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Drive line shudder

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Rut

Rut

Obi Wan
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As I inch closer to getting my BE on the road, test and retest the things I've 'fixed', I notice odd things that might be normal. I'm not use to the sounds my engine makes, the rattles, valve noise, etc. The car is still on jack stands and it runs extremely well and I've been putting it in gear to 'listen and feel' for anything I think is unusual while the engine is running. Everything is nice and smooth until I rev the engine in 3rd or 4th gear and show an indicated 40 to 50 mph. At that point it feels like something is out of balance and the car shudders. Nothing visible or audible, just a feel. Is it possible that while on stands the car might magnify any vibration, I hope? Has anyone else had this problem or experience?
Thanks, Rut
 
I wouldn't worry about it until you get it on the road, but I wouldn't run it up that fast on jack stands.
 
Trevor, thanks for the advice. The wheels are not on the car and I only show about 3000 rpm. I don't consider this fast, but I'm new to this. Is it unsafe to rev the engine while on jack stands?
Thanks, Rut
 
I would pull the driveshaft and take it to the local drive-line shop and have it balanced. I pulled my hair out about my vibration at 45-50 mph. Once the shaft was balanced, it went away. Usually costs around $70. They can inspect all your U-Joints also and let you know exactly what you need to replace.
 
I agree. I have parts from 5 spridgets and am down to 0 good shafts.If you expect an imbalance take it to a driveline shop.

Kurt.
 
Do you have the jack stands under the frame or under the differential? If its under the frame and letting the diff hand loose then your drive shaft angle will be wrong and there are all kinds of rhythms that can develop there with all the looseness.
 
Thanks for the additional info! regularman, I think you nailed it! It's hanging from the straps and it's at max angle. I think I'll put a jack under the chunk and lift it some and see if it changes. Back in the 60s I had a drive line vibration on a TR4a and had to rotate the drive shaft one hole at a time until it matched the original position...may be the same problem.
Thanks, Rut
 
it can only be mounted two ways on a sprite (rectangular hole pattern)
 
regularman said:
Do you have the jack stands under the frame or under the differential? If its under the frame and letting the diff hand loose then your drive shaft angle will be wrong and there are all kinds of rhythms that can develop there with all the looseness.
Click to expand...

X2 not to mention not being under load makes quirky noises and vibrations.
 
I put the jack under the chunk and gave it about a 5" lift, fired her up and got things warm, put her in 4th and gave it some gas. Shudder all but disappeared, much smoother at speed.
Thanks everyone!
Rut
 
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