joaquink

I had my poly motor mounts installed today. I just didn't want to
take the time for the job and it seemed like something very simple
for them to do and not mess up. Obviously they did, or I wouldn't be
posting.

So, I accelerate and all is wonderful. I take a hard left turn and
hear a really nasty double clunk from the front right/right-center
of the front end. And then it begins.

In straight line acceleration, everything feels/sounds/acts solid.
However, if I let off the gas while in gear (1,2,3,4 or 5), I hear a
nasty chattering sound from about the center of the car behind the
dash. If I push in the clutch the noise winds down quickly and then
disappears. When I let out the clutch, remaining in gear, the sound
is back until I get on the gas. As long as I am into the gas pedal
even the slightest bit, the sound isn't present.

It is no worse or better when cornering/turning though braking seems
to cause a moderate decrease in noise. Two times and two times only,
the sound was present while sitting at idle and in neutral.

Thoughts? Throw-out bearing? Could they have misaligned the engine
by some fraction? Torn up clutch? Anything they could have done to
completely fock with this? They'd only had the car 2 hours when they
called to say the mounts were done and I had all 4 done. I guess
that's long enough to do just about anything but what do you think?
I'm tryin' to get ready for the turbo but this is scary stuff.



Thanks,

JK

njmaxseltd

iTrader: (19)

Sounds like you may have tranny problems. I don't think it's an alignment issue, the trany is bolted very securely to the engine block. Perhaps the problem existed prior and now that you have the poly mounts, your hearing it!

joaquink

I thought about that but the sound is SO loud that I just can't accept
it's only an amplification of an existing sound. Anyhow, I dropped
the car off with the guy that did the Quaife, clutch and flywheel for
me. He's honest and dependable and said he'd help me pursue a claim
if it looks like it was or could have been caused by improper jacking
while the mounts were installed. Plus, he was nice enough to take it
in on no notice and said he'd be able to get through it today.

BTW, filling the motor mounts is a FANTASTIC modification. It really
feels solid when I get on the throttle and launches are much much
smoother. It's truly worth the effort, minus whatever problems were
added here.

njmaxseltd

iTrader: (19)

Sounds like a plan. Let us know what it turns out to be.

Good luck!

joaquink

It's my mainshaft rear bearing and differential side bearing that
were shot. I had Steve replace both of them and he let me out for
$500 including parts (included other bearings and speedo ring gear).

All was fine for the first drive home but then the noise started up
again. We discussed the problem while I was there and he said it
may be partially due to the Quaife adding torque and tension on
parts not designed to handle the added workload.

I'd be curious to know if anyone else with the Quaife has had these
problems. He's not blaming it on the Quaife with any certainty but
it is a possible source. BTW, this is the guy that worked with Brian
Catts on the prototypes and final specs for the Quaife so he knows of
what he speaks. He also works exclusively on manual transmissions
on Nissans and knows them inside and out. Please, no posts saying
he's full of BS. If you have knowledge or experience in this area and can offer something constructive I'd greatly appreciate it. I
have no doubt that he could have overlooked something or not taken it
back far enough after finding the bad bearings (I saw and spun them
myself - ick).

Everything is shimmed to within spec and I'll be taking it back to
him later this week. Other suggestions on what to look at here.
Keep in mind that the problem only originated after installing my
new poly-filled engine mounts. Any possible correlation?

Thanks all.

Cheers,

JK

njmaxseltd

iTrader: (19)

I'm no tranny expert but this tells me that your Quaife may not be installed correctly. I don't think load has anything to do with it. The only time it will see a strange load is when you turn and hit the gas hard. Straight line driving should load the bearings about the same as your old dif. did. The main shaft might be under to much preload from the Quaife causing the bearing to fail. The differential side bearings carry the load of the axels correct? They are the bearings that would see load on both sides, but there designed to see load even from your old differential. Either side can pull on your stock dif. The Quaife will make both pull at the same time, but the amount of force should be no greater, actually less if you think about it. 50/50 power ratio would put less load on each of the dif. bearings under hard accelleration. Stock you put almost 100% load on one bearing. Make sense?

I think you've got a preload problem somewhere. Either in the diff bearings, or the Quaife to the main shaft.

Again I'm no tranny expert, just trying to use common sense!

joaquink

Thanks for the reply. I'll make sure to bring up the pre-load issue.
I'm still wondering what it could be about the engine mounts or
something else that might cause this.

I had the Quaife installed with almost 60K miles on the car and it
was all fine for nearly 1000 miles. I did NOT have this issue until
I picked up the car with the new engine mounts installed. I'm almost
feeling like something has to be wrong there since the failure has
now occurred twice in just a span of 20 miles.

As I've never uninstalled or installed the mounts myself, is it even
possible for them to be either put in the wrong position or installed
upside down perhaps? The bolt patters seem to make that impossible
on some but very possible on at least one. However, I can't tell
well enough.

I'm just looking to exhaust all possible ideas here.

joaquink

Well the b!tch is back and we're out of ideas on this end.

Setup: Quaife ATBD, Fidanza flywheel (10-11lbs), SPEC clutch, poly-filled motor mounts.

What's been done: New bearings, shims to spec

Description of problem: Everything was fine until the new motor mounts were installed. These were brand new from Courtesy, I then filled them with the shore-A 80 poly from McCarren/Carr. Once they went in, this problem began.

Sitting at idle, everything is fine. Coasting in neutral, at any speed, everything is fine. Coasting with clutch pedal depressed, everything is fine. Accelerating, all is well except for an occasional chirping/tweeting sound (related to core problem I'm sure).

Now for the bad stuff: The sound is really hard to describe but it's analogous to a bad bearing, bent shaft maybe, or something similar causing two pieces to make contact that normally shouldn't/don't. It's more of a grind/rub sound than a hard clanking noise and it is definitely correlated to RPMs. The higher the RPMs the faster the rattle/grind sound independent of vehicle speed. So, when I can create the noise at 50MPH, it will be faster/more pronounced in 3rd than in 4th or 5th.

I consistently get the sound in reverse and when driving, off throttle and in gear. When the sound is there I can get rid of it a few ways;
1. depress accelerator ever so slightly to aggressively.
2. apply the slightest amount of braking.
3. depress the clutch and hold it down.
4. shift into neutral.

Any of the 4 methods above work equally well. Occassionally I can be driving and not hear the noise while being throttle-off and in gear (gear breaking). Generally though, the sound is there. I've made it happen at anywhere from ~10MPH up to 70MPH. I'm quite sure it's just as bad on the high side of 70 but I just haven't gone there.

WTF? How can this be correlated to the motor mounts? Steve, the mechanic who's been working on it, says that if he puts in older, non-filled motor mounts, the problem goes away. Do I have a wrong motor mount in there from Courtesy? I did not get a chance to drive it again with the older mounts installed and now my oldies are in Kevin Wong's hands.

I know that's long but I have to have some way of getting around this. Thus far, two expert mechanics haven't figured it out. I'll take any thoughts or suggestions.

Figures this would happen the week that my turbo setup finally arrived.

joaquink

Okay, I jacked up the front of the car, put it in 1st and no noise;
put itin reverse and no noise, drop the car and back out of the
garage - noise is there again. Jack it up again, put it in reverse
and 1st - no noise. So, now I'm wondering it is about either being
under heavier load or perhaps shaft angles when the wheels or loaded?

Can anyone make sense of these symptoms? I'm stumped!

njmaxseltd

iTrader: (19)

When your car is off the ground there is no load on the engine mounts. Well except for the engine weight. Once your on the ground and you accellerate, the mounts see a lot of force from the torque of the motor.

If I were you, I'd put the stock mounts in and see what it sounds like. Go from there.

joaquink

Thanks for the reply!

I've been trying that; one by one. At this point, the noise is still
present and I have only the passenger-side side mount to replace. I
have a feeling it won't go away at that point. The sound is a little
bit less pronounced with the three other mounts being back to stock
but it's still there; exactly as described before.

I should have the 4th mount swapped and tested sometime tomorrow. I
sure hope it gets rid of the jitters. I have over 7K in goodies
ready to go in that are on hold until this is resolved.

Again, thanks for the reply. I'm open to all ideas.

Joaquin

joaquink

All the stock mounts are back in place and I still have the same
f'in noise!

There has to be someone out there with an idea...

BriGuyMax

iTrader: (1)

This might be way out there...but check out the exhaust hanger between the y-pipe and the cat...mine was vibrating against the body of the car under deceleration...and it reverse...it sounded really weird though..I thought it was something with the trans at first. Just an idea

2ndGen@10psi

Try looking at ur A-Arm (control arm) bushings... mine went out on mine (even though mines an 2nd gen) car and it do the same thing u were describing

joaquink

Thanks for the input. I had checked this out a few times before and
it's all fine. I have a bit of a clearance issue at the rear of the
B-pipe (after the first bend) because the WSP Carsound Cat with their
welded on flanges is about 3/4" longer than stock. However, I made
that pretty quiet with some exhaust/header wrap.

This is interesting. I'll put it next on my list. Can I check this
visually or manually by just jacking up the car? I'd guess you're
talking about the bushing on the connections away from the wheel?
Anything in particular I should check for?

Thanks!

JK

joaquink

SOLVED!



It's the GDMF WSP Y,cat,b-pipe. The CarSound cat from WSP was about 3/4" longer than stock when it arrived with flanges welded on it. Since I was installing a full WSP exhaust (save the 2k2 SE muffler) I figured it would all work out anyway. Well, it lasted for a bit but finally gave from the additional stress being placed on the connection points. I haven't dropped the Y and cat yet but we figured it out when I was finally able to reproduce it in the garage by putting the car in reverse with the brakes on and loading the system by slipping the clutch. My neighbor pushed on the Y and the sound went away. He then put some force on the muffler and the sound went away. Went over to passenger side and pressed the flex section and the sound didn't quite disappear until he pressed harder. However, pressing directly on the cat or Y pipe sections (directly towards the driver side) fixes the sound as well.

I suggest asking WSP to either ensure the cat you get is the EXACT same length as the stocker or ask them to send it without welded flanges. I thought I'd bypassed all of the problems the longer one created by using exhaust/header wrap for the B-pipe. I'll post again after I do some FA to isolate the causing component.

Dammmmm it feels good to feel good about my car again. I'm guessing it's a trashed flex section or busted flange in there. My speculation is that the problem came about with the motor mounts because they eliminated the give that was in the system previously. That's a lot of force to exert on the motor I know but it may have also contributed to the failure of the passenger-side motor mount. Holy cow I feel like I have a new car again now that I know it's got nothing to do with the clutch/tranny/motor/bearings etc.

I LOVE MY MAX AGAIN! YEAH!!!

Time to go....TURBO!

Dave B

Dammit!!! I wish I would have seen this earlier because I would have said check your exhaust, especially your B-pipe on back and you could have saved some money. I've wrestled with the same problems before. I know the EXACT sound you were describing. Well, at least you know your tranny is in tip-top shape for the turbo now. One less thing to worry about.


Dave

BriGuyMax

iTrader: (1)

[patting self on back] Thanks BriGuyMax for the exhaust idea [/patting self on back]

congrats dude!

joaquink

Brian, thanks are in order. It was impossible to determine it was
the exhaust until it was under load. In fact, that stuff doesn't
seem to move around at all when the car is up on jack stands but then
again that just has to be changing the whole flex/dynamic of the car
when the front wheels are up. That's why it didn't yield results
last time I checked it out. Maybe I can make a recording of the sound for people's reference in the future.

Here's to hoping for a speedy Christmas.

BriGuyMax

iTrader: (1)

I hate the same type of problem....but it was becuase my cat exhaust hanger broke in half...and the exhaust was only hanging by one side....and rattling against the underside of the car when I was in reverse or decelerating. Since your problem seemed to be coming from the engine bay...which mine did too...it's probably your extra long exhuast pushing your cat hanger forward..and making it bang...good luck!