Hey Guys,

I have a bit of a vibration in a new build and I'm just eliminating possible factors.... so I have a quick question...

I'm running a 66 Hemi block in a '70 cuda with a new ram 1593 8 bolt/143 tooth flywheel and a ram 88504 11 inch clutch, 18 spline...

That combo should be ok, correct ?

Motor ran good and tight on the break in stand with the current harmonic and flywheel installed... now on the maiden voyage she's not happy. Slippage low rpm in 1st, then she grabs after winding out a bit.. and a good vibration all around, its there with the clutch depressed also...

I have a feeling I'll find the source between crank and trans but, want to eliminate the possibility that i'm running the wrong flywheel/clutch before I start searching.

It's a neutral balance wheel so it SHOULD be ok. There is no such thing as a weighted pressure plate so again it SHOULD be neutral also.

Did you take the break in stand for a drive to confirm no vibrations?

Did you have the flywheel and Pressure plate CONFIRMED as neutral ?

I've seen balance shops weld additional weight(some big hunks on one motor ) onto pressure plates. They usually will make matching marks on the flywheel and pressure plast so the engine assemblers can aligns those matching marks to keep the motor in balance
OP, check your flywheel and pressure plate to see if there are matching marks on them If so mate them up if thier not now and let us know what you find either way please

Thanks for the reply's guys... I went back to the basics and... found the vibration in the fan of all things, swapped that out and... vibration is gone.

but, clutch adjustment is still giving me a bit of a headache.

here's where I'm at:

the 88504 is a ram borg beck 3 finger style. I looked and found out the over center spring was removed by the installer... which I thought was only to be done when using a diaphragm style ?? so I tried putting that back in... but now I'm getting the pedal to the floor condition like a diaphragm...

tried adjustment on the throwout, ram calls for 1/4 inch at the bearing. At the prescribed adjustment, pedal hits the floor... as I work the adjustment out I can get it closer and closer to a point where the over center is in the correct position to pull the pedal back instead of forward but not without having next to zero clearance on the throw out.

What am I missing here ? This is a 4-speed conversion so pedals linkage, rods are all aftermarket.

Can you run a borg and beck style clutch without the over center spring ?

Just to add, I didn't find it overly difficult to depress the clutch when that over center spring was out... didn't even realize it was gone until I looked.

Spring keeps the throw out bearing off the pp. needed for diafram type too, taken off for slave cylinder type. We all ways set the pedal about 1" of free travel.

Typically they tell you to remove the over center spring with a diaphram clutch.If clutch is slipping you have a problem.With a B&B clutch you should have OC spring.There should be another spring on fork.Its small and assissts the return of the pedal.Just got another new one for my 65.Rocky

cudaman I think you are thinking the little fork spring... that is new and in place.. I'm talking the big over center spring on the pedal... it's only job is to assist with depressing the pedal on the borg beck style clutches.

Everywhere I look says remove it on diaphragm style use it on borg & beck.

yes it definitely needed adjustment from where the installer had it... thats where i'm at... when i'm at the recommenced 1/4 inch freeplay at bearing (factory is 5/32 I think?), i get the pedal to the floor symptoms of a diaphram with an over center spring... as i move the adjustment closer to zero (in full contact with pp) it starts to get better and the pedal starts to sit higher and more towards that 1 inch of freeplay at the pedal... but I run out of adjustment before the overcenter spring is functioning properly... if I had another 1/4 inch on the bearing to pp distance i'd have it.

I am now thinking the pedal rod is too short ?? anyone have a factory measurement for a 1970 cuda pedal to z bar rod ?

Ask Brewers.They can give you the info you need.Rocky

I had to use a A body clutch rod from the Z bar to the fork on my old 1970 Cuda 4 speed car to get the pedal up high enough to clear the pressure plate fingers by 1/8 inch
I was drag racing that car with McLeod racing clutches in it, not a street disc, they wanted me to have .060+ clearance between the clutch disc and flywheel with the clutch pedal depress to shift the tranny so that what it took to get both the clearances on the flywheel and the .060 + throw out bearing to the pressure plate fingers clearances
Are you using a stock 1966 to 1969 Hemi 170 tooth flywheel and bell housing? If so you may have different problems than I had with the scatter sheild and smaller flywheels, I used the 170 tooth flywheel at first and then switch to the smaller diameter 143 and 130 tooth flywheels later

No I'm talking about the BIG spring under dash, the only purpose is to keep the pedal up so the throw out bearing does not ride on the pressure plate fingers, borg&beck, long or diaphragm type. Take that spring out, it will wear the bearing out fast. You've heard of riding the clutch, that's what happens on a smaller scale with no spring. Little spring at the bell keeps the rod in its place so it won't fall out. Ask any old mechanic, they know.

I appreciate your replies in an effort to help, but. I think you have this backwards. The little fork return spring keeps the fork pulled back so the bearing doesn't ride on the fingers of the pp. The big over center spring just assists the driver with force required on the down stoke of the pedal (makes it easier) and then takes up the 1 inch freeplay and returns the pedal to the pad once over center, if set up correctly. That is why when your adjustment is out, or you have incorrect parts (as I suspect I do) you get the pedal stuck to the floor condition.

At the prescribed 1/4 in bearing gap by Ram.. I don't have enough rod length to get me past the over center point on the pedal. I am right on the very edge of everything working fine, but with about an 1/8th of bearing clearance... I noticed in the post above Cab is running with an 1/8th so maybe I'm ok then ?

I'm running a 143 with 11 inch clutch.. mild street car.

Well I'll try this one more time. If this is a non running condition and the pedal sticks on the floor, your throw out bearing is not up against the clutch fingers. The pressure fron plate will force it back. The only time a pedal will stick to the floor is at high rpm with a diaphragm type clutch and goes into an over center situation from centrifugal force, once the rpm comes down it pops back. No one that I know have ever had that problem with the other types. Again Little spring holds the pieces together and the big spring holds the pedal up period. Ask a qualified machanic that's older than 50 if you still don't believe. Not trying to be mean but until you understand this principle you're not going to be able to adjust the pedal correctly..

Sorry, my pedal isn't stuck to the floor, if I implied that somewhere I just worded it wrong... what I meant was the over center is always pulling down towards the floor...locking the bearing against the fingers.. gets stuck in that position and need to give it a tap or lift to get it to return. When freeplay at the bearing is set at about an 1/8 th of an inch, my pedal will still just stick, but only about a 1/2 inch down. Any more freeplay and the pedal drops further worsening the problem. Any less freeplay and, well, I have no freeplay, which is no good either.

With no linkage attached.. I have less than 1/2 inch travel on the pedal where the over center spring is pulling up, this wouldn't even take up slack in the linkage so I don't see how it could assist the fork in any way ? Maybe the issue is my over center point is wrong ? Feels like I need another inch at least of travel before the down force should kick in... then i'd be golden, I'd have the upforce at adjustment you are describing to pull it all back.

Can over center point be adjusted and how ? Is there a backwards/ forwards way to install the spring ? Service manuals and parts book show the spring towards the firewall with the long part to the pedal... every picture on the net shows the opposite Seeing it installed both ways leads me to believe this wouldn't affect things either way.

I'm using a repro pedal and spring assembly, maybe the pivot to spring ratio is off ??

Cudaman, funny story for you... I just found a 50 year old licenced mechanic who is a mopar nut and used to work for a dodge dealer. He has a hemi four speed runner, so I asked him the question...

the response; "mine does the same thing I just lift it with my foot when it gets stuck".

not the answer I was looking for!

My 1969 dart GTS 383 4 speed car is the same way, I replaced the Borg and Beck clutch with a diafram(SP?) Centerforce clutch and I have to use my toe to lift the pedal up past the over center spring to get the pedal up all the way to get the throwout bearing to not ride on the P.P. I may end up removing the over center spring The little spring on the bellcrank is not intended or designed to make the clutch pedal go all the way up where it belongs Dang them Mopar engineers that came up with this design anyways