Vanagon Conetastrophy

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Dual Port
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Re: Vanagon Conetastrophy

Post by Dual Port »

That was coincidence to hitting the cone, it happened to shear off at the same time you dumped the clutch to re-engage. Regardless of the cone your flywheel would have departed within minutes.

:mrgreen:
Bruce Amacker
'66 Deluxe Bus
'65 Standard Bus
Stan
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Re: Vanagon Conetastrophy

Post by Stan »

Not following your comment Bruce. Disengaging did it or reengaging did it?
Stan Levine
67 Franken-Beetle
85 Vanagon Riviera
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wwebner
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Re: Vanagon Conetastrophy

Post by wwebner »

I agree with Bruce. When the cone Knocked the trans out of gear,into neutral, the engine and trans(attached with clutch engaged) were spinning at 3000+ RPMS. Maybe even more like 4-5000 RPM. When you disengaged the clutch,separating the engine and trans,then put the trans back into gear, it was similar dumping the clutch at a drag race only in reverse.
You probably let your foot off the gas when it came out of gear,which would be a normal reaction. A race car driver would have kept his foot in the gas, keeping the engine RPM close to the trans RRM.

This same thing has been happening to the large displacement Go Westy waterboxer motors.
the stock flywheel bolts are not capable of handling the additional HP and torque.
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Dual Port
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Re: Vanagon Conetastrophy

Post by Dual Port »

Stan wrote:Not following your comment Bruce. Disengaging did it or reengaging did it?
If you had not hit the cone, you would have probably lost the flywheel at the next stop light. The flywheel had worked loose over a period of several (many) miles and just picked that moment in time to come off. The shock of re-engaging the clutch was the last straw, but that would have happened very shortly regardless. Disengaging and re-engaging the clutch harshly would do no damage to a healthy engine.

The cone had no bearing on the departure of your flywheel.
Bruce Amacker
'66 Deluxe Bus
'65 Standard Bus
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wwebner
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Re: Vanagon Conetastrophy

Post by wwebner »

Bruce, I though the same. but when Chuck showed me the bolts,they were all 5 sheared off equally. I did not see andy distortion on the threads. Although we were sitting in a bar :lol: I did not look closely at the head for any markings. It is possible that they may not have been the correct bolts. I could not find in the watercooled Vanagon Bentley a listing for the proper grade of bolt, but the T4 Bentley calls for a 22Cr 4 grade,whatever that is, the aircooled T4 uses the same size bolts,including length and pitch,but calls for a "self locking bolt" These were allen head,which Chuck says are what is used on the waterboxer. Both torque to 80-81 ft.lbs
chuckspence
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Re: Vanagon Conetastrophy

Post by chuckspence »

Ok, enough already, Bruce has made some valid points, but I have never seen the 5-bolt flywheel connection fail due to any normal operator induced action, Vanagon shift linkage is unique to rear engine Volkswagen buses as the shift arm on the side of the transaxle & the shift rod are exposed, 4th gear is back & to the right at the gear shifter, reverse, 1st & 3rd are forward at the gear shifter (back at the linkage & shift arm) when the cone hit the shift linkage at 55 mph it most likely downshifted the trans into 3rd,1st or reverse for an instant prior to popping back into neutral, at that instant the flywheel conection was most likey fatally damaged, and some miles (15-20) later it failed, This all would have happened at such speeds that it would be virtually impossible to duplicate via human effort, lesson learned? avoid road hazards, and if not possible, Vanagon owners should try to keep the debris to the drivers side away from the shift linkage.

http://www.gowesty.com/product-details.php?v=&id=24083
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wwebner
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Re: Vanagon Conetastrophy

Post by wwebner »

Well, let's just say it was a freak incident. "due to any normal operator induced action"

"This all would have happened at such speeds that it would be virtually impossible to duplicate via human effort"
Unless you are willing to destroy an engine trying :lol:

The bolts mentioned in the go westy link are the ones that Jorge at European claims have been failing on the high torque motors.
Stan
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Re: Vanagon Conetastrophy

Post by Stan »

I like the cause and effect in Chuck's explanation.
Stan Levine
67 Franken-Beetle
85 Vanagon Riviera
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Dual Port
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Re: Vanagon Conetastrophy

Post by Dual Port »

I understand the cause and effect in what Chuck's saying but I'm not sure physics agrees. If the tranny was quickly jerked into a lower gear and the energy from the road speed (stored kinetic energy?) was rapidly transferred from the tranny to the engine, two things don't add up. First is the weight and mass of the flywheel/clutch combo. If it weighed zero this would make more sense but because it has not only substantial weight but also considerable diameter it takes a lot of energy to instantly take it from roughly 3000 RPM to a theoretical 10,000 rpm(?) if it was dumped into a lower gear. If the FW/C weighed zero the energy would be transferred directly to the crank and it could be possible for the crank bolts to fail. Because the FW/C is very heavy, in order for the energy to be transferred to the crankshaft it must instantly speed up the FW/C to a huge RPM and the input shaft probably would not allow this. The weak link in the picture here is the tranny input shaft should have a lower fracture torque than the flywheel to crank junction. I have seen numerous tranny input shafts twisted or broken on HD trucks due to unknown driver error. (foot slipped off clutch, aggressive driving behavior, abuse, etc) Never have I seen a flywheel come loose from something the driver did. Actually in my memory I can't even remember any FW to crank failures at all. It's common on a HD truck to see the tranny input shaft twisted, did you inspect yours closely for twist? Also, if the shaft is twisted it would be in the opposite direction from normal torque due to the tranny "driving" the engine.

This is assuming the FW bolts were of the proper grade and size. If they were soft or wrong bolts this all goes out the window. Did you rotate the engine with the fan or front pulley to make sure no internal failures occurred? In the pictures it appears there is brinnelling or fretting from the FW walking around during operation. If your theory is correct the mating flange of the FW, crank flange surface, and bolt holes will look perfect with no fretting at all. You'd need to inspect this with something stronger than the naked eye, at least a magnifying glass.

Stan, if you have full insurance on the bus it is possible that your insurance company might cover this. I've been involved in numerous road debris claims that were strange, they might give you the benefit of the doubt. If you tell them that the cone hit the shift linkage I can see this being approved.

Good luck in any case!
Bruce Amacker
'66 Deluxe Bus
'65 Standard Bus
chuckspence
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Re: Vanagon Conetastrophy

Post by chuckspence »

I agree that the most of the rotating mass is with the flywheel/clutch assembly and that it should not have caused the connection to fail, I initially explained that to Stan adding that it didn't make sense, and as far as the condition of the crank/flywheel & bolts they appear to have damage in line with the few miles of driving after the cone impact, Stan is concerned that there may be internal issues with the transaxle and wants to open it to inspect further (as I do also), This week I will be tearing down the engine and hopefully getting to the transaxle, perhaps we'll know more then...
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