Harmonic pulsation / Vibration?????????

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My 340 does the same thing. I traced it back to the water pump and fan through process of elimination. Mine would do it weather it was in park or going down the road.
I replaced the water pump and it got better. I took off the flex fan and put on a clutch fan. When I did that the pulsating vibe changed to a less more speratic vibe, but much less noticable. If I take off the fan completely the vibration goes away. So a quick easy test is take off the fan and put bolts in to hold the pulley on. This is if it vibrates in park .
 
Mine does it with stock cooling system and it still does it with the custom griffin and electric combo. belt only drives water pump and alt....no change whatsoever except quicker times and way more consistent cooling!

I'm gonna buy the Spintech's and have them installed without changing anything else before I tear it down for the turbo 318 build. It's worth it to me just to KNOW for sure if Dr Gas is right or just advertising hype.
 
I think when I return home, because I had some distributor issues, I am gonna check timing and timing mark movement if there is any, at 1700 rpm.. sitting in the garage.
I will also check how much vacuum it is pulling and how much vacuum advance it is bringing in at the same rpm..

Then I am going to see , on the road, what vacuum it is pulling at 1700 rpm..


If that tells me nothing, I think I may borrow the neighbors mufflers and see if there is any difference..

If I can get a cheap small remote camera set up.. It would be interesting to place it at various parts of the car... fan belt area, motor, front and rear u joints, to see what is going on, if anything is visible..

And finally , maybe a small explosive device...........nah.. I couldn't do it.

Anyone around Winnipeg whose car does the same thing??.. Would like to see if it's the same problem I have..

Ken
 
69B-Cuda said:
motor mounts... When I had my golf car shop, I had 2 main parts suppliers for a certain motor mount. They both looked identical but, one had a lot harder rubber, the thing would shake and vibrate something fierce... other vendor's mounts, no issues. After a couple golf cars like that, I only bought mounts from the one vendor! I"d go get a pair of regular black motor rubber mounts and try that.
Click to expand...

Talked to Schumacher by email... they said there rubber is soft compound and should isolate vibrations.. did not think it would be it ..
Ken
 
My vote. My E body did the same thing. Turns out they made 3 different
converters for that year and the first 2 I had were the wrong ones. The
third was the charm. Smoothed out beautifully and had twice the power.



ramcharger said:
Are you using a nuetrally balanced converter and harmonic damper?
Click to expand...
 
You can try changing mounts but I ran auto zone (anchor brand?), then I bought mopar oem's, no difference....ripped them in half too LOL
switched to solid mounts....slight increase in vibration overall, no change in the rythmic vibe.
A nice thing about the solid mounts with a solid cammed 340 and a 4speed is that it just rocks the power to the ground. That was pretty cool the first time I went through the gears with the solid mounts....it made the whole car jump on shifts.

Is there nobody on this board who has tried the SpinTechs?

I found some reviews....

http://www.tundrasolutions.com/foru...nstalled-a-spintech-sportsman-muffler-review/

http://www.thirdgen.org/techboard/exhaust/200617-spintech-3444xl-vs-flowmaster.html
 
mopar340dave said:
Mine does it with stock cooling system and it still does it with the custom griffin and electric combo. belt only drives water pump and alt....no change whatsoever except quicker times and way more consistent cooling!

I'm gonna buy the Spintech's and have them installed without changing anything else before I tear it down for the turbo 318 build. It's worth it to me just to KNOW for sure if Dr Gas is right or just advertising hype.
Click to expand...

When do you plan on doing the swap?

Interested to see if this cures it for you or not.

Thing is, my system is a magnaflow.....a major brand, complete kit, and popular.

If this kit was inducing a vibration, surely it would be all over the web by now.

I plan on checking the driveshaft balance.....also going to check my angles there as I recently lifted the rear end some with spring helpers (though I had the vibe long before that).
 
It seems there are always things we can improve upon over factory spec in the balance department for sure but I am convinced that it's the exhaust. What really hammered it home for me is a friend pointed out that it will do it at idle and becomes real obvious with the hood up because it makes the hood hinges rattle. It's slower than the rhythmic vibe you feel at cruise, but it's the same vibe. I'll have to see how it feels at idle AND at other rpm while sittin in the driveway.

As far as how soon...not very. Money is tight....it seems no matter how much i make it's never enough.....
Maybe in a couple months. I just spent way too much money on parts that are actually needed. Complete suspension for the Concorde w/police car rear sway bar, poly bushings, all new strut mounts, spring seats, struts, inner and outer tie rod ends/bushings, zinc plated drilled and slotted rotors all the way around w ceramic pads and cleaned and painted the calipers w/Duplicolor caliper ceramic paint in silver. The brakes look bitchin! LOL I still have to buy two new (front) tires and get it aligned.

Then there is the $200 drive belt for my Harley that I just purchased and have not installed yet......the list just goes on and on...if I have money, i have no time and of course....if i have time and the money.....who wants to work?!?! LOL

Seriously though...hopefully in the peak of heat i'll get to the muff swap! So maybe before July...
 
Well, not sure that the hood being up and vibrating tells much.....

It just says that there is movement.

Also, there are many things that can come together to cause a harmonic like we are talking about.....and various degrees of vibration.

To be very honest, I am skeptical that mufflers could cause the vibration/harmonic that *I* have.....but hey, I would be tickled pink if it were "just" that.....I feel mine is engine/drivetrain, simply because it changed majorly (in a good way) when I swapped out the rebuilt torque convertor provided by the first tranny shop I used for a performance stall convertor. Then, once again, it could be that it is several factors coming together and all I did was slightly alter the mix.....:angry7:

I guess the other way to go is let the vibration continue, live with it and see if something breaks...LOL

$200 drive belts are why I bought my Honda VTX1300 instead of a HD. I ride about 12k a year (every day commuting to work plus fun rides) and that is just one more expense I would need to deal with on a regular basis.
 
I am going to keep at this until I find something or something breaks..

Since I am in Calgary this week... Anyone in this area who has an early A that does or does not have this issue... Would be nice to see what another vehicle feels like to compare.


I am with you on not wanting to shell out for spin techs or any other exhaust changes unless I am positive it will resolve this...

Ken
 
Shadango, there is nothing wrong with my bike or my drive belt. There is something wrong with the asswipe at the dealer who adjusted the back wheel incorrectly, putting the belt in a slight torsional load. Thats all it takes to destroy one. They are normally good for the life of the bike.
As far as your VTX goes, enjoy. To each his own. I've been riding a long time and I am always amused when a former jap bike ownin harley bashin individual shows up to show off his new harley! LOL
The only times I've seen it the other way around it's for a crotch rocket and they still keep their harley!

PS the hood up gave the vibration attenuation that was slower but virtually identical to the sound goin down the road. You have to understand that sound is nothing more than vibration that our ears can hear. There are also plenty of sounds that we can't hear. The "sound" at idle was too low on the scale to hear, but the hood hinges lit it up like neon.
 
mopar340dave said:
It seems there are always things we can improve upon over factory spec in the balance department for sure but I am convinced that it's the exhaust. What really hammered it home for me is a friend pointed out that it will do it at idle and becomes real obvious with the hood up because it makes the hood hinges rattle. It's slower than the rhythmic vibe you feel at cruise, but it's the same vibe. I'll have to see how it feels at idle AND at other rpm while sittin in the driveway.

As far as how soon...not very. Money is tight....it seems no matter how much i make it's never enough.....
Maybe in a couple months. I just spent way too much money on parts that are actually needed. Complete suspension for the Concorde w/police car rear sway bar, poly bushings, all new strut mounts, spring seats, struts, inner and outer tie rod ends/bushings, zinc plated drilled and slotted rotors all the way around w ceramic pads and cleaned and painted the calipers w/Duplicolor caliper ceramic paint in silver. The brakes look bitchin! LOL I still have to buy two new (front) tires and get it aligned.

Then there is the $200 drive belt for my Harley that I just purchased and have not installed yet......the list just goes on and on...if I have money, i have no time and of course....if i have time and the money.....who wants to work?!?! LOL

Seriously though...hopefully in the peak of heat i'll get to the muff swap! So maybe before July...
Click to expand...

Is your exhaust mounted quite tight( with rubber hangars)? I know mine is and I wonder if that might contribute to this issue..
 
Mine is currently TTI headers into 2.5" pipe all the way back to the bumper with flowmaster 3 chambers. It is mounted very similar to stock.
I had Hooker super comps way back and got the TTI's about 8 years ago (same exhaust)....no change in vibe.

P.S. What i find really amusing about this is the guy at the shop that did the exhaust when I put the Super Comps on the solid cam 340 (open headers driving to the exhaust shop in SoCal! I put a piece of paper in my back window that said "driving to exhaust shop"....a cop was just about to stop me when he saw my little sign and my signal turning into the exhaust shop! LOL) told me it would drone when cruising. I was young, didn't care and really misunderstood him. I thought he meant it would be loud inside. It was/is! LOL It wasn't until about 2 years after installing that exhaust that I noticed this really heavy vibe at certain revs.....it was when I switched to night crew and could actually cruise home. In SoCal cruising is more like doing a lot of parking in between driving LOL...so I never put the two together...

He talks a good game, they are mos def different, the quality appears to top notch, the selection of stuff appears to be almost endless and they will build anything you want.
Like I said, initially I'm gonna drop $200 on a pair of muffs and just chop my flowmasters out and clamp these in. the car will get an all new exhaust for the turbo set-up.
It will be interesting, if nothing else.
The sound from the SpinTechs is unreal!
 
With some help from a couple of FABO members here in Winnipeg, I think we have this problem pinpointed..

Advanced the timing, changed when the vacuum advance comes in and there appears to be little of this Harmonic vibration I have been feeling left..

Bumped up initial timing about 8 more degrees

Vic (Ifitsgotwheels) and I think the marking on the harmonic balancer may not be totally accurate.. It started well with an indicated 33 initial, so it would appear something might be out of wack. Timing gun is showing 24 initial.

It seems the vacuum advance was just starting to come in in the 1500-1600 rpm range.. Adjusted the canister to bring the vacuum advance in earlier.

Because timing change has affected the vibration, next step will be confirming the rotor phasing..

Ken
 
Hey Ken,always nice to have a couple other Mopar fella,s around.Glad to hear your 1 step closer to enjoying a problem-free summer!:cheers:8)
 
Well when I checked the rotor phasing it was off.. Spark was firing when the rotor was about 1/4 to 1.3 of the way past the cap tower.. Changed the reluctor back to the original pin location..
reset the timing Checked it again, and now it's firing when the rotor to at the tower..
Seems to be nice and smooth, will test run tomorrow, If it doesn't snow again!!

Ken
 
Well it was a beautiful day in Winnipeg yesterday, buttttt .. When I started the car I saw an oil puddle.. Found out the right angle adapter appears to have backed off enough to spring an oil leak...

headers are in the way for a socket , so I got a 1 3/16 inch wrench today which I will cut short enough to get at the bolt..

Maybe I will test it tonight.....
 
ken5124 said:
Well when I checked the rotor phasing it was off.. Spark was firing when the rotor was about 1/4 to 1.3 of the way past the cap tower.. Changed the reluctor back to the original pin location..
reset the timing Checked it again, and now it's firing when the rotor to at the tower..
Seems to be nice and smooth, will test run tomorrow, If it doesn't snow again!!

Ken
Click to expand...

Can you go into more detail on what this is and how you checked this?

I dont think this is my issue, really, as I have actually swapped out my distributor once already....and unless BOTh were off..well, not likely...but I wouldnt mind checking this if it works for you.....
 
Ken! Where's the pics? LOL

I am also interested in exactly what you did, though I don't think that is my problem.
I'm thinking that a high 11 second car is most likely running correctly...but I could be wrong and I would like to check it.
 
shadango said:
Can you go into more detail on what this is and how you checked this?

I dont think this is my issue, really, as I have actually swapped out my distributor once already....and unless BOTh were off..well, not likely...but I wouldnt mind checking this if it works for you.....
Click to expand...

If you search rotor phasing there are several good articles.. MSd has instructions as well... I have a spare cap with a hole cut out between the # 1 plug tower and the center cap.. i painted a white line across the center of the rotor tip. Hook the timing light up to the # 1, and run the motor aiming the timing light at the hole.. The theory is the timing light will show you where the rotor is aligned at the time that plug wire fires..

Mine was originally showing the rotor already a distance past the tower when it fired, but I had previously adjusted the reluctor by using the opposite dowel pin location. When I put the dowel pin back into the original hole and put it back in the distributor, the rotor is now lining up with the tower when it is fired..


Sorry not good about getting pictures as I do stuff..

Unfortunately.. I still think I have some of that oscillation and am leaning toward the exhaust system as producing this harmonic... changing the timing to greater advance may have changed it a bit, but as many have said in this thread, it's still there..

BTW , my water pump spins freely and easily with no belt on.. gonna run it tonight without the belt and see if anything is different..

Ken
 
I've got a harmonic in my exhaust system that excites at exactly 2000 RPM and it manafests as a loud bussing when driving along in the car, and how do I know it's a harmonic. It goes away at anything lower than 1950 RPM and higher than 2050 RPM. The only way to change where a harmonic excites is to remove or add mass to in this case the exhaust system. This however will simply change it to the point that it excites at a different frequency/RPM. Dampening it out is usually the most effective, thick rubber pads in the middle of the hangers and sometimes changing where the exhaust pipes are supported helps or changing the number of hangers by deleting one or adding one.
 
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