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Tech Forum : metric mechanic trans opinions

- BMW E21 Community
   - Tech Forum
      - metric mechanic trans opinions
imaradiostar   Posted Friday, Sep 30th 9:12pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 549
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
metric mechanic speaks very poorly of the "close ratio" BMW transmissions (the dogleg shift pattern boxes). Is this a bunch of crap? I had always assumed it was extremely similar to the overdrive 245 transmission and as such, would be a solid trans to handle a lot of power. MM says you're better off with one of their modified OD 245 transmissions as the OD 245 is supposedly more heavily built.

So...marketing BS or truth?

jamie

JJG323   Posted Friday, Sep 30th 9:26pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 945
   
Reading MA USA
1979 BMW 323i
Well I am not to sure about Jim's opinion.
When I talked to him about 524 td cranks he told me to take a hammer and hit my crank to see if it was good. LOL.


I can tell you when I used to drive my car..
the dogleg tranny was fun.

First low to second high takes some getting used too. No one wants to "money shift" and hit the wrong gear and with the dogleg tranny you half to pay close attention to what gear you are in and what gear you are going too.

RDAvena   Posted Friday, Sep 30th 9:40pm [Edit] [Quote] [IMS] [View car]
Staff
Post nr. 1503
   
SELECT * FROM users WHERE clue > 0
1981 323i, 1988 545is, 1997 528i
layshaft failure is common. Just one of those things you have to live with on the Sport 262. One of the reasons I got rid of mine. To put this into perspective the failure is common on a transmission patterned after the Getrag 265, touted as the strongest BMW transmission made by Getrag. Also you need to keep in mind that the transmissions on these care are made to handle up to a certain amount.

A 323i was never supposed to put 200 HP to the rear wheels when the engineers designed it. So they chose a transmission that handled X amount of power. Then the accountants got a hold of the amount that was supposed to be spent on each car and found an even cheaper part to use. Look at the fail rate of the later ZetaF transmissions over the earlier Getrag ones in the e30s.

Not too sure about the Getrag 245 and how sturdy the layshaft is on these but as they say "if you do not break it you are not making enough power."

imaradiostar   Posted Saturday, Oct 1st 2:34am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 550
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
Well...I talked to Jim for a while today. He's very knowledgeable and easy to talk to. He explained that the difference in between the CR 245 and the OD 245 is in the bearing sizes- basicly he can get better bearings to fit the overdrive box but not the CR box. He also stated the when it comes to absolute max power for an M20 245 gearbox he recommends the factory ratios, not his "sport OD semi-CR" box. Supposedly the gearsets he uses for the semi-CR box aren't quite as wide as the factory gears so it doesn't have quite the same power handling ability.

I also talked to him about differentials for a bit; I mentioned that one of our forum members with a big 6 in a 320 managed to destroy a differential. He said he's done the same but has since come up with modifications that allow the differntial to survive the big six punishment- more on that later if anyone wants to know.

jamie

Phasma   Posted Wednesday, Oct 5th 10:51pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 57
   
Latvia, EU
E21 323i "Phantom"
Sure, I want to know!

imaradiostar   Posted Wednesday, Oct 5th 11:00pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 554
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
he micro-polishes all the components and machines his own shims with tighter tolerances than factory BMW ones. BMW only goes down to 2 thousands shim tolerance, his go down to 1. I can't remember what else but he was quite sure that they would take huge amounts of power.

jamie

jbob   Posted Thursday, Oct 6th 12:03am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 333
   
AZ, USA
81 320i
jamie, great info!
when are you thinking about sending in your tranny for a rebuild?
i want to get my 320i's OD 245 rebuilt as well. but $2,300 (or is it $1,300) is a lot...especially considering i could yank an OD 245 (4-cyl) for $100 (or $50 if there's a 1/2 off sale), and be somewhat content blowing them up for cheap

do you think metricmechanics would offer any sponerships or groupbuys?

imaradiostar   Posted Thursday, Oct 6th 2:59am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 556
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
Truth is I can't afford a MM rebuild right now. The 245 OD rebuild without gear ratio changes (but including other upgrades) comes to about 2000 bucks. I'm getting married in two weeks and even then, I need to get my 323i painted and patch up some little areas before surface rust becomes rust holes. Too many things to think about!

The thing about shims and polishing was referring to the differentials but I'm sure those things will help a manual trans build too. The other thing about the E21 differentials is the difference in gear sizes- he says the lower the ratio the more power it will handle. This makes sense- there is more tooth area to bear the load on a taller differential.

If you go to the MM website he outlines all the things that are done in a sport tranny rebuild. He upgrades every bearing he can to roller or tapered roller bearings for increased power handling. Shift forks and syncros are replaced with their own stronger units. Shims are used to keep everything where it should be.

His prices are pretty high but I think he stands behind his products and there is a lot of thought, energy and experience behind them. Everything that tends to fail on factory designs is reworked in an attempt to make a MM unit bulletproof. Once again, these are just claims but the engineer side of me thinks that there is solid thinking behind what MM does. The fact is sometimes you just have to charge a lot because you put a lot into your business, or at least that's my guess. If it wasn't worth it they wouldn't be around for long.

Jim was extremely helpful and he realizes that people don't have a ton of money. He made some suggestions about building an M20 inexpensively and even gave me some shortcuts to avoid having to buy a bunch of his expensive parts, knowing I couldn't afford them. I have the feeling he'd do his best to help you with any of his products, judging by how he talked to me. Maybe it was just a really good day...

Wow, that was a mouthful and I kinda got off topic.

jamie

JJG323   Posted Thursday, Oct 6th 5:00am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 954
   
Reading MA USA
1979 BMW 323i
So Jamie..
are u telling me that my dogleg tranny will not handle the power that my stroker motor is going to put out??

imaradiostar   Posted Thursday, Oct 6th 8:22am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 557
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
it'll handle the power just fine, at least for a while. I'm really not an expert, just relaying info. It'll just get annoying having to shift so much and with the engine being buzzy on the highway in 5th gear.

Joe, if you and I could install a 2.79 or 2.93 differential then our transmissions would be great- closer spacing but geared taller overall. I think the dogleg would be ideally suited to a very high revving engine. Mine has the most power in the midrange and can benefit from wider gearing and a taller 5th in combination with a 3.45 differential.

jamie

bmw_m_320i   Posted Thursday, Oct 6th 6:53pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 449
   
Helena, Montana
none right now :(
I think a 7sp SMG would be pretty cool to have.....though it would be ALOT of work to retrofit

Phasma   Posted Wednesday, Oct 12th 6:49pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 61
   
Latvia, EU
E21 323i "Phantom"
Who digs in tranny rebuilding?

Question is: what gear assembly could be done (using any BMW stock gearbox gear pairs), that would be optimum for dragracing?

Current car setup: 2.7i stroker, 3.91 LSD, Getrag 5sp!

Phasma   Posted Monday, Oct 17th 12:03am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 62
   
Latvia, EU
E21 323i "Phantom"
Idea was to shorten 1-4 gear and leave stock 5th as it is or even longer for road use!

Any suggestions?

Guys?

imaradiostar   Posted Monday, Oct 17th 7:34am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 573
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
Sounds like you should check out metric mechanic's transmission pages for info on their transmissions.

jamie

jbob   Posted Monday, Oct 17th 7:38am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 334
   
AZ, USA
81 320i
yeah. not sure if they have gear ratio's listed on their website...but they do have mph to rpm graphs, which will tell you (indirectly) what gear ratio's they use.

Phasma   Posted Tuesday, Dec 20th 10:32am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 64
   
Latvia, EU
E21 323i "Phantom"
Guys, help me out! Someone who has access to bmw part catalogues, could tell what kind of gearbox is lying around in my garage.

I wrote down a number on a back (propshaft end) of the gearbox

260010'6090

Any info on this tranny will be appreciative!

imaradiostar   Posted Tuesday, Dec 20th 3:59pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 594
   
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i
you really can't tell from the casting number on the case. Can you see a stamping on the bellhousing, at the top?

jamie

M42powered   Posted Tuesday, Dec 20th 8:08pm [Edit] [Quote] [IMS] [View car]
Staff
Post nr. 606
   
Arizona, USA
1981 BMW 320i
Anyone know of a E46 M3 six speed in their area off a wrecked car? Supposedly they bolt up to M42's. Me want!

tony323   Posted Wednesday, Dec 21st 12:50am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 67
   
Pa USA
1996 318ti, 1982 323i, 1982 320is, 1988 Alfa Verde, 1983 533i
[quote=JJG323]Well I am not to sure about Jim's opinion.
When I talked to him about 524 td cranks he told me to take a hammer and hit my crank to see if it was good. LOL.

Hitting a forged crank with a hammer is a quick way to see if the crankshaft is cracked. A non-cracked crank will ring while a cranked crank will thunk. Just an old motor head trick.

Tony



Marquis_Rex   Posted Wednesday, Dec 21st 1:18pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 397
   
UK
BMW 323i 2.7-as featured in Total BMW Nov 2002,Porsche 911/993TT
M42powered wrote:
Anyone know of a E46 M3 six speed in their area off a wrecked car? Supposedly they bolt up to M42's. Me want!

It is my intention to use the 6 speed Getrag 226- it bolts up to the M42 and M20.
When I move to Germany I will be giving it top priority scouring the scrap yards there.

Phasma   Posted Wednesday, Dec 28th 9:39am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 66
   
Latvia, EU
E21 323i "Phantom"
'bout E46 M3 trans: how about propshaft lenght? Is that a straight forward swap?

'bout my misterious gearbox: the stamping on a bellhousing is NF052775 (and casting: 2600105091)
Any info on this gearbox?

Phasma   Posted Sunday, Jan 1st 6:13pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 67
   
Latvia, EU
E21 323i "Phantom"
guys? Any info on this tranny?

Phasma   Posted Tuesday, Jan 3rd 10:09am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 68
   
Latvia, EU
E21 323i "Phantom"
Imaradiostar???

JJG323   Posted Tuesday, Jan 3rd 3:51pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 1069
   
Reading MA USA
1979 BMW 323i
Marquis_Rex wrote:
M42powered wrote:
Anyone know of a E46 M3 six speed in their area off a wrecked car? Supposedly they bolt up to M42's. Me want!

It is my intention to use the 6 speed Getrag 226- it bolts up to the M42 and M20.
When I move to Germany I will be giving it top priority scouring the scrap yards there.


Marquis how about grabbing a wrecked e36 tranny and e36 engine. can you get these for us?
The german ones are double vanos and have a lot more HP/Torque and mojo than ours.

Marquis_Rex   Posted Wednesday, Jan 4th 2:44pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 403
   
UK
BMW 323i 2.7-as featured in Total BMW Nov 2002,Porsche 911/993TT
Sorry am in Germany right now desperately trying to find a place with a big double garage for all my stuff, I'll try and tackle some questions when I'm more settled!

Phasma   Posted Monday, Nov 12th 10:11pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 109
   
Latvia, EU
E21 323i "Phantom"
How about 6sp SMG on M20 in E21?
Anybody seen such conversion?


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