The trampoline example is a good way of visualising a simple system but the harmonics that apply to a crank shaft are very complex. More like a swimming pool with waves of harmonics all interacting and bouncing off things. If you could slow down time and see the crank at full load you'd see it wobbling around like jelly with waves of displacement from each firing sequence moving up and down the crank, bouncing off the end and returning. The crank will also be twisting back and forth along the rotational axis changing the timing of various cylinders a little each way. Actually some of that movement goes into the timing belt and affects the timing of the valves etc. Whether or not the accessory and timing belts affect damping depends on how rigid vs elastic vs energy absorbent they are. They may even make the harmonics worse if they are elastic.

There is an awesome video of the early F1 v10 engines shifting on the dyno. They used to get this amazing warble sound as they changed gears which was caused from the crank flexing rotationally.

Holy shit thats a cool job

I've seen enough developmental engines pop due to crank damper failure or improperly spec'd dampers.
It's not like you're going to rev the tits off it driving to the Miata club meetings.
Have at it son. What do we know?

I think that I have done enough research and read enough advice from you guys to decide to go with using a damper and not fragging my engine. Thanks guys!
Now, the next question I have is going with ATI or Fluidampr? I've read from both sides who each swear by their life to their respected side. Do we have anyone here who has tried both of these dampeners?

I have experience with both. I used to resell the Supermiata/BHJ damper, but when that left the market I was stuck with suggesting the ATI to customers who were having me build them engines. So, while I have never sold an ATI, I have installed a few of them.

I am not a fan of the ATI for several reasons. Their QC is poor at best. Earlier this year they had to RMA several dozen dampers due to misaligned crank gear teeth, an issue which I brought to their attention. They apparently have had this same issue in the past as well, since I've seen at least one post from an ATI owner with a misaligned crank gear from a damper made in ~2015 IIRC. They also hold poor tolerances to the ID of the crank hub, so pressing them onto the crank nose ranges from "easy" to "impossible". Because they integrate the crank gear to the damper, you also have to install the timing belt at the same time, which is annoying, especially when you are trying to ensure that the damper isn't drawing the woodruff key up its keyway and jamming the whole thing together.

The Fluidampr is the newcomer to the market, and IMO it is the superior product. They do not integrate the crank gear, which means you can install and remove the damper without disturbing the timing belt, and it doesn't have any of the press-fit or other QC issues that the ATI has.

I only sell products which I like/use, and I only sell the Fluidampr.

Bumping this. Just saw another confirmed oil pump failure on the Trackable Miatas FB group from a guy using a TDR pulley. 500 miles and the oil pump let go.

If you are using a TDR pulley, have your car towed to a mechanic and reinstall the stock damper

...and probably replace the oil pump while you're at it.

--Ian

Wow, TDR needs to get their head screwed on straight and take that trash off the market.

Hanging my head in shame....

Gary from TDR found out about my misfortune and called me yesterday. I give him credit for the customer service part. He explained his opinions on dampers and how the pulley didn't cause the issue. I asked if he would back his claims up and warranty my next motor, after a little hesitation he said yes.

I'm too old to deal with pulling motors like this, going with the fluidampr and a 4 rib setup. Good luck to me for finding the right sized belt.

His 'warranty' ain't gonna mean shit if he's not willing to admit his product is to blame.

You'll be fine on finding a belt, they offer them in tons of different lengths, just measure the belt path with string or a longer, cut belt and order the appropriate length.

Opinions are great like that, aren't they?

I think I found the problem...
 

I finally had time to pull apart the engine that died at Summit Point while running the TDR crank pulley. I assume this isn't what the oil pump is supposed to look like.
There is quite a bit of metal flakes at the bottom of the pan and on the pickup screen.

https://cimg5.ibsrv.net/gimg/www.mia...7f05a6fa5d.jpg
https://cimg7.ibsrv.net/gimg/www.mia...fe9591516b.jpg

Merry Christmas to everyone here, and have a safe and Happy New Year,

Andddd that's why BE pumps are a thing and also why folks don't trust TDR.

Congratulations on your purchase, lol. That sucks.

There's going to be metal flakes in all of the block and crank passages, too.

It is not.

As Sixshooter said, plan on a full teardown. Tiny bits of that gear are now surrounding the lifters (if this were an NA, they'd also be inside the lifters), in between the main and rod bearings / journals, floating around in the various oil passages, and so on.

And, in all seriousness, thank you for posting evidence of why removing the crankshaft damper is a bad thing.

Alrighty then... I have two motors in the garage for rebuild. This one, which was unexpected although it only has about ~80,000 miles on it, and one with about 143,000 miles but no big issues. Should I just abandon the motor with the explodificated oil pump?

Thanks,

Yeah, it's hard to say in situations like this.

Maybe the cam & lifter bores are fine. Maybe they're not.

Based on experiance, it's a toss up. How much is your time worth, and what, if any, special parts are in this motor that you'd really like to reuse?

I would 100% use a new motor simply for peace of mind. It sucks to have to rebuild a motor right after you blow one because of something stupid. Been there done that.