5 speed swap help

[TobyB]

1 hour ago, JQ02 said:

So an overdrive 5th gear with a built engine at full song might exceed the speed limit of the driveshaft. 🤔

At least there's breathing room for torque

I've pretty routinely spun one to damned near 9 thousand (7500 rev limit, .81 overdrive)

with a 4.21, and so far, the floor's remained unventilated.

 

And dat wun, I welded her shorter meself.

 

t

 

[JQ02]

2 minutes ago, TobyB said:

I've pretty routinely spun one to damned near 9 thousand

I kinda figured that would be the case. Glad to hear it confirmed. There are a lot of bolted together parts spinning real fast in the open, though. I would not have not thought to label the bad outcome as floor ventilation:D 

I did once see a '72 Nova attempt a pole vault midway through the quarter mile. Spectacular, but not pretty. Closed the strip for the day.

[jimk]

11 hours ago, JQ02 said:

So an overdrive 5th gear with a built engine at full song might exceed the speed limit of the driveshaft. 🤔

At least there's breathing room for torque

If there is enough horsepower to get to "full song" in 5th.

[bergie33]

22 hours ago, tech71 said:

Sorry, I cant give an exact figure on that. Think it was around 3/4 in

I decided that calculating driveshaft length by subtracting the difference in overall trans lengths would be unwise. Better to measure precisely from face of diff output flange, to face of installed guibo on trans output shaft.

As I said, I ended up adapting a driveshaft from an 85 318i by fabricating an extension mount for the CSB mount, no cutting or modifying to the actual driveshaft was required. Attaches to original CSB mounts, requires drilling 2 holes in your car, completely reversible😉

So I am not well versed on shortening the original shaft, Sorry to muddy the water.

As far as I am concerned, if a DS from an M10 E30 can be obtained, its the way to go.

 

 

@tech71 Will this work for both the 240 and the 245?  How much would one have to pay to entice you into making more of those CSB relocating brackets?

[tech71]

4 hours ago, bergie33 said:

Will this work for both the 240 and the 245?  How much would one have to pay to entice you into making more of those CSB relocating brackets?

The 245 is much longer than a 240 so this hack(using 85 318i manual trans DS) wont work on a 245, The driveshaft will be too long. 240 only.

I have another E30 driveshaft here out of an automatic, its quite a bit shorter, wondering if it might work on a 245...

If someone can tell me the nominal length required for a 245 I will check it out.

 

Sorry, I see no profit and lots of possible problems in regards to marketing the adapter brackets. Sorry😉

They are relatively easy to make using mild steel angle available at Ace, Home Depot, your scrap pile...

But a wire feed welder is required.

I basically bolted up the E30 driveshaft and built the adapters to fit.

Kinda a one off deal.

 

Edited January 5 by tech71

[bergie33]

6 minutes ago, tech71 said:

 

I have another E30 driveshaft here out of an automatic, its quite a bit shorter, wondering if it might work on a 245...

If someone can tell me the nominal length required for a 245 I will check it out.

 

 

 

 

 

Drive shaft for the 245 should be 59-3/4"

[tech71]

22 minutes ago, bergie33 said:

Drive shaft for the 245 should be 59-3/4"

Will check it out tomorrow.

By the by... I cant take credit for the idea, I took it from an article on M42 install by Jake over at www.classicdaily.net.  Thanks Jake

 

 

Edited January 4 by tech71

[tech71]

On 1/4/2024 at 3:15 PM, bergie33 said:

 

I have another E30 driveshaft here out of an automatic, its quite a bit shorter, wondering if it might work on a 245...

If someone can tell me the nominal length required for a 245 I will check it out.

 

On 1/4/2024 at 3:15 PM, bergie33 said:

 

Drive shaft for the 245 should be 59-3/4"

Well, it appears that the E30 325 auto driveshaft I have is to short to consider using with the CSB Adapters.

Short by a whopping 8 inches, you sure about that 245 Driveshaft length?

Bummer, have a 245 here needing a driveshaft

[Rusty525rusty]

So today I got the 4 speed box out and bolted up the 240. Here is what I found...

 

1. Different slave cylinder required. I need to order an e21 but fitting looks to be very tight against the 02 tunnel.

2. The e21 prop shaft I have fits!!! Mega surprised but it looks to be the perfect length! Just need to extend the centre mount bracket.

3. The box catches on the steering arm... maybe I can just grind this bit back?

4. Speedo cable fitting looks to be very tight, not yet tried it.

5. I need to do the U shape bracket for trans mount with a new rubber mount

No clue yet on the shifter but my original was completely shot. Needs replacement.

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[bergie33]

@tech71 Pretty sure. Based on the factory shop manual, the stock shaft is about 63".  The 245 is about 3.5" longer than the 4 speed, making 59.5". Adding back a little for the difference in giubo thickness, comes to 59-3/4".

[tech71]

9 minutes ago, Rusty525rusty said:

So today I got the 4 speed box out and bolted up the 240. Here is what I found...

Could you post pics in a viewable format pleaase? 

I want to help but really dont want to download them one by one on to my HD to view them.

Edited January 7 by tech71

[Son of Marty]

The answer to #1 =

[bergie33]

^^^

What SoM said. Just don't be too heavy handed with it. Bang a little, lift the tranny into place to check fitment, bang a little more. Repeat until you have a good fit. 

[tech71]

I rubber mallet massaged my tunnel prior to installing my 240, turns out I over did it and had to rubber mallet massage it back the other way.

240s are slightly narrower than the 245 so less clearance is required.

I ended up slipping a wide pry bar betwixt the slave cylinder - tunnel and gave it a mild tweak. 

[Rusty525rusty]

Good info thanks. I need to get a slave cylinder ordered now then can bolt on and offer up to see where to bash / pry then.