Flexplate noise opinions

[TT_99Cobra]

Hoping I can get some new ears on this noise to send me in another direction. My Cobra is TH400 swapped and has been making this noise for 2 years. It has a new SFI flexplate and new ARP hardware for both flexplate to crank and converter to flexplate. This noise has been the same the whole time no matter what I do. I even put a new starter on it thinking that was the issue. Noise goes away once you get above 1500rpm.

My thinking is since the converter to flexplate connection is a nut/bolt setup, I’m unable to get enough clamping force and the two are moving ever so slightly at idle since the mounting holes are slightly larger than the bolts (by design). Think this is possible?

Any thoughts or opinions are appreciated!

TH400 Noise

 

[P49Y-CY]

does your midpipe have catalytic converters?

 

[P49Y-CY]

reason i ask that is i am currently dealing with a noise on my f150 that i could have sworn was drivetrain related, but it is a loose honeycomb inside the cat.

the noise matches engine rpm exactly, goes away on wot, etc.

 

[TT_99Cobra]

reason i ask that is i am currently dealing with a noise on my f150 that i could have sworn was drivetrain related, but it is a loose honeycomb inside the cat.

the noise matches engine rpm exactly, goes away on wot, etc.

No, exhaust goes from the turbos straight to a Bassani cat-back with nothing in between.

 

[01yellercobra]

If anything is actually moving around there will be witness marks or scrapes on it. Any kind of contact will leave marks. Until it self clearances and then it'll be quiet.

Is there enough room to unbolt the torque converter, slide it back, and then start the engine to see if the noise goes away? My guess is you need to figure out if the noise is coming from the engine or trans and go from there. How loose is the converter than you're running?

 

[Badaz01]

I have the same thing on my t56 swap. My pressure plate actually has evenly spaced dashes or wear marks on it as well around the outer edge. Other than that. Zero issues and the car runs like a scalded dog.

 

[01yellercobra]

Nothing should be making any contact inside the bellhousing. I swapped a T-56 into my 01 and didn't have any noises.

Something I'm curious about is if the converter is just making noise because it's a high stall speed. When you get the RPM up the pressure builds inside and everything lines up correctly. I've never messed with a high stall converter so I don't know if that's even possible.

 

[TT_99Cobra]

Nothing should be making any contact inside the bellhousing. I swapped a T-56 into my 01 and didn't have any noises.

Something I'm curious about is if the converter is just making noise because it's a high stall speed. When you get the RPM up the pressure builds inside and everything lines up correctly. I've never messed with a high stall converter so I don't know if that's even possible.

I’m thinking it may actually be something with the downpipes. I opened the cutouts and now I’m not hearing the noise. It may be because it’s just too loud now to hear it. Here is a clip for another set of ears to hear.

Open exhaust