427 engine (part 2) - RHS block

[Rich Z]

Actually, those parts are referred to as "flex plates" or "flex disks". I have read that they are made out of titanium.

Here's a quote from Pfadt from a post they made on CorvetteForum about them.

We can't speak to the DSS shaft, but on our drive shaft durability tester we have torture tested our drive shaft for 500,000 cycles of 1350 ftlbs, then took the same shaft and it finally torque yielded at about 4500 ft/lbs. Ours is also specifically designed to use a specially designed flex disk to account for angular discrepencies that would otherwise be accounted for by the factory giubos. These flex disks remain stiff in rotation and give you the performance benefit of a billet coupler, but keep the shaft and bearings happy like the factory giubo.

http://forums.corvetteforum.com/c6-f...n-shaft-2.html

I still haven't heard back from them about the driveshaft length measurements.

[Rich Z]

And some more concerning the flex disks....

http://forums.corvetteforum.com/c6-c...ive-shaft.html

In our Carbon Fiber Driveshaft system we have replaced the rubber guibos with specially designed Flex Disks that allow for angular deflection just like the guibos do, but without the potential for failure over time. The reason we don't use a large single piece machined guibo replacement is that an aluminum guibo replacement is solid and won't allow for the slight misalignment that is present between engine and transmission. By designing a unique flex disk to account for misalignment our system keeps stresses on the driveshaft and bearings low, but provides the superior rotational stiffness that the stock guibos cannot.

I sent another nag-o-gram to Pfadt and got a reply that all of their engineers are busy with other tasks. So I'm kind of low on the totem pole. But I guess this is a moot point now anyway, as the Pfadt carbon fiber drive shaft is now just a paperweight sitting in my garage while a stock shaft is being installed in my car. Not that I'm going to be very much inclined to pull out the torque tube and do this myself later on.

Ah well, I have heard some people claim they were getting an annoying vibration at certain RPM ranges from their carbon fiber drive shaft so maybe it's for the best anyway. As soon as I find out about the measurements being correct (or not) I can consider selling it and at least try to get some of my money back from it.

[Rich Z]

I had some people over on CorvetteForum ragging on me that I really should just give up on this car and I made a statement about this that I think I should post here as well. Certainly some of you are thinking the same thing...

=================
Connie and I have discussed this extensively. I know it is wearing on her, so I told her that if she was ready to throw in the towel, then so am I.

She wants me to treat it as a hobby. An expensive hobby, no doubt, but then again, how many or them aren't? If it takes me years to get the car right, then so be it. If I have to ship the car to Lingenfelter, or Katech, or whoever, to have it straightened out, then so be it. If I have to work on everything I CAN here in my own garage, then so be it. If Connie is willing to stand by me, no matter what, then I'm just not going to roll over on this and be defeated.

The car CAN be fixed. And it WILL be fixed. Regardless of those shops and guys who through ignorance, incompetence, laziness, or whatever nearly ruining my car, taking my money for services they did NOT render, and putting Connie and myself through Hell over it.

When the car is done, then I will take it to every local show I can find knowing that everyone who knows of this will be thinking of Chris Harwood and Aaron Scott and what they did to my car, Connie, and myself in the process whenever they see it. And it will also be a testiment to all those other people and shops here locally that COULD have helped me, but didn't "want to get involved", that I did not need them after all. Shane was the only one out of the bunch willing to step up to the plate and help me. I'm a member of the local Tallahasee Corvette club and not a single solitary soul out of any of them contacted me to offer help. None of them. I got one guy to come help me by taking a look at my fuel system, but it was like pulling teeth to get his help. Heck, I had a lot more offers from this forum (meaning CorvetteForum) from guys across the country willing to drive or fly here to lend me a hand.

So yeah, I learned a LOT of lessons from all this.

And I hope YOU all are learning that I am NOT a quitter. I may buckle and drop to my knees every now and again, but as long as I am able to bring myself to my feet again, I'm damned sight gonna.......
================

[shakedown067]

That's one great wife you got there Rich and was a great read! Thanks for sharing. More power to ya man! Really sad to know not one person from your local Vette club offered to help. If you ever want any graphics for your car, hit me up and I'll do all the design for free. I've got a good connection for vinyl too if needed (just solid colors, nothing too fancy). Hope Shane buttons up the last of the issues for you!

[CorvetteJohn]

I am going to eat crow and rejoin this saga. As I have said many times you are very lucky to have someone like Connie to stand by your side. I applaud your decision to press ahead and to look forward to enjoying this car. I also am amazed by the documentation you have on this build. Your pictures and video are priceless and as you have demonstrated recently they have been an invaluable aid in resolving the latest issue to crop up from the past. I particularly liked the piece you machined to mount the MAF sensor. It showed me that you have a talent for doing things in a neat and professional manner. My only regret is that I live to far away to someday see and hear this beast up close and personnel. I believe your diagnosis of what happened to the drive line is spot on. It is surprising how little it takes to mess up a gear. I know that GM back in the late 80's and early 90's was holding there gear tooth tolerances in there manual transmissions to plus or minus 3 thousands with the acceptable tolerance in the production being less than 1 thousands.

[Rich Z]

Well, I got an email from Pfadt this afternoon.

On 8/1/2012 5:15 PM, Jarrett Bryden wrote:
> Hey Rich. After checking in with our engineering staff if your absolutely sure that the measurement of 42 1/4 is ONLY the carbon tube and does not include the length of the orange drive end as it sticks out past the carbon, your tube may be long for your C5 Manual application. The proper length of your tube should be right at 1063.5mm, and 42 1/4 converts to about 1073mm.

> I sincerely apologize for the confusion that this latest round of troubleshooting has caused. We are honestly very surprised that your shop didn't pick up on this though. At nearly 10mm too long it would have likely pushed the bearing up to or very close to the pilot bearing causing clutch engagement and release issues, as well as potentially pushing the bellhousing off of the block a small distance. This might partially explain the bolts backing off of your bell housing that your describing in your thread. Either way it would have been pretty difficult to not notice during installation that the driveshaft was too long during installation. One of the reasons you pay a shop to perform work like this is to prevent issues like this from happening. Mistakes do happen occasionally, and having a good shop recognize that parts clearly should not go together is a huge reason to take your shop to a reputable operation. Again I'm sorry for the stress this latest hiccup has caused in your build process, but we are willing to take care of it as soon as possible.

> If you absolutely had to get the car back on the road your tech did the correct thing in putting on the factory driveshaft back in. Even though your parts are over 3 years old and definitely far out of our warranty coverage range we really want to make sure you're situation is taken care of right the first time. I do have a proper length C5 driveshaft in stock that I would like to send you out immediately. I do need to get your old driveshaft back and will include a return label in the box to get the old parts back to us. At that point you can do with the driveshaft as you please, preferably to reinstall it back into the torque tube and have full Carbon Fiber driveshaft functionality.

> Let me know what you would like to do and I will get the necessary steps taken to get the correct length driveshaft in your hands.
> --
> Jarrett Bryden
> Pfadt Race Engineering

Thinking that perhaps I just measured the carbon fiber shaft wrong, as I'm pretty sure I measured from at least one of those orange drive ends, I went back over to the garage and this time used a metal straight edge to do the measurement. And I came up with 42 5/32s inches. Which works out to 42.1563 inches, or 1070.77 mm. 1070.77mm - 1063.50mm means that the carbon fiber drive shaft was 7.27mm too long.

Yep, Shane was obviously correct about that driveshaft being too long. So it appears that not only were those bolts missing in the bell housing, but the drive shaft was too long, both likely contributing to the carnage that took place. Would one without the other have caused the damage? Beats me. But one certainly couldn't have helped affecting the other. Just yet another kick to the nuts, I guess.

[ironhorse]

Hey Rich, just wanted to say I have alot of respect for both you and Connie for not throwing in the towel on this build, especially after ALL the BS you have been through.

[Rich Z]

Thanks guys. I've often thought that this life is actually purgatory, and is the test to see which elevator, up or down, we take for the next step. This whole mess sort of reinforces that suspicion...

[Rich Z]

Well, I bought one of those can opener style oil filter cutters and opened up the oil filter that came off of my car right after Mike Carnahan tuned it. I wanted to change the oil then because I figured the old tune was running too rich, and possibly put more gasoline content into the oil than I would like.

Anyway, the reason I opened it up was because Shane felt that there might be a lot of brass residue in there from that crank endplay showing possible thrust bearing damage. So I figured I might as well look.

Not as easy as I had thought it would be. The cutter works OK, but it tends to crimp the filter shell against the filter element itself, so I had to use a screw driver to bend back the crimps. Then the filter element came out fine, but I still needed to open up the accordion like filter element, and the only way I could see to do that was by using a blade to cut the element away from the metal frame it was in. So FINALLY I was able to take a look at the spread out filter material.

And there was nothing. No shiny looking brass material that I could see at all. There was some dark sludge at the bottom of the oil filter but it's not magnetic and not shiny brass colored so it's just some sludge that accumulates I guess. Nothing magnetic or brass colored on the filter element itself, neither....

But I will be changing the oil when I bring the car back home, just in case there was some damage going on during the drive up to the dealership when things fell apart in the clutch. Hopefully the filter will be clean then as well.

Anyway, I just got off the phone from talking with Shane and he said the car is finished. He took it out for a test drive and he seems real pleased with the way the clutch works now. So Connie and I will be going up there tomorrow morning to pick it up. Of course I'll be on pins and needles driving it home after that drive up there with the car, but Shane seems confident that I won't have any more issues. At least not with this part of the car. So all I can do is hope for the best....

[shakedown067]

Fantastic news. Want to REALLY know what's in your oil? For $25 you can find out via Blackstone Labs. I still need to send mine in from my last oil change. Just fill out the form and you'll get the test kit in about a week.