Thread: From the ground up?

Originally Posted by Pedro_The_Swift

What do you mean by hi speed JD ??

Engines that turn at around the same rpm as a comparable petrol motor. The 2.0 diesel was able to use exactly the same drive train ratios as the petrol motor. From memory the maximum rpm was 3600, compared to about 4,000 for the petrol motor. A good comparison would be the Turner conversion that was the aftermarket diesel offering before that had a maximum rpm of about 2,000, and seriously compromised performance. (It started life as a boat engine!)

Originally Posted by Fifth Columnist

Freelander TD4............?

No. These engines are unrelated (as I suspect you knew!)

Originally Posted by JDNSW

Engines that turn at around the same rpm as a comparable petrol motor. The 2.0 diesel was able to use exactly the same drive train ratios as the petrol motor. From memory the maximum rpm was 3600, compared to about 4,000 for the petrol motor. A good comparison would be the Turner conversion that was the aftermarket diesel offering before that had a maximum rpm of about 2,000, and seriously compromised performance. (It started life as a boat engine!)

Some early Pommie diesel engines for truck and bus power were governed to below 1,000rpm.

Originally Posted by JDNSW

No. These engines are unrelated (as I suspect you knew!)

The K series was part of the 4-5-6 family. BMW killed it and used their own Td4 instead.

This thread popped into my email, so thought I'd add a little more.

Diesel RPM is limited by Cetane number. Cetane number is similar to Octane rating. Unfortunately Cetane number cannot be increased but may be lower.

Cetane number is a measure of among other things "flame rate". Unlike petrol one cannot add a flame rate retarder so as to be able to increase the ignition advance. As recall max rpm on a mechanical injected engine is around 35-3700 RPM. With a digital control "hot rail" this engine speed can be increased to around low 4000s.

Having said all that I recall an electrical generator used for aircraft starting @ 115VAC and operation of avionics with AC frequency control of engine speed for electrical output. - a NC2. This had a GE two stroke high speed diesel which I think could rev well past the 3500 limit I mentioned above. (or maybe not??)

Cheers

RF

Originally Posted by Rick Fischer

This thread popped into my email, so thought I'd add a little more.

Diesel RPM is limited by Cetane number. Cetane number is similar to Octane rating. Unfortunately Cetane number cannot be increased but may be lower.

Cetane number is a measure of among other things "flame rate". Unlike petrol one cannot add a flame rate retarder so as to be able to increase the ignition advance. As recall max rpm on a mechanical injected engine is around 35-3700 RPM. With a digital control "hot rail" this engine speed can be increased to around low 4000s.

Having said all that I recall an electrical generator used for aircraft starting @ 115VAC and operation of avionics with AC frequency control of engine speed for electrical output. - a NC2. This had a GE two stroke high speed diesel which I think could rev well past the 3500 limit I mentioned above. (or maybe not??)

Cheers

RF

I think your memory may be a little shaky - maximum power for the Rover 2.25 is at 4,000 - which I believe is also the maximum governed rpm. The 2.0 six years earlier, was only able to run at 3,500 maximum rpm in 1965. It is unclear just what allowed the extra rpm, but it was probably refinement to the shape of the precombustion chamber and closer machining tolerance on the crankshaft to manage the higher loads. And these engines were definitely mechanically injected!

Originally Posted by Rick Fischer

This thread popped into my email, so thought I'd add a little more.

Diesel RPM is limited by Cetane number. Cetane number is similar to Octane rating. Unfortunately Cetane number cannot be increased but may be lower.

Cetane number is a measure of among other things "flame rate". Unlike petrol one cannot add a flame rate retarder so as to be able to increase the ignition advance. As recall max rpm on a mechanical injected engine is around 35-3700 RPM. With a digital control "hot rail" this engine speed can be increased to around low 4000s.

Having said all that I recall an electrical generator used for aircraft starting @ 115VAC and operation of avionics with AC frequency control of engine speed for electrical output. - a NC2. This had a GE two stroke high speed diesel which I think could rev well past the 3500 limit I mentioned above. (or maybe not??)

Cheers

RF

2 stroke diesels are in a class of there own...

8V71 is probably the best all rounder that GM made, and in a truck non turbo it produced around 318 hp max with turbo to 350.... But what a lot dont know is it can rev to 5,000 rpm...standard truck is 2,300 and 3,500 is not a problem for long hours, but to maintain 5,000 it is only for minutes... It was an engine recommended for landing craft, thus 5 minutes high revs but continuous at lower revs....

Reading JDNSW's post, I knew about the early Rover engines being in house built(Grew up with them), but I didnt realise the V8 is another buick... There has been a lot of claims that engines originated from Buick and other without any proof... As for the early Rover engines, I dont think many manufacturers pre 1950, shared engines, most made there own, so Rover did well building there long stroke little engines, but that was a standard for low revs, high torque engines, in the day....

One thing people forget, if you want speed on road, you have to give up something....

Originally Posted by Wraithe

One thing people forget, if you want speed on road, you have to give up something....

usually money,,