Too much vibe with Solid engine mounts?

Deep6

Registered User
Folks,

recently with all my trials and tribulations, I upgraded to Solid engine mounts, Solid trans mount and POly Diff mounts.

I'm pretty happy with everything, execpt, my engine really shakes at idle. Before the solid engine mounts, it would just ROCK, it kinda felt like I had a mild cam in the engine. Now it just feels really "Nervous", I can see the passenger seat moving side to side too.

When I did the mounts, I hose clamped a section of heater hose to the braket where the mounting tab would apply pressure in the eyelet. Do you know what I'm talking about? Perhaps I should remove that? It might be restricting movement...

Maybe, I've got some other engine vibe problem... like my harmonic balancer...

Also, since I've hollowed my cats out, I notice when I start my car, I get a nice puff of gray smoke that sort of smells oily when I first start the car cold... Is that normal?
 
That vibration is normal after installing solid motor mounts. Eventually you get used to it or they settle. You might add some rubber washers between the seat frame and the floorboard. Or pick-up a lady, she might enjoy the ride. :D
 
An increase in vibration? Yes.
Visible shaking of the engine? Not really. Other than the vibration does it seem to idle smoothly?
 
thats odd..i was told solid mounts would increase rattling of the motor and vibration but it acutually took it away! before, with my split mounts the engine would rattle, door pannels would vibe during idle and warm up in teh driveway......after the mounts it was absolutely gone. the car wouldn't even shake when i turned the motor over or anything......soooooo quiet now, could be a bad install or somehtinmg? i got mine off of supercoupeperformance.com, and got a local ford SVT dealer to install them for me.
 
ben04 said:
thats odd..i was told solid mounts would increase rattling of the motor and vibration but it acutually took it away! before, with my split mounts the engine would rattle, door pannels would vibe during idle and warm up in teh driveway......after the mounts it was absolutely gone. the car wouldn't even shake when i turned the motor over or anything......soooooo quiet now,

Yup, same here. No Vibration. I'm not sure what problems you guys with vibrations are having. The two cars that I have done them on idled and ran smooth as glass. :confused:
 
The stock mounts are fluid dampened. This was done to reduce the frequency of the vibration that are inherent to the design of a v-6 motor not resolved by other methods within the engine.

When you change to solid mounts, a sensitive person should notice more vibration due this. But many people don't because they have never driven an SC with fluid filled mounts in one piece. A failed fluid filled mount will cause a feel exactly like a solid rubber mount.
 
Mike8675309 said:
The stock mounts are fluid dampened. This was done to reduce the frequency of the vibration that are inherent to the design of a v-6 motor not resolved by other methods within the engine.

When you change to solid mounts, a sensitive person should notice more vibration due this. But many people don't because they have never driven an SC with fluid filled mounts in one piece. A failed fluid filled mount will cause a feel exactly like a solid rubber mount.

I think we all understand that a engine will vibrate regardless of what type of mounts are in place, but Deep6 is saying that it is so bad he can see his passenger seat moving. :eek: That is not normal with fluid or solids.

A failed fluid filled mount will cause a feel exactly like a solid rubber mount.

Mike, you're starting to freak me out! :confused:
 
A failed fluid filled mount will cause a feel exactly like a solid rubber mount.
That is absolutely untrue. A properly running engine will not show a significant increase in vibration (meaning not enough to be detectable to the driver to cause any unpleasantness). When the fluid mounts fail, the oil pan typically sits on the K member and powersteering lines and its all shake rattle and roll throughout the car. I know, my fiance's 97 3.8 has that problem right now. Joe, the vibration increase you are experiencing is being caused by other problems you have not located yet to address. I would check that the heater hose you installed does not have the clamp rubbing the mount as well as inspect the outer trans crossmember mounts as starting points.

Paul
 
BT Motorsports said:
That is absolutely untrue.

Nice guy. :( It's not just untrue, but it's absolutely untrue?

Well I know because that is what happened on my 1989. On my 1989 the oil pan did not come into contact with anything with a failed driver side motor mount. But I guess I must have been seeing things since only your experience can be a true one.

I won't bother to comment any further.
 
On my 1989 the oil pan did not come into contact with anything with a failed driver side motor mount.
It is statements like this which would cause one to question your experience. Understand, in the context of that sentence, experience meaning that particular occurance not inclusive of all failed motor mounts. Bearing that in mind, I at no time stated or implied that you had to have noted contact between the oil pan and other components causing the vibration.
At no time did I limit the cause to just the oil pan, I used it as a typical occurance. I do not feel I need to list every possiblity as the reader has the resource of the search function available to them to acheive such knowledge.
No one is trying to bicker with you, but it seems you are sharing the experience of one occurance where I am reporting back that of several (in excess of 15 individual instances I personally observed and was involved in, 6 of which were my personal cars). Having sold well over 200 pairs of solid motor mounts over the years and assisting customers who relayed their experience with the product to be similiar to that which you have posted, I believe my posting of my overall knowledge of the issue to be acceptable. In every single one of them, the excess of vibration after the solid mount install took place was diagnosed and repaired by correcting problems beyond the solid mounts.

I do not know why it is, but lately more and more people seem to have an interest in taking statements on this BBS (not just mine) out of context and forget how impersonal reading a few sentences or paragraphs really is. As I have told others before, if I have a problem with you or something you have said, I will certainly address it to you and make it unquestionable as to whether or not I feel a certain way. Since a large part of the BBS purpose is to learn, a discussion of the issue and/or experience(s) would seem much more logical than taking things as a personal slam.

Paul
 
Mike8675309 said:
A failed fluid filled mount will cause a feel exactly like a solid rubber mount.

Actualy I think that I will have to agree with Mike8675309 from my own personal experiences. About a month ago I replaced my stock mounts with solid rubber ones from SCP. My stock mounts both came out in two pieces. Now after putting in the new mounts it still has the same shake and feels the same, except for when I punch it the shifter doesn't fly to the passenger compartment. I know all the bolts are properly torqued down so there isn't much else to look at. The motor idles fine, but has a start up problem some of the time which I think plug wires will fix.

I dont really mind the little shake, I just tell people if they ask, that it is my race car and it is suposed to do that. It has power.

I guess I will be putting this theory to the test very soon as my 91 SC needs mounts also. I will be putting in a set of solid rubber ones for SCP in it too.

Shane
 
A clarification here for people.

There is an inherent vibration in the design of 3.8 V-6. When I say that the failed liquid mounts act like solid mounts in their ability to dampen vibration I'm considering all other items equal, and at idle. I.E. if the oil pan is touching the k-member with busted mounts, well then vibration is likely more severe on such a vehicle with failed mounts.

At other RPM's or at road speed other things come into play regarding failed mounts including the movement of the engine within the failed mounts.

Thus the point of my intial comment was to account for the impresson of some SC owners that solid mounts transmit no more vibration than the liquid filled mounts. If the liquid filled mounts are working properly, they should dampen vibration that the solid mounts would pass into the chassis.

Of course the vibration I'm talking about is the normal vibration developed by the engine when operating properly. If the engine isn't running properly you may have other vibrations that are of a greater frequency than even the liquid filled mounts can dampen.

For Deep6's issue, it would appear that he has some other problem with the engine that is causing a considerable vibration. He likely saw rocking in the past due to the disconnect between the upper portion and lower portion of the failed fluid mounts. This would allow the engine to show the vibration at a lower frequency as the failed mount allows greater range of movement in the engine. With the new mounts, the engine is restrained and thus is moving back and forth faster. I wouldn't discount a possible misfire leading to the vibration on Deep6's vehicle.

That's the working theory I visualize.
 
Joe,

My car had excessive vibration shortly before I found out the crank bolt had sheared off. Sounds similar to what youre describing, at times I could see the shifter visibly shaking quite a bit. I would check out the dampener, might be a better idea to get it fixed now while the bolt is still in one piece.

Good luck with it, I sure hope its something less serious. We missed you at Carlisle this year.

-Travis
 
Ok that is what I thought...

Mike8675309: At Carlisle 2003 I had the oppurtunity to sit in a fellow SC'er's 1989 SC with Solid engine mounts. I asked him if he had done any other mods to the engine and he really didn't. Just an exhaust system.

His engine was idling and was a 5-speed. I sat in it and I could barely detect that the engine was running. The 5-speed had a small vibe to it that was about it. When I tapped the gas pedal, the engine zinged right up like it should and I didn't feel any abnormal vibe coming from it.

My car with Liquid mounts HAS ALWAYS felt like it has a mild cam in it. If you would open the hood at HOT idle, the engine would be rocking side to side about an 1" or 2". You could definatly feel it from the drivers seat. Everyone that I spoke to told me not to worry about it and it was normal. But compared to other people's SC's that I've ridden around in, I can tell that my engine should be alot smoother.

Recently I've been experiencing significant vibe at highway speeds. I thought this was due to my 17" rims but I've had them balanced 3 times this year. The recommendation to me was to see if I could replace the powertrain mounts to try and isolate the vibe. The vibe remains on the highway, but now I'm getting this very nervous idle.

Paul: I'm starting to think of other problems, Such as Harmonic balancer, PLugs/wires, poor firing injector etc. I spoke with my SC mechanic about this since it's had me stumped for quite some time, he took a look at it and wasn't too worried. He claimed that actually our SC engines were supposed to have a lenghtly beaking in period that most owners didn't observe. Instead they romped on it and it caused the cam not to take a proper set. According to him. That is what explains the lumpiness at idle. Paul, have you ever had customers say that upgrading to a BHJ balancer smoothed their idle?

Tbone95: Wish I could have made it to carlisle, my SC decided that it would clog it's cats up and I couldn't drive it. Now I've hollowed them out cause that was alot cheaper than getting a new exahust, but I've still spent a significant amount of money between getting raped at a dealer and having it flatbedded to my mechanic. I'll try my damdest next year. Of course if there is anything local (such as our mini-albany meet) coming up this summer, let me know, and I'll try real hard to make it out.
 
I would be concerned with that kind of vibration. If at idle it rocks the engine, then imagine what it does at 5200rpm?

Does the engine sound smooth otherwise? No misfire?

If so, then I'd be wondering about the balance of parts bolted to it. I don't think the harmonic balancer has a large enough diameter to create the rocking motion at idle. I guess I would look at something bigger like the flywheel. Something bolted to the back of the crankshaft.

I'd start with trying to determine the frequency of the vibration in relation to crankshaft rotation. Does it match everying One rotation, ever 3rd rotation. Things like that. Then you can focus on what spins that fast.

It's always possible that the cam is involved. But I'm not sure what break in would have to do with that. But then it shouldn't create a vibration at higher RPM's.
 
back in tha day

Back when I was coming up, I saw several cars that had been hotrodded, but they didn't put in solid motor mounts. There was a terrible twist of the motor on acceleration and a loss horse power and torque to the wheels. I'm talking old Mustangs, Camaros, Chevelles and such.

To compensate for this, they would attach a strong chain to the block and connect the other end to the frame. Thus taking the movement of twist out of it on throttle. Having not done the mounts when I did the head gaskets, as I've heard this was the best time to do it, I've done the same thing with a chain and I can honestly feel some vibration that was not noticeable before.

It's not uncomfortable and the seats don't shake, but you can feel a difference. I think this would be really similar to the solid mounts you are talking about. It was different the first few days, but I'm used to it now and hardly notice it.

Just my .03 worth.

David
 
Well how's this for you...

At around 58,000miles I had my flywheel replaced with a brand new one from ford. This was along with a centerforce clutch. The ROCKing that I experienced at 27,000miles when I purchased the car was the same as it ever was after the clutch/flywheel job. In fact, At 58,000miles I got a new Harmonic balancer out of the deal since the moment the mechanic backed the car out of the garage with the new clutch/flywheel combo, the original balancer broke right there in the shop. SO that got replaced too.

Again when I drove the car away, the engine rocking at idle was about the same. It's remained that way since, until now at 9x,xxx some-odd miles I decide to replace the stock mounts with the solid rubber ones.

So I'm pretty stuck on this. Like you pointed out, the solid rubber mounts only seem to have excaserbated the problem. I only really notice this at idle. When I'm driving at speed I really don't notice excessive vibe and before I did the engine mounts I noticed around 4000+ RPM the shifter would have a high pitched rattle to it. Now that I have done the solids, that rattle is gone.


I'm not really sure what direction I should take from here.
 
Before I jump back into this thread, let me begin with an apology to Mike. It was not my intent to jump down his throat and discount his experience or opinion as having no merit. Through discussion via PM, I can see from his view why he felt I did.

Back to the subject at hand. Joe, if I sat here typing for an hour, I could probably list 30+ potential contributions or primary causes to the problem you are experiencing. As Mike already mentioned, the 90* V6 has terrible harmonics by design. Add to this the fact that the factory does not balance rotating assemblies, they just slap together parts that fall within a tolerance and you have a recipe for an earthquake at times. It is quite possible that you got one of the engines with parts on the opposite end of the tolerance scale causing an internal imbalance. I have not heard anyone mention a smoother running car from a BHJ, I have often heard reports (in any engine not just an SC) that after having a rotating assembly balanced the engine ran smoother than ever before.
He claimed that actually our SC engines were supposed to have a lenghtly beaking in period that most owners didn't observe. Instead they romped on it and it caused the cam not to take a proper set.
I cannot agree with this at all. I am refering to the cam not taking a proper set. The break in is geared more to the piston rings than the cam and with a hydraulic roller cam, there really isnt anything to break in that would cause your symptoms to my knowledge. My suggestion is to begin a process of elimination. I mentioned your heater hose on the motor mount and the possiblity of the clamps (presuming you used clamps to hold it in place) rubbing the bracket(s) but you didnt reply back on this.
I get a nice puff of gray smoke that sort of smells oily when I first start the car cold
This has me a bit concerned. I don't believe oil passing through from the PCV would be left unburnt to this extent. Here is what I suggest as starting points that require more time than money:
  • Inspect your balancer for any visible signs of damage and notate if it appears to have any runout to the naked eye.
  • Pull each of the plugs, noting which cylinder it came from and inspect each carefully. If you do not know how to read a plug, get someone that does.
  • Find out what your trusted Ford tech charges to do a fuel injector flush. This is done while the car is running and can really help out with gummy injectors. I presume this is still your daily driver and you cannot put the car down to have the injectors thoroughly cleaned off the car?
  • While the plugs are out, do a compression test AND a leak down test on each of the cylinders. Make sure your battery is fully charged and I suggest even having a charger/starter attached to your battery during the compression test. Now would obviously be a great time to change plugs if they are due or show signs of need. What wires are you running on the car and how old? I suggest before pulling plugs you ohm the wires and make sure they fall within manufacturer's specs.
Mike makes some good points about sourcing the frequency and origin of the vibrations worth looking into which will certainly aid in diagnosis.
David, I believe you may be confusing what Joe is mentioning of solid mounts to be solid metal which they are not. Unlike the older cars and hotrods which often had solid mounts installed for performance reasons (to avoid delay of getting power transfered from the engine to the pavement) these solid mounts are solid rubber as opposed to the factory mounts which are hollow inside and contain a hydraulic fluid in that cavity to dampen vibration. The solid rubber mounts were used on many 3.8 engines that had a counterbalance shaft in the lifter valley to dampen vibration (ours do not have this). On a related note to the chain, watch out for knock retard. Introduction of new harmonics in the engine by solid coupling such as the chain, can cause the knock sensor to trigger. The grand national has this issue and many people run a nylon strap off the alternator bracket to postively locate the engine without getting KR from introduced harmonics.

Joe, report back to us with your findings ;)

Paul
 
Back
Top