TKO600 clutch

[elmariachi]

Originally Posted by patrickt

In this particular case I have decided to work with this formula:

RR = Pexposed/Pnon-exposed

[patrickt]

Uh-huh. I think if that was my car with the Grade 1 K-mart bolts in it I would just leave them there. I think they're probably good enough. Seriously.

[RodgerH]

The ARP 250-2201 bolts are 3/4" long. The shoulder is 1/4" long, the threads are 1/2" long. I still have them....looking at them...never returned them to Summit after determining they were too short. The 3/4" length was the problem...too short....not enought thread engagement. You can go back and re-read the details.

The Mr. Gasket bolts (p/n 911) are advertised as 1" long. Looking at the enlarged picture on Summit's website, it looks like the shoulder may be 1/4" long and the threads may be 3/4" long.

I don't know why they are different lengths, yet both are claimed to be Ford or OEM replacement?

Rodger

[patrickt]

Originally Posted by RodgerH

I don't know why they are different lengths, yet both are claimed to be Ford or OEM replacement?

Yes, not having them in front of me the only thing I can guess is that the head itself is .25" and Mr. Gasket includes that in the 1", and the bolts are really the same size.

[elmariachi]

Using the ARP bolts with their washers doesn't leave enough thread in the flywheel in my opinion. The 250-2201 ARP bolts with some very thin washer/shims I have might work. I am still confounded as to where these bolts I have came from, and why I used them without washers. I didn't fart during this build without having either specific instructions or some pertinent reference from the build books or experience from threads here.

[patrickt]

Originally Posted by elmariachi

I am still confounded as to where these bolts I have came from, and why I used them without washers. I didn't fart during this build without having either specific instructions or some pertinent reference from the build books or experience from threads here.

Uhh, maybe it was like in Dallas when we all thought Bobby was dead but then Pam woke up and it was all a dream.

[elmariachi]

Originally Posted by patrickt

Uhh, maybe it was like in Dallas when we all thought Bobby was dead but then Pam woke up and it was all a dream.

Yes, exactly.

[RICK LAKE]

elmariachi Jim I missed the Dallas thing unless it was Football. Anyway, Couple of things here are not quite right
Pressure plate bolts rely on the first 3-4 thread for 90% of there holding powers on a clutch pressure plate to flywheel.
I have run an iron flywheel (40#) for 3 years and now run an Aluminium one. There are helicoils in the Summit one I have. Yours may also have them or a timesert for the clamping power needed. I have not had a pressure plate bolt come loose in any of my cars or the Vettes, GTO's, or trucks I have worked on in the last 10+ years. I allways used Loctite for flywheel and pressure plate bolts, RED not blue. You are worried about your bolts in your clutch, you should see the small ones now being used in the new stuff. 8 & 10MM heads on a 1/4" -5/16's thread.
If you are running a RACE clutch with a 3,800# and up clamping load and up I could see the issue with longer bolts. Most Cobras are running a 2,800# to 3,200# on the street. If you want more holding power of a clutch, multi disc is the way we are going.
I use the washer on my bolts and have no problem. I the old days there was a steel ring that the bolts of the flywheel went through to not gall the surface of the flywheel. I never found loose bolts on one of these motors with 20-50 thousand HARD miles.
There is alot of heat and expansion going on in the bell housing, also alot of stress on the pressure plate bolts. Having washer washers spreads out the load bearing on the heads of the bolts, they may even absorb some of the loading and unloading pressures. I believe in ARP bolts, nuts, washers, and other fasteners. I have used them on motors for more than 30+ years. I have broken everything in a block but have yet to have a bolt break of theirs cause the main failure.
Jim go with a longer bolt if you want, just make 100% sure that the other end doesn't hit the block, or block plate in a full 360 degree rotation. I have seen this happen a couple of times. Rick L

[undy]

The rule-of-thumb for thread contact is, 1.5 x diameter of bolt/stud. This is a generality, variables like hardness, materials, threaded hole depth etc impact on it. Bottom line, if you follow this you'll never come up "short".

That was one of the first concepts I learned in the Navy's Machinist Mate "A" school back in 1970..

[patrickt]

Originally Posted by RICK LAKE

You are worried about your bolts in your clutch, you should see the small ones now being used in the new stuff. 8 & 10MM heads on a 1/4" -5/16's thread. ... I use the washer on my bolts and have no problem. In the old days there was a steel ring that the bolts of the flywheel went through to not gall the surface of the flywheel. I never found loose bolts on one of these motors with 20-50 thousand HARD miles. ... I believe in ARP bolts, nuts, washers, and other fasteners. I have used them on motors for more than 30+ years.

If anything, Rick tends to fall on the "alarmist" end of the mechanic's spectrum. For him to allay our fears of the ARP bolts speaks volumes. Just periodically stick a torque wrench in the fork hole and make sure they're snug -- that's all you need to do. And if you've been running non-shouldered Grade 8 bolts without a hitch for a couple of thousand miles, I don't think you need to change them out either. Rick is great -- Rick is my hero -- I love Rick.

[elmariachi]

Maybe this thread is being taken way too seriously. Seriously.

ARP exaggerates a lot, in my opinion. After all, their job is to scare us into buying their bolts, even when we don't need them. I am leaving my grade 8 bolts right where they are, and I am going to do my damndest to shear them off during my ownership of this car. If I am successful I will report back here.

[patrickt]

Originally Posted by elmariachi

I am leaving my grade 8 bolts right where they are, and I am going to do my damndest to shear them off during my ownership of this car. If I am successful I will report back here.

Oh yeah? Well I'm going to loosen my bolts a turn or two.

[RICK LAKE]

elmariachi Jim that's the stuff I like to hear, more work for MEEEEEE. I do hope one thing, That the bellhousing in your car is a good one like Lakewood. If you blow that clutch, I hope it stays in the can and not come visit you in the drivers seat. Rick L.

[patrickt]

Originally Posted by RICK LAKE

elmariachi Jim that's the stuff I like to hear, more work for MEEEEEE. I do hope one thing, That the bellhousing in your car is a good one like Lakewood. If you blow that clutch, I hope it stays in the can and not come visit you in the drivers seat. Rick L.

They're Grade 8, they just don't have the shoulders on them. C'mon Rick, tell the truth, have you EVER seen pressure plate bolts sheared off? Not from an exploding clutch, but just from the twisting force of the clutch itself. Tell the truth now....

[patrickt]

Alright, I tightened my PP Bolts this afternoon and two of them MIGHT, and that's a big MIGHT, have been slightly loose. I can't swear to that because the angle of the universal joint and socket on the bolt wasn't great so I can't say I had a great "bite" on those two bolts and it could have been the socket turning a little bit. I torqued them to 25 ft/lbs. I snapped a quick shot with the BB that shows you the angle on one of them. It's a crap shoot as to the angle you get because I just kept bumping the engine over until I got a bolt in the window, then torqued it, and then made a mark over it with a magic marker. This is not a particularly difficult job; getting the bolts to line up in the window is just luck -- if you turn the engine over by hand it would take you less time, but more energy. Regardless, you should probably check to make sure your bolts aren't loose. One tip -- you can see in the picture that I have some blue painters tape on the end of the extension. That's to make sure the universal joint and sock don't get pulled off and fall in to the bottom of the bell housing. A mistake like that could easily turn a quick afternoon job in to a huge PITA.

[elmariachi]

Originally Posted by RICK LAKE

elmariachi Jim that's the stuff I like to hear, more work for MEEEEEE. I do hope one thing, That the bellhousing in your car is a good one like Lakewood. If you blow that clutch, I hope it stays in the can and not come visit you in the drivers seat. Rick L.

It is a Lakewood. Like Pat, I checked mine and they are all right where I left them at 28 ft lbs with Loctite. But if the OP of this thread comes up with a better bolt, please post it up here.

[RICK LAKE]

patrickt Sorry pat, not on my own fleet of toys. I have broken about 4-5 discs with either schattering the hub in the center or breaking the springs in the hub housing. My FE motor has the smallest bolts for the PP in any of my stuff. I have repaired the disc once already.
IMO if you are shearing bolts, as you know there are only 3 ways I can think of doing this, ABUSE, abusey, AH CRAP ABUSE. I don't know why your bolts are coming loose but I am running a higher torque than you, I will have to check the numbers but it's like 38-45 ft pounds with the red. I do run a tap through all the holes before installing the bolts. Maybe this makes a differents. I also torque down the pressure plate like a wheel being installed on a car with a star pattern of 180 degrees per bolt. I have stopped with the 5,000 rpm holeshots and blowing the hell out of my equipment. 30 years ago, race parts where cheap along with trannies, rearends and clutches. Today a junk center section of a Jag with an open carrier is $6-800 dollars. No parts but the center. I have been lucky at swap meets and picked up some parts cheap. Major Destructor has retired from his stupid ways.
Pat I have seen alot of breakage and with people who I help and want to listen, I tell all of them to OVER BUILD your car. Bests parts, fasteners, motors, tranny and rearends. If they can't afford them then wait 2 months, put it on plastic, but get the best stuff you can. Maybe this is why the bolts have not sheared. I am not worried, I have a Lakewood. Rick L.

[elmariachi]

Maybe we can get him to put it all in a book. He could title it:

"All The Crap I Really Need To Tell You"
by Rick Lake

p.s. This is a great book full of all kinds of really interesting stuff about engines transmissions clutches shocks socks flywheels flyrods gaskets girdles Hi-Tack horse tack lug nuts car nuts temp senders mail senders timing lights Miller Light distributors high strength fasteners bell housings Bell Helicopters driveshafts mine shafts and other life-long experiences of spending all my money to learn things the hard way.

Just gigging ya Rick.

Sorry for the thread hijack.

[blykins]

You guys still going at this?

I hate to see the stuff that you say behind my back......

[patrickt]

Originally Posted by blykins

I hate to see the stuff that you say behind my back......

We say nothing behind backs. Everything is out in the open. After all, it is written in the founding documents of Club Cobra that gratuitous ball-busting is de rigueur.