madkaw

Well, I am back to this issue that hasn't been resolved. Latest updates is that I DID have a bad halfshaft on the passenger side. There was excessive play between the casing and the spline. I replaced the shaft with another one and had the universals changed out. I believe it mostly eliminated the high speed vibration that was there at constant speed, but I obviously have more then one issue. It's still amazing to me that the DS shop can balance a bad halfshaft. I still have a rhythmic vibration around the 3k rpm range. It is most noticeable during deceleration. It has been very subtle until recently. Recently I had shoved my diff foward about 3/8" . The reason I did this was that my previous install of the diff I shoved it too far back and the moustache bar was about riding against my downlinks to the rear control arms. My RT mount does allow for some foward aft adjustment. Being shoved too far back caused contact with any flexing of the moustache bar and I was getting a clunk in the rear. Anyway, after moving the diff FOWARD, the vibration has gotten more intense. So can someone help me picture what is going on as far as driveline forces during decel? What changes occured in my driveline moving the diff like this.

Not sure if the sound quality has anything to do with the engine size. I think it's a challenge to get the L6 to sound good with duals. I was told on this site that duals would sound funny because of exhaust pulses -blah blah blah The drone will always be an issue, but manageable . Chambered mufflers are better for quieting the beast, but I went with 10inch magnaflows- turbo type. I also have 12 inch resonators in there, not sure if they do much at all. Your set up doesn't allow the room for the larger mufflers so it will be louder. I posted a video called " music to my ears", that barely does the sound justice, but listen with headphones. I will be making another video now I have my triples on, because the sound got even better. The biggest thing to avoid for me is the cackle sound, but I think you need bigger mufflers to avoid that.

Duals are a total pain in the a$$, and it is really tight under there. Then there's the extra cost, noise, weight--so my recommendation is hook them babies back up to your duals and run it The sound of my exhaust is in the top things I love about this car. As far as worrying about matching up the primary lengths, not sure if it's going to cost you much HP in the end. The arguments could go on forever as far as what's better, single ,dual, but I vote duals- IMHO

What about under load going up a hill or something- does it sputter or anything even in the lower rpms? Almost sounds ignition related- like a weak coil

So have you checked the TPS, isn't it just a simple ohms test? So have you checked your timing, isn't it just a timing light check? Not much info here for us to help- at least I'm in the dark here! This knd of rant doesn't do you any good- just makes you sound bad

On a fresh rebuild I would want to see oil before lighting a fire. It might take a little bit to see oil pressure, or you could rig a drive spindle to prime the pump before starting. I think I used an old chevy dizzy drive and a drill to prime the motor

You ve gone thru 3 bearings ? I'm running the bw trans and always wondered if it could be an issue. So you can hear the problem turning the shaft by hand or does it have to spin faster? Did you ever put a dial guage on to measure run out on the shaft or just went by ear

Boring would have been a good description of my drive.

A friend with more money than sense bought a 2012 Roush Mustang Stage 3 -600hp with smaller pulley. He traded his SS 2010 Camaro for it and kept wanting me to come over and drive it. Of course, I wanted to drive it too, I've never driven anything with that much HP!! Of the new "retro" looking muscle cars, I do favor the mustang better than the others-camaro and challenger, I think Ford did well with the look of the car. The car sounds racy, but almost to barbaric. The mufflers are smaller than the ones on my Z-LOL . The car is very loud outside, but so quiet inside you can't even hear the supercharger whistle-that was kind of a disappointment. Handling-what do you think with a car that is probably just shy of 4000lbs. I'm quite sure it would be fun stepping out the rear around a track, but it felt numbing when driving. I don't get a chance to drive cars like this enough to judge, I can only compare to my Z. After driving that Mustang I realize how much I like my Z. I like feeling the road, I like turning the steering wheel and getting instant response to my input. The mustang was more like -point and shoot. Even with all that power the mustang had, it felt slow and or lethargic. Just my 2 cents...

I think you could get away without balancing if you only did this only every 90 degrees= 4 holes. As long as you took your time and measured out carefully. I actually used a 11 inch degree wheel and marked the flywheel every 10 degrees and went from there. Most cases the flywheel is balanced independently, yours obviously is different

The idea came from this site in the megasquirt forums. I believe it was member X4 or something. He only used 4 points to trigger his edis and he said it work great. The best part of this set-up is cost. I did this myself on a drill press and then had the flywheel rebalanced. The hall effect sensors are 20$

Still a long way from using this set-up, but it is there for when i'm ready This is the approach I'm taking for the "wheel". Then use a cherry hall effect sensor. Maybe more work, but if you happen to have the engine and tranny seperated...

I feel your pain. I have been chasing a buzzy vibration in my car that is most prevelant at 80+ mph. Enought to blur the rear view, but not scary. Had everything balanced and angle of dangle checked by a driveshaft speciality shop-this is with a RT mount, and they said it was perfect. I started looking at straight line alignment-ran a string line from the tailshaft on the tranny to the center of the pinion-you might to try that. My alignment is close enough to not be able to tell from the naked eye whether it is dead nits or not. I would ASSUME that the driveshaft shop checked that alignment as well as the angle. While under there I started yanking on thinks again and found a bad halfshaft. I had always concentrated on checking the U-joints, never thought to grab the center of the shaft and work it. In my case I had plenty of slop on one side-there should be NONE. Haven't taken it apart yet, but assuming a bad ball bearing or worn spline. I notified the shop that supposedly balanced my halfshaft- the tech claimed that regardless of me finding that bad shaft, it would not cause my vibration. I just got a different shaft and replaced U-joints, I haven't mounted it yet, so sorry for the no-report! You said you swapped out shafts, but have you checked them for this kind of wear?. It's best to put the body in a vise so you can really yank on the spline with it pulled out.

Great thread. I don't remember the OP stating what HG he went with. Did you alter your squish by going non-stock HG thickness?

Guys. I actually found one in all my junk that looks OK Thanks

Okay, I dived under the car today and started checking things again. I ran a string line down my driveline to check straightness- looked pretty damn good. So good that I started looking elsewhere and found the culprit- I think. Halfshaft- shaft is worn . Universals are great, but there is audible and visual slop between the housing and shaft. So now I'm pretty happy to find this, but kind of pissed at ADM driveline ; who had a chance to inspect these when they balanced them , because I brought them in because I had a vibration. So I call them up and they recall having my car there. I told them what I found and the tech said that couldn't be my vibration because the shafts turn to slow. Then he proceeded to tell me that my car will always have vibrations because of the urethane bushings . Anyway, when I find a good halfshaft, we will see!

I need a halfshaft, and I'm looking for a servicable one, like I can bolt ir right up!!! s_finnerty1018@comcast.net

I have read many posts of the importance of alignment, and this has been revisited several times. When I original set this up I actually put a laser pointer on the tailshaft and pointed it towards the diff to set everything up. I have also bought a protractor and measured and made an adjustment later by dropping the nose of the diff, it did not make a difference. Then I gave up and took it to ADM driveline that specializes in making and aligning driveshafts. Before I took it there I set up the diff on the RT mount to my original position. They said my alignment was great-near perfect. I would only assume they checked all parameters-angle and straightness. During all these processes, I have literally removed, replaced or reinstalled every component of the drive line. I've had 3 different diffs in this car, which meant two different moustache bars, which involved removing all driveshafts. At this point I think I am going back to ADM to help troubleshoot. They have a vibration monitor that involves hooking up sensors to the car to narrow down the vibration. I figure if they missed anything looking and balancing all of my driveshafts I can throw it back at them. These guys have been in the business for years with some very senior techs. As for today, the car goes up on jacks and gets some more scrutiny!!

You here it all the time-"SEARCH", but sometimes that takess a lot of time and reading. My recent search was regarding deck height and cams. I am currently running p-30 with an early e-88. .005 shaved of the deck with stock .040 over pistons and the head shave .012. At the time of the rebuild I was very new to these engines and relied on my machinist, with the help of 'How to Modify' book in his hands. Now I am doubling back to see where my engine is as far as quench and other data. My build sheet never specified actual deck height , so I can only figure it out by what I know and what I have read on these forums. What I have found is that average deck height is .019 with stock flat-top pistons, minus my .005 cut and a .047 Nismo head gasket puts me at .022 head to piston clearance. From what I read, my machinist nailed it, by luck maybe, not sure. The reason for all this search was more for finding the max cam for flat-tops and still have valve clearance. I know that measuring actual clearance is prudent, but I was looking for ballpark examples. After jumping from one link to another in different threads I found the ideal piston/head clearance and this post 1 fast z HybridZ Supporter Group:Donating Members Posts:1119 Joined:02-December 04 LocationPhoenix, Arizona Posted 25 July 2007 - 06:02 PM Ill ad some imput on piston valve relifes. I run a .585, 286 duration cam, on my NA car, with shaved P90, yada, yada. I measured piston to valve clearence on my last install, which was with a 270, 280 duration .475 lift cam, and had .215" EX valve clearnce, and .115" intake. I had then installed the BIG .585 cam about a year later and had .120" on the EX, and .050" on the intake, and have run it this way for about 5 months now. 8000RPM plus and no tapping. I do run titanium retainers, light valves, etc. Just some imput. This is on a DIRECT flat top, NO dish, and .022" piston to head clearnce also. bandmzcars.com This pretty exciting info for me because I want to move up from my "wussie cam", as Jon calls it, to something that takes advantage of my triples. Not saying this is the definite answer, but it shows you there is a wealth of info in this threads if you pursue it. Love to hear from others that have run a BIG cam with there flat-tops with no reliefs.

Wow, this is getting crazy. I wonder if I am chasing my tail here thinking I have several issues when one might be causing all. If anyone remembers I brought this up before and Tony said he thought it was the mount under the tailshaft of the tranny. There was definite play in the mount and I thought I compromised it(the rubber) when modifying(welding) my original tranny bracket. I made a steel cable strap to go over the tailshaft and moored the tranny against the mount. As I remember this just amplified the vibration and noise-but I passed that off as getting closer to having a solid mount. I loosened the cable thinking I made it to tight, which did lessen the severity of the vibration. Somewhere is all this I had changed diffs trying to chase a whine coming from there. Well the different ratio changed the rpm of the vibration. Confused yet I am. Well, let me review what I do know; Main driveshaft has been checked twice for balance and the angle of the dangle was checked by the same shop that specializes in driveshafts. I also had them check the halfshafts for balance. I have an RT mount that I made myself from instructions on this site.Now this might be an issue. I still get clunking when shifting at low rpm if I don't work the clutch just right. When I look under there I notice that my moustache bar is just about riding on my lower control arm down-brackets. It might actually be touching, it is hard to stick my head up in there to see. When I install my front diff RT mount, I have to shove the diff back to get my holes to line up in the chassis, but didn't think I was that close to the control arm brackets. When I remove the wheels and look at the alignment of my halfshafts to my diff, it is almost 90 degrees, but the diff is shoved back just a few degrees. The tires have also been checked, but ready to check again. Just replaced my moustache bushings with new stock rubber, and everythings tight. The rear bearing seems to be tight, and I went thru these when installing my Wildwoods. I followed Dave's instruction to the letter. . Soooooo,maybe my vibration is being carried thru the brackets because they are touching, because my RT mount is in the wrong place? The clunk is basically for the same reason, since the r-180 moustache bar is flexing under load it is hitting the brackets causing the clunk? Damn, I have a lot to figure out here. Also, haven't I read somewhere that the T-5's have issues with the output bearing? everything feels tight.

I'm listening to the advice here and I'm having a hard time visualizing the flywheel making my vibration. I took about a 100 mile trip the other day and did some more troubleshooting. My vibration is most noticable in 5th gear around 2700 to 3000rpm. When I shift down to 4th gear and try and duplicate around the same rpm, I can't even notice the vibration. Running thru the gears, I don't notice it either, probably because I am running thru the trouble rpm area to quickly. Revving the engine or holding the engine at rpm while in neutral I can't pick-up anything either. The other times I have noticed this same rythmic vibration is during decel under hard driving. The vibration will happen as the rpms come down thru the magic rpm zone. I have had this happen rarely( maybe I just don't drive that hard a lot), but I know for SURE, it was the same type of vibration. So why would this vibration be most prevelant in 5th-is this a clue?

fresh battery means new/never been used? I would check voltage at battery first, then possibly load test it. Grounds are tight-especially at the starter? Doesn't even click at the starter selanoid?

I have an e31 ad on classic z car and you can contact me thru PM

Have you wrapped your pump and outlet hose with heat wrap near your tank? Next time you take a long drive, jack the car up and feel around your tank and pump-you will be suprised how hot it is under there. Your diff puts out a ton of heat and bakes verything around it. Check all your rubber hoses because if they are too close to the diff and too old they will get soft under the heat. Also lay your hand on the gas tank, you would be suprised how hot it gets--almost scary! I noticed all this stuff when I was having issues with my daughter's ZX. In the end it turned out to be a partial blockage of my return line at the sending unit. I was just amazed how much heat was under there.

Leon , That needs to verified- but I think it does. I will double check. Just had the assembly out for a rear main seal fix and everything was tight and went back tight- with Loctite . Also replaced pilot bushing and yes 220mm. Clutch was new ACT unit I believe . Talked to my machinist and I am going to closely inspect my damper before tearing things apart