1 Fly wheel 2 PP thread bad

[40 Deluxe]

Isn't there an identical bolt diametrically opposite? Just drill and tap it to 3/8" and use identical 3/8" bolts in each. Balance problem solved! You will still have 4 shouldered 5/16" to locate the pressure plate. Or check a GM pressure plate bolt. I believe they are 3/8" bolts with the required shoulder.

Oh boy, did I goof! Never type a response late at night! Apparently I was thinking of a '50-'51 Merc with a Borg and Beck diaphragm clutch. At least, that's my (lame) excuse!
Sorry about that!

[Mart]

^^ Actually there isn't. because of the 3 sets of holes offset by 32 degrees there are not two holes opposite each other.

I think I would have helicoiled the original hole, but that's me.

Actually the make a template comment isn't a bad one. You could rotate the PP 32 degrees so three bolt holes are still in use and drill and tap three new ones to the original spec.

Many ways to do this job, some better than others.

Some threads go like this where I bet the Op wishes he had just not mentioned it.

But the bottom line is the car is now capable of being driven. Balance was taken into consideration so I would say that it is an okay repair. There might have been better ways, but that way is okay.

Mart.

[cadillac512]

Once again, Mart is a voice of reason. Well said. Carry on...
Terry

[Kube]

Originally Posted by Mart

^^ Actually there isn't. because of the 3 sets of holes offset by 32 degrees there are not two holes opposite each other.

I think I would have helicoiled the original hole, but that's me.

Actually the make a template comment isn't a bad one. You could rotate the PP 32 degrees so three bolt holes are still in use and drill and tap three new ones to the original spec.

Many ways to do this job, some better than others.

Some threads go like this where I bet the Op wishes he had just not mentioned it.

But the bottom line is the car is now capable of being driven. Balance was taken into consideration so I would say that it is an okay repair. There might have been better ways, but that way is okay.

Mart.

Perhaps it's my (former) career as a tool maker that makes me cringe when I see suggestions to "make a template" to properly and (necessarily) precisely locate threaded holes.
And perhaps it's simply my decades of mechanical experience that screams "ARGHHH, NO, don't do it that way".

Yes, there are many ways to preverbally "skin a cat". However, while some of those methods will get the job done, many will surely turn out quite ugly.

[AnthonyG]

six, lousy 5/16" bolts screwed-into Helicoils

Just 4 the record it’s 1 lousy 5/16” bolt that would b screwed into 1 Helicoil not 6. It’s 1 threaded hole that’s bad 5 are fine. But point taken!

[Jack E/NJ]

Sponsored Links (Register now to hide all advertisements)

Your one lousy, probably stronger than original, 3/8" fix should be fine if you try to keep revs under 10K. 8^) Jack E/NJ

[V8COOPMAN]

Originally Posted by AnthonyG

Just 4 the record it’s 1 lousy 5/16” bolt that would b screwed into 1 Helicoil not 6. It’s 1 threaded hole that’s bad 5 are fine. But point taken!

Hey Anthony....NOW I get it! Only ONE lousy bolt out'a six. Of course, we all know how stingy and frugal the auto makers are. Hell, if they can POSSIBLY save 10 cents per car, they WILL! That adds up to a remarkable $100K savings for every million cars produced. The corporate bean counters love that thinking. Ya reckon that if they figured they could get by with only five GOOD pressure plate bolts, they WOULD?


The picture below is the result of a clutch explosion in what appears to be a '37-'41 Willys coupe, which ironically is close in configuration and size to a '35 Ford. DD

[AnthonyG]

Several have indicated shoulder bolts? As supplied from MAC’s they’re not, they’re hardened 5/16-16 X 1” long full thread no shoulder?

[GOSFAST]

Originally Posted by AnthonyG

Several have indicated shoulder bolts? As supplied from MAC’s they’re not, they’re hardened 5/16-16 X 1” long full thread no shoulder?

ALL pressure plate bolts MUST have the shoulder to "center" the cover on the wheel, if not you run a very high risk of a vibration!!

The bolt shoulders MUST reach into the counterbored section of the flywheel!

Thanks, Gary in N.Y.

P.S. Just went down this road with a member here on his "blown" unit, Here's a a couple shots of how the bolt should be and some asst'd ones! The third bolt over shouldn't be used! Maybe even the last one as well.

[AnthonyG]

Thinking MAC’s sent wrong hardware? Will call them today!

[V8COOPMAN]

Originally Posted by AnthonyG

Several have indicated shoulder bolts? As supplied from MAC’s they’re not, they’re hardened 5/16-16 X 1” long full thread no shoulder?

Funny, that's the grade-8 bolt I warned about using from Lowes in lieu of the correct parts, and one more reason I keep trying to warn folks about THAT outfit in general! Below picture is an example of some precision, shouldered "pressure plate" bolts. I don't believe I've ever seen a plated pressure plate fastener like depicted in your picture. DD

[AnthonyG]

Thx, will buy a set of ARP’s

[Bored&Stroked]

Originally Posted by AnthonyG

Thx, will buy a set of ARP’s

Now you're talking . . . why the heck scrimp on something so cheap as flywheel or pressure plate bolts - makes no sense. This is absolutely the last place I try to save a few dollars - on any engine.

Along the same line, I know quite a few guys that have no problem putting their cast iron flathead flywheel on a lathe and carving the crap out of it to get it down to 22 - 24 lbs. Been done lots of times . . . and every time I hear about it, it scares the heck out of me. Who can possibly know how much carving is "safe" on their specific cast flywheel - before it explodes that one BAD day???

Here is an example of how I get to a 24 lb steel flywheel . . . via a custom billet steel version. Yes, it costs $440 for a custom machine and profile cut version (to get to my weight) - but I know it won't explode and take out my thin cast iron integral bell housing - on the way to my legs. I run my engines hard (at times) - have had my 284 up to 6200 in 1st and 2nd . . .

IMG_8369 copy.jpg

IMG_8371 copy.jpg

[Kube]

Originally Posted by Bored&Stroked

Now you're talking . . . why the heck scrimp on something so cheap as flywheel or pressure plate bolts - makes no sense. This is absolutely the last place I try to save a few dollars - on any engine.

Along the same line, I know quite a few guys that have no problem putting their cast iron flathead flywheel on a lathe and carving the crap out of it to get it down to 22 - 24 lbs. Been done lots of times . . . and every time I hear about it, it scares the heck out of me. Who can possibly know how much carving is "safe" on their specific cast flywheel - before it explodes that one BAD day???

Here is an example of how I get to a 24 lb steel flywheel . . . via a custom billet steel version. Yes, it costs $440 for a custom machine and profile cut version (to get to my weight) - but I know it won't explode and take out my thin cast iron integral bell housing - on the way to my legs. I run my engines hard (at times) - have had my 284 up to 6200 in 1st and 2nd . . .

Attachment 429959

Attachment 429960

You make a good point.
I have removed the bell from nearly every flywheel I've installed. However, I grind them off and always well bathed in coolant while doing so.
They are then balanced and checked for cracks.
Perhaps I've simply been lucky, but I have never found a bad flywheel after grinding.
I have tossed a few that were heat cracked - seen upon visual inspection prior to grinding.

[AnthonyG]

It appears the ARP bolts required r used from 1949-to modern small block Fords. Looks like ARP# is 150-2201? Is this the preferred replacement for originals?
Also does anyone have a reasonably priced flywheel ready to go in?

[bobH]

Regarding the part of this discussion that has to do with the correct, shouldered, pressure plate bolts.... This all becomes a little 'fuzzy' to me, as my local clutch rebuilder ALWAYS supplies a fresh/new set of correct, shouldered, PP bolts with the pressure plate he sells. It's automatic, and part of the package. I'm wondering if some of the folks here are not getting the same service.

[Kube]

[QUOTE=AnthonyG;
Also does anyone have a reasonably priced flywheel ready to go in?[/QUOTE]

What size clutch ?

[AnthonyG]

10”, also trying to verify ARP pressure plate mount hardware, wanna buy new. Think it’s Arp#150-2201? Any insight?

[V8COOPMAN]

Anthony.....I want you to understand that I have NOT been trying to bust your chops in this thread. I just don't want to see you damaging your stuff, or end-up injured in any way. I've just spent better than an hour trying to verify that ARP part number, although that 150-2201 is the one that I tentatively jumped on initially. The problem is that ARP doesn't seem to list specific application info as far back as our flatheads. Those 150-2201 bolts "look" about the right size, BUT...…….! Those -2201 ARP bolts' actual dimensions are 5/16"-18 thread, with an overall length of shank UNDER the head (shoulder AND threads) of 0.780". So, how long are the shanks on your current bolts...UNDER the head?


I see where it looks like Kube may be attempting to find you a GOOD flywheel. Isn't your engine an 8BA-type ('49-'53) engine? If so, the replacement flywheel MUST be a matching 8BA-type. DON'T let anyone tell you differently!! 8BA f'wheels can be identified by the six bolt holes being drilled all the way through the flywheel. Earlier f'wheels have "blind" holes….NOT drilled all the way through to the opposite side. You need to stipulate WHICH type of flywheel you need.


If I had a spare wheel layin'-around, I'd send it your way for the freight. Unfortunately, I DON'T have one layin'-around, but I'll bet half a dozen guys reading this thread have a decent one layin' in a corner, never to be used again, that could sell or donate to your cause for the freight cost. So, what type of flywheel you got, and what is bolt shank length of your six original bolts? And just to be sure, will a common 5/16" "coarse"-threaded bolt thread into one of the undamaged, threaded holes? DD

[Gene1949]

Originally Posted by AnthonyG

Also does anyone have a reasonably priced flywheel ready to go in?

Last year I bought a Centerforce II [10" PP, duel friction disk] and flywheel from J*gs using their discount.

Instillation was a breeze and smooth as silk. AND really easy on old knees