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He said this engine has problems and also said it had crank case pressure issues that will leak oil past the rear main seal. Looks like he was right on both accounts, only time will tell how far down the rabbit hole this goes.
I am surprised the Engineers at GM did not experience this issue (too much POSITIVE crank case pressure) at some point during testing.
I am not an Engineer or a Factory Test Driver by any stretch but in the past if any of my new builds were going to have positive crankcase pressure issues I could make the condition appear in about 2 laps.
I am surprised the Engineers at GM did not experience this issue (too much POSITIVE crank case pressure) at some point during testing.
I am not an Engineer or a Factory Test Driver by any stretch but in the past if any of my new builds were going to have positive crankcase pressure issues I could make the condition appear in about 2 laps.
I'm surprised that with a dry sump oiling system there is any positive pressure at all, it should operate in a vacuum.
I'm surprised that with a dry sump oiling system there is any positive pressure at all, it should operate in a vacuum.
Mine does at all RPM but the highest I rev it to is 7600 rpm and the build uses a ported ring. Many sealed dry sump engines engines with only two scavenge stages do not and depending on blow by levels they still can see significant positive CC pressures. The question asked is how would someone even know if they don't measure the CC pressure? Because they have a dry sump they may just assume there is no positive CC pressure.
I believe the C8Z has 4 scavenge stages? I would be shocked if they didn't see a positive CC pressure issue before public release. Could possibly be the reverse. Too much negative pressure. I happen to use a check valve. Would be surprised if they didn't see that as well.
Mine does at all RPM but the highest I rev it to is 7600 rpm and the build uses a ported ring. Many sealed dry sump engines engines with only two scavenge stages do not and depending on blow by levels they still can see significant positive CC pressures. The question asked is how would someone even know if they don't measure the CC pressure? Because they have a dry sump they may just assume there is no positive CC pressure.
I believe the C8Z has 4 scavenge stages? I would be shocked if they didn't see a positive CC pressure issue before public release. Could possibly be the reverse. Too much negative pressure. I happen to use a check valve. Would be surprised if they didn't see that as well.
Curious to see how it all works out for everyone.
My Dailey Dry Sump Pump pulled so much vacuum we had to put an adjustable vacuum regulator on it to make sure it didn't suck the seals in. (top, front of right valve cover).
The LT6 has 4 crankcase scavenge stages and at least two others. In the deep dive into the LT6 it was reported that the scavenge side did draw vacuum in the crankcase and that helped them to get the rated 67 0CHP.
My Dailey Dry Sump Pump pulled so much vacuum we had to put an adjustable vacuum regulator on it to make sure it didn't suck the seals in. (top, front of right valve cover).
I use the same pump and regulator if you have the regulator Bill Baroody recommends. I log every session and I haven't seen any anomalies in my set up where it makes potentially damaging amounts of vacuum at any RPM. During break in it made POSITIVE crankcase pressure. Now it makes negative vacuum throughout the RPM range.
Is it possible that some of these C8Z engines are making significant amounts of positive crankcase pressure and damaging the seals? Could be I guess. How would you know if you don't have a sensor installed and aren't data logging? My feeling on the whole thing is if GM keeps putting in engines under warranty then great. It's just a PITA that I would rather not have to contend with. I think AZDave's new C8Z will be a great test of overall reliability..
I use the same pump and regulator if you have the regulator Bill Baroody recommends. I log every session and I haven't seen any anomalies in my set up where it makes potentially damaging amounts of vacuum at any RPM. During break in it made POSITIVE crankcase pressure. Now it makes negative vacuum throughout the RPM range.
Is it possible that some of these C8Z engines are making significant amounts of positive crankcase pressure and damaging the seals? Could be I guess. How would you know if you don't have a sensor installed and aren't data logging? My feeling on the whole thing is if GM keeps putting in engines under warranty then great. It's just a PITA that I would rather not have to contend with. I think AZDave's new C8Z will be a great test of overall reliability..
Exactly. You need definitive data to know anything. Post mortem evidence - if you have enough of it and if it all points to the same thing would be second best evidence.
The one that died at like 50 miles that we all heard about, one other one, and his. So with about 1000 cars built, 3 engine failures. So about a 0.3% failure rate so far.
Out of those 1,000 cars built, how many are garage queens, and how many have only been driven a few miles? Given that, the math says that the failure rate is much higher than .3%.
April 2nd update. Had another trans code issue at NCM. P0700 Car didn't make it a full session. I did get to meet another C8 Z06 owner / instructor that recognized me from the forum. Since it was my first time at NCM - I asked if he could ride with me and give me some pointers. Great meeting you and thank you Cy! I got to also ride along with him in his E90 M3 in track. Great driving!
Taking the Z to the dealer tomorrow. 18 hour round trip drive for one 18 minute session. I tried to call around and get some local help but the service dept was obviously closed. The track mgmt was very empathetic and even offered to rent me a C8 (but I declined due to cost and the fact I already was out 3 sessions out of 6 for that day). Thanks Zack!
I did get to see the museum - which was a super cool experience! Hate to report the bad news, was hoping it went better this weekend because NCM is one great track. A lot of blind turns, technical sections, high speed turns and elevation changes.
April 2nd update. Had another trans code issue at NCM. P0700 Car didn't make it a full session. I did get to meet another C8 Z06 owner / instructor that recognized me from the forum. Since it was my first time at NCM - I asked if he could ride with me and give me some pointers. Great meeting you and thank you Cy! I got to also ride along with him in his E90 M3 in track. Great driving!
Taking the Z to the dealer tomorrow. 18 hour round trip drive for one 18 minute session. I tried to call around and get some local help but the service dept was obviously closed. The track mgmt was very empathetic and even offered to rent me a C8 (but I declined due to cost and the fact I already was out 3 sessions out of 6 for that day). Thanks Zack!
I did get to see the museum - which was a super cool experience! Hate to report the bad news, was hoping it went better this weekend because NCM is one great track. A lot of blind turns, technical sections, high speed turns and elevation changes.
Sorry to hear of your woes. I've only seen a grown man cry several times, once at Watkins Glen when his F12 Superfast died after one lap (electrical problem that couldn't be fixed trackside). We all prep our cars in advance of track days, but things happen, and no one is 100% guaranteed to run full sessions.
I will be at NCM later this month doing an arrive and drive C8, but I generally bring my own car and always keep my fingers crossed I don't get shut down. It happens and I've seen it lots.
That's a shame... I'd write a letter to GM corporate. Buy their flagship trackday oriented car and it's on it's 2nd motor pushing oil and now will need a trans.
Sorry to hear of your woes. I've only seen a grown man cry several times, once at Watkins Glen when his F12 Superfast died after one lap (electrical problem that couldn't be fixed trackside). We all prep our cars in advance of track days, but things happen, and no one is 100% guaranteed to run full sessions.
I will be at NCM later this month doing an arrive and drive C8, but I generally bring my own car and always keep my fingers crossed I don't get shut down. It happens and I've seen it lots.
Keep us posted, that is a bummer for sure.
I just got a call from the dealer and they are going to replace the trans. I spoke to the Corvette technician this morning and he says they get them directly from Tremec now. Advisor says 7 to 10 business days. Does anyone know if it will require another 1,500 mile break in? Tech did not have an answer on this.
Originally Posted by RapidC84B
That's a shame... I'd write a letter to GM corporate. Buy their flagship trackday oriented car and it's on it's 2nd motor pushing oil and now will need a trans.
If anyone has an email / address to someone at corporate - I would be happy to send them a note with my story. Unfortunately, the customer care route that I toold was not a fruitful exercise.
Thanks for the support everyone. I really need the car back soon as I'm raising funds / awareness for Racing for ALS at Road Atlanta (Carolyn's Race) and VIR (Dave's Race). Also raising funds at Barber with Jzilla in October.
Thanks for the support everyone. I really need the car back soon as I'm raising funds / awareness for Racing for ALS at Road Atlanta (Carolyn's Race) and VIR (Dave's Race). Also raising funds at Barber with Jzilla in October. https://www.mightycause.com/story/J32kgf
I run all three of those tracks and I hope we can arrange a meetup sometime when you get things squared away. My best wishes for putting these problems in your rear view mirror.
I just got a call from the dealer and they are going to replace the trans. I spoke to the Corvette technician this morning and he says they get them directly from Tremec now. Advisor says 7 to 10 business days. Does anyone know if it will require another 1,500 mile break in? Tech did not have an answer on this.
If anyone has an email / address to someone at corporate - I would be happy to send them a note with my story. Unfortunately, the customer care route that I toold was not a fruitful exercise.
Thanks for the support everyone. I really need the car back soon as I'm raising funds / awareness for Racing for ALS at Road Atlanta (Carolyn's Race) and VIR (Dave's Race). Also raising funds at Barber with Jzilla in October.
@soulsea might be able to point you in the right direction to reach out to corporate. He is the person who sent an email to someone at GM and was a big part of GM changing the "anti flipping policy" based on his feedback. So someone there was listening. https://www.corvetteforum.com/forums...r-warning.html
I just got a call from the dealer and they are going to replace the trans. I spoke to the Corvette technician this morning and he says they get them directly from Tremec now. Advisor says 7 to 10 business days. Does anyone know if it will require another 1,500 mile break in? Tech did not have an answer on this.
If anyone has an email / address to someone at corporate - I would be happy to send them a note with my story. Unfortunately, the customer care route that I toold was not a fruitful exercise.
Thanks for the support everyone. I really need the car back soon as I'm raising funds / awareness for Racing for ALS at Road Atlanta (Carolyn's Race) and VIR (Dave's Race). Also raising funds at Barber with Jzilla in October.
I'd be strongly requesting a buy-back and the next available allocation, assuming you want to stick with a Z06. There's no way I would keep a brand new vehicle of any kind, let alone a $150k+ (not sure what you paid) Z06 on its 2nd engine and transmission. I, personally, would move on to something else and let GM have their lemon back.
