no more leaking tailshaft

[Mills Marauder]

i installed my new tailshaft from bc automotive (thanks darrin) yesterday. the drive shaft yoke had a hot spot on it about 3 inches long from exess wear and heat i guess. anyway the bushing and seal was fried, dropped the pan to check for shavings, sludge and to change filter the pan was spotless inside. test drove the car NO MORE LEAKS:banana: i plan not to drive the car until i get a new high speed balanced drive shaft and loop. a lesson learned about no governer and stock drive shaft. :burnout:

[magindat]

i installed my new tailshaft from bc automotive (thanks darrin) yesterday. the drive shaft yoke had a hot spot on it about 3 inches long from exess wear and heat i guess. anyway the bushing and seal was fried, dropped the pan to check for shavings, sludge and to change filter the pan was spotless inside. test drove the car NO MORE LEAKS:banana: i plan not to drive the car until i get a new high speed balanced drive shaft and loop. a lesson learned about no governer and stock drive shaft. :burnout:

It's cool to drive JJ, just not FAST! Call DR. He has a less expensive (than MMX) 6061 shaft he put in my car. Smooth as glass for over 25K even in the trippple digits with 4.10's...

[Blackmobile]

i installed my new tailshaft from bc automotive (thanks darrin) yesterday. the drive shaft yoke had a hot spot on it about 3 inches long from exess wear and heat i guess. anyway the bushing and seal was fried, dropped the pan to check for shavings, sludge and to change filter the pan was spotless inside. test drove the car NO MORE LEAKS:banana: i plan not to drive the car until i get a new high speed balanced drive shaft and loop. a lesson learned about no governer and stock drive shaft. :burnout:

:(No more track time for you young man:nono:, until problem is fixed.

[magindat]

:(No more track time for you young man:nono:, until problem is fixed.

You mean that REALLY LONG track that goes across the bottom of the state?!

[Blackmobile]

You mean that REALLY LONG track that goes across the bottom of the state?!

I was refurring to ANY track, that one included.

[DOOM]

How much was your new tail shaft?

[Darrin]

I can get a whole mess of those stock MMX police shafts if they are worthwhile. Just didn't want to pull the trigger on any funds for them if they aren't.

Darrin

[Zack]

Id buy one Darrin

[gmtech]

Me too..these will eliminate the vibration w/ 4.10s right?

[Darrin]

Let me see what they have and see how much it is to get them balanced the way I want. It might be worthwhile and it might not. Looks like there is enough interest. I can also get very nice aluminum shafts made that are reasonable. Not MMX, but a 6061 heavy duty shaft that is already balanced and has new heavy duty U joints.

Darrin

[UncleLar]

I'm expressing interest. Let us know what you find out please.

[Embassy]

I'm expressing interest. Let us know what you find out please.

I too am interested in hearing more.

[Stranger in the Black Sedan]

Isn't the stock shaft already 6061? Replacing the stock AL shaft with another AL shaft is a waste of money because you won't be improving the cricital speed.

[sailsmen]

If balancing something made it stronger than why don't we just balance cast crankshafts instead of replacing them w/ forged?

[red]

I can get a whole mess of those stock MMX police shafts if they are worthwhile. Just didn't want to pull the trigger on any funds for them if they aren't.

If you can get the police MMX (not the aluminum one you mention above) and get it rebalanced, I'm in. Just PM me when available.

[magindat]

Isn't the stock shaft already 6061? Replacing the stock AL shaft with another AL shaft is a waste of money because you won't be improving the cricital speed.

I'm not a Drive Shaft expert at all. I know things change with shaft diameter, material, balancing, etc.

I also know that even a balanced shaft develops a harmonic at a given rotational speed. Why the one from Dennis is better, I do not know. I do know I could FEEL the stock shaft starting to wobble even on 3.55 gears and I know the new shaft is glass smooth. That is: there's no 'strange vibrations' in the car at any speed and I've driven for hours sustained in the triples. I also know there's no tailshaft issues at all after 25K+ with said shaft.

So go figure. That's all I know. Take it for what it's worth.

[Stranger in the Black Sedan]

The one from dennis is better because it is a much lighter material, and has a higher critical speed.

You guys with higher than 3.55 gears really need a lighter shaft, the stock type aluminum shaft hits 70% of critical speed well under 100 mph. Not good. The stock shaft is barely adequate for 3.55s in this car, if you really want it to be totally safe from an engineering standpoint.

As far as balancing, the only way that rebalancing a shaft will help it at all, is if the shaft was improperly balanced in the first place. Other than that, you won't improve anything. Some shops have better machines that will balance at higher rpms than others, which will give you a more accurate balance than spinning a shaft at low rpms.

[Darrin]

The one from dennis is better because it is a much lighter material, and has a higher critical speed.

You guys with higher than 3.55 gears really need a lighter shaft, the stock type aluminum shaft hits 70% of critical speed well under 100 mph. Not good. The stock shaft is barely adequate for 3.55s in this car, if you really want it to be totally safe from an engineering standpoint.

As far as balancing, the only way that rebalancing a shaft will help it at all, is if the shaft was improperly balanced in the first place. Other than that, you won't improve anything. Some shops have better machines that will balance at higher rpms than others, which will give you a more accurate balance than spinning a shaft at low rpms.
I agree.

Except that I think any used shaft should always be checked for balance before use. Just the fact that people using stock shafts had vibrations at normal highway speeds go away with a good aftermarket shaft speaks clearly that balance shouldn't always be assumed.

Darrin

[Stranger in the Black Sedan]

But the vibes go away because they are replacing the stock, probably balanced just fine, shaft with a shaft w/much higher critical speed. At 1/2 critical speed you will get a harmonic vibe even with a correctly balanced shaft. 1/2 crit speed is about 70 mph w/ a stock shaft. No amount of balancing will correct that. Although if the balance is off the vibe will be worse. The aftermkt shaft will have much higher 1/2 critical speed so you won't be cruising in that range

[Darrin]

I really haven't messed with the shafts on these cars much, but I do have some experience with the one piece aluminum shafts from the Mark VIII vehicles. What I found there was that with a vibration issue there was a balance issue. I keep a rebalanced shaft on hand to swap out with customers that have a vibration. It always works.

Again, I don't know about the stock shafts on these cars. I have never had a problem with the aftermarket aluminum shafts that I sell. I do know that much. My interest is in the factory MMX shaft. Getting a few of those down to the guy that does my driveshafts will tell that story.

Darrin

[Darrin]

I will know something this week on those shafts I hope.

Darrin

[red]

I will know something this week on those shafts I hope.

Great! Looking forward to a good deal. :D

[Darrin]

That is the concern that I have and why I haven't been able to make quicker progress. Making these an affordable type of good deal is the only way it's worth it. I am doing the best I can.

Darrin

[magindat]

Darrin,
When/if you get the shafts deal to work, you should start a new thread in your forum.

[Darrin]

I plan to. I just need to iron it out and look at the final investment to see if this can be an affordable option or not. I ordered 3 of the shafts and I am going to do at least those, win or lose.

Darrin

[magindat]

I plan to. I just need to iron it out and look at the final investment to see if this can be an affordable option or not. I ordered 3 of the shafts and I am going to do at least those, win or lose.

Darrin

Good luck, Bro!!

[MarauderTJA]

I never had a problem with my stock Marauder driveshaft at all. Driven daily and made an 11.3 run with it, driving it to the track and back. I bought a Dynotech 4" driveshaft from DR to handle the increased power and lower ets with the car. A friend of mine loss his Lentech Tranny because of a bad driveshaft in his Marauder due to a high speed run across Aliigator Alley. Driveshaft got bent, broke the tailshaft, loss all the fluid and toasted his $4K Lentech transmission. If you are going to go with a high HP engine, get a good driveshaft. $600.00 well spent IMO.