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adamdrives' 78 242


Thanks, I found the right seal and am just waiting to make sure I don't need anything else from skandix before I cough up for shipping.

Current focus is getting speedo working. The amount I drive its not crucial, but I like having a working trip. I saved the old tailshaft with the speedo gear in it from the bw55, but obviously that doesn't bolt up to the m46 overdrive. Next step will be to see if I can somehow change just the speedo drive gear or if I need to find the correct overdrive for a 78, which would be from an m45 I think.

Had a blast driving the absolute piss out of her on a rally upstate, and got this great shot of the car as a bonus. It's the first time since the manual swap that ive really pushed her, and man is she peppier and more fun to drive. I spent most of the time at the top of 2nd or 3rd gear, and honestly the power was surprising. They were curvy roads without many straights but I was still keeping up with a 740 turbo in front of me and not holding up the mk 1 and 2 mustangs behind me.



 
Speedo drives were sold in a range of ratios to match the speedo head (& FD). They are color coded, but the online catalog doesn't list them anymore, need the microfiche as paper catalogs were not printed by Volvo for 70's vehicles.

The OD trans for -78 was the M41, so I don't think it would bolt up to the 79 - M46 gearbox....
 
Speedo drives were sold in a range of ratios to match the speedo head (& FD). They are color coded, but the online catalog doesn't list them anymore, need the microfiche as paper catalogs were not printed by Volvo for 70's vehicles.

The OD trans for -78 was the M41, so I don't think it would bolt up to the 79 - M46 gearbox....

The last year for the M41 was '75. It would be an M46 in 1976 onward.
 
Adam - I have a couple gears I pulled from junk J types at Skyview - different colors are different gear ratios. Let me know if you want me to send them to try. Red was from early coarse spline M46, black from from later fine spline M46

PXL-20210512-215938290.jpg


The last year for the M41 was '75. It would be an M46 in 1976 onward.

OK - faulty memory. It was the obvious coarse spline vs fine spline on the input shafts, switch from cast iron to aluminum cases then....
 
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Thanks guys, appreciate the love. Once the windshield is ready to go in I'll get her properly detailed and she should really look great.

Adam - I have a couple gears I pulled from junk J types at Skyview - different colors are different gear ratios. Let me know if you want me to send them to try. Red was from early coarse spline M46, black from from later fine spline M46

Cool, I will pull current gear and see what it looks like. Trans donor car was an 80 I believe, maybe that's when it switched to fine tooth? Would make sense, because my speedo reads too high. Are the gears interchangeable?
 
Thanks guys, appreciate the love. Once the windshield is ready to go in I'll get her properly detailed and she should really look great.



Cool, I will pull current gear and see what it looks like. Trans donor car was an 80 I believe, maybe that's when it switched to fine tooth? Would make sense, because my speedo reads too high. Are the gears interchangeable?

The gears are interchangeable. They are tied to the ratio of the FD - and the speedo head is designed to match that - I think the old gauges have a number on the face of them - does yours? It doesn't really matter in terms of figuring out which one is correct unless you can access the old catalogs that list the gears by ratio

EDIT: this thread has info on the gears/ratios http://forums.turbobricks.com/showthread.php?p=6179557#post6179557
 
Sounds like I need to know the FD of the donor car to get the right gear. It was an 80 non turbo wagon. Wish I would have grabbed the cluster from it too.

My cluster is a 980. Not sure on rear axle.

edit: drank some coffee and it sounds like I just need to match my rear axle to the correct gear, right? Cluster is just for correction in tire size from wagon/sedan.
 
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Located the correct speedo gear thanks to lookforjoe (thanks dad), now just need a chance to install it. I've been busy with my 245t 15g swap and hammering out some gremlins. Beginning to consider swapping to efi to simplify and improve.

I'm not sure if I've mentioned it but the blower motor stopped working once I got the dash buttoned up. I tested it while I had the center stack out to verify wiring and it was good, but somethings not right now. I think I may have pulled a wire from the AC switch while I was tugging connectors into place. Once I have speedo I'll focus on that. I've been putting it off because I can't stand that center console and the messy wiring.

I ordered the correct windshield trim, now just need the glass guy to come around so he can remove the old glass, hopefully not break it, and install new clips. I'm debating ordering new glass myself from VP, but with shipping its about the same as letting him order it, and if I end up not needing it, I wont be on the hook for $250.
 
Ended up getting the right speedo gear, only to still have speedo off. Looks like my car is supposed to have 195/70s (sedan/coupe?) on it, and it has 185/70s (wagon?). That would explain the speedo reading too high. At 67 actual speed, it reads 80.
 
Wonder if the '80 donor had an OD unit from a 1983-85 non-turbo 240 on it. On those, the worm gear on the shaft is different. For the 3.31 rear axle, it uses the black speedo gear normally used in 3.91 rear axle cars. A red 3.73 gear would wind up being a 3.15 ratio, and a blue 3.54 gear would wind up being a 3.07...
 
Wonder if the '80 donor had an OD unit from a 1983-85 non-turbo 240 on it. On those, the worm gear on the shaft is different. For the 3.31 rear axle, it uses the black speedo gear normally used in 3.91 rear axle cars. A red 3.73 gear would wind up being a 3.15 ratio, and a blue 3.54 gear would wind up being a 3.07...



Thats exactly the case. I took apart a spare OD unit and compared it to the drive from the original BW and they are not the same. I think all I need is the original speedo drive, which I can get, and all will be well.
 
Wonder if the '80 donor had an OD unit from a 1983-85 non-turbo 240 on it. On those, the worm gear on the shaft is different. For the 3.31 rear axle, it uses the black speedo gear normally used in 3.91 rear axle cars. A red 3.73 gear would wind up being a 3.15 ratio, and a blue 3.54 gear would wind up being a 3.07...


Hey John, thanks for chiming in on IG. This project is on the back burner but I want to get this speedo ordeal wrapped up. can you confirm which years m46 has the worm drive i'm looking for? Is it any year turbo, diesel, or 82-83 box that has the correct gear?
 
Been a long time since I gave an update here, just brushed off the dust and drove her home today from the shop. The dynamat definitely helped with tire and road noise but the motor is still very noisy in the cabin, I need to do the underside of the hood and maybe the firewall. Still a nice, smooth cruiser on the highway on the untouched suspension. OD works perfectly after the swap.

I was going to swap to modern a/c, but for now I'm just going to get the York working. I really had enough of dealing with wiring when I did the blower motor.

Did the front seals and fuel pumps, but she's still groaning. May try to add a fuel damper in the future.

Still need to deal with the driver seat foam and skin, and the rear backrest.

My glass guy has gone totally MIA, so I'm also going to have to figure out a solution for the windshield trim. I may try to DIY it so I can keep the original glass and trim and just replace the clips.
 
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