Vibration through accelerator pedal & best crusing speeds

[swood1]

Hi all,

 

I drove my car on it's biggest outing for 5 years yesterday. We did a whole 65miles up the motorway. Out of interest I didnt really go over 55mph, temperature and oil pressure both stayed the same. I am a bit relucatant to drive the car much faster, am I being over cautious? FYI. My car doesnt have overdrive.

 

Also, I noticed a bit of vibration through the accelerator pedal; I suppose the pedal is only working against a spring but just wondering if it maybe a good idea to replace or add a stronger spring on the pedal to reduce the vibration as the pedal push seems light.

 

 

Steve

[Paul Harvey]

Steve

 

TR engines go best when you drive them hard, at least some of the time.

 

It should be Revved to at least 4500 fairly often to keep it all sweet, and will run all day at 5,000 rpm in top quite happily.

 

If you have never tried this I suggest you do, assuming all the gauges indicate normal readings and you have no doubts about any new parts fitted recently.

 

Then report back about any minor sensations - adrenaline fixes most of these.

 

Cheers,

[Alec Pringle]

" I am a bit relucatant to drive the car much faster, am I being over cautious? "

 

Yes.

 

A non-overdrive TR6PI ought to be capable of cruising at the ton all day . . . . . .

 

Cheers

 

Alec

[swood1]

I have never dared to take the rev's up so high. Next time I take it out I shall give it some stick and report back.

 

It sounds like I am being over cautious....

[Lebro]

" I am a bit relucatant to drive the car much faster, am I being over cautious? "

 

Yes.

 

A non-overdrive TR6PI ought to be capable of cruising at the ton all day . . . . . .

 

Cheers

 

Alec

I think it's aTR4A

 

Bob.

[TR 2100]

Steve,

 

You are definitely being over-cautious - and them some.

 

But - be aware that there is invariably a band of engine

resonance at about 2800-3100rpm. Drive through this

and the engine becomes smoother.

65mph in a non-overdrive TR4 (assuming the standard

3.7 rear axle) equates to 3250.

 

Alec's comment above refers to TR6s that rev lower for

the same road speed.

 

AlanR

[RogerH]

Hi Steve,

the throttle pedal is hard connected to all the bits in the linkage so there may be some vibration coming in that way.

However the pedal shaft goes through the bulkhead and will get any body vibration that is going on .

 

It may be wise to check the timing and carbs to ensure they are as smooth as possible and look for any body issues.

You don;t want to be over revving it if the engine is lumpy etc.

 

At 55mph with no OD you are revving in the band where there is a resonance from engine/gearbox. Have you got the big steel lump hanging on the back of the box.

This was fitted by TRiumph to stop/reduce the resonance.

 

My car doesn't know what 5000rpm is I tend to run about 3000-3500. in top/OD.

However with the new crank I will have to eventually get some big revs under its belt.

 

Roger

[stillp]

Don't assume the roughness around 3000 rpm is just a TR 'feature' though. Mine turned out to be a loose propshaft flange.

 

Pete

[Alec Pringle]

Apologies, indeed a 4A, so that's a couple of pots and a decent induction system short . . . . . .

 

It should still pound the tarmac at 90 without batting an eyelid, and top the ton if the need arises, but 80 is a decent enough cruising speed,

 

Any TR cruising at 55mph on a motorway is a liability, and an embarrassment . . . . come on Steve, give it some beans, it won't bite you.

 

Cheers

 

Alec

[swood1]

Ha ha

 

It's is a TR4a. I shall open it up when I pick it up from my colleagues workshop, he's retrimming the whole interior for me.

 

Out of interest the previous owner fitted a TR6 gearbox with 3.7diff.

Edited May 17, 2016 by swood1

[TR 2100]

Normal TR4/4A diff is 3.7:1.

TR6 is 3.45:1.

TR6 gearbox alone doesn't change anything.

 

AlanR

[swood1]

 

It may be wise to check the timing and carbs to ensure they are as smooth as possible and look for any body issues.

You don;t want to be over revving it if the engine is lumpy etc.

 

At 55mph with no OD you are revving in the band where there is a resonance from engine/gearbox. Have you got the big steel lump hanging on the back of the box.

This was fitted by TRiumph to stop/reduce the resonance.

 

Roger

Hi Roger,

 

I rebuilt the carbs and they have been running fine and are both balanced. But I shall have a look at the linkage.

 

With regards the lump at the back of the box, I assume you mean gearbox? I dont know, is there any easy way to check for this?

 

Steve

[RogerH]

Hi Steve,

regarding the lump - simply look under the car.

The lump hangs down at the back of the gearbox and should be visible looking under the ccar from the side of the car.

 

Roger

[graeme]

Steve, this is what your looking for and for anybody who hasn't seen the 'lump', there is one currently on ebay.

 

http://www.ebay.ca/itm/Triumph-TR4-Original-Transmission-Tailshaft-Balance-Weight-/131811888140?hash=item1eb099cc0c:g:UHgAAOSw5ZBWOirl&vxp=mtr

 

Cheers

Graeme

[swood1]

Well I never. I shall have a look underneath, dont think I have seen one but I now know what im looking for.

 

Steve