285 replies to this topic

[EunUCh]

Nice looking 'old school' ute,sometimes going taller gears will give worse economy because the smaller engine will have to labor

for you to get up to speed which means foot buried more than usual.

I think a six usually ran 355 ratio on the stock wheel/tire combo. which equated to about 3000 rpm @ 100 kph....just above peak torque of engine.

 

A healthy 'in tune" 253 on 336 gears will probably give better economy if driven 'normally'(whatever that is),but because there is a bit extra

'power' there it will get used which may pull the the numbers down a bit.

 

Other alternative is a good six with triple SU's...you would be surprised at difference they make in pulling power...they won't rev harder on a stocker but get up nicer and make nicer power curve,,,bit of a cam and it would go a bit harder and still nice to drive....

Edited by EunUCh, 23 October 2014 - 05:33 PM.

[EunUCh]

Could always go a V6 conversion,keep 355 ratio,front springs,auto with overdrive,same rego. costs,might need to "tweak" the governer in trans. for the short ratio but should go ok and give good mileage.

Edited by EunUCh, 24 October 2014 - 05:09 PM.

[N/A-PWR]

Hello Danny,

 

Has the Tacho got a selector switch so you can select a 4/8 or a 6cyl engine?

 

im idling around 300-500, when i think i set it around 750-800

[N/A-PWR]

Hey Danny Mate,
 
I always had a workshop method that said a 3.55:1 is at 3500rpm @ 100kph. 
 
So I did a bit of research for you:-
 
Holdens with standard 14" rear wheels and tyres HK-HZ (say 195/75 SR 14)
will initially display the diff ratio on the tacho at exactly 100kph in top gear (1:1) in a Trimatic.
i.e a 3.55 will display 3550 rpm at exactly 100kph

 http://holdenpaedia....Ratio_selection

195/75-14
tire diametre=25.52
tire width=5.76
 
215/65-14
tire diametre=25.00
tire width=5.50

 

as you can see, both tires are almost exactly the same diametre.

So I say you have lost 500rpm from Idle right through the RPM Range, hmm.   

 

100ks is 3000rpm which is spot on, with 3:55 1:1 4th, and 215 65 14 tyres

 

 

Correct me if I am wrong, but am sure about this one. 

Edit:-

do you have the correct speedo gear in the transmission?

 14" wheels x 3.55 diff = Red 23 teeth

Edited by NA-PWR, 06 December 2014 - 10:31 AM.

[N/A-PWR]

Well, you are right after all Danny sorry,

 

after seeing that calculator I did the Maths ( should of done that first ).

 

 

I know where I went wrong, was using the 13" wheels back then ( 1980's ).

 

 

But this makes the Holdenpedia needing adjusting too, as that info there is not right hey.

 

 

3500 rpm divided by 3.55 = 985.9 rpm x 1995 mm ( 635 mm x 3.142 = 1995 mm tire circumference )

= 1966870 mm per minute x 60

= 118012230 mm per hour divided by 1000

= 118012 metres per hour divided by 1000

= 118 kph

 

i was using the gps and it said 100 and the tacho was right on 3000,

and i just did this aswell to double check everything http://www.osella.co...gear-ratios.htm

 

Good job, so 3000 rpm x 3.55 is 100 kph.

 

So I wonder what is going wrong at idle like you say. 

[Ice]

Mine sits on 3000 rpm at 100 ph with 3.55 and 13 inch rims

[Dave6179]

I no longer fart around with crap tyres. However... I put new Hankook RA03s on last year and they are crap! Even worse than some of the old second hand tyres I've used in the past. Hope the Mazda owner doesn't give you too much stick.

[Rockoz]

A few things Ive learned about tyres over the years.

 

Expensive tyres arent always better than cheaper tyres.

 

Wider tyres arent always better than skinny tyres.

 

Some expensive tyres can be lethally bad in the wet.

 

Cars will generally handle better with the exact same tyre on each corner. Mixing sizes and or brands can cause issues.

 

But. If the car is being driven by someone with little experience it can be advantageous to go a slightly narrower tyre on the front.

This will help with understeer. Learners can handle understeer better than oversteer. Plus they can see what they are going to hit.

 

For those on a budget.

Remoulds are better than retreads. There is a difference. But should still be treated with respect.

Second hand tyres from importers are a good budget choice.

[hawk]

I am currently a tyre fitter and see the worst of it. There are some really bad tyres out there.

Stick with the big brands like bridgestone, michelin and continental. Stay away from brands like maxxis, toyo and anything you have never heard of before.

Cheap tyres will suffer tread separation, bad wear and a much shorter lifespan.

[Rockoz]

I used to fit tyres too.

No machines.

Slide hammer bead breaker.

Tyre levers

Rubber Mallet.

Balancing with a spirit level machine.

[Rockoz]

Nah Bomber

Late 70s through to late 80s

Got technically better in mid 80s

Got a leverage system to break car beads.

But still had to do truck tyres with the slide.

Owner was too tight to buy equipment.

Luckily there wasnt a high volume.

Used to pump petrol for them too.

No auto bowsers.

Very late 80s he got a deal on an old KMart workshop and even got a 4 post hoist

Until then all work was done on stands/stumps or the timber ramp

[Rockoz]

It was unreal.

Learned so much from the old blokes.

It was originally started by their father.

The 2 brothers inherited it.

Money was always a problem,

Seemed one brother earned the money and the other brothers wife spent it all.

Anything that didnt have electronics they were absolutely fantastic with.

Made pistons with wood and bearings with leather during the depression

[Rockoz]

Sorry for the thread hijack Macca.

One of the old blokes friends owned a silver mine.
During the war he wasnt allowed to mine it unless all the silver went to the govt. or something.

So he stopped mining during the war.

But he didnt.

All the silver he mined he cast into 2 bob bits.

Its how he survived the bad years.