I hate flex discs

[Jean]

A big thanks to Pinepig for letting me use his lift and tools.

Replaced the guibo, engine and tranny mounts. We inspected the u-joint and the csb and they looked fine, no play in the u-joint and didn't look like it was binding. The CSB wasn't perfect but did spin fine and showed no extra wear, rubber housing was intact.

What a difference now from IE engine and tranny mounts to OEM mounts, it's like a new car. I did notice (feel) a ticking sound that sounded different from the valve lash and figured it was the spark plug covers touching the strut bar.

On the way home my car started to back fire and I had to pull over to the nearest parking lot and yep, with oem mounts bar is too close to the distributor. I had a spare rotor in the glovebox, replaced it in the parking lot, slowly drove back to my house and removed the front strut bar in about 15-20 minutes.

Not sure if I want to modify the bar, sell it, or keep it for a 24v swap. It came from an 87 325is but obviously is a tight fit on the m10 cars if used with rubber mounts..

[maniacmatt]

OEM is different than OE. OE is BMW or whoever makes them for BMW. oem can be any supplier made to supposedly the correct specs. OEM can be shit or it can be fine. just depends

Isn't it the other way around? I always thought OEM stood for original equipment manufacturer, meaning made by the same manufacturer as the the original. And that OE was original equipment just meaning it is the same specs as the original?


Maybe I am wrong though.

[Simon S]

no bigger in diameter, just beefier.

Has anyone swapped to the E34 M5 Guibo/flex disc ?

When I look up the respective parts on RealOEM, the M5 disc uses m12 bolts/nuts and the e30 disc uses m10 bolts/nuts.

I'm seeing sources saying "yeah, the M5 disc works- just need to use the M5 hardware".
Does the M5 hardware (m12 bolts/nuts) work with an e30 prop shaft?

[Jand3rson]

I would like to know this as well. I'm down for spending the extra cash for beefier parts that will stand up longer.

[Erick]

I first heard of the beefier M guibo from Mike Edler's personal experience.

[z31maniac]

Ugh, just replaced the flex disc and CSB and there is still a slight vibration. I'm wondering if the shop realigned the driveshaft.

But it seems to happen at the same RPM in every gear, which makes me think my engine mounts are trashed vs a tranny/driveline problem.

[FredK]

I'm seeing sources saying "yeah, the M5 disc works- just need to use the M5 hardware".
Does the M5 hardware (m12 bolts/nuts) work with an e30 prop shaft?

No. The transmission output flange has 10mm holes. M12 hardware won't work.

To run an M5 flex disc, you must use longer M10 bolts and use M12 to M10 reducing sleeves.

HOWEVER, this mod will only work on >5/86 production date 325e cars with 96 mm bolt circle diameter trans output flanges (or an E30 M3).

5/86<= 325e have 78 mm bolt circle diameter (BCD) trans output flanges which are INCOMPATIBLE with the 96 mm BCD of the E30 M3 and E34 M5 flex discs.

The 325i, 318i, or 318is trans output flanges are all INCOMPATIBLE with the E30 M3, E34 M5, or E36 M3 flex disc.

[Simon S]

FredK- Thank you for your time and input.

Excellent/informative answer. (now I can move on to other things to obsess about)

Cheers.

[Jand3rson]

HOWEVER, this mod will only work on >5/86 production date 325e cars with 96 mm bolt circle diameter trans output flanges (or an E30 M3).

5/86<= 325e have 78 mm bolt circle diameter (BCD) trans output flanges which are INCOMPATIBLE with the 96 mm BCD of the E30 M3 and E34 M5 flex discs.

The 325i, 318i, or 318is trans output flanges are all INCOMPATIBLE with the E30 M3, E34 M5, or E36 M3 flex disc.

EXCELLENT.

<-- 01/86 build date. :up:

[ethree]

This must be the other good reason to have an eta besides the mpg. My car also has an 01/1986 builld date so this is all very good info.

[FredK]

Yes, so since 1/86 is before the 5/86 crossover, you both will need 78 mm guibos, unless you replaced your transmission or trans output flange to a larger 96 mm flange.

[elemenohpee]

I replaced my guibo today but noticed the csb was coming apart in the rubber surround so I ordered a new one from the dealer. I know everyone is going to tell me it wore out because of the u joints and that I need the driveshaft rebuilt, but is it possible that it could have came apart just from being old and normal wear?

Also, the marks I made on the spline got rubbed off while working on it. Is there any other way to properly align the driveshaft so it is balanced?

[Jand3rson]

This must be the other good reason to have an eta besides the mpg. My car also has an 01/1986 builld date so this is all very good info.

We also have single-mass flywheels, while the rest of the eta boys have big giant dual-mass buggers.

[Jand3rson]

Also, the marks I made on the spline got rubbed off while working on it. Is there any other way to properly align the driveshaft so it is balanced?

Short of putting it in, driving it, removing it again, moving it around one spline, re-installing, repeat until you get it right? No.

You should have scratched marks into it with a screwdriver or something. You're pretty much effed.

[elemenohpee]

Yeah, thats what I thought. I've heard of some drive shafts that have two white dots on them from the factory to align them though.

You should have scratched marks into it with a screwdriver or something. You're pretty much effed.

Yeah I used a yellow paint pen but I guess with all the grease and dirt it got rubbed off. Hopefully there are some scratch marks from some previous owner that I can align. I will have a look tomorrow.