4 speed questions

[kcmash]

Gang.

I am having a tougher time than I should with fastners. After the disassembly of the clutch assembly yesterday I broke one of the AMK bolts when shooting for the 35 ft-lb goal. The Centerforce instructions say you MUST use a shoulder bolt for attachment. The only ones I can find have a small shoulder at best

What do you guys use? I have really lost confidence in the ability of my digital torque wrench to measure low value torque. I don't want to break and drill out a more bolts.I due want to get to 35 ft-lb though and put this darn thing together.

Advice please!

 

[rocket366]

http://www.jegs.com/i/ARP/070/150-2201/10002/-1?parentProductId=744904

Check that

Paul

 

[Duncan Mach72]

I did a write-up on my 429 swap. Here is my bit on clutch bolts:

I had some ARP clutch bolts which were ok on the steel Cleve flywheel but they did not have anywhere near enough length for me to be happy using them in aluminium. I started looking for some 5/16” 12.9 grade bolts, preferably 1¼" overall length with a 3/8” shank to locate the clutch cover & in the counterbore of the flywheel. Pretty much only socket head capscrews are available in this grade below 1½”. All the short ones are only available as screws not bolts – no use at all. It's bizarre that performance bolt manufacturers do not appear to offer choices of length & clutch/flywheel suppliers do not offer bolts or even info on what to use.

After much searching I finally found some with 1¾” overall length to get a ½” shank and cut off the excess length. That’s just a bit too long shank – I had to use a washer + a spring washer under head which I hope will be ok. I can't understand why Ford didn't use 3/8” bolts in this location. It would be easy to bore out the clutch cover & have the flywheel drilled & tapped to do this, then I'm pretty sure it would be safe to use 8.8 bolts due to the larger size, which would be much easier to find.

Maybe you can find a better choice of 12.9 bolts in the USA?

 

[mjlan]

I can't remember if I got mine from Ford Racing or ARP?

ARP I know had two blister packs: one for early small blocks and one for later 5.0's.

I usually replace the stock Ford stuff with ARP for the flywheel and clutch.

 

[Carolina_Mountain_Mustangs]

I did a write-up on my 429 swap. Here is my bit on clutch bolts:

I had some ARP clutch bolts which were ok on the steel Cleve flywheel but they did not have anywhere near enough length for me to be happy using them in aluminium. I started looking for some 5/16” 12.9 grade bolts, preferably 1¼" overall length with a 3/8” shank to locate the clutch cover & in the counterbore of the flywheel. Pretty much only socket head capscrews are available in this grade below 1½”. All the short ones are only available as screws not bolts – no use at all. It's bizarre that performance bolt manufacturers do not appear to offer choices of length & clutch/flywheel suppliers do not offer bolts or even info on what to use.

After much searching I finally found some with 1¾” overall length to get a ½” shank and cut off the excess length. That’s just a bit too long shank – I had to use a washer + a spring washer under head which I hope will be ok. I can't understand why Ford didn't use 3/8” bolts in this location. It would be easy to bore out the clutch cover & have the flywheel drilled & tapped to do this, then I'm pretty sure it would be safe to use 8.8 bolts due to the larger size, which would be much easier to find.

Maybe you can find a better choice of 12.9 bolts in the USA?

In the U.S. for Inch bolts we have Grade 2, Grade 5 and Grade 8 being the tougher one. . There are no marks on a Grade 2 bolt head, A Socket Head Cap Screw is about the same as a Grade 5, 3 lines on a Grade 5 and 6 lines on a grade 8. The marks on the head tell you what you have like the numbers on the metric ones you see a lot of. They use metric here now. Link to chart for reference. https://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx

I don't know that the ARP are any better than a grade 8. The threads in the flywheel are the weak point not the bolt usually. A good rule of thumb for thread engagement is 1 1/2 X the dia. of the bolt engagement in steel. 2 X the dia. of the bolt engagement in cast iron. 3 X the bolt dia. engagement in aluminum.

I would not lube threads that are being torqued to a specification unless specifically told to do so by the manufacturer. Some lubes just let the bolt keep going until it breaks, molykoate is one.

David