Bullnose Enthusiasts Forum

Flywheel Bolts

Classic

List

Threaded

11 messages Options

Gary Lewis

Flywheel Bolts

Administrator

I had an emailed question from a gentleman w/a SEFI 460/E4OD combo asking about what bolts are spec'd for holding the flex plate or flywheel to the engine. As it turns out, that bit of info was missing from the garagemahal's page on Flywheels. However, it has now been added, and the answer is the manual transmissions take D2AZ 6379-A 7/16*—20 x 1" r/b F1ZZ-A, and the autos take D2AZ 6379-B BOLT (FLYWHEEL TO CRANKSHAFT)- 7/l6"-20 x 3/4. However, other places in the catalog show the bolt as being 23/32" long.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

CountryBumkin

Re: Flywheel Bolts

For the flexplate mounting, 23/32" is only 1/32" shy of 3/4". I can't see it making a difference either way.
Grade 8 I would expect.

-Mike
1982 F250 4x4 XLT Lariat, 460cid, 9.5:1, TFS 290 Street Port heads, Crane Hyd. Roller cam (278/286 adv.,216/224 @.050, .560"/.586" lift), Edelbrock Performer 460 intake, MSD Atomic TBI fuel injection, MSD 6AL ignition, MSD Billet distrib., Hedman headers, NOS Cheater system, 4" Suspension lift, 3" body lift, 4.56 gearing, 17x12.5Rx37 tires MT Baja ATZ-P3.

Gary Lewis

Re: Flywheel Bolts

Administrator

Jim is the expert here, but I think they are probably "place bolts". How Place Bolts Work

Gary, AKA "Gary fellow": Profile

CountryBumkin

Re: Flywheel Bolts

This post was updated on .

ARP makes the 3/4" long ones. http://arp-bolts.com/kits/ARPkit-detail.php?RecordID=767
$23 for six. Not sure if that is cheaper than Ford's price.

I never heard of Place bolts before. Amazing what you can learn around here.
https://wilsongarner.com/how-place-bolts-work/

I've handled my share of flywheel and flexplate bolts and don't recall ever seeing those. Maybe I didn't notice. I always put Loctite on the threads.

CountryBumkin

Re: Flywheel Bolts

In reply to this post by Gary Lewis

Referring to the info on the bolts...

Gary Lewis wrote

However, it has now been added,

Maybe you should put this info under the title/section "Fasteners" too. These are important bolts, and Fasteners would be a place many newcomers to this site would probably look first.

Gary Lewis

Re: Flywheel Bolts

Administrator

Good idea. Let me see what I can do.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Flywheel Bolts

Administrator

Arrrgh

I just spent 5 minutes making a post and lost it...

Stock Ford bolts are the best.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: Flywheel Bolts

Administrator

Jim, they may have been, but according to Ben Cavileer at Kool Ford, they are NLA from Ford. I ended up ordering some from Summit, CSR Performance as ARP only has the M/T 1" ones. That is what the engine builder provided with the engine, he didn't realize the A/T takes shorter bolts.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

CountryBumkin

Re: Flywheel Bolts

In reply to this post by ArdWrknTrk

ArdWrknTrk wrote

Stock Ford bolts are the best.

Purist !

Ford F834

Re: Flywheel Bolts

Administrator

In reply to this post by Gary Lewis

Just for the record, a guy on the IDI Facebook group needed flywheel bolts for his turbo'd 6.9L. He was on a time limit to put the thing together and used grade 8 hardware store bolts. Within a few weeks he sheared them all off starting out from a stop light. Just sayin'.... he replaced them with ARP 8740 chromoloy fasteners and so far no more problems. Needless to say I'd be very interested to know if the stock fasteners are "place bolts" or not. It sure isn't a place to cut corners...

SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD

STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering

BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2

ArdWrknTrk

Re: Flywheel Bolts

Administrator

In reply to this post by CountryBumkin

CountryBumkin wrote

Purist !

Yes, they're place bolts.
You can tell by the castellated and undercut head.

You shouldn't really need any threadlocker.
The undercut head of a place bolt acts as a belville washer to maintain clamping force.

Carroll Smith mentions in his book that these bolts are used on farm and construction equipment.
That Deere or Caterpillar bolts are just as good.

ARP have made a name for themselves and are good fasteners, but they probably weren't around when he took the GT40 to LeMans to trounce Ferrari.

It's been eight years since I swapped engines.
The bolts were ~$1.25 from Ford at that time.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.