73.105.131 writes: ....5/16" bolts? I thought Pauter was the only one making rods with 3/8" bolts for VWs but I may be wrong on that. My Eagle rods have 5/16 8720 arps and take 22 ft lbs (Approx, have to check bolt stretch on them per the supplied instructions). My Pauters are 3/8s arp 2000 bolts and take 50 ft.lbs. Double check your bolt size. Tom H.

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I have the same rods. Here's some theories. Friday, 23-Jun-2000 01:00:55 63.252.128.79 writes: I have the same Ibeam rods with the 3/8 ARP 8740 cap screws. The spec is 40 ft/lb with a .0050" stretch. What I did was to lube the screws up real good, including under the bolt head so any friction spot would be lubed, with the supplied lube. Then, I tightened all the rods on both sides hand tight. Then, I snuck up in 5 lb increments on both sides evenly, starting at 15 ft/lbs. Check to make sure the rod spins smoothly on each increment. Once I got to the 35 to 40 lb foot final step, it took a little more turning to get to the 40 ft/lb "click". This is where the stretch occurs I believe. Maybe if you torque too quickly or unevenly they will stretch and break. I did mine slow and smooth up to 40. It did feel a little odd, but this is normal I believe. All of mine torqued down fine. I don't know if this helps, but this is what I did. Good luck. Mike I used a Craftsman "click" style torque wrench. Mike Fritz

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Re: WTF!? rod bolt snapped!! Friday, 23-Jun-2000 01:22:30 172.145.162.105 writes: I think tom and mike have the right idea. Wow, they really have a 3/8" bolt?. I know pulling my Pauters to 50 always give me that oh sh_t i hope this isnt going to far feeling. What i did on a motor i recently worked on, since it wasnt mine, i did a little test of my torque wrench. and pulled 5lb increments and took my dial calipers and measured the streach on the bolt. pull another 5 lbs and measured again, and was happy that at the proper torque on my wrench, it had streched the bolt to the manufacturers spec. (arp 2000 5/16"@28#, streach between .0047-.0052ish) You might want to try that. do it on the bench, and when you are reaching the specified bolt streach, check the torque your wrench is at. maybe its way off. Is it a well known name wrench? I'm using the same as mike, craftman, and it was dead nuts. Im using a 10-75 range wrench. even if it is way off, at least you know what to set it at to make it work. also maybe as you see the bolt strech, drop it to a pound or two increment. good luck and i guess its time to call scat up and get some more, or call arp direct, i know they have a web page too. Muffler Mike

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My rod card is missing! Friday, 23-Jun-2000 02:44:39 195.93.0.145 writes: I've got two sets of (Eagle-)rods laying around, one set from a customer in 5.5", for a Type 1 crank, with ARP 8740 bolts. As there was no torque card delivered with the rods (from the customer), I thought to pull them on like the ARP 2000 with 22 lbs./ft.(second set, 5.7", Chevy-dia.), but it seems to be wrong. Isn't 40 a little bit much for the ARP 8740? Please help? Thanks. Oliver

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Re: My rod card is missing! Friday, 23-Jun-2000 12:18:10 212.37.96.143 writes: well the 40lb is for a real 3/8" bolt your playing with the 5/16" and i think the ones your talking about are only 22lb and the arp2000 5/16' are 28# I posted the web pages that have the specs for the bolts, and you might give eagle a call just in case. I could be wrong on the number, im trying to take them off the top of my head. so verify. Muffler Mike

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Re: WTF!? rod bolt snapped!! Friday, 23-Jun-2000 09:16:54 209.206.2.134 writes: Hey guys, I am using a Husky professional torque wrentch. Was like 65 bucks at Home Depot. I used to always use Craftsman, but I like the quality of the Husky line way better. Anyhow, I did lube up the 3/8 8740 bolts with ARP lube and also under the head. I then hand tightned. I worked from 20 ft lbs, to 35 in 5 ft lbs increments. Seemed like after 35 it just never got tight. Muffler Mike, you say you checked bolt stretch with calipers. How did you do this? Do you have something to get into the bottom of the bolt. All I can reach is the top (head). The bottom is inside the rod cap. I will call Scat today, and see what they have to say. Thanks for the advice guys. Hopefully today will be a better day then yesterday......although I cant do anything till I get somemore bolts. Thanks, Jay Boudreau Jay Boudreau

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two arp web sites Friday, 23-Jun-2000 12:13:34 195.84.203.108 writes: http://www.arp-totalseal.com/ this one has on line catalog and spec sheet. http://www.arp-bolts.com/ this one has downloadable catalog and spec sheet. Muffler Mike

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torque math... Friday, 23-Jun-2000 13:09:40 216.190.8.17 writes: 22lbs/ft + MOLY = 45lbs/ft + Oil. 45lbs/ft + MOLY = SNAPPED BOLTS guaranteed. John Connolly

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John, are you saying the Scat specs are incorrect as I notated in my post above? (n/t) (Mike Fritz) (23-Jun-2000 14:07:15)

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I was just throwing them out off the top of my head. I do know there is around a 20lb/ft difference depending on WHICH lube you choose to use. Moly is so slickery it's TIGHT as hell at 25lbs/ft. You are just stretching the bolt since there is almost no friction on the fastener. (n/t) (John Connolly) (23-Jun-2000 15:13:46)