Hi all,

I'm looking to build a rally car for long distance event. Is the M45 or M46 a worthwhile upgrade behind a B20? I know I need a special bellhousing.

Also, is the transmission tunnel from an auto bigger than the manual tunnel?

Regards

JohnH
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JohnH, Sydney, Australia

Hello,

Do you think the officials would know the difference between a M40 and a M400?

What if a 1970 1800e was going to be in the race?

Would the officials disqualify the car?

A M410 came stock in a 1970 1800e!

Besides the M400/M410 was an option for the later 140 Volvos.

The shift tunnels are the same for 140/160 regardless of transmission style.

The 4 speed part of M45/M46 transmissions are stronger than M40.

However, there was several years of early M46 that were stripping the splines on the mainshaft that goes into the overdrive.

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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Hi Eric,
I doubt if the scrutineers would know the difference, but one of the competitors might! The penalty for the car failing to conform to its declared identity certainly is exclusion, and I'm not keen on that.
I'll check if the 144 was homologated with a M400/410. I've only got homologation papers for a 1971 144 and that only shows the M40 or M41. If the 1974 is homologated with the M400/410 I'll get more into it. I've had a search on the web and I can only find references to the later 164s using 400/410s, not the 140s.
Regards
John
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JohnH, Sydney, Australia

I'm going to present a bit of the opposite view (from Eric) here, because I'm of the opinion you may be fretting over nothing. I've run stock rebuilt (did them myself, and I'm no professional) M40 transmissions many, many race weekends between failures. I typically find the 3rd/4th gear synchros to be a failure point, but have also occasionally worn out a bearing. The last M40 that I had to remove from the car was a synchro failure (broken) and it had been in the car for about 1500 road racing miles.

I'm going to suggest that Eric's experiences with the M40 while drag racing would be very typical for that type of motorsport activity, but very atypical for road racing or high speed road rallying. For example, how many times would you expect to have a need to slam-shift the car from 1st to 2nd gear in competition? I know that in my case, the answer would be zero... I'm in 1st gear only in the pits, because there are no 1st gear corners on any circuit I've ever raced. I do, however, accomplish a fair number of full throttle upshifts from 2nd to 3rd and 3rd to 4th. But the majority of my upshifts are very quick lift-throttle shifts. Over the course of a weekend, I will probably do about 400-500 shifts, the majority of them between 3rd and 4th gears. I would suspect your rallying would show a similar pattern?
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Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

I went to the drags once. I had to use 7000rpm to launch, then changed up at 6500rpm. Had a 3.13 1st, 4.10 diff & weenie 195/60-14 of average grip. '71 144 with some bits missing.
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Three 164's, Two 144's, One 142 & a partridge in a pear tree.

The early ones with brass syncro forks bend really easy & they all are a bit feeble if you have the back wheels leaving the ground a lot.

M45 - Horror ratios.

Early M400's have early M40 ratios, but first you have to find one & then you have to find a bellhousing.

Are you allowed a Toyota box? Dellow can do steelcase Celica & Supra box conversions.

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Three 164's, Two 144's, One 142 & a partridge in a pear tree.

Hi Paul,
Supp regs aren't out until Feb next year, but going by previous similar events, Volvo boxes only but they allowed M45 and M46: hence the question.
Regards
JohnH
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JohnH, Sydney, Australia

M45 is strong, but the ratios suck horribly, making it fairly useless. Have you read about the Canberra 240T guy taking out his M46 & fitting a Supra box?

I did a Celica box conversion on mine in the '80's. I have a D type I managed to find along the way, but I think it might be a little weak to be flogged.

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Three 164's, Two 144's, One 142 & a partridge in a pear tree.

I had a look at M45 ratios and certainly 1st is a stump puller (3.71) and it's a fair jump to second (2.16). By comparison the M40 ratios are 3.13 and 1.99.
3rd is virtually identical (1.37 vs 1.36) and of course 4th is 1.00.

Do you know if any alternative ratios are available for a M45? The extra strength does have appeal.
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JohnH, Sydney, Australia

I don't know if R-Sport made different gear sets for the M45 like they did for the M40. M40 isn't that weak if it's in good nick, just have to use caution on the gearstick if it's the long one because the extra leaverage makes it ease to bend the brass selectors used in the early boxes.

M40 ratios aren't that bad either, if you have 2000 to 2130cc with stock stroke, then 6000 to 6500rpm gearchanges fall back in to peak torque, especially with a pair 45 DCOE's. Reserve 7500rpm for when you are too busy too change up.
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Three 164's, Two 144's, One 142 & a partridge in a pear tree.

The regs limit us to to a max 60thou oversize, so that puts the engine at 2055 by my calc, in the middle of your peak torque range. I'm planing on using 2 x HIF44s for simplicity. If anything goes wrong in the middle of nowhere, at least I can pretty easily fix a HIF. I can't do that with a weber. After talking to the guy who will build the engine, he's expecting in the 150-160hp range. Can the M40 take that reliably?
Regards
JohnH
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JohnH, Sydney, Australia

Easily, because you aren't going to be making much torque without the Webers. I don't understand why you are so against them? It's not like you are switching to fuel injection.

If you stay with the M40 & take a spare, cut a piece of Allen wrench off so that you can use it with a spanner to get to the allen head bolts on the bellhousing, that saves a time if you don't need to look at the clutch. Don't be indecisive on the accelerator when driving through rough bits, either hold it flat or roll through pot holes, washouts, etc.

Don't forget to alter the transmission tunnel at the diff end. It's not hard to bend the rear prop shaft because of the offset pinion.

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Three 164's, Two 144's, One 142 & a partridge in a pear tree.

Hello,

It all depends on how you drive the car.

I can tell you from personal experience that it is not hard to break a M40.

That is why Volvo installed M410 transmissions with bellhousings to fit the 4 cylinder engines from a 164 for the 135 HP 1970 Volvo 1800e.

FYI, you can not bolt a 164 transmission to a 4 cylinder motor unless you have the 3 special parts needed to convert a 164 M400/M410 to a B18/B20 M400/M410.

We used to drag race and we broke many M40s, usually stripping off all the teeth for second gear from the cluster.

We then installed a M400 that we put together using pieces from an M410 from a 1970 Volvo 1800e and a M400 from a Volvo 164 and have not broken a transmission since.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

"We used to drag race"

Tell us more! Enquiring minds would like to know.
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Three 164's, Two 144's, One 142 & a partridge in a pear tree.

Hello,

Most of our drag racing was done at an 1/8 mile track called the Terminal Island drag strip, but sometimes was called the "Brotherhood Raceway" which no longer exists.

My brother took the last pass in our 1967 Volvo 122 we called "Gort", before the track closed for the last time.

The racers were mostly street racers taking advantage of the safer racing conditions and the timing equipment.

The races were arranged in the staging areas without an organizers, just people mostly out there for some fun and bravado.

I sure do miss those days when we could go out on a Friday night and stay out till midnight laying down some rubber down by the ocean near the Los Angeles Harbor.

No one complained about the noise because we down in the harbor.

Big Willie Robinson was up in the booth calling the races over the PA occasionally making a 25 cent bet on 1 car or another.

Of course betting was illegal, but most races had a small, sometimes large private stake to make things interesting.

Big Willie almost always called our Volvo 122, a Volkswagen, but you could tell he was doing it on purpose because he would usually laugh and correct himself.

Beside taking the last pass at Terminal Island, the most memorable race was again run by my brother in Gort against an early 1970's Camaro in which 2nd gear in the M40 transmission was destroyed, but my brother still won.

The Camaro gave us a couple of cars lengths advantage and the Camaro spun his tires on launch and because my brother shifted to 3rd quickly, he was able to beat him.

I can still remember the Camaro driver insisting on a rematch.

He could not fathom we broke our transmission and still beat him.



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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Hi Eric,

Thanks for that, although I'd rather have heard something more positive! The regs for the event I'm planning for only allow us to use the M40/41 or a M45/46. I've got a spares 244 car with an M45: do you think the M45 is that much stronger than the M40? Is it is worth going to the trouble of making up the bellhousing to suit, because I don't know where I can get one of those.

Regards

John
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JohnH, Sydney, Australia

Surprising they don't allow an M410 -- perhaps because it isn't original to that car -- though the m45 isn't either, and the M410 *did* appear behind a B20.

There's a big difference between drag racing and rally racing -- just don't dump the clutch going into second with the motor at redline while on tarmac and you'll be okay?

You going to be using a LSD / locking diff? That'll make it much easier to break your transmission.

I'll certainly be using a LSD - this is a gravel rally. Maybe I should toss a spare M40 in the spares box.
Regards
John
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JohnH, Sydney, Australia

Hi,
Still waiting for supp regs, of course to see what gearbox is allowed. I have a J type in my 142 which should be good enough for me to use but I'll keep an eye out for a spare to put in the parts truck.
Regards
JohnH
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JohnH, Sydney, Australia

I cannot imagine a real need here. With fresh syncro's and decent bearings, the M40/41 is nearly indestructible behind a B20, even if the engine is "beyond" stock.
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Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos

I would imagine that a M40 would hold up pretty well so long as it was not beat on.

Automatic and manual 140s used the same transmission tunnel.
The shape of the tunnel changed in '72 though when they went to a remote shifter. But it was still the same.

Also, The driveshaft tunnel changed sometime around '71 or '72. I remember the earlier being slightly smaller.

I believe the driveshaft tunnel changed in '70. Which is something for John to keep in mind... not sure if there's a carrier bearing support donut for the large driveshaft/small tunnel... therefore, fitting large driveshaft in a pre-'70 might not be an option, or at least not without some modification/fabrication.

I do know that I fitted a large driveshaft from a '71 142E into my wagon, manufactured January '70...

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-Matt I ♥ my ♂

Matt, actually there is a 2" drive shaft mount for the early smaller tunnels. I found one originally for my swap of a '74 drive line into my 68 wagon. I can't for the life of me trace where I bought that thing, but I did successfully use it and haven't had issues with the larger shaft in the smaller tunnel. The U-joint clearances are smaller, but no hits so far.

Maybe for your purpose it would be---everything is bigger in the M45/46. 1st gear in those is way low. I recall a pictorial of a sliced B21 bellhousing repositioned for the B20--probably here on the BB.
For me I want a transmission that shifts nicely. The 45/46 is clunky in comparison to the 40/41. I have a long shifter 144/B20. -- Dave

Thanks for the replies. That pretty much convinces me to stay with the M40 or M41 and toss a spare gearbox in the parts bin, just in case.
Regards
JohnH
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JohnH, Sydney, Australia

Good idea. A properly treated M41 can last for a LONG time!
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George Downs Bartlesville, Oklahoma

I've been savaging my PV's M41 for years with a 175-ish hp b20. No issues at all, although the light weight of the PV might help?

M45/46/47 transmissions may or may not be slightly stronger, but if so it's not by enough to make a real difference. They tend to start breaking 3rd gear at somewhere around 225-ish hp.

So I'd say that if you start breaking M40's, then you'd probably want to spend more time and swap to somthing actually a lot stronger, not just slightly stronger. Like a T5, or a BMW Getrag. Both fairly common swaps on higher HP OHC Volvos, at least. At least onve swap kit vendor that I know of makes their adapter work on both slanted (normal OHC) and upright (B20 and modified OHC) positions.
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'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)

If the rules are volvo only *and* you want indestructible -- go with an M400.

There were M400s on early 164s and there were B20 to M410 bell housings in some of the early FI motors.

Sure you're probably looking at a custom propshaft and stuff but you're also using an absurdly rare bellhousing anyhow (probably easiest to just have one made out of a giant chunk of alloy and a CNC machine to be honest).

There are other issues -- cable clutch vs fluid, but the M400 is indestructible.

The M400 MAY be indestructible but I can tell you that at about 100,000 miles they start
developing shaft/shaft bearing issues because of lube problems and get pretty noisy.
I have never had one fail outright but the noise can be pretty objectionable.
BTW I have only used themm behind B30 engines.
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George Downs Bartlesville, Oklahoma