Gear Ratios

[steveg]

Hi Ray, I was always a little disappointed in the results of my 3:54 gear change in that it didn't drop the rpms enough for my satisfaction. But there is no denying it is a help, obviously. I have 165 tires and my rpms run between 2700 & 2800 rpms in OD with the 3:54 gears at 65 mph. I was hoping that it would be more like 2500 rpms. As a reference my '70 Vette runs about 2500 rpms at 65 mph with 3:08 rear gears and similar diameter tires. I verify the speed in both cars with a gps unit so speedo calibration is not a factor in these figures. If I could get 3:08 gears for the Healey I would do it because I believe the torgue of the engine is satisfactory for street use.

IMO your 165 tires are too short.
The 28% OD, 180 x 15 michelins & 3.54 axle: 3000 rpm is about 78 mph. Closer to 2500 at 70 mph.

 

[RAC68]

Hi All,

How difficult would it be to convert another car's R&P to an AH? What would make the job least difficult and still give us choice? Is our rear so different from other British cars to make it unique? Would it be simpler to acquire a full rear housing, with chosen rear gear set, and modify to accept the Healey's hubs and match its suspension mountings?

At the scarcity price of a 3.54 conversion, I can't help but believe we could find a way to widen our choice of ratios and widen our Comfortable driving experience. When new, I drove my Healey on a 13K odyssey from cost to cost and boarder to boarder. Back then, driving at 60MPH was driving fast. Today, even local Highways have slow moving traffic exceeding 65MPH and as Gonzo stated "

Healey needs longer legs to cope and not become a hazard to navigation​

". I have made every change (except in-line fuses) reversible and would like maintain that practice with this change as well. Although I would prefer just exchanging pumpkins, replacing a full rear back to original could also be an option.

Is what I am thinking reasonable, ridiculous, impractical, too expensive, etc.?
Ray(64BJ8P1)

 

[Michael Oritt]

Ray--

I'm sure that Nasty Boy owners and others have installed different rear axle tubes, axles, and differentials for lots of reasons, but I believe you'll spend a lot more doing any of the alternatives you mention than you will on a 3.5 ring and pinion even after having it installed and set up. If you want to lengthen your car's legs the quick and easy way the diff sets available are pretty close to bolt-in and you will know what you are getting without having to re-engineer a critical section of your car's driveline.

 

[steveg]

Ray--

I'm sure that Naty Boy owners and others have installed different rear axle tubes, axles, and differentials for lots of reasons, but I believe you'll spend a lot more doing any of the alternatives you mention than you will on a 3.5 ring and pinion even after having it installed and set up. If you want to lengthen your car's legs the quick and easy way the diff sets available are pretty close to bolt-in and you will know what you are getting without having to re-engineer a critical section of your car's driveline.

Agree strongly. People I know who've installed the 3.54 gears have wished they'd done it 10 years before. Of course we live in the west and often have to drive freeway miles to get to the fun roads.

 

[vette]

Steve, I agree with your assessment of the tires and OD ratio. I'm still on the fence about moving up to larger tires and I don't honestly know what my OD ratio is.

"The 28% OD, 180 x 15 michelins & 3.54 axle: 3000 rpm is about 78 mph. Closer to 2500 at 70 mph."

It would seem to me that if Ray or myself or others want to help with some crusing comfort then your configuration as stated above would be the simplest and probably the least expensive as well. As well as keeping everything specific to Healey.
What would be the best way to verify the OD ratio? Thanks.

 

[HealeyRick]

Nice but necessary?

​Maybe I'm being a contrarian, but is a 3.54 rear really necessary to enjoy modern highway cruising? I was just reading a story on the opening of the M1 in the UK in 1959. A Daily Herald reporter took a Healey to 130 mph. The Healey was well-known for being long-legged and a great choice for Continental touring. Speed limits in the US are generally in the 50-75 mph, right where they were when the cars were new. I'm wondering if it is just that we've become so used to quieter cars in recent years that the Healey feels "overstressed" on the highway. A car with a top end of 130 mph shouldn't have any trouble keeping up with today's traffic. Maybe a pair of earplugs to quiet the car down would be a cheaper alternative than a set of new gears. (True confession, my Nasty Boy with a 5 spd and 3.54 rear turns 2,000 rpm at 70 mph).

 

[steveg]

Steve, I agree with your assessment of the tires and OD ratio. I'm still on the fence about moving up to larger tires and I don't honestly know what my OD ratio is.

"The 28% OD, 180 x 15 michelins & 3.54 axle: 3000 rpm is about 78 mph. Closer to 2500 at 70 mph."

It would seem to me that if Ray or myself or others want to help with some crusing comfort then your configuration as stated above would be the simplest and probably the least expensive as well. As well as keeping everything specific to Healey.
What would be the best way to verify the OD ratio? Thanks.

There's a brass plate conveniently located on the top of the OD - the first number is the percentage. You can just make out the 28 on mine. Apologies for the lame pic:

 

[red57]

I agree with HealeyRick. These cars were supposed to be sporty, not smooth like the family sedan so noise, wind, snappy handling & acceleration sort-of come with the territory and, in my case are mandatory. Part of the fun of canyon carving is the echoes of your own motor at 2800 or 3000. My 100-6 still has the 4:10 with a Quaife and I love it, I tried a 3.9 for a while but the car didn't feel as 'lively', gears are 'torque multipliers'. I don't have a very hot motor, maybe 170-180hp or so and on the track the top speed I have seen is about 125 and I'm not out of revs, so why would I want a taller rear end and give up some 'torque multiplier'? As for the highway, I've logged a lot of miles over the years and 3500 on the freeway is no problem, these motors are not stressed even at 4000+rpm.

 

[vette]

I suppose it is relative to each of us about what we consider a good crusing rpm. Yes the motors will run 4k rpm all day long but is it comfortable when doing it all day long for a couple days or more. And I am sure that you among us who track their cars will attest that these engines can take it. But even high rpms on track on and off the go pedal don't equate to continuous high rpms on an interstate for 7 or 8 hours. Yes the cars will do it, do I believe that alot of highway miles at above 3500 rpms will contribute to more wear on the engine, yes I do believe that. And many of our engines are not as prestine as they were back in the '50s and 60s. Lower rpms just makes things go better. (unless your racing). When I mentioned that my '70 Vette runs about 2500 rpms at 65 mph I consider that a good reference. You can note that many american cars before the advent of Automatic Overdrive transmissions ran around 2500 rpms at highway speeds back then. Wonder why? Because it contributed to a more comfortable ride and long engine life. If I could just get my Healey down to 2500 rpms at 65 I know my ear drums would appreciate it. Back around 1971 four cars left New London Ct for a weeks trip into Canada and and Old Quebec City. They were an MGA, 2 MGBs and an MG Midgit. I can tell you that each of those cars were exceedingly quieter than a Healey. An we were running between 3500 and 4000 rpms all week. Would they still be running today, probably not the way we ran them.

 

[Michael Oritt]

It makes a world of difference in the comfort level to reduce rpm's at the same ground speed, and I think it works out to a 12% reduction when going from a 3.9 to a 3.5. It's like walking downwind versus upwind and even though the car is doing the work the strain translates to the way it feels, esp. when you momentarily lift the gas pedal. It's not just the lower engine noise level--if you have overdrive I am sure you probably already know that shifting between 4th and 4th OD simply feels more relaxing at the same speed.

 

[RAC68]

Hi All,

Back in my younger days, my resilience, self reliance, and positive outlook were such that I would confidently drive my Healey anywhere. Highway speed limits seemed a suggestion and, although we didn't go crazy when exceeding them, 60 mph was a direct translation for a 50 mph post with 65 mph pushing it. Today, I drive across state on a local 4 lane road and the average driver sees 65 mph on the 55 mph sign with others 70 and 75. Although still the +10 mph in theory, actual speed has gone up much higher and where the common drive distance then would have been 15 or 20 miles, now 50 or even 100 miles is not uncommon.

As one who has resisted this rear gear change for decades and likes driving my Healey around town as it is, a once common trip to Mass is now not anticipated as enjoyable but concerning. Add to the fact that this trip will feel like I'm pushing the car there and I wonder if I have the stamina.

As I see it, when all is said and done, paying close to $1000 to gain a 12% advantage is ridiculous. So, I have 2 alternatives. The first would be to find a more economical mechanical approach and the second to only drive back roads. From the feedback already received, the primary alternative to installing a 3.54 would be more expensive and only driving on back roads is unrealistic. So, what do creative minds think is a reasonable alternative ....one with a cost closer to $300 as a target?

The beauty of the Healey is in the creativity of their owners.
Ray(64BJ8P1)

 

[Michael Oritt]

Ray--

Assuming you have the tires you want there is no way for you to raise speed without raising rpms. Perhaps you must learn to be content driving in the right lane at something below the now-higher speed limits. A good sound system might be helpful--oh wait, we just talked about that....

 

[HealeyRick]

Ray,

The drive up the Rte 95 corridor from Jersey to Mass. is a miserable one in almost any vehicle. There may be more than just rpms that are a factor with huge traffic jams, giant semis next to you and inattentive drivers being just a few that come to mind. I prefer to go around the city and take the Palisades Pkwy to the Sawmill to I-684 to 84 up to the Mass Pike. It's not perfect but probably a route better suited to a Healey than trying to battle Rte 95.

 

[RAC68]

Rick,

Having worked for Digital Equipment for many years with offices in Marlboro, Mass and Nashua, NH and refusing to relocate for family reasons, at the end I traveled the route you suggested every Sunday and Friday nights and would be the path I take.

Michael,

Although I have quite a substantial sound system and do enjoy driving while listening to the Beach Boys, after driving a 3.54 Healey, I can see how it would make a long drive more enjoyable. If WE can't come up with a reasonably priced alternative, music will be part of my alternative plan. However, driving Rt 84 from Hartfort to the Mass Turnpike is an awfully boring high speed stretch and one that music can't help.....maybe books on tape.




Ray(64BJ8P1)

 

[vette]

I have planned to take the Healey to the British Invasion for the last two years but have not made it. But i have mapped out the route. Avoiding almost all stretches of 4 lane highway (and my wife's supportive comment to "just make two days of it") I mapped out 2 lane roads up thru the Adirondacks with a stop over near Lake George, then across near Albany then near Bennington,Vt and north. I even internet searched possible repair garages along the way if necessary. I would consider the trip fun and pleasurable, much more so than droning on on the Super Slabs.