Broken CV Axles

[05smoker]

Here is one of 5 (yes 5) broken CV axles we had last season. All happened while trying to build boost on the line and all broke in the middle of the shaft like it was cut. No high boost. Any thoughts why we are soft breaking so many parts?

Front end is welded. When we tried to launch 2nd gear at Scheids it did not break. When we broke one at Eaton, OH the other stocker held on a softer launch. Whenever one of the Advanced Auto shafts broke, the other broke right after.

 

[TNRGreene]

I'd bet there is more force wihile power braking then while spinning out at the end. At the start you are building boost & trying to get the heavy truck & sled moving. When we build boost, it kinda rolls just a bit. I've seen this when you are PLANTED on the brakes sitting still. That is a ton of torque on that shaft with the brakes locked. I figure moving 2 or 3 feet & then letting it rip is better than sitting still & breaking. You give up allot more than 3" in 2wd. BUT to quote Jon..."What do I know"

 

[codyn]

if you want to power brake you need to get a straight axle. or they make billet cv shafts you could try

 

[05smoker]

I agree for the most part. I still think something else may be factoring in possibly in the braking proportioning or something along those lines. The issue has been spooling with the header/turbo setup which is now being revised. We won't need to ride the brakes so hard next season. My brother wants nothing to do with a D60 conversion and I pretty much agree. If others make this work with more power than us, we should be able to as well. Plus we like the low slung look of the truck with the IFS. If it goes solid axle, it goes open driveline.

Thanks guys.

Ed

 

[codyn]

I agree for the most part. I still think something else may be factoring in possibly in the braking proportioning or something along those lines. The issue has been spooling with the header/turbo setup which is now being revised. We won't need to ride the brakes so hard next season. My brother wants nothing to do with a D60 conversion and I pretty much agree. If others make this work with more power than us, we should be able to as well. Plus we like the low slung look of the truck with the IFS. If it goes solid axle, it goes open driveline.

Thanks guys.

Ed

no need for the open drive line since alot of the pull for the 3.0 class in ohio are oem drive line they wont bump up to open drive line

 

[05smoker]

no need for the open drive line since alot of the pull for the 3.0 class in ohio are oem drive line they wont bump up to open drive line

Where can you find the most recent Ohio rules?

 

[codyn]

Where can you find the most recent Ohio rules?

PERFORMANCE TRUCK & TRACTOR PULLING SERIES
740-819-6200
740-468-9045 FAX
RULES FOR 2008
8000LB. “PRO STREET” 4X4

1. TRUCKS COMPETING IN THIS CLASS MUST RUN TRANSMISSIONS, TRANSFERCASES, FRONT ENDS AND REAR ENDS THAT CAME FACTORY IN A 1 TON OR LESS PICKUP. HOWEVER THE INTERNAL DRIVETRAIN PARTS CAN BE UP GRADED AND MODIFIED.

2. ENGINES MUST BE OEM AND AVAILABLE IN 1 TON OR LESS PICKUPS. NO AFTERMARKET HEADS OR BLOCKS PERMITTED.

3. NO SIGMA INJECTOR PUMPS PERMITTED.

4. SINGLE CHARGERS ARE LIMITED TO A 3.0" INDUCER BORE. THIS WILL BE TECHED USIN A 3.05" PLUG.

5. LIMITED TWIN CHARGER SET UPS ARE PERMITTED AS LONG AS THEY FIT THESE RULES. TOP CHARGER MUST BE A DIRECT BOLT ON AND THE BOTTOM CHARGER MUST HAVE A 3" OR SMALLER INDUCER BORE AND WHEEL SIZE. NO RESTRICTORS OF ANY KIND MAYBE USED TO PERMIT A LARGER TURBO TO PASS INSPECTION. A 3.05" PLUG WILL BE USED TO TECH THESE TRUCKS.

6. NO NITROUS, OR PROPANE. ALL TANKS AND LINES MUST BE REMOVED FROM TRUCKS BEFORE COMPETING.

7. FRONT WEIGHTS AND BRACKETS MAY NOT EXCEED MORE THAN 60" FROM CENTER OF FRONT AXLE.

8. REAR SUSP. BLOCKS AND TRACTION BARS ARE PERMITTED.

9. PULLING TYPE HITCHES ARE PERMITTED, HOOK POINT ATLEAST 36" BEHIND THE CENTER OF REAR AXLE.

10. ANY D.O.T. APPROVED TIRE PERMITTED. NO CUTTING OR SHARPENING OF TIRES PERMITTED.

11. SAFTEY REQUIREMENTS. MUST HAVE DRIVE SHAFT LOOPS AND U-JOINT SHIELDS ON FRONT AND REAR SHAFTS. BLOWPROOF BELLHOUSINGS, OR BLANKETS OR BELLHOUSING SHIELDS REQUIRED. AIR OR FUEL SHUT OFF KILL SWITCHES REQUIRED.

12. SMOKE MUST EXIT STRAIGHT UP. TURN UPS REQUIRED ON TAIL PIPES.

they dont want open driven line for next year because the ones pulling in the class dont want it:rofl:

 

[dieselson]

Owww we've only broken two, one was on warranty, and the other was $666

 

[Dmax Grizzly]

I hope someone can find a solution for the weak link. I did something a couple weeks ago that I shouldn't have and broke the front right unit bearing and somehow the halfshaft broke too right at the splines. I think the bearing was going out and it caused the shaft to shear. Pissed me off and learned a lesson too. I'm glad I was able to fix it at my buddy's house the next morning. Advanced Auto had both in stock and the upper ones also.

 

[codyn]

they are making billet cv and half shafts but they are pricey

 

[SRomans84]

where you having this problem when the front wasnt welded?? I've seen a loft of front and rear shafts break because the diff is welded or spooled, there isn't anything to make up for traction differences from side to side which puts a lot of torsional strain on the shafts, but you do get a hell of a lot of traction

 

[McRat]

Torque multiplication by the 4WD Low range is huge. 2.7 times the force of a normal dragstrip launch.

Bandaid fixes (not optimum):

Program a 2nd or 3rd gear launch to reduce torque.
Less weight on nose to move some of the force on the stronger rear axle.
Cut the front brake pad material area to use more of the rear brakes, or eliminate the front brakes.
Torque peak is usually 2000rpm with a tuned Dmax, use a looser converter to get past that point to build boost without as much preloading.

 

[McRat]

PERFORMANCE TRUCK & TRACTOR PULLING SERIES
740-819-6200
740-468-9045 FAX
RULES FOR 2008
8000LB. “PRO STREET” 4X4

1. TRUCKS COMPETING IN THIS CLASS MUST RUN TRANSMISSIONS, TRANSFERCASES, FRONT ENDS AND REAR ENDS THAT CAME FACTORY IN A 1 TON OR LESS PICKUP. HOWEVER THE INTERNAL DRIVETRAIN PARTS CAN BE UP GRADED AND MODIFIED.

2. ENGINES MUST BE OEM AND AVAILABLE IN 1 TON OR LESS PICKUPS. NO AFTERMARKET HEADS OR BLOCKS PERMITTED.

3. NO SIGMA INJECTOR PUMPS PERMITTED.

4. SINGLE CHARGERS ARE LIMITED TO A 3.0" INDUCER BORE. THIS WILL BE TECHED USIN A 3.05" PLUG.

5. LIMITED TWIN CHARGER SET UPS ARE PERMITTED AS LONG AS THEY FIT THESE RULES. TOP CHARGER MUST BE A DIRECT BOLT ON AND THE BOTTOM CHARGER MUST HAVE A 3" OR SMALLER INDUCER BORE AND WHEEL SIZE. NO RESTRICTORS OF ANY KIND MAYBE USED TO PERMIT A LARGER TURBO TO PASS INSPECTION. A 3.05" PLUG WILL BE USED TO TECH THESE TRUCKS.

6. NO NITROUS, OR PROPANE. ALL TANKS AND LINES MUST BE REMOVED FROM TRUCKS BEFORE COMPETING.

7. FRONT WEIGHTS AND BRACKETS MAY NOT EXCEED MORE THAN 60" FROM CENTER OF FRONT AXLE.

8. REAR SUSP. BLOCKS AND TRACTION BARS ARE PERMITTED.

9. PULLING TYPE HITCHES ARE PERMITTED, HOOK POINT ATLEAST 36" BEHIND THE CENTER OF REAR AXLE.

10. ANY D.O.T. APPROVED TIRE PERMITTED. NO CUTTING OR SHARPENING OF TIRES PERMITTED.

11. SAFTEY REQUIREMENTS. MUST HAVE DRIVE SHAFT LOOPS AND U-JOINT SHIELDS ON FRONT AND REAR SHAFTS. BLOWPROOF BELLHOUSINGS, OR BLANKETS OR BELLHOUSING SHIELDS REQUIRED. AIR OR FUEL SHUT OFF KILL SWITCHES REQUIRED.

12. SMOKE MUST EXIT STRAIGHT UP. TURN UPS REQUIRED ON TAIL PIPES.

they dont want open driven line for next year because the ones pulling in the class dont want it:rofl:

Boy, you have to be a fool not to run twins in that class. There is nothing stopping you from running a custom GT45-47 as a top charger with a 3" cover.

But it doesn't say OEM suspension, it says 1-ton or less, so a Dana live axle up front should be OK.

 

[codyn]

Boy, you have to be a fool not to run twins in that class. There is nothing stopping you from running a custom GT45-47 as a top charger with a 3" cover.

But it doesn't say OEM suspension, it says 1-ton or less, so a Dana live axle up front should be OK.

dana 60 will hold its the rear end that wont hold up with the power

 

[05smoker]

Torque multiplication by the 4WD Low range is huge. 2.7 times the force of a normal dragstrip launch.

Bandaid fixes (not optimum):

Program a 2nd or 3rd gear launch to reduce torque. DONE AT TERRE HAUTE. DIDN'T BREAK
Less weight on nose to move some of the force on the stronger rear axle. RC PULLER WANT ALL WEIGHT POSSIBLE OUT FRONT OBVIOUSLY
Cut the front brake pad material area to use more of the rear brakes, or eliminate the front brakes. THOUGHT OF NEW PROPORTIONING VALVE OR SWITCHING THE CURRENT FACTORY LINES ON THE MASTER CYLINDER TO SEE IF IT CHANGES THE PRESSURE ENOUGH
Torque peak is usually 2000rpm with a tuned Dmax, use a looser converter to get past that point to build boost without as much preloading. STILL CONSIDERING SWITCHING TO A 1055

See Above in caps. Thanks Pat.

 

[bullfrogjohnson]

I love my 1055, I can spool it alot more off the line than compared to my 1057