heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Shipping company has held the crank holder tool hostage for a few days, which means work on the front main seal is stalled. Supposedly delivers today, so should be able to wrap that up soon. I did go ahead and start disassembling and cleaning, but more on that later.

While I was waiting, I finished up the design for the strut bar brackets:



Orange piece is 4.75 mm thick 304 SS and grey piece is 3.18 mm thick 304 SS. I would have loved to try these out of aluminum, but unfortunately sendcutsend doesn't bend anything besides 5052, which is not gonna cut it.

I plan to weld the two parts together along the red lines:




No welds on the angled interface so as to avoid weakening the metal.

Clearances are stupid tight in that area, so I printed some prototypes for a final fit check:





Hell yeah, things are finally coming together! I'm really happy with how stock this all looks. Hardware isn't final, of course. I'll order studs of the correct length for the real part.

One thing I don't think I've mentioned is that this design requires camber plates where the studs can move independently of the top hat (e.g. Turner street plates). There is not enough space to slot neither the E86 brace ends nor the brackets, which means that the brackets are essentially constrained to one spot. The studs in the stock top hats would require the bracket to move along with them when setting camber, which is not possible with this design. It's an annoying limitation, but using the E86 braces wouldn't be possible otherwise.

I still need to modify the design slightly so that it's actually manufacturable, but no big deal. Just need to add some extensions so that the smaller flanges can be bent correctly.

I did also quickly run it through FEA using that same 21 kN figure that should buckle the E86 braces:



As you can tell, the analysis says that the welds will fail before the E86 braces. There's also some areas in the part where the safety factor is worryingly close to 1. Not ideal, but I'm gonna go ahead with this design anyway for the following reasons:

• There is no space for another design. The engine harness box gets in the way on one side and the positive terminal gets in the way on the other. A beefier design will require modifications to both of those.
• Simulating welds is not straight forward. There's a bunch of spots that will be welded together in real life that the simulation software didn't let me mark as welded.
• The real loads that this will be seeing will likely be below 21kN. This is more of a max value and not a typical load value. If I had a way to know what loads the braces will typically be seeing, I would have ran the simulations with those.
• The cost to get both brackets manufactured is less than $200 and they take 5 min to install. These are not like the windshield mount where I only get one shot, I can easily swap in updated parts if needed.

Additionally, seeing how thin the aluminum end pieces on the Slon brace are makes me confident that my design will survive. I have yet to hear of one of those failing. Pic for reference:



Anyway, lots of coming up with excuses for lazy engineering and very little doing. I'll get myself in the machine shop this week and finally trim back the stock brackets. Once I have confirmed the final dimensions of those, I'll order my brackets.

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



Potentially a future upgrade?

[heinzboehmer]

I just use the crank lock timing pin and break the 4 bolts loose.

Yeah that is an option, but I've always been worried about cracking the timing chain cover by doing that. Especially when torquing the new bolts.

I bought the tool for like 40 bucks last year I think?

Edit: 83300493843

Okay well, turns out this tool wasn't as hard to find as I thought. Thanks for that info.

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

[bmwfnatic]

Cut the remaining ends of the E86 braces to size, installed in their final position along with the 3D printed strut tower brackets, then took a couple scans.




I think I have all I need to finish the design now. Just need to get lost in CAD land for a bit.

Unfortunately, not all good news. When I was putting things back together, I noticed this:



I think the leak is coming from the front main seal. There's grime all over the front of the engine, but no drips from above:



The seal that's on there now is an Autozone special, since last time I did the job, I only had one seal on hand and destroyed it when trying to install. Learned my lesson and ordered four from FCP this time.

In preparation for the install, I printed out cobra's tool (thanks!) and then remembered that the BMW crankshaft holder tool is impossible to find for sale. I found a replica on eBay for $120, but it's all the way across the country and will take forever to arrive. Instead of buying that, I decided to just make my own, using the pictures from TIS as a reference:




Scanned the engine and came up with this:


Having SendCutSend make it out of 304 SS was like $3 more than mild steel, so I opted for that. Ended up being right around $20 out the door, nice.

Since I had the engine bay disassembled, I decided to swap out the AC pulley. I forget who posted this, but someone mentioned one of the E92 M3 pulleys (11287549557) bolts right in. Only "modification" necessary is to screw the bolt out of the backing plate:




More updates to come once I get the seal installed and the bracket design finalized.

I bought the tool for like 40 bucks last year I think?

Edit: 83300493843

[bigjae46]

I just use the crank lock timing pin and break the 4 bolts loose.

[heinzboehmer]

Damn, I think I have a spare crank holder tool laying around I could have sent ya.

Let us know how the tool works!

(What are you using to scan?)

Ah man, appreciate that! Fortunately this only took like 10 min to design and was super cheap. I'll share the dxf once I've validated fitment.

As for the other scans, I'm making braces that triangulate the strut towers to the firewall using E86 braces (see the last few pages of this thread for more). The scans are just a reference for where the braces will land on the strut tower side. There were a lot of assumptions in my math for the brace positioning when I designed the firewall piece, so just wanted to make sure it all translated nicely to real life.

[cobra]

Damn, I think I have a spare crank holder tool laying around I could have sent ya.

Let us know how the tool works!

(What are you using to scan?)

[heinzboehmer]

Cut the remaining ends of the E86 braces to size, installed in their final position along with the 3D printed strut tower brackets, then took a couple scans.




I think I have all I need to finish the design now. Just need to get lost in CAD land for a bit.

Unfortunately, not all good news. When I was putting things back together, I noticed this:



I think the leak is coming from the front main seal. There's grime all over the front of the engine, but no drips from above:



The seal that's on there now is an Autozone special, since last time I did the job, I only had one seal on hand and destroyed it when trying to install. Learned my lesson and ordered four from FCP this time.

In preparation for the install, I printed out cobra's tool (thanks!) and then remembered that the BMW crankshaft holder tool is impossible to find for sale. I found a replica on eBay for $120, but it's all the way across the country and will take forever to arrive. Instead of buying that, I decided to just make my own, using the pictures from TIS as a reference:




Scanned the engine and came up with this:


Having SendCutSend make it out of 304 SS was like $3 more than mild steel, so I opted for that. Ended up being right around $20 out the door, nice.

Since I had the engine bay disassembled, I decided to swap out the AC pulley. I forget who posted this, but someone mentioned one of the E92 M3 pulleys (11287549557) bolts right in. Only "modification" necessary is to screw the bolt out of the backing plate:




More updates to come once I get the seal installed and the bracket design finalized.

[0-60motorsports]

I’m always amused thinking about runs on parts because of
the forum. Things BMW has been storing for decades at this point. E.g. how many people ordered that non M e46 vert under brace? I bet at least 10.

hahaha I still need to get one.

[Obioban]

I’m always amused thinking about runs on parts because of
the forum. Things BMW has been storing for decades at this point. E.g. how many people ordered that non M e46 vert under brace? I bet at least 10.

[heinzboehmer]

It‘s a mistake in the catalog I think, but regardless, who knows. BMW has 6 left so if anyone wants one, be quick.

True, would not be too surprising if it was a mistake.

FCP shipped to me directly from one of their US warehouses, so there seems to be a stash of them over here. Probably because everyone started ordering them after karter16's thread

[Obioban]

It‘s a mistake in the catalog I think, but regardless, who knows.
BMW has 6 left so if anyone wants one, be quick.

Fwiw I think 51488204055 is the correct part, listed for Sedan/Touring but looks a lot more like what the coupes came with from factory.

51488204055 Looks like the stock rubber stuff. Do not want

[karter16]

Oh look at that! Yours doesn't fit well either:

Hahaha - oh man I must have been tired last night. I tried to find a photo of mine and couldn't - thanks for finding this. That answers that!

[bmwfnatic]

Interesting. Parts diagram says 51488252759 fits the M3. Maybe they consolidated the two parts at one point into something that (mostly) fits both the coupe and the compact?

It‘s a mistake in the catalog I think, but regardless, who knows.
BMW has 6 left so if anyone wants one, be quick.

Fwiw I think 51488204055 is the correct part, listed for Sedan/Touring but looks a lot more like what the coupes came with from factory.

[heinzboehmer]

That part is for a Compact, which has a whole different rear bench area, I am surprised that it fits reasonably well tbh.

Interesting. Parts diagram says 51488252759 fits the M3. Maybe they consolidated the two parts at one point into something that (mostly) fits both the coupe and the compact?

[bmwfnatic]

Installed this piece after being inspired/reminded by Obioban's recent post in his journal:



Curiously, the cutouts for the isofix brackets did not line up and I had to extend them a bit. This part seems to fit well on Obioban and karter16's cars. Maybe it's an early production thing?

The other thing I had to trim was the flange the extends into the trunk, but only because I have the Slon wall in the way. Looks like it would have fit just fine without that.

Also, pleasantly surprised that the extra cutouts on the side line up perfectly with the anchor points for my harnesses. Very nice.

That part is for a Compact, which has a whole different rear bench area, I am surprised that it fits reasonably well tbh.