[64speed]

Can you use standard Grade 8 bolts with lock washers as flywheel bolts with no ill affect? I had ARP FLYWHEEL bolts installed and when I went to remove them to install the motor plate the threads on EVERY one of them stripped upon restarting them. Not the threads in the crank the threads on the bolt. It must be a bad batch and I have emailed ARP about it. No I did not try to start them with an impact, no I am not stupid, the grade 8 I went and got from ACE threaded right in. The tips of every one of the bolts flattened when I tried to screw them back in using a breaker bar. I have never had a problem with ARP. Now I am anxious about using Grade 8 bolts but I have to get this trans job done while I have help.

[64speed]

I just read on the Chevelle website that anything but the pro series is considered one time use and those bolts were torqued to spec when the engine was first ran. I don’t know what is up with them but the tensile strength rating posted on ARP site and what I could find on Grade 8 bolts was only 500 PSI difference. The MR. Gasket bolts that I can get same day from Advance Auto are only Grade 8 so unless someone knows something I don’t I am gonna run them???????

[Scott Thelander]

I had some ARP flywheel bolts in a package new from some where and they listed big block mopar on the package also
WTF ? so ok I tried em and they were so long they almost hit the block...

I have a set of MR gaskets on one motor ,,, and they are working fine .... I would recomend grinding the face of your socket down
flat and get rid of the rounded face on the socket.... the heads on the mr gaskets are so flat the sockets I have ,,,, crap on and kraftsman
all sit to high on the bolt and liked to slip off ,,,, so I ground the face off an 11 /16 and it sits down over the head alot further

just my .02

Scott

[lust4speed]

Many of the ARP blots and most of the hardware store Grade 8 bolts have too thick of heads and the springs on the clutch disc will come in contact with them.

I agree with Scott on both counts listed above. Many of the bolts sold are too long and rub on the block, while the block usually comes out second best in the encounter it will bugger the ends of the bolts up. I also have a socket just for flywheel and flexplate bolts. Many sockets are too generous with the taper on the face of the socket so a nut or bolt head will slip in quickly, but this also gives up about a fourth of the contact surface. Dressing the socket down flat and removing the indexing taper really helps keep the socket firmly on the bolt.

[Half-Inch Stud]

Factory bolts sound real good huh. Try N buy in the Parts section

[Rincon]

I've had no problem using factory bolts several times. But the head on standard hardware bolts are too tall and can interfere with the center sections of most clutch discs. ARP sells hard ware that will work. Same problem could happen with aftermarket flywheel, some of them have thicker center sections so factory bolts and some aftermarket hardware may also interfere with the center section of some clutch discs. I ran into that problem with a Hays flywheel 8 years back

[track73]

Use these.

[64speed]

Well I can’t get any of the Mr Gasket bolts today so I took the lock washers out and put blue loctite on the regular grade 8 bolts with a thin flat washer and there is no interference so I guess that’s what we will go with

[track73]

I had flywheel bolts that had heads that were thicker than the Mr Gasket ones. The springs on the clutch hub hit the heads. When rebuilding a trans, I noticed the witness marks on the springs. I used my 4” grinder and ground down the heads. That works but I bought these the next time I switched engines.

[64speed]

I checked and it has no interference so I’m good

[Bermuda Blue]

Do not use lock-washers on any critical clamping application. Like flywheel to crank. Those things do more harm than good. The factory didn't use them for a reason.

[lust4speed]

As the clutch disc wears it comes closer to the bolts, and every time the flywheel is turned the disc gets closer so allow for extra clearance.

[64speed]

I have never turned a flywheel before. I just replace them. I think I will be ok with the disc wearing out because with the flat washers the bolts weren’t THAT tall and the Hayes flywheel has a pretty deep recess. ARP is sending me new bolts but I can’t wait so I guess I will sell them on here

[lust4speed]

I missed the part about the washers before. Pontiac didn't run washers and it is just an added failure point that can be avoided by not running them. I have run them way, way back and nothing catastrophic happened, but a little blue Loctite with no washers would be my choice. Plus it gives a little more room between disc and bolts.

[64speed]

Originally Posted by lust4speed

I missed the part about the washers before. Pontiac didn't run washers and it is just an added failure point that can be avoided by not running them. I have run them way, way back and nothing catastrophic happened, but a little blue Loctite with no washers would be my choice. Plus it gives a little more room between disc and bolts.

You’re probably right but it’s too late. I’m still pissed about the ARP. They did ship new ones but I have to do it while I have help. The wedding between drivetrain and chassis will be done tomorrow

[Old Man Taylor]

Originally Posted by lust4speed

I missed the part about the washers before. Pontiac didn't run washers and it is just an added failure point that can be avoided by not running them. I have run them way, way back and nothing catastrophic happened, but a little blue Loctite with no washers would be my choice. Plus it gives a little more room between disc and bolts.

Ditto.

[Dragncar]

1/2" factory bolts are overkill for anything you can throw at them. No lock washers, I hate them. Hardly ever use them even in industrial settings. You can spread them out just tightening the nut.bolt. Even grade 8 ones.

[64speed]

I took the lock washers off and used the washers that came with the **** arp bolts. I used blue loctite and torqued the grade 8 bolts down. The Hayes flywheel has a deep recess so I don’t think the clutch disc will ever touch the bolts and if it does then when it disintegrates I will buy a new clutch and pressure plate. I really think it will be ok.

[4dblnkldude]

Reviving old thread here... I took the 455 out of my firebird on Friday and noticed the clutch springs were hitting the flywheel bolt. They werent hitting much maybe .010 to .015. The bolts I are factory I believe and I always had those star lock washers on the there. So if I remove the lock washer that should be about my .015. The heads of the bolts are .320 thick...perhaps put them on a belt sander and sand off another .020 to be safe? Then blue loctite and install them with no washer I would think I would be good. What say ye?

[Scott Thelander]

either the disc was in backwards ...very unlikely
or
the flywheel has been turned too thin