Throttle Pedal Height

[a1barry]

Hi Folks,

Have recently purchased a 1964 Austin Healey 3000 BJ8 that has been converted from left to right hand drive. The problem that I am having is that the throttle pedal height appears to be far too high in comparison to the brake and clutch pedal and it is uncomfortable to drive.

Is there a process to rest the height of the pedal? does it involve altering the 'bump stop' and is that a standard part?

Thanks in advice of your input.

Barry.

 

[Bob_Spidell]

Yeah, that pedal height is not correct; it should be level with or, maybe, slightly above the other pedals. I just started fussing with my linkage--LH drive--after changing the 'relay shaft' bushings, and I'm not a pro on this, but I can offer some suggestions. At idle, the throttle plates are stopped closed by a small tab on the intake manifold and a bracket on the throttle interconnect shaft. The pedal height is determined only by the 3 (or more) connecting rods and a lever; item# 38 on this page:

https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28873&SortOrder=10

You should be able to change the pedal height by loosening this lever--note: mine looks different, but it'll be on the footwell where the pedal shaft comes out into the engine bay or, for a RH drive car it might be on the opposite end of the shaft--and changing the position of the lever relative to the shaft. But, you'll want to check that the throttles come to the stop at idle, and open fully when the pedal is pressed to the floor. There is a fairly complicated setup procedure in the shop manual, and it involves adjusting the distances of all the adjustable rods on the linkage. I suspect you can just change the position of this lever WRT the pedal shaft, but check that throttle closed and fully open are still obtainable with the new setting.

 

[John Turney]

The throttle pedal height should be 2 1/2 inches.

 

[Duane_Rhynard]

From your picture it looks like the gas pedal assembly was installed 180 degrees off in relation to the linkage. On the early (BN4/BT7/BN6/BN7) LHD cars (Picture Below) their are two positions that the gas pedal shaft can be attached, since there are two flat spots for the bolt. In the incorrect position, the pedal would be way too high. I know the RHD BJ8 shaft is longer, the shaft end and the short attaching arm are different, but I think this still applies. Let us know what the outcome is!

Thanks,
Duane

 

[Bob_Spidell]

That's the lever I was talking about; although, on my BJ8 the clamp end is more box-shaped--as you noted--and can be installed in any position; i.e. no flat spot. Barry has a BJ8, so he probably has the later style clamp/lever--that would be the first thing to check. You want the correct pedal height at idle, but you also want to be sure the throttles fully open when you apply 'pedal to the metal.'

 

[Duane_Rhynard]

That's the lever I was talking about; although, on my BJ8 the clamp end is more box-shaped--as you noted--and can be installed in any position; i.e. no flat spot. Barry has a BJ8, so he probably has the later style clamp/lever--that would be the first thing to check. You want the correct pedal height at idle, but you also want to be sure the throttles fully open when you apply 'pedal to the metal.'

Barry,

Bob is correct, your BJ8 gas pedal and clamp arm should look like the pictures below, (Courtesy of AH Spares!) and is able to be installed in any position. As Bob stated earlier, the shop manual has a detailed description on how to set the pedal and linkage. If you don't have a manual yet, it is really worth having one. If you don't have one yet, let us know, I can post a picture of the page.

Thanks,
Duane

RHD Pedal

Clamp Arm

 

[a1barry]

Hi guys,

Managed to sort it thanks.

I used the method as shown in the manual by releasing the pinch bolt.

It was the pedal 'bump stop' that threw me. On removing it, it is obviously home made. I can only assume that it had been previously been owned by a vertically challenged person with short legs.

Thanks again guys.

Hi Folks,

Have recently purchased a 1964 Austin Healey 3000 BJ8 that has been converted from left to right hand drive. The problem that I am having is that the throttle pedal height appears to be far too high in comparison to the brake and clutch pedal and it is uncomfortable to drive.

Is there a process to rest the height of the pedal? does it involve altering the 'bump stop' and is that a standard part?

Thanks in advice of your input.

Barry.

View attachment 47719

 

[Randy Forbes]

I kind of went in a different direction__at least as far as the pivot-point goes__when I was setting mine up with Weber carbs. I had always hated the original linkage's vagueness, and it never seemed to return to the same spot twice. I was able to do away with plastic/nylon & grommet pivots in the process.

We all know that Healeys were designed well over sixty (>60) years ago, and few things were ever redesigned/changed unless mandated, but I can't help but think the entire throttle linkage, from pedal to carbs, was the least well thought out system on the entire car. Back in the day, Healeys were frequently being towed into the shop when the throttle linkage fell apart; only those that knew the "flat paths" around San Francisco could drive their cars in with the choke's fast-idle setting (can't get up some of those hills at <2000 rpm...).

[/rant]

I've since added Denis Welch brake & clutch pedal pads (polymer coated in gloss black, along with the accelerator pedal) but here's the general layout. Whenever I drive a Healey with the original setup, I am immediately reminded of its shortcomings.

 

[Bob_Spidell]

So .... You reverted to the 100's 'pivot-on-the-floor' layout

I've got both--in a BN2 and a BJ8--but the BJ8 setup seems to be a little smoother, but we may not have the BN2 setup aligned perfectly. Now, I'm trying to assure I'm getting WOT in the BJ8 when the pedal is fully depressed; there's so much slack in Rube Goldberg's throttle design it's hard to get it all out and not overstress the linkage. Advice welcome.

 

[John Turney]

first thing is to make sure the bushings are tight - replace the felt ones with Teflon. Then adjust the ball joints so they are tight. Finally, have someone make sure you're at WOT when the pedal is all the way down. Adjust the relaxed height so you are.

 

[Bob_Spidell]

first thing is to make sure the bushings are tight - replace the felt ones with Teflon. Then adjust the ball joints so they are tight. Finally, have someone make sure you're at WOT when the pedal is all the way down. Adjust the relaxed height so you are.

Thanks. Worked on that today.

 

[rgfrey]

Hi all!

I'm having the same issue with the pedal height except now when I push the pedal back down to the floor the carburetor linkage doesn't move to open the butterflies on the carburetors. Duane, can you post the picture from the manual that you spoke of earlier please? And, can anyone point me in the direction to get a good shop manual? I can't seem to locate where the accelerator pedal shaft comes out and has it's first connection with the linkage under the hood. My car is a 1959 Austin Healey BN4 100/6 LHD.

Thanks ahead of time for anyone's input.

rob

 

[Healey Nut]

See attached

 

[BobHaskell]

And, can anyone point me in the direction to get a good shop manual?

Used factory manuals are available on ebay. Bentley Publishing reprinted the factory manual. Haynes also did a workshop manual.

 

[rgfrey]

Thanks Luke and Bob.

 

[Bob_Spidell]

Hi all!

... I can't seem to locate where the accelerator pedal shaft comes out and has it's first connection with the linkage under the hood. My car is a 1959 Austin Healey BN4 100/6 LHD.

Thanks ahead of time for anyone's input.

rob

The 'first motion' (sort of) for the throttle linkage is a shaft running from foot box to foot box, in the upper inner corners tucked under the scuttle/bulkhead and gearbox cover (at the very front; it's next to 'X' in Bob's pic). It's difficult to see, and all but impossible to access with the engine in the car and it sometimes gets bent when removing engine+gearbox (at least, I bent mine). It has felt bushings--later cars have brass/rubber--which are very likely shot, making it all but impossible to get good adjustment on the entire linkage. There are Teflon replacement bushings available (Moss has them).

If you're getting no motion at the carbs, one or more of the 'pinch' clamps is likely slipping; the interconnecting shafts are stout and have turnbuckles for adjustment. After I straightened the interconnection shaft, installed the Teflon bushings and adjusted the linkages per the book the throttle was so much easier to work I thought my throttle return springs had failed.

Wow, the manual has gotten expensive, but you pretty much have to have it (probably limited supply):

Bentley Shop Manual, 100-6 & 3000

Bentley Shop Manual, 100-6 & 3000

mossmotors.com

 

[rgfrey]

Bob,

Thanks for the input. I had a feeling access was going to be difficult. I still haven't been able to see the pinch bolt that is most likely slipping. As for the manual, I found one like the one you referenced a little cheaper so I'll order one today. I'll get out there again today and take a more educated look.

Thanks again.

rob

 

[rgfrey]

Solved! The pinch bolt on lever "A" was lose enough to allow the accelerator shaft to spin. I tightened the pinch bolt and it's holding...at least for now. I may need to get a new accelerator pedal assembly. I think the end of the shaft where the "A" lever pinch bolt attaches may be stripped out. I can't really tell unless I disassemble it and I'll wait to see if just tightening it holds.

Thanks all for the input.


rob