hey guys, got another quick question. What do you all usually torque the flywheel bolts to? Do I need a spacer inbetween the bolts & flywheel? I have an .840 flywheel I bought from a member here that is supposedly a brand new WCF flywheel, and ARP 234-1001 bolts. also, what bolts are people using for clutch plate to flywheel? thanks
You will find different values on different sites, Mostly I see about 60 to 65 ft pounds. I don't know if your custom flywheel is tapped for the same bolts as stock, so you probably need fo figure that out first. I think only the flex plates used a spacer under the flywheel to crank bolts. I have one sitting here some place. Larry
Stock 3.1 FW to crank bolts are 61 foot pounds, I think I would check to see what they spec the flex plate to crank bolts on your stock engine, else you may end up with a flywheel loose in the bell housing some day. Larry
[This message has been edited by trotterlg (edited 05-03-2013).]
IIRC 3800 crankshaft bolts are only 3/8" . Anything over 40 ft lbs. of torque may strip the threads.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Who is that? The bolts are actually only 5/16-18, I wish we had 3/8 bolts.
I guess that I was off by 1/16" but 5/16-18 is even more reason that those bolts won't take high torque. They are the same size as big block Chevy cam bolts.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
According to ARP's website, those bolts are the 200,000 Pro series, in 5/16 with a -18 thread pitch. Based on the chart (see link below) the nonminal torque is 28 ftlbs which gives you a clamping load of 6588 lbs. For what it's worth, I've used those same bolts and torque value on my installs without an issue. -Jason
According to ARP's website, those bolts are the 200,000 Pro series, in 5/16 with a -18 thread pitch. Based on the chart (see link below) the nonminal torque is 28 ftlbs which gives you a clamping load of 6588 lbs. For what it's worth, I've used those same bolts and torque value on my installs without an issue. -Jason
That would work if he was using the stock GM bolts, but hes using the ARP big block cam bolts which are a different animal entirely.
quote
Originally posted by Flux:
11ft-lbs? that seems very low ...
It is if that was all you were torqueing them to, but I think you missed the +50 deg turning torque you have to do to them after the initial 11ftlbs. This is what actually gives the bolt the clamping force required to hold the flywheel. -Jason
Sorry I was typing when both you guys posted.
[This message has been edited by Fierofreak00 (edited 05-05-2013).]
just over a 1/4 turn ya. It prob turns out to be like 25ft lbs or something. If you're using aftermarket bolts, they would be different anyways and you would have to go with whatever the manufacturer says. But, the site is handy though for anything you are needing specs on that are using stock bolts.
Funny how this question comes up, gets many different answers and creates just as many more questions. They are indeed 5/16 x 18, and as far as I can tell, torque specs are different for different types and manufacturers recommendations, as well as different with or without washers. I bought grade 9 bolts from Fastenal, used 35 lbs and never looked back. Results may vary, as they say.
GM factory flywheel/flexplate bolts are torque-to-yield, one time use only bolts. The factory GM torque spec is 11ft/lbs + 50 deg. They are 5/16 - 18 threaded, harder than grade 8 bolts. Some say they are grade L9 but I've never seen anyone test a GM bolt to see what it actually was. ARP probably has the best rating system for bolt strength and they measure them in PSI.
If you don't use a new replacement bolt from GM, then DO NOT use the GM torque specs. You should contact the manufacturer of the specific bolt you are using and obtain their torque specs. If you are using ARP bolts and ARP says to torque them to 28 ft/lbs, then torque them to exactly that. No more. Overtorquing will stretch and weaken the bolts, possibly causing future failure.
Of all the 3800 SC swaps I've done where I've had to replace the flywheel/flexplate bolts, I've only ever used new GM replacement bolts and torqued them to factory specifications. I've never had any bolt failures.
I see people on this forum try to use other bolts all the time and I see a lot of threads with pictures of broken bolts. Why is that? Answer: Either the bolts were too weak for the application or they were NOT torqued properly.
-ryan
------------------ OVERKILL IS UNDERRATED Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
[This message has been edited by Darth Fiero (edited 05-06-2013).]
guys, like i said, i'm using an .840 flywheel with arp bolts....... that's all i need to know the torque specification for. it would seem that either fierofreaks00's suggested 28ftlbs or FIEROFLYER's suggested 40ftlbs would be the way to go.
guys, like i said, i'm using an .840 flywheel with arp bolts....... that's all i need to know the torque specification for. it would seem that either fierofreaks00's suggested 28ftlbs or FIEROFLYER's suggested 40ftlbs would be the way to go.
CALL ARP AND ASK THEM WHAT YOU SHOULD TORQUE THEM TO.
CALL ARP AND ASK THEM WHAT YOU SHOULD TORQUE THEM TO.
Just an FYI for everyone, I ordered the ARP 234-1001 kit (3 sets of 3) after calling ARP. Tech support at ARP recommends between 26 and 26 FT/Lbs with red locktite.
Just an FYI for everyone, I ordered the ARP 234-1001 kit (3 sets of 3) after calling ARP. Tech support at ARP recommends between 26 and 26 FT/Lbs with red locktite.
hope this helps!
The ARP Tech we talked to about the ARP bolts said they were NOT designed for 3800 flywheel to crankshaft mounting duty and he could not recommend them as such; further stating they weren't even as strong as the factory Grade L9 bolts GM sells for this application.
Just buy 8 GM p/n: 24505092 flywheel bolts, torque them to 11ft/lbs + 50 deg, and be done.
[This message has been edited by Darth Fiero (edited 05-22-2014).]
In the process of replacing my clutch so have been searching the existing posts ... like this one. Just picked up my flywheel after having it turned and decided to bolt it up tonight. I had purchased grade 8 5/16" bolts (like what I removed). Looked up the torque specs in the factory manual and it clearly states 50 ft lb. Seemed like I was having to turn the torque wrench way too much and it wasn't clicking to declare value met. I backed it off to 40 ft lb and the bolts started to click tight ... all except one. A few more turns and it snapped. Luckily there was enough of it sticking out of the crank hub to cut a groove with a hacksaw and turn it out with a screw driver ... tense moment. I reviewed this thread and also researched bolt torque values online. Here's one from Fastenal https://www.fastenal.com/co...0Gr5%20Gr8%20Gr9.pdf For a grade 8 coarse thread they list the value in inches that translates into about 17 ft. lbs. For a grade 9 5/16" they also list in inch pounds at which comes out to about 29 ft. lbs. A couple of members had commented that they felt 60 ft lb was asking too much from a 5/16' bolt and I guess that I agree with them. Not sure what Pontiac was thinking when they listed the torque value to 70 nm/50 ft lb, but the grade 8 bolts will not survive that amount of torque. I'm going to see if the local Fastenal has grade 9 bolts, go with 28 ft lb and use blue thread locker. Any other thoughts/ideas are welcomed.
The ARP Tech we talked to about the ARP bolts said they were NOT designed for 3800 flywheel to crankshaft mounting duty and he could not recommend them as such; further stating they weren't even as strong as the factory Grade L9 bolts GM sells for this application.
Just buy 8 GM p/n: 24505092 flywheel bolts, torque them to 11ft/lbs + 50 deg, and be done.
Is this bolt (GM# 24505092) correct for the 3800 series 2 automatic flexplate to crankshaft? Or just for the manual flywheel? Should I use loctite?
[This message has been edited by carguy8t8 (edited 12-05-2017).]
Originally posted by carguy8t8: Is this bolt (GM# 24505092) correct for the 3800 series 2 automatic flexplate to crankshaft? Or just for the manual flywheel? Should I use loctite?
GM p/n 24505092 is for the (longer) manual transmission flywheel bolts. If you have an automatic flexplate, then you need the (shorter) p/n 24501365 bolts. Same torque spec (11 ft.lbs. + 50 deg turn).
I always use red loctite on the threads of these bolts upon installation. Never re-use these OE GM bolts, they are one-time-use only / torque-to-yield bolts.
