Went for a little drive...

First time I've had the car out in over 2 months. The drivetrain noise I have been having off and on for, well, years, seemed to be getting a lot worse, so it kind of took the fun out of driving it. Well, that and we had a lot of rain from around mid May thru mid June, and I didn't feel like going mud bogging in the car on our sandy road.

I wanted to do a test drive, looking for evidence of a possible bad pilot bearing and set up my GoPro Hero 6 to take video. First time I have really used this camera. But as you will see in the video, the drive was pretty much noise free. Except from the exhaust, of course... :grin01:

What I wanted to do was to run the car up to speed, and then leaving the transmission in gear, let off the gas pedal to bring the engine speed down to idle, then push in the clutch pedal to disengage the clutch pressure plate from the clutch disk. Therefore the car's speed would actually be high, but the engine speed would be at idle. That would have the drive train from the clutch disk back to the rear wheels spinning rapidly, yet the pilot bearing, flywheel, and clutch pressure plate would be only at idle speed. The idea was that if the pilot bearing were bad, then in this condition, with the torque tube input shaft spinning rapidly, if the pilot bearing were shot, I would hear a clatter or squealing as the nose of the input shaft rattled around in the bad pilot bearing. However, no such noise was evident when I tried that. I tried it a couple of times, just to be sure. So much for that idea.



https://www.youtube.com/watch?v=FM3b5ol3bQo&t

Actually, except for a minor squeal when coming out of my driveway, you would never think there was a drivetrain noise problem at all.

The GoPro seemed to do a pretty decent job. I guess image stabilization was enabled, because the video seems very smooth and stable to me.

Even with my hearing aids turned up I only heard the mellow pipes and the turn signal. It drives me nuts when I hear a strange noise, but cannot reproduce it for the technicians at the dealership. As long as there is no vibration I wouldn't be too concerned, but keep investigating. I hate it when the technicians (mechanics) tell me to wait until a problem gets worse and bring the car back. I want it fixed BEFORE the problem gets worse.

The noise did get pretty bad a couple of months ago. Which is why I stopped driving it. I was trying to arrange with a shop down near Tampa that I have had do work for me a long while back to take a look at it for me, but the guy insists on being hard to reach. So I just gave up. I'm not going to chase someone down and tackle them to the ground to take my money.

So I am talking with another shop that says they can bring the car in sometime next month when they have an opening in their scheduling.

When the clutch engages, yes, there is a vibration that can be felt through the shifter shaft. I'm just leaning more and more to just accepting that the clutch itself is the cause of the problem. It's a Centerforce clutch, and from what I have read on the net, they have a reputation for being noisy.

Yeah, if the noise were to stay no worse than it was the other day when I took it out for a drive, I wouldn't be worried about it. I would just hate to break down along the road. Happened twice with this car. Once when the damage being done by Pfadt sending the wrong sized drive shaft finally came to a head (plus the accumulating damages done by the previous two shops that worked on the car). The clutch slave cylinder failed, leaving me without a clutch. Second time was when the fuel line to my fuel filter popped off. That one was my fault, because I had tried to remove that line to replace the filter, and when it proved to be resistant to my efforts, I figured it wasn't all that important because I had changed it out not that long ago. Well, apparently I had loosened the connector, and when I took it out for a drive and accelerated, raising the fuel pressure, that was enough to pop it off. Fortunately a fire didn't result from that one, as gasoline was being sprayed underneath the car when the fitting came loose. That could have been the end of the story, right then and there.

I have read that the weights in CenterForce clutches can cause vibration. I'm almost sure my brother had a McLeod in his Corvette. I have also heard good things about the Textralia Z series. I would ask my brother about them, since he's a certified master mechanic with years of experience, but he was wiped out on the expressway riding his motorcycle Saturday in Daytona. He won't be able to answer any questions for a while for sure.

Twolunger said:

I have read that the weights in CenterForce clutches can cause vibration. I'm almost sure my brother had a McLeod in his Corvette. I have also heard good things about the Textralia Z series. I would ask my brother about them, since he's a certified master mechanic with years of experience, but he was wiped out on the expressway riding his motorcycle Saturday in Daytona. He won't be able to answer any questions for a while for sure.

Click to expand...

Ouch, hope he is OK. Back when I had first gotten my driver's license, I was driving my mom's car up to the local hangout and happened to drive by a guy on a motorcycle who had apparently just wiped out and laying in the road. There was a crowd around him, but traffic was still passing through slowly. The oddest damn thing happened. The guy looked at ME and said loud enough for me to hear in a pleading voice, "I can't feel my legs." Sends chills up my spine even now thinking about it. Tell you what, absolutely KILLED any interest I ever had in owning or riding on a motorcycle.

Connie once said that she wanted to get a motorcycle. All I said is that I will never try to stop her from doing that, but I really wish that she would not. Regardless, I wasn't going to get on one. She never did get a bike.

Anyway, I've read good things about McLeod clutches. Also Monster brand seems to get very high marks. I think my choice will depend a lot on where I take the car too and what they recommend. Some shops won't guarantee their work unless you go with what they recommend. Which is how I wound up with a Centerforce clutch in my car. During the build I had a Fidanze clutch in it, but with the Pfadt driveshaft destroying it in short order, I really didn't run it long enough to form any opinion about it. I do know that I did NOT like the aluminum flywheel. For street driving, I think you need some rotational weight at the flywheel to make driving the car easy to live with. Otherwise you have to put a lot more RPMs on the engine just to move away smoothly from a dead stop, which, obviously, will cause premature wear on the clutch.

It's touch and go whether he will make it. Sue and I were excited about riding our cycles down here until we started seeing motorcycle accidents. If people can't see a full dress Harley I sure don't want to ride around here. We sold our cycles immediately.

My brother in the Keys said last week he turned on to his street and there was a full dress Harley laying in the road. He stopped, and what he described as a 90 year old woman came walking over. He asked if she saw what happened to the rider and she said she was the rider. He couldn't believe it because she didn't weight 100 pounds. She said she was going too slow and lost her balance. He asked her how many years she had been riding, and she said two weeks. She said she always liked seeing motorcycles so figured she would get one. She said she took a course and passed her driving test. He asked if she thought a full dress Harley wasn't a bit much, but she said it was what she wanted. The cycle was so heavy he said the two of them could barely stand it up. But they finally got it upright and she took off at about 10mph. Now there's an accident ready to happen. I hope her family knows what she is doing.

Twolunger said:

I have read that the weights in CenterForce clutches can cause vibration.

Click to expand...

Looking through some threads concerning Centerforce clutches making noises.

https://www.corvetteforum.com/forum...2-bad-move-on-my-part-centerforce-clutch.html

Thinking that I would improve my car for HPDE's I replaced my stock clutch with a Center force clutch. My Tech said that he's used it on all his customers cars without a problem but I should know that there will be some chatter for a time period, the chatter is getting less as expected. With the Center force I'm hearing all sorts of rattling noises at idle with the clutch let out but goes away when the clutch is depressed. Also, if I don't let the clutch out and add throttle perfectly I hear a metal grinding and scraping noise as I roll forward or reverse but goes away as rpm increases. I never had this happen with my stock clutch and I've been driving manual transmissions for over 30 years and never had this happen. Has anyone had this happen

Click to expand...

I spoke with Centerforce and my tech, both stated that the rattling at idle and the metal on metal noise as you release the clutch and give it throttle are totally normal.

Click to expand...

So, Centerforce says it is "normal", eh? Maybe for a Centerforce clutch it is, but not what I want to be hearing when I am driving my car.

Twolunger said:

It's touch and go whether he will make it.

Click to expand...

How is your brother doing? I hope he pulls through ok.

Doesn't look good. 60 units of blood so far and heart stopped twice. Medically induced coma for a couple days, but the paralytic was stopped 2 days ago and they expected him to open his eyes. Now they want to test for brain activity. Many broken bones, but he's too weak to try to fix them now. If he makes it there will be months of recovery and more surgeries. He's 65 so things don't heal fast. Sure doesn't make you want to ride a motorcycle.

Damn.... Sorry to hear that things don't look good.

Yeah, having 4 wheels underneath you traveling at high speed is much safer than 2 wheels. But I don't think anyone rides a motorcycle with personal safety reasons uppermost in mind. I can see the attraction, but just not my cup of tea.

Even though it will still be a long and rocky road, I hope he pulls through.

In my younger days we were all mad when Michigan passed a law that you had to wear a helmet. As I got older I thought you had to be crazy to ride without a helmet. I see many riders down here riding with no helmets, including women. I've seen 8 people on the pavement so far (8 years) and only 2 had helmets. I know some of them didn't make it. My brother was wearing his helmet, so that was a blessing anyway.

Believe it or not, we were heading to Tampa 2 weeks ago on I-75 and I looked in the rear view mirror and a guy on a motorcycle behind me popped a wheelie at 70 mph.
He rode that wheelie for at least 1/4 mile and I told Sue to look at that nut. He came out of the wheelie and sped up so fast he had to go between cars like a blur. Looked like a Suzuki Hayabusa and all I could think was that he won't be around long.

No matter how good of a bike rider someone is, just the slightest dab of bad luck from Mr. Murphy will overrule all that experience and ability.

Well, guess it's a good thing I took the car out for a ride when I did. The rains have set in for a few days, it seems. Unless I want to take the car mud bogging on my dirt/sandy road, the car stays in the garage till the road dries out enough. I really hate cleaning mud out from underneath the car.

Several years ago I was driving my Corvette to Florida and I stopped for gas in Tennessee. As I took off I heard a grinding noise in the first 3 gears but it quit when I got to 4th. I got off the expressway at the next exit and slowed down and put it in 3rd and heard the grinding again and what seemed like a little vibration. I drove to a couple small garages but none had a lift, and wouldn't jack the car up. The Chevy dealers were all closed, so I got a motel room to wait till they opened. The motel owner said there was an oil change place down the road with a pit, so maybe they would take a look. I drove there and the guy on duty came up from the pit after checking for anything obvious. He said it was all fixed and charged me $5.00. Turned out a shield under the car was dangling because a little rear bolt had fallen out. At slow speeds the shield dragged, but once the air pushed it up there was no noise. I gave him a twenty and left much happier.

Lordy, I wish my drivetrain noise were that easy to fix. I've spent I don't know how many hours with the car up on the lift tugging and pushing on things, looking for anything simple that I could just be overlooking. When I replaced the starter and the motor mounts, I was hopeful that perhaps one or both were contributing to the noise. I put in motor mounts that were 3/8ths of an inch shorter than stock. The starter was to correct a design flaw from GM. The starter mounts with two bolts to the block. In the stock C5 starter, there is a shorter side and a longer side to the flange the bolts go through. There have been cases of that shorter (and weaker) flange breaking on some folks. When that happens, the starter is only being held on by the single bolt. Well that wouldn't be that much of a problem, except those folks that discovered the problem found out about it when the starter just broke off from the block. The WAY it broke off was a really big deal. Because part of the engine block broke off that the single holding bolt was attached to.

Needless to say, I didn't way long to get a replacement starter and get that older one out of there. That RHS block I have in the car is NOT cheap. Yeah, I guess someone could weld that part of the block back together, but not easily (if at all) while the engine is still in the car. Any way you look at it, you were looking at a very expensive repair, which I certainly didn't want to have to experience first hand.

But in any event, neither of those repairs/mods made any change in the drivetrain noise, unfortunately.

I meant to ask you if there are any speed shops, or hot rod shops, in your area. Those guys usually seem to know more about cars than the factory engineers. I loved hanging around the local speed shops, and couldn't believe how fast they could rebuild an engine.

Twolunger said:

I meant to ask you if there are any speed shops, or hot rod shops, in your area. Those guys usually seem to know more about cars than the factory engineers. I loved hanging around the local speed shops, and couldn't believe how fast they could rebuild an engine.

Click to expand...

Not really. About the only notable place is this one -> http://transamdepot.com/

They build some very high end custom Trans Ams. Top of the line one (the 455 Super Duty) is something like $170,000.

Had a couple of shops professing to be experts about such things, but from the evidence I saw with my C5Z, they are anything BUT experts. People will try to talk the talk, however.

There are some places that will do engine machining and the sort, but they are more like general machine shops and not apparently "hot rod" oriented as far as I can tell. But maybe there are some low key places that I just haven't heard about. Seem to be a fair number of hot rods around here, but I get the impression that most of them are doing their own wrenching.

You might want to attend any car shows in your area and talk to some of the car owners. They will know who is dependable to work on the Corvettes and high performance cars. I agree, some car owners insist on doing their own wrenching, and are knowledgeable, but down here some of the guys have money, but not knowledge, and seek good mechanics.

I always wanted my brother to convert a Miata to the 5 liter Mustang engine version. He did the conversion for others but I never had the extra cash to pay for the project.

Connie and I do go to some of the car get togethers now and again. Really can't call them car "shows", since that seems more formal with prizes and such. Mostly older cars are there, but some new ones, most of which seem to be Mustangs. Doesn't do much good asking an owner of a C2 Corvette who works on his car (which is probably himself anyway), since there is a world of difference between the older Corvettes and the new ones. I certainly don't want someone who thinks it is OK to get paid for OJT working on MY car.

After the fiasco I went through with the C5Z, I look at everyone who claims to know what they are doing with a very jaundiced eye. And, of course, my car is not very close to being stock any longer.

I compiled a list a while back of all the mods I have done, and had done to that car.

1. 427 engine built by LME
   • RHS 9.240" DH aluminum block
   • Callies Compstar forged 4340 4.0" stroke crankshaft
   • Callies Compstar 6.125" H-I beam rods w/ARP 2000 7/16" bolts
   • Wiseco forged FI 4.125" x 1.115" x -20cc w/ multi fit VP's
   • NPR Seal stainless top, napier 2nd 3mm HT oil rings
   • Cam motion custom hyd. roller cam (pn XA-232-350-228-350-16)
     • Duration @ .050" = 232 228
     • Lift. = .630" (intake & exhaust)
     • Lobe separation = 116
     • Intake center line = 109.25
   • RHS double roller timing chain w/ torington bearing
   • Melling HP ported oil pump (10295)
   • Performance Induction heads
     • Jesel Pro Series shaft mount J2K 1.8 1.8 rocker arms
     • REV hollow stem stainless intake valves (X1129)
     • REV severe duty stainless exhaust valves (X1123)
     • PAC dual valve springs (KIT199-675)
     • Titanium retainers
2. F.A.S.T. LSXR 102 intake manifold
3. LS2 polished and ported 90mm throttle body
4. Dual in-tank fuel pumps by Lonnie's Performance
5. 2 BAR MAP sensor, relocated to front of intake manifold
6. Oil PCV Catch can
7. Breather can to valve covers
8. Fuel pressure regulator - vacuum/boost regulated
9. Vacuum line manifold
10. LGM long tube headers Jet Hot ceramic coated
11. All exhaust pipes wrapped and insulated
12. Turbo charger insulated covers
13. Granatelli zero ohm stainless steel cored ignition wires
14. Centerforce Dual Friction clutch
15. Dewitts Aluminum radiator
16. STS dual rear mounted turbochargers (T3/T4, 57 trim compressor, stage 3 turbine)
17. Dual turbo wastegates with 14 lb springs
18. RPM Level V transmission T56 2.66 Convert to M6 from M12
19. RPM Stage II differential
20. ECS transmission brace
21. Pfadt transmission mount
22. Pfadt adjustable shocks
23. Pfadt sway bars
24. Polyurethane suspension bushings
25. Hinson 3/8s inch short urethane motor mounts
26. Elite engineering 1/4" Torque tube Tunnel plate
27. Elite Engineering rocker panel rails
28. Gauges: Fuel pressure and boost/vacuum
29. Stainless steel braided brake lines
30. Drilled and slotted brake rotors
31. Tuned using EFILive with COS, semi-speed density tune
32. Harness mount bar
33. MGW shifter
34. AntiVenom transmission shifter detent mod
35. ACDelco reman starter with 2 long bolt mounting flanges.

Awesome list and I know why you want a quality mechanic working on the C5Z. But I was talking about someone who has specific knowledge about clutches and drive trains. They don't need to do anything to the engine itself, other than change the flywheel, if necessary, along with changing the clutch assembly. There's got to be someone with the ability to work on the C5Z, you just need to locate him.