186 Tooth hydraulic bell flywheel help please

[plymsatellite66]

Hey everyone, working on my 67 W200 at the moment, trying to install a 440. Currently it's got a 318 with the Hydraulic bellhousing set up. I bought a big block bell housing, pressure plate, friction disc, starter and flywheel from a medium duty truck. Can't recall off the top of my head which specific truck the setup came from, the yard near by me has two or three big block hydraulic setups, but I think it was bolted to a 361. I'm hoping to use the old 13" clutch assembly as it measures only .005" under the new spec according to my book. My problem now is that the flywheel is an 8 bolt and my 440 is a 6 bolt.

Does anyone have any suggestions on finding a flywheel to work with this setup? I would assume all flywheels with the 186 tooth ring gear will accept the 13" clutch, but if there's one out there that would work, I'd change to a smaller clutch if needed.

Just a though, but is there any chance of having the 8 bolt flywheel re-drilled for the 6 bolt pattern? It already needs to be neutral balanced for my 440, so could a machine shop drill a new pattern without weakening the flywheel?

thanks for the help

Corey

[712edf]

So what you really need is a 6-bolt 186 tooth flywheel that's neutral balanced? What flywheel did the 318 have? In the mechanical clutched later years trucks 318 & 440 flywheels would interchange if the balance was the same (neutral). I don't know if small blocks/polys/big blocks used different sized flywheels in the hydraulic era or not.

A hydraulic era 383 flywheel should be neutral balance 6-bolt.

[plymsatellite66]

My small block hydraulic flywheel is a 172 tooth, which is the same as my '74 mechanical clutch linkage 440. From what I've found, the hydraulic bell housing flywheel for the big blocks is the oddball using the 186 tooth ring gear. Also, the hydraulic bell housing takes it's own starter, the small block hydraulic bell housing takes it's own starter, then the mechanical linkage bell housings use the typical Chrysler starter.

[712edf]

I'm following you. My 70's 440 (mech clutch) has a 143 tooth flywheel, which small blocks also used......I've heard of the 172 fly & know it came on hydraulic trucks & used different starter. Didn't know it (the 172 toother) would even fit the 70's trucks.....Never heard of the 186 version.

As complicated as Dodge makes things it a wonder they didn't go bankrupt 40 yrs ago.

[plymsatellite66]

Partial update for anyone following; After talking with a few local machine shops about drilling the six bolt pattern on my eight bolt flywheel, I decided to go for it. With the 6 bolt pattern laid on top of the old 8 bolt, it doesn't look like much material left over. What we decided on was to have 8 plugs made, pressed into the holes, welded in place and then dressed flush. After the plugs are in, they're gonna drill the 6 bolt pattern. The shop estimated the middle of next week for completion, then I'll send it to another shop to have the balance checked and grind the surface. Once it's all said and done, my big block hydraulic bell housing, clutch, flywheel, etc. should all ring in at under $400. Not too bad considering I was quoted over that for a flywheel alone.

Corey

[712edf]

6 bolt vs 8 bolt

One other thing to maybe consider: Seems like I read years ago that 8-bolt cranks & 6-bolt cranks differ in the distance (depth?) of the flange mounting surface from the back of the block. In other words the cranks were different lenghts behind the rear main resulting in differing depths of how far into the bellhousing the flywheels sat.

Maybe I'm crazy, but could've swore I read that! It mainly created issues with automatic equipt vehicles because the torque convertor would bottom out before the bellhousing was tight against the engine.

Does anyone here know of such a difference between the two cranks, or did I dream this up?

[plymsatellite66]

I was wondering just that myself, I don't have the 440 out yet to do a test fit, but I did some rough measuring on my small block setup; the position of the flywheels I think should be somewhat similar between small and big block since the input shaft remains the same. I may have to shim the flywheel out a little, but I don't think it will be enough that it will affect the work to the flywheel. I should stop back and take a look at the 361 to see how far the crank flange sticks out. Sounds like a project for tomorrow while I'm waiting for the flywheel to return.

Corey

[Fred_M]

from my limited knowledge on it
I started with an 8 bolt crank and put engine in a 75 D-600
then discovered that the flywheel was to far away for the starter to reach,

the polly bell comes down behind the flywheel, newer bells are open
so flywheel can set closer to the back of the engine

your flywheel will set closer to the back of engine with the 440
so you may have to shim the starter back some so it will not go past the ring gear on the flywheel.

some bells have two positions tapped for starters, allowing for flywheel size

[plymsatellite66]

Fred,

That's a great idea I hadn't thought of yet. Hopefully I can get by with shimming the starter instead of the crank. I'll just have to make sure the flywheel will clear the front of the bellhousing and that being set more forward won't interfere with the operation of the clutch. I don't recall another set of starter bolts, but still need to take the bellhousing to the carwash to clean off the 40 some years of gunk.

While it would have made things simpler if I could have used say a 172 tooth with a 12" clutch, the specs my parts catalog lists for the 13" clutch should make for a very stout unit and if the big 186 tooth flywheel doesn't work out for some reason I'll still have a backup plan.

As it sits right now I can't slip the 11" clutch enough to get the 318 rpm's up and the 318 doesn't have the low end torque to pull off the line at low rpm's. I have been able to manage a 301' pull, but it took close to a 3000rpm launch and a run down the track at 6000. I just don't think those numbers will last too long with a stock engine, especially since I broke half the teeth off two of the spider gears on the next run.

I'm sure I've rambled enough for the time being, for anyone interested in a big block swap in a hydraulic bell housing truck, I am going to do my best to detail the whole thing and take lots of pictures.

thanks for the help
Corey

[712edf]

So I'm not crazy in saying there's a difference in flywheel position depth behind 8-bolt vs 6-bolt crank? Relieved:-)

[712edf]

Also a Hemi crank was 8-bolt IIRC. May or may not be more like the 6-bolt crank in this regard than an 8-bolt from a wedge motor.

Glad you're making progress & that there's still a old Dodge gasser still pulling.

[plymsatellite66]

If I'm correct, this eight bolt pattern I'm fighting with is actually the hemi pattern and it was used on most everything, but the hemi was the motor that retained it.

And, in the club I pull in, there's actually a decent Dodge crowd; and from what I've seen so far, they're kickin some serious butt. Last year a mid 70's Dodge with a 383 won the points championship in the 5800lb Street Stock; an 80's Dodge with I think a 440 took both the 5800 & 6200lb Improved Street and the club president took the 5800 & 6200lb Pro Stock in an 80's Dodge. For the time being, I've got the only Sweptline, but the guy running Improved Street is putting together a 69 two wheel drive with hopes of having it out next year.

[plymsatellite66]

Just a quick update in case anyone is still interested. I got my flywheel back from the shop about a week after they estimated it would be done, but to make up for the delay they surfaced the face and only charged $160 for the work. They ended up tapping the old 8 bolt holes and threading plugs in with some loctite before drilling the new holes. It looked like everything should work out fine so I had it neutral balanced for my 440. The real nightmare occurred when I tried installing it. I figured I was going to need to add a spacer between the 361flywheel and 440 crank so it would clear the bellhousing and so the starter would engage, but I never figured the machine shop would drill the bolt pattern backwards.... just my luck. At this point, the 440 was going in one way or another with or without the 13" clutch setup. A few hours of fab work one night and I made a plate that bolts in place of the inspection cover that holds the direct drive starter so it can get close enough to the 172 tooth hydraulic clutch flywheel from my small block setup to engage the ring gear. I've made it to one pull so far and managed a 300.7' pull on the stock 11" clutch, but it took some life out of it. I've got the flywheel back once again from the machine shop, this time with the correct bolt pattern. Now I'm in search of a 13" friction disk with a 1" x 10 spline hub to replace the ~1 1/8" x 10 spline hubbed disk that came out of the big truck. Once that's found, I'll do some measuring to see how thick I need to make the spacer for the flywheel and finally get the proper components all back together.

[712edf]

murphey's law

It happens!