Marshall8hp
Well-Known Member
The D doesn't refer to anything, it is part of the engine number prefix.
GEMS
42D = 4.0 High Compression (9.35:1)
44D = 4.0 LC (8.2:1)
46D = 4.6 HC (9.35:1)
48D = 4.6 LC (8.36:1)
THOR
57D = 4.0 LC (8.23:1)
58D = 4.0 HC (9.38:1)
59D = 4.6 LC (8.37:1)
60D = 4.6 HC (9.37:1)
92D = 4.0 Canada
93D = 4.6 Canada
95D = 4.0 NAS (USA)
96D = 4.6 NAS
You also have:
61D to 68D for factory replacement short or stripped GEMS engines
73D to 84D for factory short or stripped THOR engines
As for capacity, which end of the tolerance specs do you want to use? The largest standard bore and stroke or the smallest? 4.556 is the usual number you see.
As for power, which engine prefix, which market etc. etc. Published data:
GEMS 4.0 = 132kW/140kW
THOR 4.0 = 132kW/136kW or 140kW in NAS
GEMS 4.6 = 157kW/165.5KW
THOR 4.6 = 150kW/160kW or 165.5kW NAS
GEMS
42D = 4.0 High Compression (9.35:1)
44D = 4.0 LC (8.2:1)
46D = 4.6 HC (9.35:1)
48D = 4.6 LC (8.36:1)
THOR
57D = 4.0 LC (8.23:1)
58D = 4.0 HC (9.38:1)
59D = 4.6 LC (8.37:1)
60D = 4.6 HC (9.37:1)
92D = 4.0 Canada
93D = 4.6 Canada
95D = 4.0 NAS (USA)
96D = 4.6 NAS
You also have:
61D to 68D for factory replacement short or stripped GEMS engines
73D to 84D for factory short or stripped THOR engines
As for capacity, which end of the tolerance specs do you want to use? The largest standard bore and stroke or the smallest? 4.556 is the usual number you see.
As for power, which engine prefix, which market etc. etc. Published data:
GEMS 4.0 = 132kW/140kW
THOR 4.0 = 132kW/136kW or 140kW in NAS
GEMS 4.6 = 157kW/165.5KW
THOR 4.6 = 150kW/160kW or 165.5kW NAS
300bhp/ton
Well-Known Member
Where have you seen the figures? Handbooks don't normally show power, as things can change.
Horse Power also has different units of measurement and different ratings/standards.
In some markets the use of a metric HP, which is sometimes written PS. But not always!
Imperial HP will give a different number. Although ultimately it is still the same power.
The 4.6 went through a few guises. Early ones had single exhaust. And quite a high HP claim. Although in the USA Land Rover were sued due to vehicles not making the claimed power. And they recalled them to make mods at the dealers. To my knowledge, nothing was done to UK/EU models, despite having the same claim of HP.
I'd guess when switching to the dual exhaust outlet power might have changed slightly and maybe was even part of addressing the fact they didn't make the power.
In 1999 the fuel injection system changed as did the intake manifold, known as Thor. These are technically rated lower output than the earlier ones. However that would seem a crazy thing to spend the R&D on. I suspect the truth is, the early models never made the claimed power. And the late model Thors are the most powerful.
Marshall8hp
Well-Known Member
The numbers are in HP to DIN standard and taken from the workshop manual. DIN HP is a closer reflection of true output as opposed to SAE HP which may be higher.
DIN requires that the engine is tested with all ancillaries connected, water pump, fan, alternator, exhaust manifolds, oil pump etc. SAE HP allows (or at least did allow) an the engine to be tested without the ancillaries being driven by the engine (so remotely powered water pump, no alternator, no fan, remotely driven oil pump etc.). SAE HP was designed to gauge the total output of the engine as a way to gauge one engine against another, as one may have a bigger fan, larger WP etc.
The fan on a P38, at full noise, can draw over 20HP, which is one reason replacing it with electric fans will never give anything like the airflow you get from standard. Electric fans can of course be set to cut in at lower temperatures and can run flat out with the vehicle at idle, so swings and roundabouts I guess.
DIN requires that the engine is tested with all ancillaries connected, water pump, fan, alternator, exhaust manifolds, oil pump etc. SAE HP allows (or at least did allow) an the engine to be tested without the ancillaries being driven by the engine (so remotely powered water pump, no alternator, no fan, remotely driven oil pump etc.). SAE HP was designed to gauge the total output of the engine as a way to gauge one engine against another, as one may have a bigger fan, larger WP etc.
The fan on a P38, at full noise, can draw over 20HP, which is one reason replacing it with electric fans will never give anything like the airflow you get from standard. Electric fans can of course be set to cut in at lower temperatures and can run flat out with the vehicle at idle, so swings and roundabouts I guess.
300bhp/ton
Well-Known Member
Reckon some of you live under a rock. SAE as you describe hasn't been used for nearly 50 ****ing years!!!!!!!!!!!!
As a rule DIN often uses PS or metric HP, so will show slightly higher numbers. DIN and SAE Net are pretty similar overall, although I'd argue that SAE Net is likely more reflective of real power. Many car makers have been sued and lost in the USA for not making the claims; Land Rover as mentioned above. But Ford, Mazda and others.
lazbaz
Member
This is where I saw the 3 different CCs and KW/HP: https://www.ebay.co.uk/itm/15397474...h=item23d99c3323:g:p9EAAOSwNRZg0wOs#vi-ilComp .Under the engine dropdown they show up.
300bhp/ton
Well-Known Member
ok, I wouldn't pay any attention to that data. Just pulled from a DB and usually highly inaccurate.This is where I saw the 3 different CCs and KW/HP: https://www.ebay.co.uk/itm/153974747939?fits=Model:Range+Rover&hash=item23d99c3323:g
RangeRoller dt
Well-Sprung Member
HP In Any book won’t be same as your actual engine. You’d have to get engine out on a dyno to see what it’s actually pushing out, which will differ from a rolling road output.
Get yourself a diesel and sod the figures.. who needs clacky liners...
who needs clacky liners... 
