heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Nice work! I missed your question, I used a carbide bit in a dremel and ground into it enough to get an easy out and then spun it out. Last one I did was a racecar so I cheated and took the front end off.

Nice! I probably should have taken the front end off as well. Was too lazy to drain the coolant...

Do you see these broken frequently? I wonder what factors influence the failure.

[George Hill]

I've seen a handful. I guess its pretty common on track cars where engines live in high RPM with the harmonics and banging gears?

Who knows though, maybe its from people not retorquing the damper correctly or reusing the bolts. That would seem likely to happen more often on race cars than a street car I'd imagine.

All I know is it can't be good for the damper to be moving around (which it obviously is by the damage to the crank gear adapter).

[heinzboehmer]

All I know is it can't be good for the damper to be moving around (which it obviously is by the damage to the crank gear adapter).

Yeah, most definitely not ideal.

I'm pretty sure this seal was replaced prior to my ownership. Previous owner mentioned resealing some parts on the front of the engine in an effort to find an oil leak. Oil leak ended up not having anything to do with this seal, but fairly certain it was replaced due to the witness marks on the crank sprocket. Totally possible that whoever replaced it did not torque the bolts to spec or reused them (or both). Fun times.

[heinzboehmer]

First try!



...if you start counting after the second shipments of seals arrived, of course

Let's backtrack a bit to see how we got here.

Started by drilling out the dowel in the damper and cleaning up the mating surface. This is what it started out like:



Center punched the dowel and it started to move around, so I kinda just kept at it to free it up:



Did a bit of drilling and got it out fairly easily. After that, I hit all those super marred/galled (not entirely sure where that built up material is from, if I'm being honest) spots with a dremel and then went over everything with some wet 800 grit. I taped the sandpaper to a large socket to have somewhat of a flat reference for it:



Any imperfections that remain are below the mating surface, so they're staying. I did pull the harmonic balancer from my spare engine out of storage to see if I should just use that one instead. Turned out to be a bit rustier than I remember. It needs refinishing and I just have no desire to tackle that additional project right now, so sticking with the one above.

Next up, I ran the 800 grit around the edge of the crank sprocket to knock off any high spots from all the marring. I also taped some wet 800 grit to the handle of my crank holder tool (it's multiuse!) and used that to quickly skim the mating surface. The marks you see are all below the mating surface, so I decided not to risk getting a dremel near them and just left them alone. Less is more approach for this one:



I realize that these parts are in kinda terrible condition, but I just really don't want to take the engine apart any further. Car has 14X,000 mi on it, so the head gasket will likely need to be swapped soon. I plan on taking the timing chain cover off and swapping the sprocket then. Might refresh the spare harmonic balancer I have or just install a new one, we'll see.

Front main seal installed perfectly on the first try. It did start off a bit crooked, but a quick tap got it squared away. I wish all my previous install attempts had been as easy as this one!

Last bit of the puzzle was to get the dowel installed. I was able to tap it in most of the way, but the last couple mm required pressing. I installed the damper and finished pressing it in with that. To make sure that it was fully seated and both mating surfaces were making adequate contact, I (terribly) cut some clearance into a piece of paper and put everything together with the paper in between the damper and the crank:



Wiggled the paper around as I was tightening the bolts to check if the surfaces had mated or not. It caught as the bolts bottomed out and I wasn't able to wiggle it around any more, nice!



And finally, here's the "fixed" crank sprocket:



Happy to have gotten the hard parts out of the way. Now just need to get everything reassembled and take the car out for a spin. It's been out of commission for waaay too long.

[Obioban]

That looks unfun. Bet you're glad to have it out.

[bigjae46]

Happy to have gotten the hard parts out of the way. Now just need to get everything reassembled and take the car out for a spin. It's been out of commission for waaay too long.

I may have missed it but where there any symptoms of that dowel pin shearing off?

[heinzboehmer]

That looks unfun. Bet you're glad to have it out.

Yep no fun at all. Forearms are all cut up and bruised, but so glad to have finished the hard parts. Now it's just a matter of bolting the easy things back together and driving the car.

I may have missed it but where there any symptoms of that dowel pin shearing off?

Nope! Absolutely zero.

It's been sheared since before my ownership (so more than 7 years) and has done many, many trips to redline with no issues. Except for the horrible looking mating surfaces, of course.

Honestly, I can't believe I never thought of finding a replacement for the dowel and fixing it up the first time I found it like this.

Although, looking back through seven year old pictures, the sprocket looks about as bad as it did a couple days ago: