EXCESSIVE Vibration after engine swap

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Dec 14, 2012 | 08:29 AM

#26

revsteve

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From: Rockville, MD

Quote:

Originally Posted by DaleClark

Is it possible the engine is out of balance? The rotors, front counterweight, and rear counterweight or stock flywheel make the balance assembly. If you had a wrong counterweight or the rotor's weight codes were too far apart you could have bad vibration.

Dale

Dale -

This would actually be the best possible scenario. The engine I got from Ray @ Malloy comes straight from Mazda. If its out of balance, I can swap it for a new one.

I'll spend some time getting a finer point on the problem this weekend and report back.

Thanks for the help so far - you've given me some good places to start.

Dec 14, 2012 | 08:44 AM

#27

RotaryOtakU

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I agree, if there is vibration when free-revving the engine, then most likely there is nothing wrong with the drivetrain.

Dec 14, 2012 | 09:02 AM

#28

DaleClark

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Also could be possible it's REALLY misfiring or something, like if you have the trailing plug wires backwards or something crazy. Or injector plugs backwards.

Dale

Dec 14, 2012 | 11:05 AM

#29

Fritz Flynn

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Have you removed the engine torque brace yet?

Very easy to do and may answer all your questions.

Dec 14, 2012 | 11:37 AM

#30

GoodfellaFD3S

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A brand new engine from Mazda is not likely to be out of balance.

Remove that ETB, and toss it in the recycling bin

Let us know what you find

Dec 14, 2012 | 12:41 PM

#31

mono4lamar

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Quote:

Originally Posted by GoodfellaFD3S

Remove that ETB, and toss it in the recycling bin

Dec 15, 2012 | 11:08 AM

#32

revsteve

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Etb gone. Slightly better but vibrates hard at free rev around 5500-6k rpm.

I'm thinking trans tunnel to engine mounting. Getting under the car now to check.

Other thoughts?

Dec 15, 2012 | 11:56 AM

#33

Fritz Flynn

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Quote:

Originally Posted by revsteve

Etb gone. Slightly better but vibrates hard at free rev around 5500-6k rpm.

I'm thinking trans tunnel to engine mounting. Getting under the car now to check.

Other thoughts?

Is the engine reman or NEW

Stock flywheel from factory or from reman/rebuild

After market LWFW

New oem/aftermarket clutch pressure plate or used clutch pressure plate

OEM under drive pulley or aftermarket

Based upon what you are describing it sounds as though something is out of balance on the rotating assembly of the motor worst case it's in the motor itself.

I suppose it is possible the brace could cause a vibration while free revving but I'd think it would be more of a rattle not a shaking and you could diagnose it quickly.

Dec 15, 2012 | 01:21 PM

#34

revsteve

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Oem fly came with reman. Oem everything.

Vibration seems To have died down. I'm thinking it maybe the resonating from the mid pipe. Gonna switch it out for the stock cat and go from there.

Dec 15, 2012 | 01:53 PM

#35

MR_Rick

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IMO it is a combination of all the added braces and stiffer engine mount. I hated my diff brace. I couldn't have a nice conversation in the car with it. Got rid of it the minute I came back from the test drive.

Dec 16, 2012 | 12:01 PM

#36

revsteve

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Ok update time.

Same symptoms when free-revving and in gear. Not noticeable between 1000-4000 RPM. 4000+ it gets worse and worse until there is a noise under both doors from high frequency vibration.

ETB Gone - no change.
Hi-Flo Cat Gone - no change
Diff Brace gone - No change

Looked at Trans and it looks right. Inspected the spin of the pressure plate/clutch, and it looked perfectly circular.

Last thing is the engine mounts (at least that I can think of) or the engine itself. If its the engine...

Rich - you got time to work on my car?

Dec 16, 2012 | 12:27 PM

#37

silverTRD

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how could it be the braces stiffening the drivetrain if it has the symptom free reving?

Dec 19, 2012 | 12:06 PM

#38

Tom93R1

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I would get out the timing light and check all 4 plug wires.

Dec 19, 2012 | 01:19 PM

#39

cewrx7r1

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My first diff bushings were delrin which is very hard and it made the whole rear vibrate at a high frequency. After replacing them with polyurethane the vibrations greatly reduce but were still there. I added Dynamat to the hatch area and sprayed the underside of all the plastic with sound deadening material. Now it is more of a low rumble sound than a vibration.

Dec 19, 2012 | 01:22 PM

#40

revsteve

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I did replace my OEM diff cradle with one with Derlin bushings. However, i get the vibration free-revving. Unless its just passive vibration coming down from the engine, through the trans, down the PPF, into the diff....

Ill check my plug wires when I get home and start there. If thats not it, maybe I'll mess w/ the diff to see if thats where the vibration is coming through.

Steve

Dec 19, 2012 | 01:24 PM

#41

RotaryEvolution

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remove the drive belts and try it again. just free rev it for a minute, don't drive it obviously.

Dec 19, 2012 | 01:25 PM

#42

revsteve

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Drive belts, diff, spark plugs... check.

Hopefully i'll get a chance to tinker this weekend.

Dec 20, 2012 | 02:33 AM

#43

jantore

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Just my 2 cents.

I had the same excact problem with a freinds engine. Was rebuilt by someone not to good im afraid

The flywheel nut was not properly torqued down so the flywheel was just abit off, and ratteling abit causing a bad vibration in the flywheel. Was smooth untill about 3000 rpm and then it would get worse and worse.

Also seen the same problem if the front asembly is out of alignment. Should not be that on a Reman. But it could be a bad engine.

Also when freereving the only thing spinning is the engine and the input shaft to the trans.

How bad is it? Could you post a video? So that we can hear the noise of the engine? Sounds to me like something is loose on the engine causing the vibration. Or the engine is not balanced at all.

JT

Dec 20, 2012 | 03:06 AM

#44

Bubble Tech

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Quote:

Originally Posted by XLR8

I second this question...

I have the IRP "race" mounts or harder durameter of the two options. I feel barely any vibration, in fact, my car drives and rides quite smooth.

The culprit could be a few things.

1. When you re-attached the PPF, did you make note of the placement of the nuts? I have heard of excessive vibration being caused from binding the PPF causing the tranny to arc more which in turn causes excessive vibration from the driveshaft

2. Did you change the clutch, flywheel, or tranny during the swap? If something isn't mated correctly or tight, it could cause this.

3. I would remove the torque brace and the diff mount first. You said EXCESSIVE vibration which seems unnatural caused by a common mod like poly engine mounts. However, all 3 combined just might cause this. If I had to keep one, it would be the engine mounts. The others help, but poly engine mounts are a very common mod and likely the most beneficial for stability.

First off i stopped reading after the first page, ignore this is any is a repost... lol.
but the whole time i was thinking the same thing as XLR8 posted.. I would double check the PPF. my bolts rattled loose a bit and some annoying vibration (i thought i broke the PPF)

I highly doubt its the motor mounts. I have IRP "race"? or the hardest ones they make.... my engine doenst vibrate.....

also has the car been tuned? i know when i first put my motor in, when the idle was off it cause a lot of vibration.. (idk if its relevant but its a HBP)

just my .02 and im am by no means a mechanic so take it for what its worth

Dec 30, 2012 | 11:28 AM

#45

johnmo

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Did you manage to solve your vibration, I have similar issues, but from idle get bad at 2500 rpm

Dec 30, 2012 | 12:26 PM

#46

revsteve

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Nope. I took it to IRP.

They seem to think its the placement of the PPF. Apparently if it is not adjusted properly it can cause vibration.

Try loosening it and make sure it is not touching anything it shouldn't be. Then tighten it back up!

Steve