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

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Originally Posted by isuzurover

Now I have a spare (possibly cactus) 300tdi head, I have been doing some measuring... It will bolt straight onto a 2.25 diesel block by the looks.

Now it seems that all that would be needed to convert a 2.25 to DI would be swirl pots in the pistons??? (either modified 2.25 pistons or 200/300 pistons).

Does anyone know if the CAV DPA pump on the 2.25 has the same operating pressure as the bosch VE pump?

Can anyone see any problems with this? I would only have a sucky 3MB crank, but no more timing belt!!!

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Reckon it would probably be an interesting exercise to try if you didn't spend too much time and money on it. May work, but I would not expect very well. Maybe including a fair bit of smoke which is very politically incorrect nowadays and needs good design and components in good order to minimise. The Bosch VE pump operates at much higher pressures than the CAV DPA type. Also, it is a two stage, which I gather all late electronic diesels are. Firstly a small amount of fuel is injected, then a millisecond or whatever later the rest. One reason is to reduce the diesel knock caused by the delay period, ie the time from the start of fuel injection to when it explodes. This is more of a problem in direct injection diesels than in the old Rover diesel, where fuel is injected into Ricardo (engine development company) precombustion chambers. Also, it seems that direct injection engines with old type injectors do not run well at over about 3,000 rpm.
Some older diesels including the Rover and the very common 6.354 Perkins made from the early '60's to 1989 had a skew gear drive off the camshaft to the injector pump. These may be satisfactory for petrol engine distributors but have problems including high wear rates with the load diesel injector pumps impose. Note how on the subsequent Phasar Perkins and direct injection Rover diesels designers have gone for injector pump drives on the same axis as the crankshaft.
Timing belts on 300 Tdi's do not seem a problem when all the updated components are installed AND what seems was one main basic cause of problems is avoided. ie Apparently original tension recommendation caused housing to flex and tensioner pulley to misalign. Not a problem with lower tension.

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Originally Posted by Psimpson7

Just to add, the diamater of a td5 piston is 84.5mm


cheers
Pete

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Thanks, that's what I get for believing wikipedia! It says bore x stroke is 94x71 mm!!!

Thanks for all the other measurements also. Looks like TD5 pistons are out then.

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Originally Posted by mox

Reckon it would probably be an interesting exercise to try if you didn't spend too much time and money on it. May work, but I would not expect very well. Maybe including a fair bit of smoke which is very politically incorrect nowadays and needs good design and components in good order to minimise. The Bosch VE pump operates at much higher pressures than the CAV DPA type. Also, it is a two stage, which I gather all late electronic diesels are. Firstly a small amount of fuel is injected, then a millisecond or whatever later the rest. One reason is to reduce the diesel knock caused by the delay period, ie the time from the start of fuel injection to when it explodes. This is more of a problem in direct injection diesels than in the old Rover diesel, where fuel is injected into Ricardo (engine development company) precombustion chambers. Also, it seems that direct injection engines with old type injectors do not run well at over about 3,000 rpm.
Some older diesels including the Rover and the very common 6.354 Perkins made from the early '60's to 1989 had a skew gear drive off the camshaft to the injector pump. These may be satisfactory for petrol engine distributors but have problems including high wear rates with the load diesel injector pumps impose. Note how on the subsequent Phasar Perkins and direct injection Rover diesels designers have gone for injector pump drives on the same axis as the crankshaft.
Timing belts on 300 Tdi's do not seem a problem when all the updated components are installed AND what seems was one main basic cause of problems is avoided. ie Apparently original tension recommendation caused housing to flex and tensioner pulley to misalign. Not a problem with lower tension.

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Considering that Perkins persisted with the skew drive to the injector pump for about thirty years, and Rover for over thirty years, and both engines are regarded as fairly long lasting, it seems unlikely that it is a serious problem.

John

(just as an aside - the Rover 2.25 engine is extraordinarily high revving (4,000rpm) for a diesel in 1961, or even today - although it is indirect injection, but still very high for the time.)

Well... This definitely fits the "polishing a turd" category, but I have almost acquired all the bits to give this a go... (more for fun than anything else).

The only $$$ item will be a set of 0.040" 300Tdi pistons, as my 2.25D block is already bored to 0.040". Unless anyone wants to donate a good 2.25 Block?

the injector pump should tolerate the injection pressures required But Im not sure if the drive mech and angle gears are going to appreciate the load.

you could drop the crack pressures on a set of injectors to compensate.