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Discussion Starter #1
Over the summer I installed a Tremec TKO in my 70 Eliminator. It is originally a BOSS 302 car, but now sports a 351c-4v. I ordered the kit from darhorse performance. I had to replace the clutch disc becuase the TKO has a 26 spline input shaft compared to the original 10 spline. I got everything installed and switched my rear end from a 3.89 open to a 3.50 Posi. I put it back on the road and found that as I get close to 2000 rpm the whole car shakes. It shakes the same amount @ the same rpm no matter which gear it's in. I never had a problem with my 4 spd. It stops shaking when take my foot right off or put it in nuetral. If anyone has any input it would greatly be appreciated.
 

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You must have a flywheel with balance factor appropriate to the engine you are using. You only mention replacing the clutch disc, did you replace the flywheel as well? Does it shake when revving the engine sitting still?

Another thought would be that maybe the crossmember mount is not aligned properly. The pinion angle should be the same as before, if for example you had to lower the transmission mount to get floor pan clearance then you must raise the rear axle angle to match the engine / transmission angle. Under no circumstances can you aim the transmission / engine directly at the rear axle. That would cause binding in the U joints and severe vibration.
 

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Shake

I just went through a similar Saga. Royce is right on about the ballance issues. That would be a concern when swapping flywheels, if you did indeed change the flywheels. Mine had the right ballance, but the flexplate (mine is an auto) had a broken weld where the starter ring attaches. This caused the ring with the starter teeth to elongate ever so slightly at the broken weld and give me a wicked shake that was very pronounced around 2000 RPM's. I'd definetly scope out the flywheel first.
 

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What about the pilot bearing? could it be a little bigger then the TKO needs?
 

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Discussion Starter #5
With regards to the flywheel. It is the same one I've had on for 2 years with this same engine. It will only shake under load. I can rev it up to 5000rpm in neutral with no problems. I'm using a crossmember that came from darkhouse that is supposed to be a direct bolt in for this application (designed using a 1970 mustang I presume). It took a fair bit of effort to get it installed. It seems to be pulling the rubber transmission mount hard towards the drivers side of the car.

I will have to check about the pilot bearing.
 

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In order to figure out what the problem is you need to break it down. If the viberation is there with the clutch pushed in then the problem is in the motor. If the problem is only there when you drive the car then the problem is most likely in the driveline.


If it is in the driveline, you might want to make sure that the trans is not contacting the body. It is common mistake for the top of the transmission case or shifter to contact the body sending viberations.

Another common problem is using 5.0l flywheels on pre 82 302 and all 351. The problem is the 5.0L flywheels are 50oz and the motor listed above are 28oz. 28oz flywheels are availabe that have the same clutch pattern as the 5.0L so that a 10.5" metric pattern can be used.

Drive anlges are important. Most driveline problems do not show themselves until the car is coming up to speed or only slowing down. Driveline angles range from 1 to 5 degrees for a smooth system.
 

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Mounts?

Just a side suggestion, the motor mounts, were they replaced at the time of the swap? The motor gets "comfortable' and the mount "remember" where they were. They may be causing the sideways condition.
 

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Discussion Starter #9
I'm using an early seventies cast iron bellhousing and flywheel (out of a van that had a 351C-2v) with a new Mcleod 11" clutch disc that is modified by darkhorse to fit the TKO's input shaft. The pressure plate and throw-out bearing are the same ones I was using with my toploader (less than 2000 miles on them). I'm pretty sure the flywheel is not the problem.
 
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