Harmonic balancer bolt torque?

[rwade]

After changing the cam, timing chain, and oil pump, I've read conflicting methods of reinstalling and torquing the balancer bolt (which is a new bolt because it is a torque to yield bolt). How are you guys going about this. Thanks for any advice and insight.

Wade

[Kim57]

I found these specs on three different sites
Kim

Crankshaft Balancer Bolt (Installation Pass-to Ensure the Balancer is Completely Installed) 240 lb ft
Crankshaft Balancer Bolt (First Pass-Install a NEW Bolt After the Installation Pass and Tighten as Described in the First and Final Passes) 37 lb ft
Crankshaft Balancer Bolt (Final Pass) 140 degrees

Crankshaft Balancer Bolt (Installation Pass-to Ensure the Balancer is Completely Installed) 240 lb ft
Crankshaft Balancer Bolt (First Pass-Install a NEW Bolt After the Installation Pass and Tighten as Described in the First and Final Passes) 37 lb ft
Crankshaft Balancer Bolt (Final Pass) 140 degrees

Crankshaft Balancer Bolt - Installation Pass-to Ensure the Balancer is Completely Installed
330 N·m
240 lb ft

Crankshaft Balancer Bolt - First Pass-Install a NEW Bolt After the Installation Pass and Tighten as Described in the First and Final Passes
50 N·m
37 lb ft

Crankshaft Balancer Bolt - Final Pass
140 degrees

[Hart_Rod]

Wade - if I were you I would buy a ARP LS crank bolt and not use the factory TYL (torque to yeild) bolt. They factory bolts are not supposed to be reused and they are very difficult to torque them the way the factory recommends. With the ARP bolt you just torque it like you normally would and they are reusable. Just my .02. Take care.

Rob

[littlevictories]

are you having a question about the angle torque spec of 140 degrees?

or just the variations in the torquing process?

[Robznob11]

buy a new bolt for 5 bucks . for 20$ get the homemade tool off of ebay. go get you the balancer tool install kit and 250 psi tq wrench from auto zone or oriles. install the homemade tool. leave all the bolts on timing cover loose. heat the center of the balancer lightly with heat gun. use the homemade tool and the thrush bearing out of the borrowed kit to install the balancer and bring it up to tq. then remove the tool install new bolt and tq to spec! that simple. I cut the fingers out of a glove and put them over vice grips locked them one fly wheel to tq it down. use a breakover to get the proper degree on final install of bolt.

[Blackpony]

I just used red loctite and a 1/2'' impact on my bolt. a year later not a single issue.

[rwade]

Thank you all for the responses. No question about the 140 degrees, just had found conflicting numbers on the interweb. I think I'm gonna buy the aftermarket bolt and tourque it to 37, then go 140 degrees past that and call it good.

Wade

[littlevictories]

that's my plan. have used a ton of arp stuff in the past and not one problem. just follow their instructions.

[Jon01]

Originally Posted by Blackpony

I just used red loctite and a 1/2'' impact on my bolt. a year later not a single issue.

I've done this dozens of times, never had an issue.

I have on the other hand heard of ARP's backing out.

[rwade]

Sounds like no one answer, or law on this subject. You guys who used the thread locker and impact, are you using the old or a new GM bolt?

Wade

[Jon01]

I've done it both ways.

[rwade]

Have you experienced an ARP bolt backing out? Or someone you know? I had at 1st bought a bolt from GM, but also trusted that ARP is a reputable part used in race applications too. Sooooooooo, not sure which way to go now? Ill do some more thinking in it I guess. Thanks guys

Wade

[rwade]

Jon01- when you u used the 1/2" impact and loctite, was it on a new GM bolt? If so, how hard was it to torque compared to the times you used an ARP bolt?

Wade

[Jon01]

A friend of mine with a C6 had all sorts of trouble with an ARP bolt backing off.

I have done the stock bolt/impact route both with an old and new bolt. Depends on if I feel like buying a new one. I just use my big IR impact, set it on kill and ran it down good and tight.

[Gumby]

Ill go find it, is an article how an ARP crank bolt adds HP.

Edit
found it but the site is dead, only txt is aviable.

"Crank bolt worth 13.X hp???

Pasted from: gofastnews.com



Text, Photos and Drawings,

By

Jon ‘Dusty’ Kennett


After spending four hours grinding on a set of iron Chevy heads, believe me, lunch time is a very welcome break. It was over one such lunch hour that I got to talking with DV about unusual or unexpected sources of increased power. I had supposed, that with over 40 years of prolific dyno testing, DV might have one or two stories to tell here. As it turned out one or two was not even close. Some examples were the 25 hp airline trick for restricted intake turbo motors, the 4 hp donut deal for street stockers, the 14 hp knife edged jet, and the list goes on. But one just happened to hit close to home and that is the crank bolt scenario we are going to look at here.


http://gofastnews.com/photos/data/512/bolts.jpg


Over the last couple of years I have accumulated time in several engine shops. These shops are pushing engines out of the door every day and the way they stay in business is to have a streamlined assembly process. One aspect of assembly that always takes time and involves a lot of carefully applied brute force is installing the crank damper. Over the years this job has involved increasingly higher install and removal forces. Although the cranks and dampers are, in the main, made to GM or Fords original tolerances the materials that the cranks and dampers are made of has become better. The harder and tougher the steels involved the more force it takes to install/remove a damper. To expedite installation and removal it seems that it has become relatively common practice to hone out the damper so that it has less press fit interference. While this might make assembly quicker and easier it needs to be understood that a damper only works as it should when it is bonded to the crank to a degree where absolutely no motion, however small, can take place between the crank and damper.

An extensively modified small block Chevy comes into DV shop and is loaded on the dyno. After calibration of the carb and timing a graph of the output shows two fairly large dips in the output curves. These occurred at 5800 and 7000 rpm. At this point Tech Ed Vizard told the engines owner that he seemed to remember being told by one of GM engineers that the crank in a small block Chevy went through torsional peaks at 5800 and again at 7000 or so. That was just where these troughs in the curves were occurring. The power loss here was thought to occur by un- damped torsionals in the crank being transmitted to the cam. From here it was theorized the cams dynamics got fouled up and drove the valve train into a spring surge or seat bounce situation.

After evaluating the valve springs for sufficient poundage they were provisionally pronounced probably OK for the job. From here attention was turned to the damper. This came off far too easy for something that is supposed to have a really tight press for. Inspection with an eye glass indicated some fretting of the keyway and the cranks damper diameter. To fix this would normally mean a new (and expensive) damper and that would take about a week to get. As it happens the damper was used together with a stock Chevy crank bolt. It was suggested to the engines owner that a higher strength (and hence a little more torque) ARP crank bolt torqued to the limit might just tie the damper in sufficiently to at least temporarily solve the problem. Being a simple move it was worth a try. Based on an average of three runs the results of a before and after installation of the ARP crank bolt are shown in the following chart.


http://www.gofastnews.com/photos/data/512/bb_chart.jpg


As interesting as looking at the raw numbers of the chart is, the situation can be seen far more clearly when shown in graphical form. Take a look at graph Fig 2 and the dips in the output curves where the suspected crank torsionals are at there supposed peaks can clearly be seen.


http://gofastnews.com/photos/data/512/graph1.jpg


When a crank damper has been honed, a practice conducted far more than the engine building fraternity might admit to, it might be a good idea to simply specify you want an ARP damper bolt not a stock one. For the small price difference it brings about on an overall engine cost it looks like cheap insurance to me.

AS with any ARP product the quality of workmanship is simply top notch. With this in mind I would have to award the ARP bolt a GFN 5 star product rating."

[Blackpony]

Originally Posted by rwade

Sounds like no one answer, or law on this subject. You guys who used the thread locker and impact, are you using the old or a new GM bolt?

Wade

I have installed new and reused the old one on many separate occasions with no issues either way.

[crazy longhorn]

Originally Posted by Hart_Rod

Wade - if I were you I would buy a ARP LS crank bolt and not use the factory TYL (torque to yeild) bolt. They factory bolts are not supposed to be reused and they are very difficult to torque them the way the factory recommends. With the ARP bolt you just torque it like you normally would and they are reusable. Just my .02. Take care.

Rob

2nd that....any bolts I have replaced in my LS, have been ARP The head bolts were not cheap, but the fact that you can use them again (2 or 3 times), really offsets the cost? I also opted for the water pump bolts ,from ARP...not too big on the price? The flywheel (stick shift, has ARP bolts in the crank to flywheel, as well as the clutch cover). The fasteners for the clutch/flywheel, did not cost any more coin than the stock pcs Pan bolts, or valley cover bolts...I would not sweat too much ,on reusing the stockers...TTY, & toss the next time don't work for this old school player...Longhorn