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3.54 Ring and Pinion

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I can see these being more desirable in the US where people might be travelling longer distances on freeways. It will really depend on what type of driving you like to do. The 3.5 diff will of course reduce acceleration through all gears making the car feel more sluggish.
 
DerekJ said:
I can see these being more desirable in the US where people might be travelling longer distances on freeways. It will really depend on what type of driving you like to do. The 3.5 diff will of course reduce acceleration through all gears making the car feel more sluggish.
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Can't speak to the 100-4 aspect or gallery head or 26D but there's no way I would describe it as "sluggish".

2 friends and I have gotten it done and the usual comment is "the factory should have done it that way to start with." We're all running 29D engines. One has a 28% OD and he likes it for the freeway cruise of around 80 at 3000 rpm. My Toyota Supra trans is around 75 at 3000 which I believe is the same as the 22% OD.
 
After a few days driving with a gallery head engine and 3.54 diff I'm entirely sold on it. The speedo is a long way out but that is to be expected and I need to use 1st gear a fair bit which makes a very loud howl but once moving there is more than enough power to play in modern traffic. Kickdown out of OD is needed for overtaking and adds to the enjoyment of driving. Driving with the OD off at 70mph is boomy and gets tiresome after a while, especially with the hardtop on.

Engine has raised compression and a BJ8 cam which dynoed at 106hp as-installed so if AH were honest about the power rating of the 4 cylinder engine then there should be no problem on the earlier cars.

Andy.
 
I ordered mine from Dan a few days ago... looking forward to it arriving!
 
Dan mailed me today. The price on his website is (edit; was) from two years ago.
The recent price is 525 USDollar incl US Transport. IMO up in a reasonable way ...

Hans
 
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I'll add my endorsement of the 3.54 modification. I got in on the original project by Mike Lempert to reproduce the 3.54 gear sets in the late '90s. After plunking down my deposit, it was two years before I got the result. Most of the 107K miles I have put on my BJ8 has been on long cruises, and the 3.54 ratio lets the engine lope along at a much more comfortable RPM on the road while keeping up with (and passing, when necessary) traffic. I also think it's the best mod I ever did to my car.
Overdrive (and the 3.909 differential) remained an option to the end of BJ8 production, but most of the cars that did not get overdrive (and therefore got the 3.545 differential) at the factory were Home market cars or Personal Export Delivery where the first owner ordered the car without overdrive. Consequently, non-overdrive differentials were rather rare on Healeys. I believe they were used on other UK cars such as Austin Westminsters, though.
 
anybody have the toyota 5 speed conversion and the 3.54 gear set. I have the 5 speed conversion but have not had the car out yet, a few months away from initial test drive. Interested to here comments, I also ordered and am waiting for the gear set

Phil
 
MCS said:
anybody have the toyota 5 speed conversion and the 3.54 gear set. I have the 5 speed conversion but have not had the car out yet, a few months away from initial test drive. Interested to here comments, I also ordered and am waiting for the gear set

Phil
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I have the 3:54 with Toyota 28% 5th gear and like it. I also run AC and really enjoy the cruise down the highway.
 
My MKVI Bentley has a 3.54 instead of a 3.727 and it too, is a big improvement, because the engine is so torquey. However I'd advise against higher axle ratios with sports cams that push the revs up, but at the expense of torque.

My TR3A has overdrive, a 3.54 and a fast street cam and it only just gets away with it. More gearchanges are necessary and you're out of overdrive more often, whereas my Bentley still pulls from 12mph or 500 rpm in top.

I'll fit a 3.54 with overdrive to my BJ7, which pulls from 600 rpm in top like the Bentley.
 
EV2239 said:
My TR3A has overdrive, a 3.54 and a fast street cam and it only just gets away with it. More gearchanges are necessary and you're out of overdrive more often, whereas my Bentley still pulls from 12mph or 500 rpm in top.
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The Toyota trans gives a more usable first gear which provides increased 3.54 drivability in a situation like the Triumph above or perhaps in a 100-4.
 
thanks, sounds like I will need to modify the modification before I drive the car, I get it do it at least 3 times to get it right

Phil
 
Just an update on the diff - Now that I've had the car out on a few drives (still running it in) I can say that I wish I had changed it earlier! I love it.
 
Rob Glasgow said:
BJ8TONY, I think it's the best modification for all the reasons Bob mentioned above. It really makes the car a pleasure to drive.

Keith, I believe the 3.54 ratio was standard on Healey's made without an overdrive. The OD was an option on the early cars but not many were build without OD. That's why those rear ends were scarce. I don't know if the later cars (BJ8) all came with OD and the 3.9 ratio.
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Overdrive was always optional equipment on BJ8s, although almost all cars had it from the factory -- especially those coming to North America. Most BJ8s that did not get factory O/D were Home market (RHD) cars. Occasionally, someone would order their car without O/D. There are some BMIHT records showing where an O/D gearbox (and engine with the O/D code in the serial number) was exchanged at the factory for a non-O/D gearbox (which also required changing the engine to one without the O/D code in the serial number). The only reason I can fathom for anyone doing this was just to save a few bucks.

The 3.909 rear end was standard for O/D-equipped cars.

I also got in on the first production run by Mike Lempert, and I agree that it's the best mod I ever did to my car. I've put 110,000 miles on my BJ8 since 1984, most of that on long-distances cruises, with 52K on the 3.54 gears. Having the 3.54 with O/D makes all the difference in the world as far as comfortable cruising is concerned.
 
Its so 'right' that I wonder why they didn't leave the factory like that. My engine is a bit stronger (just fast road spec) than it left the factory though, which might make some difference...
 
My Bn4 makes only 4hp more than the claimed factory output and works like a dream with a 3.54 out of a Wolseley 6/110 automatic. Imagine the money they'd have saved if all cars had the one ratio... Andy.
 
There are some mechanical considerations that may have influenced the factory decision to use a numerically higher (but "lower-geared") differential ratio of 3.909, rather than 3.545, with overdrive-equipped cars. Wikipedia has some interesting information about this: "Overall drivetrain reduction comes down to three basic factors: transmission gearing (including overdrive), differential gearing (in the axle), and tire size. The rotation speed problem comes into effect when the differential gearing is a high ratio and an overdrive is used to compensate. This may create unpleasant vibrations at high speeds and possible destruction of the driveshaft due to the centripetal forces or uneven balance.
The driveshaft is usually a hollow metal tube that requires balancing to reduce vibration and contains no internal bracing.
The higher speeds on the driveshaft and related parts can cause heat and wear problems if an overdrive and high differential gearing (or even very small tires) are combined, and create unnecessary friction. This is especially important because the differential gears are bathed in heavy oil and seldom provided with any cooling besides air blowing over the housing."

By "high ratio" above, I would interpret that to mean in this case the "higher" geared 3.545. The complete wikipedia article is at https://en.wikipedia.org/wiki/Overdrive_(mechanics)
 
Steve

Wouldnt it be the other way around? The 3.54 (used with an overdrive) ratio allows everything preceding the diff to be at lower rpm for a given ground speed? High ratio would surely mean something like the 4.3?
 
i put the 3.54:1 gears in my '65 BJ8 10 years and have been very happy ever since ......
 
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