EXCESSIVE Vibration after engine swap
 

So before I swapped out my engine, I got almost NO vibration through the car.

Now that my swap is done, i have a TON of vibration especially above 4500 RPM.

I added the following during the build that is different than before:
- IRP Engine Mounts (street version)
- Engine Torque Brace
- Hi-Flo Cat
- Diff Brace

I assume the vibration is coming from the mounts, but i keep reading how they are only "slightly" stiffer than stock. Maybe its everything combined (the cat resonates fairly loudly especially at high RPM).

Anyway - I wanted to gather some input on why the vibration is now SIGNIFICANTLY worse given what I've added. It really takes away from the driveability of the car.

Steve

The engine mounts will cause some

Sounds like the combination of new mounts causing additional vibration. It could also be the swapped engine was shady but let's hope it's the mounts :)

Out of curiosity, who did your rebuild?

Does the vibrating taper off in the higher RPM's? Such as, between 4500 and 6500 it's severe but then it's moderate above 6500?

Mazda did my rebuild :) Its a reman from Ray.

@Ledge - it does not taper off between 4500 & 6500 - it gets worse.

@AllRotor - if its the mounts, you wanna trade a set of stockers for my 60 mile old IRP mounts? :)

start by taking off your torque brace. its easy to remove and (my opinion) they are not really needed if you have a good set of motor mounts... if its the culprit, you won't miss it.

Also. If your mounts are poly, try loosening the bolts on them. They more you tighten them, the stiffer they get.

Good luck.

I will try removing the TB. The bolts are tightened to IRP's direction (barely flattening the red bushings). The only way to tighten them less would be to take them off!

I guess im gonna have to drop & swap various parts until it sorts out. :(

Some people say their poly mounts are not so bad. Those people are mostly 18 years old and dont care about comfort. Poly mounts will never ride like the stock mounts.

If you want to you're welcome to pop down to Alexandria this weekend. I have a pristine set of stockers that i was going to use on my new motor (putting it in this weekend). You're welcome to try them to isolate the issue.

At the very least that will be faster/cheaper than shipping stuff.

I have some good stock mounts that are like new you can have for 325 shipped.

If you aren't drag racing or road racing you don't need any of that junk.

Does it also vibrate during free revving?

That sounds like a good plan. Do you have the tools to help me swap them out? I have them in my garage but I can't bring all that with me.

Also - would you be interested in a trade for some new poly mounts?

Thanks Fritz but no thanks! Too much money given what i've spent on the rest of the build.

Adam - I don't expect them to but i didn't expect this much vibration. So many others have been pleased with the IRP mounts so I want to eliminate all the other things before swapping them out.

All we should really need is a jack and stands. Otherwise it can be done with a basic socket set and wrenches I believe.

I've got a jack and one set of stands, also have tools needed for a full rebuild here, so should jabbed it covered.

Honestly I'd prefer to use my stock mounts with this build (I went from bad stock mounts to polity mounts, to solid mounts. Now that i have good stock mounts I'd rather give them another go). It should still help you diagnose the source though :)

I just hope that your oil pan doesn't start leaking from it..

Well good thing I have that banzai brace.

PMming you now :)

Given what you've spent on the build motor mounts are not the place to cut corners ;)

Just giving you hard time and hopefully you and Levi can get it sorted out :icon_tup:

Stock or mazdacomp mounts are the only way to fly :nod:

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.

[QUOTE=XLR8;11315781
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[/QUOTE]

Do you mean the Driveshaft into the diff? If so, yes I noted the position of the nuts and believe I put them back on properly. I suppose I could try rotating the drive shaft around to find a smoother fit if thats the case.

Yep - new clutch (ACT Street/Strip) but OEM flywheel and same tranny. Clutch feels fine and works great so I doubt its a mating thing.

I'll try both of these as they are easy to remove before going any further as they are the easiest to do!

IRP mounts wont cause all that vibration ur refering to. i have their hard version and they work just fine..

Something is left loose i bet you... OR that engine brace you installed it causing it

Diff mounts ALSO will not cause any vibrations.. I used OEM, Aluminum and nylon and i dont see any difference

Check if the clutch is aligned properly.. gonna have to to remove the tranny first of course

Actually for the engine mounts i had a much harder mount (KSP ATTAIN SEMI RIGID MOUNTS) and there was zero vibrations

Feel free to PM or text me anytime you need help, big Steve..... or just call so I can hear your silky smooth voice :D

I doubt it's the mounts, as those speaking from personal experience have already mentioned. Personally I'd lose the Engine Torque Brace first, I had one way back in the day and promptly decided they are 100% unnecessary. My money is on that being the cause.

I'd also look at drivetrain components, to include examining the clutch through the inspection plate while someone free-revs the engine. Also, if you have a PFC, do the knock readings go haywire when this happens?

Rich - I was trying to hide this from you :) Im tired of bothering you for my stupid questions. It makes me feel like I should have brought the car to you to begin with! :icon_tup:

I'll remove the ETB then check out the clutch during rev, but what should I be looking for? And yes, I have a PFC. I'll check the knock readings and get back to you. What is the range that is good/bad or is it just variance from the baseline?

I had a similar problem after I've had my diff changed a while ago.

We looked at everything but couldn't find the culprit until the mechanic looked at the driveshaft where a little metal sheet (the balance weight) used to stick on the surface. It's really easy to ovelook as it's really small.

When he took off the driveshaft off he must have hitten something against it and it fell off. So we looked for a little piece of metal cut it into shape (you could see the shape of the original weight because it left outlines on the surface) and welded it on the driveshaft.

e voila there we had professionally balanced drifeshaft without any vibrations :)

^That's possible, but a driveshaft vibration will only show up when driving down the road and the driveshaft is spinning. If it vibrates like hell free-revving it, it's not the driveshaft.

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.

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

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

Have you removed the engine torque brace yet?

Very easy to do and may answer all your questions.

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 :icon_tup:

:icon_tup:`

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.

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.

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.

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? :)

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

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

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.

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

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

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

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

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

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:icon_tup:

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

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