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luck is not on my side seemingly. Did a little tour with the C6 fresh out of the workshop. Heard a little "Bang" and than a crunching noise. Stopped the car. After a short search found this :
Screw that holds the balancer is completely out. Oil everywhere, although I don´t know where it came from. It´s no motoroil for sure, but all 3 reservoirs (steering, brake, clutch) are completely full and I had a huge puddle under the car. I think maybe the A/C compressor got damaged.
The car was towed back to the shop, more tomorrow. As you see, it´s a Summit racing balancer, ever heard about such a thing ? Mechanic says he is 100% positive he torqued it to spec and used Loctite.....
A hypothetical question : even if the bolt was re-used but still torqued and loctite'd, would it come loose after 10 miles light driving and one spirited launch ? Seems unlikely to me, I suspect they completely forgot to tighten that bolt.......
When getting to the correct torque, the bolt stretches. If it's only made to stretch one time, the next time it stretches might break it. It could have been in two pieces when you left the shop.
SO when you get to the shop in the morning, casually ask if he replaced the bolt. Is it on your invoice? That should clear things up quickly, or move on to some other issue. Like is there Locktite residue on the bolt.
Things clear up. The bolt is broken and they didn't install a new one as there was none in the Summit kit. But they are willing to make things right, and replace the bolt with a new one. All the oil was actually my brandnew motor oil leaking from the front crank seal. This seal will be replaced, too.
When researching that bolt, I sometimes read about a specific washer, and now I'm confused. When using the original GM bolt, is a washer mandatory?
Things clear up. The bolt is broken and they didn't install a new one as there was none in the Summit kit. But they are willing to make things right, and replace the bolt with a new one. All the oil was actually my brandnew motor oil leaking from the front crank seal. This seal will be replaced, too.
When researching that bolt, I sometimes read about a specific washer, and now I'm confused. When using the original GM bolt, is a washer mandatory?
Thanks
Oliver
The special diamond embedded washer goes between the timing gear (the oil pump drive) and the main pulley. In other words, it goes on the _back_ of the pulley, inside the front cover. GM introduced the washer in the first year of C6 production to address the problem of pulleys coming loose. The washer is really thin, so it doesn't make a significant difference to belt alignment.
I would use the washer regardless of the bolt or pulley used. It performs the same task: to increase the bite against the timing gear, which is what the pulley is clamped against. If the interference fit on the crank was all it required, we wouldn't need a crank bolt in the first place.
A hypothetical question : even if the bolt was re-used but still torqued and loctite'd, would it come loose after 10 miles light driving and one spirited launch ? Seems unlikely to me, I suspect they completely forgot to tighten that bolt.......
Yes, A torque to yield fastener (TTY) or stretch Bolt is a fastener which is torqued beyond the state of elasticity and therefore undergoes deformation, causing it to become permanently elongated. TTY hardware must be assumed to be compromised and must be removed from service if subsequently loosened or damaged.
Your shop owns this mishap due to improper maintenance procedures.
My problem is, that this diamond embedded washer is literally unobtainable in Europe, even in the USA it´s not to be found easily. Rockauto also doesn´t have it available. And they are the only supplier who delivers within 5 working days to Germany, Summit Racing for example take 2-4 weeks to get stuff over the pond. I would very much like to use a pinning kit such as this one here : https://www.summitracing.com/parts/INW-966
I even have it here, but is is of no use as it doesn´t fit to the original GM balancer nor to the Summit Balancer (Mine is a SUM-C2501). Summit does not recommend the washer in the recommended parts, though.
The screws and front crank seal should be here tomorrow from Rockauto, I guess I have to take it from there....
Last edited by C4Oliver; Feb 25, 2025 at 05:10 AM.
....you live in the US, where Amazon Overnight is a real thing. I just tried to order it at Amazon for delivery to Germany : Will be here March 11th. It is not available at any European warehouse. The joy of driving an american car in Europe I guess.......
I wait for an answer from Summit, they can be fast in delivery (at a very high price). Have to talk to the workshop how long they can store the car there waiting for parts.....
Things clear up. The bolt is broken and they didn't install a new one as there was none in the Summit kit. But they are willing to make things right, and replace the bolt with a new one. All the oil was actually my brandnew motor oil leaking from the front crank seal. This seal will be replaced, too.
When researching that bolt, I sometimes read about a specific washer, and now I'm confused. When using the original GM bolt, is a washer mandatory?
Thanks
Oliver
Bolt is broken!? Oh, ****, I hope they can get the broken piece out. And I hope they don't half-*** it again like they did when re-installing the old bolt.
Buy the ARP crank bolt for the vette. I would also buy the pin kit to pin balancer to crankshaft. My C6 was repaired at a Chevrolet Dealer about 7k miles before I purchased it. Bolt backed out balancer walked forward. Due to time constraints I had a shop near my shop actually do the job. Took on trip next day 2300 miles and 0 worrys about bolts backing out etc. Got on it a few times , no issues. Bought an SFI balancer ,pin kit and ARP bolt. So for future upgrades the work is done. Parts were around $500. One use bolts are just a waste to me. Spend the extra money and get something that is high quality. Also make sure they are holding crank from spinning while attempting to tighten it. No impact gun ! Torque to spec.
Anthony
Last edited by Highwayman9011; Feb 25, 2025 at 07:24 AM.
Lost my harmonic balancer
