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Facime
02-04-2013, 10:47 PM
Im looking for a little bit of advice to hopefully narrow down the efforts to fix the vibration I have in the 90GTS I have.

The car has an engine related vibration that I suspect is the motor mounts, I just want to avoid going and changing them all out in some kind of fishing expedition repair. I suspect either the front of the rear (or both) even though I cant see anything visually that tells me they are bad.


The car has a constant vibration when running. At cold start high idle its pretty strong and quite annoying. Once the car warms up and idle drops all the way to its lowest point the vibration almost entirely disapates, until you give a blip of the throttle. Any RPM above idle starts the vibration again until rpms drop to full ilde again. Its very buzzy feeling, but not sounding. I woudnt charactorize the vibration as violent or harsh or metallic. Its not like a knock, and the motor sounds perfectly fine at all times and runs normal. Its got 139K on it.

I dont feel the vibration in the transmission or drivetrain. Speed doesnt affect it, nor does gear changes or clutch actuation. However, load DOES seem to affect it to some extent. Acceleration, either light or strong, reduces the vibration noticably, maybe even completely. Deceleration doesnt increase the vibration beyond what I get anywhere above idle. (doesnt make it stronger, just back to normal)

Ive looked at all the motor mounts and I cant see any tearing or rotting of the rubber material. Nothing looks bent or displaced or out of the ordinary.


So, beyond just speculation that either the front or back or both or all of the mounts are bad, does anyone have any experience with this problem that can offer at least a "best guess" to where to start?

4thgenceli
02-04-2013, 10:53 PM
Open the hood and start the motor. Hit the gas a couple times to see if the motor moves.

Car_Barn_Bandit
02-04-2013, 11:08 PM
Harmonic balancer worn out? How about that dampening block that hangs off the lower radiator mount. Are the bushings for the engine brace that runs from the radiator to the firewall shot?

I'd start with the big items like that. Exhaust is another big vibration item. I'm replacing mine and redoing the mounts for that as well. A vibrating hood could be another place. Start big and work small.

Facime
02-04-2013, 11:09 PM
Open the hood and start the motor. Hit the gas a couple times to see if the motor moves.

did that, yes it moves a little, no more than I would expect it to. Maybe an inch deflection of the intake manifold back towards the firewall. Seems about the same doing it under load (e-brake on, slipping the clutch a little, light throttle)



Harmonic balancer worn out?

That was indeed another idea that came to mind. I based that on the fact that at low idle I have almost no vibration at all. I will add however that the vibration isnt stronger at much higher RPM than it is just off idle. Its all about the same.


Are the bushings for the engine brace that runs from the radiator to the firewall shot?

the what now?

(5S 90 GTS by the way. forgot to mention this)

underscore
02-04-2013, 11:42 PM
^ I'm assuming he means the North South engine crossmember.

Car_Barn_Bandit
02-04-2013, 11:52 PM
^ I'm assuming he means the North South engine crossmember.

The member with 4 bushings that has two braces to prevent motor rotation. I imagine most, if not all of the vibrations on the engine and transmission find their way through a failure on this member under load.

KoreanJoey
02-05-2013, 12:03 AM
Yeah if the rubber bushings for the fore-aft crossmember are toast the engine will transmit a lot more vibration into the cabin.

Facime
02-05-2013, 02:14 AM
Ahah! now we're talking. I'll get under there and take the undercover off and take a look. Thanks for the idea!

KoreanJoey
02-05-2013, 07:27 AM
Should be rubber on either side of the crossmember with a metal centering ring between them. I can't remember if the centering ring stays on the top or the bottom part of the bushing.

underscore
02-05-2013, 06:52 PM
Facime your PMs are full.

Facime
02-05-2013, 09:18 PM
ahh, yes I dropped out of subscriber status a while back. I cleaned it out.

Facime
02-08-2013, 03:54 AM
so the bushings for the crossmember are fine. I removed the undercovers and the crossmember. The front motor mount was further gone that I initially thought. I ordered replacements for the front and rear.

I dont however think the new mounts are going to fix the issue. I started the car up with the motor just hanging from the left and right mounts and the motor still just feels buzzier than it should. The front damper looks ok and spins ok from what I can see. Im now suspecting that there is a balance issue most likely in the flywheel/clutch area. I dont see any indication that the motor or trans has been out of the car, but theres no telling for sure. The clutch is near endlife anyway (at the top of the pedal) so I know I will have to go in there sooner or later. Maybe a piece of the friction material has chucked off?

Im also leaking oil from the weep hole at the bottom of the timing cover with the engine running (cam seals is my guess), and I know it needs a timing belt done as well. might as well pull the motor and do it all at once...bleh!

KoreanJoey
02-08-2013, 08:20 AM
Where's it idle at? I might be a little low. Oh, and how are the plugs?

4thgenceli
02-08-2013, 03:15 PM
With all that weight just hanging on the side mounts most definitely you'll feel more vibrations.


Off topic, are those dampers really necessary?

89vertSE
02-08-2013, 06:52 PM
if your replacing front and back mounts, get the red poly ones from tworus, they work well with minimal vibration, cant even tell after a little bit of having them, plus cheaper then oem mounts

underscore
02-08-2013, 08:57 PM
I just went with the Kirkasaurus inserts, my mounts were pretty toasted until I put them in, I think a set was $50 or so.

celica9303
02-08-2013, 09:26 PM
I also have Kirk mount inserts waiting To go in.

4thgenceli
02-08-2013, 09:31 PM
I'm using the speedsource poly mounts on mine. Front has a damper, rear doesn't.

Facime
02-08-2013, 09:44 PM
Where's it idle at? I might be a little low. Oh, and how are the plugs?

Idle is fine, plugs are brand new, timing set. Motor sounds fine, revs fine, has normal power.

At full hot idle, in fact, the buzzing goes away. When you blip the throttle the vibration manifests and as the idle settles back down, right about as it crosses the 1.1 or 1K mark the vibration drops away. The sweet spot (or in this case, perhaps the sour spot) for the vibration seems to be around 2K. Thats where its most obnoxious. So of course on cold start/high idle its particularly bad.

Just to be clear, the vibrations Im feeling seem harmonic in nature, not exactly related to the engine RPM (dont become more obvious or violent as RPM increases), and dont seem altered in the least bit by the rest of the drivetrain


Im pretty convinced its in the rotating mass.


as for motor mounts I went cheap with some overstock on Rockauto and got both, shipped, for under $40

The Captain
02-08-2013, 10:08 PM
Time for a 3S!

Facime
02-08-2013, 10:46 PM
I bought this car cheap for my sister to drive. Shes got this POS S10 Blazer V6 4x4 and its eating her alive in gas. I just need this one to be safe and reliable for a year or two.


I took a chance on it because it was cheap enough but in the end I should have walked away. By the time Im done fixing it I could have had a nice low mile 6G or newer camry.

4thgenceli
02-08-2013, 11:08 PM
I bought this car cheap for my sister to drive. Shes got this POS S10 Blazer V6 4x4 and its eating her alive in gas. I just need this one to be safe and reliable for a year or two.


I took a chance on it because it was cheap enough but in the end I should have walked away. By the time Im done fixing it I could have had a nice low mile 6G or newer camry.

I'd take that S10 Blazer off her hands :)

Facime
02-08-2013, 11:14 PM
shes giving the blazer to her daughter. You wouldnt want it, Its got a buttload of miles.

4thgenceli
02-08-2013, 11:31 PM
shes giving the blazer to her daughter. You wouldnt want it, Its got a buttload of miles.

Like our Mazda doesn't? I have a thing for those suvs, especially the vortec motors.

Sent from my DROID BIONIC using Tapatalk 2

rizin
02-09-2013, 01:57 AM
On the timing belt cover weeping oil sometimes the rubber shaped gasket that seals the two halfs of the oil pump likes to crack and leak. On the vibration see if there is a crap load of stuff stuck in the lip of the harmonic balancer also.

Facime
02-09-2013, 02:28 AM
Balancer looks clean and straight, no dings in the belt grooves or anything. I watched it spin at idle and it looked smooth.

Im going to do a timing belt so I'll do the oil pump stuff at the same time, but thanks for the tip.

Facime
02-09-2013, 03:37 AM
Got the balancer off and it "appears" fine, dont see any good reason to replace it. Found my oil leak is indeed the cam seal. I'll order up a replacement, a timing set and a water pump.

pulled the inspection cover on the flywheel but that was a fail design (at least for manual trans cars) on toyotas part as you cant see shit besides the backside of the flywheel. I think I stuck having to drop the trans.

Ive got the axles out for replacement, the crossmembers off and the front half of the motor apart. At this point Im considering just pulling the motor/trans entirely as a unit to do the clutch and timing stuff. Would give me a chance to clean up some other stuff and detail the engine bay.

celica9303
02-10-2013, 03:46 AM
Good plan

Facime
02-19-2013, 10:44 PM
Update: still have this problem.


So I pulled the motor from the car, replaced the water pump, and all the seals up front (oil pump shaft, cam, crank), and installed new idler, tensinoer and timing belt. Since I took the pan off for the oil pump I looked inside. I didnt see anythig out of the ordinary. I did NOT pull any caps or look at the bearings, but again, I dont have a knock so I didnt expect anything. Inside was unremarkable otherwise.


Out back I resurfaced the flywheel, replaced the disk, pressure plate and TOB. Everything looked good, the trans input shaft had no play and no signs of leakage. The trans had ATF in it, but I changed it out for 75-90 synth blend. New output shaft seals and new CV axles on both sides.

I bolted it all back in with new front and read engine mounts. The left and right side mounts looked ok. The crossmember bushings were a bit hard but not damaged. nothing unusual to report on the exhaust, its stock back bast the secondary cat, and after that its got some kind of glasspack resonator. The rear muffler appears stock original.


After putting it all back together I still have the exact same vibration! GRRRRRRR!


I now wish I had just bought a NEW flywheel (not much more than resurfacing cost) to rule that out as a cause.


Does anyone have a spare Harmonic damper for super cheap they are willing to send me just to give that a try?

rizin
02-20-2013, 01:11 AM
I have two but I would think junkyard would be as cheap as shipping.

Facime
02-20-2013, 02:37 AM
yeah, but getting one off in a pick a part yard wouldnt be worth it. I could try a regular yard I suppose. I really just think its going to work so I really dont want to just throw money at it.