2.25 engine rpm

[harry]

i suppose someone here has already posted an informative article on this,
i have been looking at fitting a tachometer, sorry rev counter to my series IIA which has a 2.25 petrol engine,
however i have been unable to find what rpm this engine operates at.
most importantly is max rpm for sustained cruising, obviously as these little jiggers don't exactly like to sit on 100 kph in todays world and i am frightened of breaking it.

so can anyone help me with what the factory rpm reccomendations may have been?

thanks for your help.....:cool:

[101 Ron]

My experience is the little 4 banger is unbreakable.
80 kph/50 mph is a good cruise speed.
I have had a ex army 2a up to 75mph.......wouldn't recommend sitting on that speed for a long period of time.

[harry]

yep, i think it sits well at 80 with a couple of indescrescions to 90'
but i really want to know rpm, so my rpm ear can get recalibrated.

i have looked at kph speedo's as well, but that ain't original.

[isuzurover]

This may help: Ashcroft Transmissions - Ratio Calculator (http://www.ashcroft-transmissions.co.uk/calc/ratio_calc.html)

2.25P was 4250 max rpm, 2.25D 4000.

4000 rpm will give you ~70 mph on 32's (7.50s).

As Ron said the 2.25P is pretty hard to break. At one point I do recall having the speedo wound past the numbers on the Newell Hwy... ~80 mph...

Edit: ~2800 is 50 mph, ~3600 is 60 mph. Again on 32" tyres.

[harry]

This may help: Ashcroft Transmissions - Ratio Calculator (http://www.ashcroft-transmissions.co.uk/calc/ratio_calc.html)

2.25P was 4250 max rpm, 2.25D 4000.

4000 rpm will give you ~70 mph on 32's (7.50s).

As Ron said the 2.25P is pretty hard to break. At one point I do recall having the speedo wound past the numbers on the Newell Hwy... ~80 mph...

Woo, I will look that up, thanks.
80 mph might be a death sentence for a 42 year old engine!

[cookey]

i suppose someone here has already posted an informative article on this,
i have been looking at fitting a tachometer, sorry rev counter to my series IIA which has a 2.25 petrol engine,
however i have been unable to find what rpm this engine operates at.
most importantly is max rpm for sustained cruising, obviously as these little jiggers don't exactly like to sit on 100 kph in todays world and i am frightened of breaking it.

so can anyone help me with what the factory rpm reccomendations may have been?

thanks for your help.....:cool:


For all Series 2, 2a, 3 2.25 petrol
7.50x16 tyres
Road speed in 4th gear / rpm
40 mph / 2268 rpm
50 mph / 2835 rpm
60 mph / 3402 rpm
70 mph / 3969 rpm
Providing the engine is in good order it will sit on 4000rpm all day, although at higher speeds the noise will drive you crazy and the fuel consumption increases dramatically.

Cookey

[JDNSW]

The 2.25 (diesel or petrol) is quite happy to run all day close to maximum power rpm (over 4,000rpm), which is over 100kph.

There are a couple of provisos - cooling system must be in good shape, and for the petrol engine lead replacement supplement should be used.

The petrol engine will use a lot of fuel at these speeds.

Compared to many modern engines, these engines are very flexible, pulling smoothly from idling up to maximum rpm, although not powerful by modern standards. But operating at high rpm is probably preferable to using the same power at lower rpm, as cooling (both waterjacket and oil) will be less due to lower rpm of the water pump and oil pump.

The use of an overdrive will give the driver a quieter life, and perhaps lower fuel consumption, but there is no evidence that I am aware of that it affects engine life.
John

[Johnno1969]

The 2.25 (diesel or petrol) is quite happy to run all day close to maximum power rpm (over 4,000rpm), which is over 100kph.

There are a couple of provisos - cooling system must be in good shape, and for the petrol engine lead replacement supplement should be used.

The petrol engine will use a lot of fuel at these speeds.

Compared to many modern engines, these engines are very flexible, pulling smoothly from idling up to maximum rpm, although not powerful by modern standards. But operating at high rpm is probably preferable to using the same power at lower rpm, as cooling (both waterjacket and oil) will be less due to lower rpm of the water pump and oil pump.

The use of an overdrive will give the driver a quieter life, and perhaps lower fuel consumption, but there is no evidence that I am aware of that it affects engine life.
John

Hey John,

I can see the point, but I have always felt more comfortable about the engine at higher speeds when I have the overdrive engaged (and in my car it's always been noisier with it engaged anyway - just a different noise (gear whine) replacing engine roar). Once I nudge over 50mph I just feel more comfortable knowing that I am not holding the engine up high in its rev-range for extended periods. Perhaps I actually needn't worry; it's interesting to read what you say.

I have definitely found the 2.25D really tractable. It lugs away off the mark really easily and pulls smoothly up to where it runs out of puff...

Cheers,

John

[UncleHo]

G'day Harry

I have had my 109 GS 2a up to 100kph no overdrive,and the sound of valve bounce is deafening! But,it will happily sit on 85-95 which would be about 3800-4000 rpm BUT, I run extractors and a 2 inch system with a hotdog muffler,throaty yes,but get 14-16 mpg on a highway run,I should get a Tacho for it,Ihave a good cooling system and use a full mineral oil in 20W40 spec by Penrite,most of my use has been at highway speeds living close to Bribie and needing to travel to Caboolture regularly.Yup! and I run 750-16 's


cheers

[JDNSW]

At 100kph there should be no valve bounce - it is below the rated maximum power rpm, and in any case, if you can hear valve bounce over the intake roar, wind noise, tyre noise, gear noise and body rattles, not to mention flapping canvas and fan, you have far better hearing than I have.

While I do not often drive my 2a on the highway, when I do, I routinely drive at 100kph, without issues. While I have an overdrive, I do not use it on the highway (too noisy), only using it as a gear splitter in offroad low range. I too have 7.50x16 tyres.

John

[series3]

Hey John,

How is your fuel consumption on 100km/h runs? Does it increase dramatically over say 80-85km/h or just a bit?

Sam

[isuzurover]

At 100kph there should be no valve bounce - it is below the rated maximum power rpm, and in any case, if you can hear valve bounce over the intake roar, wind noise, tyre noise, gear noise and body rattles, not to mention flapping canvas and fan, you have far better hearing than I have.

While I do not often drive my 2a on the highway, when I do, I routinely drive at 100kph, without issues. While I have an overdrive, I do not use it on the highway (too noisy), only using it as a gear splitter in offroad low range. I too have 7.50x16 tyres.

John

I too used to do 100 km/h runs daily when my IIA was a 2.25P and I used it as a daily driver.

Fuel consumption was 17-18 l/100.


Hey John,

How is your fuel consumption on 100km/h runs? Does it increase dramatically over say 80-85km/h or just a bit?

Sam

Only a bit.

FWIW, I did the nullarbor in a 2.25 D on 90-100 without an OD (but with ear plugs). Averaged about 9.5 L/100.

[JDNSW]

Hey John,

How is your fuel consumption on 100km/h runs? Does it increase dramatically over say 80-85km/h or just a bit?

Sam

Bit hard to say. Most of the time it is used offroad on the property or across neighbour's places to the village, and when on the road it is a long way to anywhere, so I must admit I have not really tried driving moderately on road far enough to measure the consumption. Both on long trips and offroad consumption remains around 18l/100km.

John

[harry]

i hadn't thought about fuel consumption, but i was trained early, my first car was a 49 vanguard, 18 mpg, so anything better than that is great.
you gotta burn it to go, so lets go.

thanks for your comments,
just had a good weekend drive around, absolutely no idea of consumption or mileage as the speedo reads in mph about half of the gps kph readout,
but about half a days drive means add 35 litres, which is meaningless...

[incisor]

but about half a days drive means add 35 litres, which is meaningless...
not quite, it means you had about 5 usable ones left... :D

[harry]

not quite, it means you had about 5 usable ones left... :D

which I could have used to take me 20 odd miles from the nearest petrol supply...

but like all sensible series owners, I carry spare fuel in a jerry can.

and have an overhauled second tank in the garage to fit one day.

[UncleHo]

They do about the same as a V8 Disco, a 49 Vanguard,with the rear wheel spats and the one with the right hand column gear change,dad had one,and if you rushed 1st to 2nd it would jam,and my job was to lift the bonnet and unlock the levers,it was traded for a 54 Spacemaster sedan.

cheers

[vnx205]

They do about the same as a V8 Disco, a 49 Vanguard,with the rear wheel spats and the one with the right hand column gear change,dad had one,and if you rushed 1st to 2nd it would jam,and my job was to lift the bonnet and unlock the levers,it was traded for a 54 Spacemaster sedan.

cheers

With a right hand column change, you wouldn't have been able to signal a right turn and change gear at the same time, would you?

I have a vague recollection of some other vehicle I travelled in as a passenger have a similar problem of the gear change mechanisms getting confused. I think something used to go over centre when the parts were a bit worn. It might have been a side valve Hillman.

[JDNSW]

....
I have a vague recollection of some other vehicle I travelled in as a passenger have a similar problem of the gear change mechanisms getting confused. I think something used to go over centre when the parts were a bit worn. It might have been a side valve Hillman.


I remember a similar problem with my b-i-l's 49 Ford Custom.

John

[UncleHo]

G'day JDNSW.

Yup! All the custard lines had the same problem,US gearboxes with the shift mechanism on the left side of the box,and the Aussie bracketing bolted to the bottom to give access to the right hand column levers,I had several Customs and Customlines and they were all worn in the X-over linkages,brazing/wielding flat washers to the worn holes was a common fix.


cheers

[harry]

the old rh shift was good, as you could seat four in the front, we were skinnier then, arm around the girlfriend, bottle of beer in hand and still change gears.
didn't have spats, earlier than that!
spacemaster, got one for parts, chopped it up with an axe and buried it under the silkworm tree!
right turn signals,
just hang the gear first and stick the arm out.
mine had trafficators, so no need to stick the arm out..