Continuing the restoration and rebuild of an early 90 or 110 2.5 17H petrol engine, the ultimate version of the old faithful 2.25 that served Land Rover so well. The engine will be an upgrade for my Series 3 when completed.
there's a very good (and reasonably priced) engine machinist in Buckinghamshire, Thatch at EMS (engine machining services). I've always been more than happy with his work :)
Northants engine services did a great job on my v6 machining. Just get it bored , get fresh pistons . Youll spend a few quid but from experience you wont regret it ! At the same time they can deck the block to give a really good mating surface :) At the begining you mentioned the compression ratios relative to the fuel , on my essex i had heads skimmed and block decked as it is vital on the v6 to ha e a good mating surface . I have run it well on e10 and e5 , doesnt seem to bother it at all !
I run a ACR 2.8 5MB in a 109. Big-valve head. SU. 123 Dual-curve dist. etc. I run gas over petrol. For a daily it's about a good as a Series LR gets. Slightly more grunt than a TDi. All without the racket. If it's a breathed-on 17H you're wanting, for my purposes ACR are better than Turner. Turners make the copy. You want the Big-valve and ACR cam too.
Interesting question you raise about E10. Compression ratio is directly related to Octane rating and given E10 fuel is 95 octane, then 9:1 or 10:1 should be fine. After all modern engines designed to run on E10 have compression ratios higher than 10:1. Raising the compression ratio improves the efficiency of the engine so should reduce fuel consumption. Having said that, I am only an "armchair expert" that watches too many RU-vid videos about cars and follows too many forums, so doesn't come from personal experience or any formal education. I do not know what effect time has on the octane rating has of E10. I know it "goes off" quite quickly, which I guess means it loses octane rating if left in the tank? If it were me I think I would happily go to 9:1 then fill with E10 during periods I was using the vehicle regularly and premium (non-E10) when I wasn't. Premium grade is more expensive, but if you're not using the vehicle much then the actual cost difference isn't going to be that much. Graham
Thanks for the comment, I suppose I was thinking out loud really with that one, realistically it will probably be absolutely fine being what it is. My thoughts stemmed from something of an ongoing discussion with my colleagues in the engine shop at work, but all just healthy debate/ scepticism on our part! The worst case scenario is likely just having to alter the ignition timing a little. Interestingly, my modern car returns notably better fuel economy on E10 and runs that bit better. A chain of local independent garages sell ethanol free petrol which generally is what goes in the Land Rover, but I may well just try it on E10 once back on the road and see what the effect is, if any.
Turner Engineering are the best for the Series Engines , i am from Sri Lanka , i imported all the parts for my 2.25 5MB engine from them , well worth the price
I've had a few bits from Turners in the past and they have been very good. They are about a two hour round trip from me, so I intend to take the block and head to them when the time comes.
Question? Looks like you used the Series rather than the 2.5 manifold. Agreed it'd mean moving the down-pipe back to mate the 2.5 manifold to the Series down-pipe, but is there another reason you went for the Series manifold?
I run E10 in my 88 with 8:1 compression with couple degrees more advance and more vacuüm advance, and it runs mint. Mine will need a rebuild and i will be increasing the compression ratio. Hoping it wil make it more efficiënt lol.
It's still not built yet, other things have got in the way but I'm hopeful it'll be done this winter. Anyway if you are building one, obtain the workshop manual- there's lots in there that you need to know. It is available free online if you search it out.
@Steamwally...your videos are absolutely outstanding. I live in the States and have an '83 Series 3 SWB with a 5MB 2.25L diesel. It's pretty slow, smoky, and noisy. I've been considering a petrol engine swap and have been trying to find resources on converting the unit I have to running petrol (knowing I'll have to change pistons and many other ancillaries). I keep reading the 5MB block used for the 2.25 petrol is the same as the 2.25 diesel AND the 2.5 petrol and other subsequent LR engines. What are your thoughts about using the block I have as the foundation for a 2.5 petrol engine with new pistons, new crankshaft, new gasflowed head from Turner (if I can get one), and ancillaries? Many thanks for posting these videos! ~Pete
Hi Pete, Yes I think you are right in saying the block may be interchangeable. You will probably have to find a cylinder head first, then send it to Turners - the later metric heads are actually quite rare to find now and they certainly won't have them on the shelf. There are some differences that I'm aware of, the valve rockers have different lubrication ports, the flywheel may be different as there are different limits listed for petrol and diesel. The starter motors were different, so it would be worth investigating the bellhousing used, likewise the flywheel ring gear. ISTR that the connecting rods are also different in the diesel but I am no expert - all I can suggest is plenty of research. I suppose the thing to do might be finding a well worn 3MB 2.25 petrol and using the cylinder head, they can be fitted to the 5MB block. If you can find a fully dressed engine, then it will have the various ancillary bits you need. Phill.
@@steamwally Thanks so much, Phill. This is really helpful information...I do, in fact, have a spare 3MB petrol 2.25 so could, to your point, use that head. I will keep you posted. Apologies for the delayed reply and gratitude for your response to my question. All the best, Pete
Thanks! Yes, both the camshaft and the connecting rods are different between 2.25 and 2.5. The valve timing is slightly different on the cam and the driving sprocket is also a different type, as is the timing chain tensioner. The connecting rods are different because the increased capacity was achieved by increasing the stroke. I believe the rods and crank are the same as the 200TDI.
