Thread: Land rovers haven't changed much in 40 years - DI 2.25 anyone???

Ben

You need to find one of the very last SIII 5 bearing blocks/cranks they were usually labeled 2.3. It doesn't matter if it's a petrol block because they are all diesel blocks.

Diana

Would it matter that much if you were not using the turbo (3 bearing vs 5 bearing).

Ben, a thought, might want to measure the depth of the piston and length of con-rod. I can't remember from the top of my head if they simple bored out the 2.25 to 2.5 or they lengthened the stroke, or a little bit of both? Might be worth a check. Or how about mounting the 300Tdi head on a 2.5D block...if they fitted? I guess that would make a 2.5DI?! Just thinking aloud

J

Originally Posted by Veryan

Would it matter that much if you were not using the turbo (3 bearing vs 5 bearing).

Ben, a thought, might want to measure the depth of the piston and length of con-rod. I can't remember from the top of my head if they simple bored out the 2.25 to 2.5 or they lengthened the stroke, or a little bit of both? Might be worth a check. Or how about mounting the 300Tdi head on a 2.5D block...if they fitted? I guess that would make a 2.5DI?! Just thinking aloud

J

The 2.25, 2.5 and tdi engines are all 90.47 mm bore. The 2.25s are 88.9 mm stroke, and the 2.5s 97 mm stroke, to give the extra capacity.

my 2.25D is already 0.040" oversize (~91.5 mm), which gives a capacity of 2.35 L. Fortunately there are 40 thou oversize 300Tdi pistons - so that may be the easiest option.

However... another consideration - Td5 pistons are 94 mm. That is 139 thou oversize!!! But if it worked would mean a 2.25 would become a 2.5 L!!!

Though it may just be easier to convert a 300tdi to a timing chain Or get a real engine like a 4JB1T.

Information needed:

I would appreciate some info before I throw any money away on parts I may not be able to use.

Can someone with parts lying around please measure:
(1) Gudgeon pin diameter and (2) gudgeon centre to piston crown, for:

A. 300tdi Piston - edit JustinC, legend that he is has phoned to say that a 300Tdi piston is ~56 mm gudgeon centre to crown, and ~30.1 gudgeon OD
B. TD5 Piston
C. 2.25 Piston (petrol or diesel)
D. The length of a 300Tdi pushrod

Does anyone in Perth have a 2.25 (petrol or diesel) block that hasn't been sleeved that they would be willing to donate to the project? (happy to pay a carton or cash equivalent). NB - I will only go with this option if it looks like I can fit TD5 pistons. My engine has been sleeved on one cylinder. Edit - OEM sleeves are 94.425

Originally Posted by Lotz-A-Landies

Ben

You need to find one of the very last SIII 5 bearing blocks/cranks they were usually labeled 2.3. It doesn't matter if it's a petrol block because they are all diesel blocks.

Diana

Yes, but I thought they were very rare in AU? A petrol 5MB block won't be much use unless I can also find a (forged) 5MB diesel crank. However if this works, a 5MB series bottom end should be as strong as a Tdi - as mentioned with no rubber belt.

Downsides: The CAV DPA pump has much less room to play with the settings. The TDi probably has better cooling in the block, and larger oil galleries.

Originally Posted by isuzurover

..... The TDi probably has better cooling in the block, and larger oil galleries.

Might be worth remembering that the 2.5 turbo diesel gained a reputation for unreliability, including, I seem to remember, a tendency to crack blocks. The change from 2.5 turbo diesel to Tdi did not only involve a change to direct injection, and a timing belt, but, I suspect, a number of non-obvious changes, probably including, as you suggest, better cooling in the block, but also probably including strengthening at key points as shown by experience with the turbodiesel!

John

Haven't got one to look at, but would there be sufficient space for the Bosch VE pump to fit in the same location as the old DPA one?
Think the bottm centre main bearing on a 3mb engine would be up to it? I've replaced a few on petrol engines back in the day
Wagoo.

Originally Posted by JDNSW

Might be worth remembering that the 2.5 turbo diesel gained a reputation for unreliability, including, I seem to remember, a tendency to crack blocks. The change from 2.5 turbo diesel to Tdi did not only involve a change to direct injection, and a timing belt, but, I suspect, a number of non-obvious changes, probably including, as you suggest, better cooling in the block, but also probably including strengthening at key points as shown by experience with the turbodiesel!

John

Good points - however the 2.5D had a good reputation for reliability (well as good as any LR diesel...). IDI engines are less efficient and tend to need better cooling.

Most of the 2.5TD problems I remember reading about were manufacturing problems with the cam bearings, causing oil starvation and cam failure.

This is more just an exercise to see what is possible - and if it proves reliable. I will only do it if it ends up quite cheap - i.e. I can mainly use parts I have in the shed.

Originally Posted by wagoo

Haven't got one to look at, but would there be sufficient space for the Bosch VE pump to fit in the same location as the old DPA one?
Think the centre main bearing on a 3mb engine wud be up to it?
Wagoo.

I like your idea re the VE pump!

I suspect that NA the centre main would hold up OK, however with a turbo I would probably have to change main bearings every other service .

I can always do oil analysis to see what is happening...

Originally Posted by isuzurover

Good points - however the 2.5D had a good reputation for reliability (well as good as any LR diesel...). IDI engines are less efficient and tend to need better cooling. ..

The 2.5D was well regarded and reliable (although going of course on second hand information as none were sold here); but the 2.5TD was not. In fact the problems with it were directly responsible for the bringing in of outside design expertise to get a reliable turbodiesel. But it is worth remembering that at the time the 2.5TD was introduced, there were very few if any small turbo diesels in existence. (For that matter, it is worth remembering that the original Landrover diesel was almost the only small diesel in existence in 1956, certainly in the English speaking world, and preceded the Japanese four wheel drive diesels by about fifteen years. It is also, together with its petrol version, I believe, the only engine ever designed specifically for a utility four wheel drive to actually see production in large numbers.)

John