heinzboehmer's 2002 Topaz 6MT Coupe

[Obioban]

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

[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.

[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.

[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]

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]

But I got it out of the crank!

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.

[heinzboehmer]

Forgot to add clearance for the crank damper e torx bolt heads in the press cup bolt guide, duh. Fixed:



Also, this sucked:



But I got it out of the crank!

I ended up center punching the dowel and then very slowly drilling it out. This took absolutely forever, since I was being very careful to not damage the crank (I know it's hardened, but still).

I have absolutely no idea what I was thinking, but at one point I decided to hammer a torx bit in to try and spin the dowel. Of course, the tip of the hardened bit broke off inside the dowel as soon as I put any torque on it. Managed to fracture the stuck bit piece with a center punch and then fish/drill the chunks out with the drill bits. Extremely stupid of me, but I got the job done in the end.

I managed to do all of this without removing the radiator by using hex shank drill bits on my stubby impact driver. Drilling is not exactly what that tool is made for, but the dowel is fairly soft steel, so it didn't complain much. Made sure to give it 10s or so of full throttle spinning off the car every once in a while to make sure the electronics stayed cool. A bit more jerry-rigged than I like, but it did work. I should probably get myself a right angle drill...

Also, a motivational picture:



That's one of the damaged seals installed successfully (!) using the modified tool. At that point, I had not cleaned up the crank at all (as is obvious) and yet, the pre-damaged seal went in perfectly. Gives me hope that a new seal will go on smoothly as well. Will get to that soon.

[heinzboehmer]

Also, here's the design for the bolt guide that goes in the cup. This won't be taking any load, so can be printed with a low infill %

[heinzboehmer]

You can increase the end taper OD by .1-.2mm or something without having to create an overlap. That might be enough to get you over the transition.

Also, I don’t see a downside to a small file or sandpaper as long as it doesn’t reach the sealing surface as you pointed out. Good luck.

edit: also krytox on install can help.

Was installing with Krytox on the timing cover edge of the seal. Crank surface I was leaving dry as per the repair manual. Hopefully the increased OD of the tool helps out.

I don't have a good suggestion on your seal issue, but are you using a BMW seal?

Tried both Corteco and Genuine seals yesterday. They appear to be identical.

The bigger problem is your broken damper pin. Do you have a plan for that?

It looks like the crank adapter has some marring on it too. I would dremel that piece out of the crank. Then take some very very fine wet sandpaper on a solid piece of stock and knock down the high spots. Same with your damper if you can.

This is the replacement pin you want. They are sold in packs of 50 so I have a lifetime supply. If you want one (or 2) send me your address and I'll send some.

Yeaaah, it's been that way since I bought the car, so my plan was to ignore until I do the head gasket. The sprocket (11211401036) is surprisingly affordable, so I was planning on swapping it with the head/timing chain cover off.

I don't know why I didn't think of just buying a new pin, but really appreciate that link and your offer to send me some! Looks like McMaster delivers tomorrow, so that should work.

How do you get the broken pins out? Screw extractor? Very careful drilling/dremeling?

May want to use a +/- 45 deg biax? Carbon is an option as long as it is not being elongated.

Yeah that could work. Gonna start with the laser cut parts cause they're dead simple to make, but will consider carbon for a V2.

[George Hill]

This won't work. The lip would increase the OD past the limit of how much the seal can stretch:


Modified geometry in grey, cobra tool in blue. Outer edge of the highlighted red region is where the cobra tool ends.

I'm also starting to think that my crank is part of the problem. The outer edge has been slightly marred by previous mechanics, which is likely contributing to the seal catching. Terrible pic, but you can kinda see it here:



I'll take some super fine sandpaper and try to knock down any high spots, but I likely will only do a super light pass. I really don't want to scratch the sealing surface. Fortunately, I have all these failed seals I can install to use as protection for the crank.

Additionally, I'm planning on increasing the taper OD by 0.5 mm. Hopefully that helps gets the seal over the edge without it catching.

I don't have a good suggestion on your seal issue, but are you using a BMW seal?

The bigger problem is your broken damper pin. Do you have a plan for that?

It looks like the crank adapter has some marring on it too. I would dremel that piece out of the crank. Then take some very very fine wet sandpaper on a solid piece of stock and knock down the high spots. Same with your damper if you can.

This is the replacement pin you want. They are sold in packs of 50 so I have a lifetime supply. If you want one (or 2) send me your address and I'll send some.

[bigjae46]

Carbon might work! Part is gonna need to be strong both in tension and in compression. It'll be seeing loads from the E86 braces, as well as loads from the stock strut bar. Compression case for reference:

May want to use a +/- 45 deg biax? Carbon is an option as long as it is not being elongated.

[Bry5on]

You can increase the end taper OD by .1-.2mm or something without having to create an overlap. That might be enough to get you over the transition.

Also, I don’t see a downside to a small file or sandpaper as long as it doesn’t reach the sealing surface as you pointed out. Good luck.

edit: also krytox on install can help.

[heinzboehmer]

They are in the US. I had a homemade tool and your post inspired me to get the correct one. Got it in (2) days from my dealer.

Oh nice! When I checked, most online places said they would ship in July, so I assumed they had to come in from Germany.

I have yet to use my design, but it does bolt right up to the harmonic balancer.

What about carbon fiber? How would the part be loaded? Might be able to increase the strength by using a unidirectional layup.

Carbon might work! Part is gonna need to be strong both in tension and in compression. It'll be seeing loads from the E86 braces, as well as loads from the stock strut bar. Compression case for reference:

I think I'm gonna experiment with modifying the design of the press tool slightly. I plan on adding a lip to the part that bolts to the crank, so that the seal has nothing to catch on.

This won't work. The lip would increase the OD past the limit of how much the seal can stretch:


Modified geometry in grey, cobra tool in blue. Outer edge of the highlighted red region is where the cobra tool ends.

I'm also starting to think that my crank is part of the problem. The outer edge has been slightly marred by previous mechanics, which is likely contributing to the seal catching. Terrible pic, but you can kinda see it here:



I'll take some super fine sandpaper and try to knock down any high spots, but I likely will only do a super light pass. I really don't want to scratch the sealing surface. Fortunately, I have all these failed seals I can install to use as protection for the crank.

Additionally, I'm planning on increasing the taper OD by 0.5 mm. Hopefully that helps gets the seal over the edge without it catching.

[bigjae46]

Also, simulation seems to work out if I make these out of Titanium...

Potentially a future upgrade?

What about carbon fiber? How would the part be loaded? Might be able to increase the strength by using a unidirectional layup.

[George Hill]

Looks like there's no stock of them in the US, so at least the laser cut part will get to me sooner.

They are in the US. I had a homemade tool and your post inspired me to get the correct one. Got it in (2) days from my dealer.