So I'm trying to iron out the last issue from my motor swap and it is this:

After coming to a complete stop, when I take off again at a normal pace, there's a groaning sound that usually occurs for less than a second. If I had to guess, I'd say it's coming from around the transmission tunnel near my butt. This makes me think maybe the PPF or transmission is rubbing or something. I know when you bolt the PPF back up it's adjustable. Maybe I bolted it up wrong?

Things to note:

- When I changed the motor, I put on an oil pan brace. This raises the motor up a little on the stock motor mounts. Not sure if this is causing clearance issues anywhere.

- I also lowered the car (Eibach springs/Tokicos) and installed Tanabe sway bars with widefoot mounts at the same time. This does not sound/feel like a suspension related problem. I also used bushing grease and lubed the snot out of the bar bushings so it'd pivot without any binding.

- I reused the big nuts on the PPF even though the shop manual says you should use new ones. Anyone care to comment on why this is recommended?

Thanks!

 

A groaning noise comes from the air pump below 2500 or 3000 rpms if it is going bad. I dont know if you still have it or if you deleted it though.

 

Yea, this is definitely not the airpump. It is something binding or shifting or rubbing with the shift in loading of the weight of the car. It's one of those noises you can kind of feel through your seat.

 

Have you checked the driveshaft?

 

Hrm, I didn't remove the driveshaft when I changed the motor/trans. What in particular should I be looking for? Thanks!

 

Wasn't sure if you had removed the trans or driveshaft during the R&R. I'm out of ideas

 

Could it be bad motor mounts perhaps? Any other ideas?

 

So you dont have an airpump? You havent said clearly yet...

 

when you did the swap, you removed the transmission? Did you replace that pilot bearing inside? Have you inspected the transmission through the inspection hole? Do you feel any kind of vibration when the noise occurred? does it happen when you engaged the clutch(releasing the clutch pedal) or disengaging (depressing the clutch pedal)?

-AzEKnightz

 

I removed the trans with the motor. I replaced the pilot bearing and seal with new parts. It occurs when releasing the clutch in 1st gear from a stand-still only. There is no significant vibration but it is a noise you sort of "feel" as well as hear. It does not happen when disengaging the clutch or coming to a stop.

I do have an airpump that makes the usual mooing noises, etc. But this is not that.

 

Here's what I would do if you cant access to a lift. Jack up the rear wheels and put jack stands on them. Have a trusted friend try to duplicate the problem while you stay under the car and pinpoint the exact location of where the noise is coming from. Then you should be able to figure the problem easier rather than guessing.

-AzEKnightz

 

what kinda of clutch is in the car?

 

Clutch is stock Mazda. Brand new disc/PP/TOB/release fork when I did the motor.