hi ive been doing my research here on the possible culprit of what is causing this problem for my car. i just got a complete tii swap and i soon noticed that when i get the engine speed above 5.5k rpm's, i would get a rumbling sound from the engine or tranny area and the shifter would shake violently. this would happen with the clutch depressed or not. also happens in gear or in neutral. pretty much whenever the engine speed gets at or above that range. i am determined to get it fixed by a professional but would like to know if anyone would know what the problem is so i can buy the part and fix it one time than spending more and more money fixing things that dont fix this problem. ive already thought it may be a broken motor or tranny mount, out of balance flywheel or driveshaft, broken u joints or fan clutch. if its any of these please confirm with me or throw me your expert suggestions. you can also PM.

here are 2 links that i took a video of with my phone so you can see the problem that i am experiencing with commentary. please click. thanks and i hope i can get some good input to make my rx7 happy again the first time

part 1
http://www.youtube.com/watch?v=_w1CwZ2btxU

part 2
http://www.youtube.com/watch?v=yIAlclpvc2U

 

As you suggested, Have someone rev it up and see how bad the engine shakes. It seems like it only does it on decel (left off the gas) and you can see your shifter move to the side. It would be a easy diagnosis if you just had somone rev it while you watch whats going on

 

when the car is rev'd and i was looking from the engine bay i can see the motor moving a lil bit but i dont know how much is bad compared to an engine that has broken motor mounts

 

Could be out of balance flywheel or engine rotating assembly.was it doing this from day one of your swap.might also be a loose fan clutch,happened to me many years ago but my trans shifter wouldn't vibrate or shake that bad.if the engine was rebuilt was the rotors,front counterweigh,rear flywheel all matching by series.

 

i noticed this from day one of my swap. it was apparently rebuilt + streetported. i dont know the history or have papers/receipts of the rebuild. all i know is that it was rebuilt by RRR and the i saw the vid of it running and rev'd in the donor car and it looked good. i just dont understand that when it got in my car it got outta wack. but i will consider those options you suggested when i bring it in to my mechanic thanks dave hopefully its not too serious cuz i just spent a fortune on this swap

 

any one else got any bright ideas or suggestions?

 

If this started happening recently and the motor DID run smoothly before - look at replacing the water pump. I had this exact problem and after tearing through the whole car it ended up being trashed water pump bearings.

Take the belts off the water pump pulley and turn it by hand, it should be smooth and not 'bumpy'.

 

i actually have the same problem but only when i reach about 65mph @ 4krpm.. i just recently changed my motor mounts both left and right and the tranny mount are okay still.... but still after that was done it still has vibration similar to yours

im also thinking its could be the flywheel or u-joints but

 

hmm.. never thought of the water pump. thats something look out for and consider, thanks.

 

and yes i dont want to be spending money on parts that dont fix the problem

 

but also happens when the motor is stopped. the flywheel doesnt turn when the car is not moving. so it has to do with the engine or tranny area give or take. any other ideas?

 

Flywheel rotates at all times car stopped or not as long as your engine is running its spinning.have you tried reviving it up with the clutch petal pressed in to see if it changes anything.or like suggested above water pump bearing,just remove your waterpump belt and try revving it up to see if that is the cause.

 

cool thanks dave ill give it a try

 

if anyone else have any suggestions feel free. lets diagnose this problem. ill keep you all posted so we can get to the bottom of this

 

okay so im going to start replacing parts to try and fix the problem and hope it goes away. i will first start with buying and replacing the motor mounts, tranny mounts and upgrade the water pump. what do you guys think? if that doesnt work il get into the more expensive fixes like driveshaft and u joints. also ill have the fan clutch and flywheel looked at in the process. i hope i can get to the bottom of this and not have to spend to much money.

 

Don't just throw parts at it. Unless you need them anyway. It happens in neutral so it's from the flywheel forward. I would lean toward something with the flywheel. Is your swap an S4 or S5? What about parts used on the swap. Is it a stock flywheel?

 

its an s4 swap. i dont have any receipts on the parts used. but yes ill have the flywheel looked at first, thanks for the advice 1sweet7

 

but about it might being the flywheel, can anyone explain how this can be the problem because even in neutral and without the clutch engaged it will still rumble and vibrate at wot

 

Flywheel is bolted to eshaft.

Any imbalance in the rotating assembly (including flywheel) will cause vibration.

 

ahh ok thanks. ill look into that

 

Im going to say motor mounts. You can not visually inspect the motor mounts, they could be seperated but since the parts sit on each other, you could not tell from visually looking at them. Even if that was not it, at least you would have new motor mounts. The originals should be near garbage by now.

 

wait i just watched the video... so was this a fresh swap that was just done? when did you start experiencing these things? yeah something in the drivetrain isnt balanced

 

yeah its a fresh swap. after i drove it i noticed this problem and planned on bringing it back but they been too busy. so i right now i just take it easy on it 'till i can bring it in, but its been 4 weeks now. it just annoys me and i'm anxious to get this problem fixed

 

check your clutch fan. i had this problem a while back. take it off and see if it fixes it.

 

try aiming the video camera at the engine bay while you go to start and rev it, might show you something