4-speed chatter problem

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440nika

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Hey guys, I installed a 4-speed in my 70 dart with a 440 motor. I can not pull the car out in 1st gear after the car is hot without a vibration so bad in the car you'd think the windows are going to pop out. You can pull the car out in 2nd gear if ya slip the clutch without the vibration. I am working on this project with qualified mopar guys who have done a few of these BB 4-speed conversions in the past including bouncing things off Wayne brewer on a daily basis. This just seems to be one of them issues that nobody can put a definite finger on yet. All the parts (clutch, pressure plate, flywheel) was purchased from brewers performance. Wayne also replaced the 1st ceramic clutch and pressure plate with an new organic clutch and new pressure plate and I got the exact same problem. I also had the flywheel cut which was out less then .002 thousands to eliminate that possibility. Any knowledgable advise/options would be greatly appreciated. I hope I'm just overlooking something obvious but it's starting to get a little frustrating. You can reply here or drop me an email at [email protected]. Thanks Dave..
 
440nika said:
Hey guys, I installed a 4-speed in my 70 dart with a 440 motor. I can not pull the car out in 1st gear after the car is hot without a vibration so bad in the car you'd think the windows are going to pop out. You can pull the car out in 2nd gear if ya slip the clutch without the vibration. I am working on this project with qualified mopar guys who have done a few of these BB 4-speed conversions in the past including bouncing things off Wayne brewer on a daily basis. This just seems to be one of them issues that nobody can put a definite finger on yet. All the parts (clutch, pressure plate, flywheel) was purchased from brewers performance. Wayne also replaced the 1st ceramic clutch and pressure plate with an new organic clutch and new pressure plate and I got the exact same problem. I also had the flywheel cut which was out less then .002 thousands to eliminate that possibility. Any knowledgable advise/options would be greatly appreciated. I hope I'm just overlooking something obvious but it's starting to get a little frustrating. You can reply here or drop me an email at [email protected]. Thanks Dave..
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Stupid question: is your pilot bushing/bearing installed?

Someone may have asked elsewhere already, but was the runnout checked? If your bell housing and input shaft aren't centered to the crank, you'll have this issue. I lost an alignment dowel on a car once during install and it did this until the clutch couldn't take it anymore.. No fun.

If you're handy with a dial indicator you should be able to measure fairly easy, but the trans has to come off the bell.

It's also possible the bore in the bell and the locating ring on the trans are not the same size and allowing misalignment.
 
Yes. I bought a pilot bearing from brewers that takes place of the brass pilot bushing. It fits/rides in the back of the crank where the automatics convertor was seated. No I did not check the "run out or bell housing"??? I never thought anything could be wrong in that area. I bought the trans and bell housing as a set together..
 
You really should check your belly run out and make sure you have the right bellhousing and bearing retainer match.

Seeing how you went with the bearing, is you crank drilled for a bushing? Or, the better question, it it finished machined for a bushing? The pilot shaft could be hanging up in the crank.

I'm just spitballing, it's something to check. I've also seen this on engines with heavy cams and an improper tune. You start letting off the clutch, the vacuum drops right off and now you're fighting the engine, too.
 
No my crank is not drilled for a standard trans. I originally bought a brass pilot bushing and machined it down to .913 to fit the crank and I had to cut 5/8" off the end of the pilot shaft on the trans for clearance in the crank. Then brewer told me that going with the bearing was a more "true" way to go on case the hole in the back of my automatic crank wasn't exactly centered. So I took out the brass bushing and installed the bearing.
 
I had a new driveshaft made. The A833 is shorter then the 727 that was on the car.
 
440nika said:
Then brewer told me that going with the bearing was a more "true" way to go on case the hole in the back of my automatic crank wasn't exactly centered. So I took out the brass bushing and installed the bearing.
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Bush or bearing, if the hole is off center its off center and may have issues.. This is where runout checks are needed, otherwise its all a guessing game.
 
Besides bell alignment.........

How much does the engine move on the mounts?

What are you using for clutch linkage?

It is possible a bad clutch pressure plate can cause this.

Anything you missed? How is the transmission bearings, any chance the input shaft is damaged, etc
 
440nika said:
No my crank is not drilled for a standard trans. I originally bought a brass pilot bushing and machined it down to .913 to fit the crank and I had to cut 5/8" off the end of the pilot shaft on the trans for clearance in the crank. Then brewer told me that going with the bearing was a more "true" way to go on case the hole in the back of my automatic crank wasn't exactly centered. So I took out the brass bushing and installed the bearing.
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That does not sound good.

I got a 833 once that had the pilot shaft cut and was terrible. My crank was right with the oilight bushing and had to get a new shaft.

Sounds like you do not have all the right components and maybe steering Brewer in the direction you want to hear. Perhaps you need to re-evaluate what you have and decide to fix your crank or go Auto.
 
I don't know what a run out check is. My ignorance, sorry. What and how do I check???
 
1969383S said:
That does not sound good.

I got a 833 once that had the pilot shaft cut and was terrible. My crank was right with the oilight bushing and had to get a new shaft.

Sounds like you do not have all the right components and maybe steering Brewer in the direction you want to hear. Perhaps you need to re-evaluate what you have and decide to fix your crank or go Auto.
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I've done the bearing with several conversions (including 5&6 speeds), it's a viable option. Just make sure the shaft isn't hanging up in the crank.
 
I have the standard BB clutch linkage (special z-bar and clutch adjustment rod). I've had 2 new pressure plates with the same results. I have not checked my pilot shaft. I'm not in any way leading Wayne, he is calling me practically daily leading me in directions he wants me to try. All the parts changed to this point has been on his suggestions. I feel at this point the checking of my bell housing run out and checking the pilot shaft is going to be good directions to go. The car ran fine as an automatic car. These issues came up after the 4-speed swap took place. I can't imagine having a crank problem.
 
Revhendo said:
I've done the bearing with several conversions (including 5&6 speeds), it's a viable option. Just make sure the shaft isn't hanging up in the crank.
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Bingo, same thing I was thinking maybe too tight in crank bushing, and clutch not centering itself right, also dumb question, is the driveshaft balanced ? vibration issues can be a ***** to find, check all the obvious things first.
 
Yes the driveshaft is balanced. Does anyone have any idea how much of the pilot shaft needs cut when installing the 4-speed with a crank from an automatic trans. On the web site bigblockdart.com it stated to cut 5/8" off the pilot shaft. Maybe that's not enough??
 
I can agree with that logic.

The pilot bearing failed and flat locked up my Cummings diesel 6 speed for example.

There is much more to alignment and fit. How was the input shaft shortened and runout checked?
 
The input shaft was cut 5/8" and a beveled edge at the factory 45 degree angle and I didn't do a run out check. How is that done???
 
440nika said:
. I feel at this point the checking of my bell housing run out and checking the pilot shaft is going to be good directions to go.
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Search "how to check bellhousing runout" on Google and you'll find a ton of info. It should be quick, but is by no means the only thing that can cause this. Improper pressure plate installation or even throw out bearing issues can contribute.
 
440nika said:
Yes the driveshaft is balanced. Does anyone have any idea how much of the pilot shaft needs cut when installing the 4-speed with a crank from an automatic trans. On the web site bigblockdart.com it stated to cut 5/8" off the pilot shaft. Maybe that's not enough??
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You're gonna hate me for this....

I don't have the exact measurement. 5/8" sounds about right. What I always did was to install the bell without the clutch or flywheel installed. Measure from the trans mounting face of the bell to the bottom of the converter register in the crank. Transfer the measurement to the trans from the mounting face of the transmission to the end of the pilot shaft. That should show you how much you need to cut. I would suggest leaving it a little long, you can always trim more off. Install the trans with out the clutch or flywheel installed and make sure the pilot shaft doesn't bind. If it all works, put it back together and drive.

Regardless of whether your driveshaft is new. Check your installed angles.
I doubt a balance problem will give you problems taking off, but a bad angle will.
 
2 good points. I'll set the trans with just the bell to make sure I ain't got any binding and I gotta check that driveshaft angle. I'm pickin up good directions to go. Thanks
 
I am having the same problem. Did u ever fix it and how. I live in the same area as you. Sent you a pm and an email too. That is how interested I am in your solution. Thanks
 
Bell housing register needs to be aligned with crank. They were never a working pair and won't be till you align them. It is important.
Good of you to check the input shaft for binding in the pilot like mentioned.
 
hi, I assume you have long dowels in back of block to support bellhousing? I found four speed housings need longer dowels versus automatics. I changed mine long time ago.
 
Here is a youtube video that explains how to do it. It is the one I learned from. It is GM stuff, but it is all done the same way, no matter what the brand.

[ame="https://www.youtube.com/watch?v=rzc2tmFKUhI"]Part 17 How To Align The Bellhousing Using Offset Dowel Pins For The Big Block Chevy - YouTube[/ame]
 
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