stripped crank threads

[grumpyvette]

now its been my experience that most stripped crank threads are the results of guys trying to use the damper retaining bolt to draw on the damper rather than use the tool that's designed for the job.only a small percentage of the threads are engaged during the first few fractions of an inch of the process and they will easily pull out or strip, the correct tool will be engaged with about 90% of the threads , before the tension loads are applied,so it won,t have that tendency to strip threads.

read these two threads (below)first, they contain a good deal of info you need to know and understand! and it may prevent you needing to repair your crank or have striped threads

http://www.jegs.com/p/ARP/ARP-Harmonic- ... 6/10002/-1

viewtopic.php?f=53&t=1480

http://www.crouchsales.com/hex-bolts-grade-8-fine.aspx

http://www.atiracing.com/products/dampe ... ctions.htm

viewtopic.php?f=53&t=83


http://www.go-fast.org/z28/damper.html
btw if youve ever tried to draw on a damper with a crank bolt from a local hard ware store this is frequently the result, that or stripped crank threads, ID strongly suggest use of the correct Damper tool, and use of ARP crank bolts once its properly installed

next time BUY AND USE AN ARP BRAND BOLT
I,ve generally found that if you've stripped the SBC crank snout threads the best answer is to drill and re-thread to the standard and larger BBC crank snout bolt threads size

Measure the crank-snout diameter with a micrometer (above left). Ours measured 1.600 inch, which is right on spec. Then use a dial-bore gauge to determine the inside diameter of the Fluidampr damper (below). Ours came in 1.599-inch, resulting in a .001-inch interference fit. This is the right amount of clearance to provide a good snug fit on the crankshaft, but still be able to install and remove without difficulty. Another method of measuring the damper hub ID of your is with a snap gauge (above right). After setting the gauge, the micrometer is used to to determine the final measurement. In this case, the same measurement as the dial bore gage was reached.
http://www.enginebuildermag.com/Article ... stons.aspx
http://www.arp-bolts.com/

http://www.summitracing.com/parts/ARP-134-2501/

http://www.summitracing.com/parts/ARP-234-2503/

viewtopic.php?f=53&t=1798&hilit=damper

viewtopic.php?f=53&t=1480&hilit=+damper

viewtopic.php?f=53&t=1798
if your current crank bolt is an ARP bolt, heres the dimensions,
keep in mind a bolt threaded in steel should have 1.5 times its diam. MINIMUM in the threads before the bolt starts to draw or tighten or clamp and TWICE its diam. in the threads is better as a minimum to prevent stripped threads, and remember the bolt should never be allowed to bottom out in the crank snout threads and tighten against the bottom of the drilled hole either

Summit Racing Part Number ARP-134-2501

Thread Size 7/16-20 RH in.
Underhead Length (in) 2.470 in.
Head Style 12-point
Washer Included Yes
Fastener Yield Strength (psi) 200,000 psi
Fastener Material Chromemoly
Fastener Finish Black oxide
Quantity Sold individually.
Notes Features 5/8 in. socket size.

One tough bolt.

As the crankshaft flexes, the damper absorbs incredible amounts of energy. These damper bolt kits from ARP will ensure that your balancer is locked into position. They feature a 1/4 in. thick wide-area washer and an extra tall 12-point head that accepts a deep socket to eliminate the fear of stripping the head.

http://www.summitracing.com/parts/ARP-134-2501/

now you can probably re-tap the current threads and use a longer bolt and get by for now, but drilling it with the correct larger drill diam. and re-threading for the big block Chevy bolt is the more common route taken once you strip crank threads
viewtopic.php?f=53&t=1480&p=6221&hilit=stripped+crank#p6221

viewtopic.php?f=53&t=1798&p=5680&hilit=stripped+crank#p5680
there is supposed to be about a .0001 -.0002 INTERFERENCE fit! so the damper has far less tendency to spin on the crank snout or work the woodriff key loose, you can generally polish the crank snout, and internal damper hole with a flap wheel and 400 grit sand paper enough to get a smoother surface, then, place the damper in boiling water to heat and expand it and oil its mating surface, use the correct damper installation tool, pick the damper up with oven mitts so you don,t get burned, use the tool to install it

http://www.summitracing.com/parts/otc-6505

I,ve generally found that if you've stripped the SBC crank snout threads the best answer is to drill and re-thread to the standard and larger BBC crank snout bolt threads size

https://www.nookandtranny.com/Info_LT1.html

these tools work well, fit most engines and if you do break off a thread adapter you can order a replacement without needing to pay for the whole new tool, and keep in mind the threads strip or adapters break if the dampers OVER TIGHTENED,ALL TOOLS WILL BREAK IF OVER STRESSED, this CAN generally be avoided with simply taking a few accurate measurements and use of some marvel mystery oil on the damper, crank and the installing tool threads
Yes I busted one thread adapter years back , but it was a P.I.T.A. waiting on a replacement and I learned not to over tighten the tool, and watch carefully on the measurements and have not had that happen for 30 plus years keeping the tool and damper and crank snout well lubed makes it slide on easier
measuring and checking the interference fits correct helps

read thru these threads, for info on seating a damper and re-threading a stripped crank

http://www.summitracing.com/parts/ATI-9 ... mage=large
http://www.fluidampr.com/DOWNLOADS/STRE ... NSTALL.pdf

drill and tap sets
http://www.amazon.com/Tap-Drill-Set-met ... roduct_top

sbc engines are normally threaded for 1/2" SAE fine threads and BBC for 7/16" SAE FINE threads

ITS not uncommon to drill and tap the 1/2" sbc chevy cranks when they get stripped threads to the larger big block chevy damper bolt to repair those stripped threads to the larger 7/16" thread size or the larger 7/16" bbc cranks for the 9/16 SAE or 5/8" SAE fine threads
now re-threading the sbc crank for the larger BBC thread size presents no huge problems, but the standard balancer installation tool wont fit the 5/8" threads
a grade 8 bolt about 6" long and a large stack of about 2" of 9/16" or 5/8" FENDER WASHERS and a NUT threaded for the 9/16" or 5/8" THREAD can FREQUENTLY be used as an emergency tool if you grease the washers, nut and threads with moly assembly lube

for those guys that don,t know thats a
9/16"-18 or 5/8" -18 tap size youll be using to re- thread the crank[/b]
tap----------drill size
9/16-18 33/64
5/8-18 37/64

http://buy1.snapon.com/catalog/item.asp ... up_ID=1166

http://www.victornet.com/cgi-bin/victor ... Drill.html

http://www.tavia.com/cat12.html#1


BROKEN BOLT REMOVAL

viewtopic.php?f=50&t=729&p=1026#p1026

 

[fast84vette]

for my crank will i use 7/16 20 tap to retread my crank?

 

[grumpyvette]

http://www.jegs.com/p/ARP/ARP-Harmonic- ... 6/10002/-1

select the bolt, and thread pitch you intend to use in an ARP damper bolt size and GET THAT BOLT FROM ARP,and go to the local hardware dealer and buy the correct tap & drill, be aware that a 7/16-20"NF thread size TAP DOESN,T USE a 7/16" drill, 7/16-20 NF Tap , use a 25/64 Drill bit
USE LOTS OF CUTTING OIL AND DRILL AND TAP SLOWLY WITH LOTS OF BREAKS TO RE_OIL

heres a cheap one time use set

http://cgi.ebay.com/Performance-Tool-7% ... dZViewItem

http://www.fluidampr.com/DOWNLOADS/STRE ... NSTALL.pdf

http://www.atiracing.com/products/dampe ... ctions.htm

http://www.sears.com/shc/s/p_10153_1260 ... rigin=prod

http://www.youtube.com/watch?v=p7wd2Len ... re=related

viewtopic.php?f=59&t=1264&p=2715&hilit=taps#p2715

btw if youve ever tried to draw on a damper with a crank bolt from a local hard ware store this is frequently the result, that or stripped crank threads, ID strongly suggest use of the correct Damper tool, and use of ARP crank bolts once its properly installed

next time BUY AND USE AN ARP BRAND BOLT

link to order replacement parts you may loose or break on that damper tool
https://www.summitracing.com/parts/otc-4531/replacementparts


https://www.amazon.com/gp/product/B000F5LIW4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

https://www.otctools.com/products/harmonic-balancer-pullerinstaller-set


damn the gal in that video, makes that process, look a whole lot more difficult in the video that it generally is,
and yes its very easily possible to over tighten the interchangeable central adapter screw,parts
if your not careful, and yes they do sell replacement adapter screws
(never lend tools to your friends, or you'll be buying , and replacing those replacement threaded, adapter components)
use moly grease on tool threads

http://www.arp-bolts.com/

http://www.summitracing.com/parts/ARP-134-2501/

http://www.summitracing.com/parts/ARP-234-2503/

viewtopic.php?f=53&t=1798&hilit=damper

viewtopic.php?f=53&t=1480&hilit=+damper

viewtopic.php?f=53&t=1798

[quote-
Indycars]
Since I'm going to be replacing the damper bolt with the bigger BBC component, I'm also going
to upgrade the balancer while I'm there.

I'm trying to decide if the gold Race Series dampers is any better than the black Streetdampers ....
without the consideration of money.

I found the below info on the Fluidampr website.

http://www.fluidampr.com/what/

Fluidampr Dampers Performance over 6,000 RPM

the damper is engineered to allow for quick acceleration and the rapid increase in torsional vibration frequency associated with higher rpms. There is a clerical difference between “meets SFI standards” and “SFI certified”. The former means we construct our Streetdampers to the same rigorous standards as those that are SFI Certified. The later means, we have worked diligently with SFI Foundation Inc., who sets the rules and regulations for most racing organizations, to have our Race Series dampers independently tested, officially certified and regularly scrutinized by SFI. SFI Certified is a very scientific and costly endeavor to ensure that the construction of our product will hold up in the racing world. Regardless of terminology, the engine owner wins because our Streetdampr are manufactured to the same high level race quality outlined by the SFI Foundation Inc.

I found this, but it's still not conclusive about which damper would be better.

http://www.enginelabs.com/engine-tech/engine-harmonics/ati-fluidampr-tci-offer-expert-damper-advice/

LeBarron: Fluidampr offers a value-priced line of non-SFI rated Streetdampr brand dampers for popular small block Chevy and Ford applications. Streetdampr products can be used from mild to heavily modified applications whenever SFI 18.1 specs are not required because they provide similar benefits of broad range protection coverage and superior durability as Fluidampr just without a final protective finish. With some select applications we also offer different diameters and weights. It’s a compromise; a larger, heavier damper will provide more damping but slower throttle response and a smaller, lighter damper will improve throttle response but provide less protection. It is always best to consult with your engine builder or damper manufacturer if you need assistance.

https://www.summitracing.com/parts/flu-620101
https://www.summitracing.com/parts/flu-62260d/overview/

Any Opinions ??? Which one would be better ???

If I was making the choice ID call fluidamprs tech line and ask....
several questions ,
simply because
if your not sure its simply that you don,t have enough facts,
to make a logical fact based decision.

For Technical Support and Product Information Call or E-mail us at:
Phone: (716) 592-1000
Email: sales@fluidampr.com
Office Hours:M - Fr 8:00am - 4:30pm EST.
If after hours, please leave a message and we will get back to you as soon as possible.

https://www.summitracing.com/parts/flu-62260d/overview/
but ID certainly be looking harder at the gold version simply because it looks like theres,
been a few minor improvements made and the cost difference is insignificant in the long term
be aware theres internal and externally balanced damper and several diameters from about 6.25", 7" and 8" so ask pointed detailed questions, and know what you need.