I Need Help to make a Decision!! - 2.25 5mb petrol or 2.5n/a diesel????

Dear Wise Men!!
I am almost finished restoring my series 2a/3 1970 109'. I currently have a 2.25 petrol 5mb in it. I have been wondering about the fuel economy and lack of power (even for this) that I was experiencing and decided to pressure test it. The results were that 2 of the cylinders were running at least half compression compared to the others (it was cyl 1 - 122, cyl 2 - 75, cyl 3 - 122, cyl 4 - 55 with no gas on, and 150,95,150 and 65 respectively at high throttle.
I also have a 2.5 n/a engine in my garage and would like your advice as to which I should fit. I will take whichever to a machine shop to get them honed, new pistons and valves etc so they are as good as reconditioned.
I potter around London but also would like to do longer drives, and not have bleeding ears, to Dorset possibly towing a trailer or caravan occasionally. I am more than happy doing 50 - 55 mph but would like to keep at least 30 mph up any sort of hill. I think I may have a bad view of the petrol as it has probably always been low compression.
Am I better off with the petrol or the 2.5n/a ?? Is the fuel economy so different in a 109? I have power steering and front disc brakes also, but the tyres are on 1 ton wheels. MAybe freewheeling hubs would help?
I would appreciate your advice as my gut tells me the 2.5n/a for reliability and economy of sorts, but is it that deafening? (I do have the sound deadening mats in the front.
Your knowledge and expertise is much appreciated.
many thanks

Personally I'd stick with the petrol. I'd get 20-22 in my swb on a long run
The fwh help with a bit of noise reduction, they must help a bit with mpg but not really sure. You need to use them every once in a while so they don't seize. No experience of the 2.5

2.5 is it diesel, you don't say in your post, only the thread title?

Petrol is more powerful and quieter.Mpg will be marginally better with the diesel, maybe 10-15% I'd guess.

Personally I'd fit a V8.

My 109 station wagon is 2.25 petrol and gets about 18 mpg. It also has a.couple.of.cylinders with low pressure but it will get up to 60 mph and will keep at 30 on steep hills in third gear. Mine has an electronic dizzy which does seem to help. The more sound proofing you add, the better. I added soundproffing to the bonnet, bulkhead and seat box and can now have.a.conversation at 30-40 mph. I dont have power steering. If I was you, Id keep the 2.25 petrol engine and have the head skimmed and new gasket or get a machined head that has been converted to accept lead free.fuel. Mine is the 3 bearing engine. If yours is.the 5 bearing in a 1970 model then it has obviously been replaced in the past.

Col

i have previously had a 88 with a lead free head, it was fairly thirsty and with the amount of miles i was doing combined with the documented problems with the 'e' petrol going off in petrol tanks,there are no petrol stations anywhere near me selling the older type of petrol so i was having to just use a few gallons of the new type rather than filling my tank,
I prefer diesels as in my personal experience they last longer and less prone to breakdowns so when looking for my bigger historic class land rover a diesel was a must,
As it happens the one i found, the same body as yours in post 1,it has a 2.5na with an overdrive already fitted, and although i have not driven it for more than a few miles it does seem to be easily powerfull enough and smooth,
i know that a tank of diesel will not 'go off' which is happening with the new petrol, i can safely store diesel in jerry cans where the new petrol cannot be,
There is a government site which has a check service to see if a vehicle will run on the new petrol,
Thats just my view,
Atb
Ryn
Any chance of some pics of the rear interior of your 109 for reference?,

petrol vs diesel and reliability etc, i think it depends somewhat on your experience. i grew up on petrol engines and distributors, points etc isnt a problem for me, put i would be clueless if a diesel didnt start
the engine will run on e10 no problems, the issue is water content rusting the tank etc and petrol left in the system for weeks or months at a time if you only occasionally use it. if you drive weekly then it shouldnt be a problem
re. jerry cans, you should be ok for a while if its kept full and the seal is good

I have noticed that the new petrol doesnt even smell strongly like petrol after a while, i like my bikes and my day to day hack is an xr250, with the new fuel it is a sod to start when cold and much lumpier, the power/mpg is down, this was noticable when both types of fuel were available and i would use the new if the older wasnt available, a new plug,filter and service do nothing to change this, if anybody is storing anything that runs on petrol, ie chainsaws and mowers etc the widespread advice now is to switch off fuel then run them to a stop and drain the tank, i have other pals with running probs in older classic vehicles, we used to buy old style petrol locally but now its hard to find, some are using additives, i have seen for myself in my matchless 350 tank how quickly rust is formed where before it would not if left with fuel in the tank,
I have been given advice for older veteran vehicles that additives should be added to a jerrycan, which as in the previous post can be stored and the vehicle topped up from that but the vehicle should be drained if not used for weeks, not months, i wonder what the official advice is to do with this 'stale' concoction, i will be sticking with diesel due to the increasing adulteration of petrol being sold in the u.k,

This is only my personal view,

rynner said:

I have noticed that the new petrol doesnt even smell strongly like petrol after a while, i like my bikes and my day to day hack is an xr250, with the new fuel it is a sod to start when cold and much lumpier, the power/mpg is down, this was noticable when both types of fuel were available and i would use the new if the older wasnt available, a new plug,filter and service do nothing to change this, if anybody is storing anything that runs on petrol, ie chainsaws and mowers etc the widespread advice now is to switch off fuel then run them to a stop and drain the tank, i have other pals with running probs in older classic vehicles, we used to buy old style petrol locally but now its hard to find, some are using additives, i have seen for myself in my matchless 350 tank how quickly rust is formed where before it would not if left with fuel in the tank, i will be sticking with diesel due to the adulteration of petrol being sold in the u.k
This is only my personal view,

Click to expand...

You can get additives, which stabilise E10 petrol, Wynns make one, but others are available too. Modern petrol contains Ethanol, as it says on the tin, but also a lot of detergent, which is good for modern fuel injected engines, but makes not much difference to old carbs. It also has a bit less octane value than old petrol.

Bad news is, diesel is also adulterated, it contains up to 7% biodiesel, and also more detergent.
I use additive in that in my boat engines, prevents diesel bug, now found in all tanks in the UK, and improves lubricity, and gives a slight cetane boost.

In an old Land Rover, I would go petrol every time, unless was going to do a lot of miles.

I too would go petrol every time in any series LR V8 is lovely, but thirsty, but...oh that sound

Diesels of that era are too noisy for my ears now, and I wouldn't bother, even with the slight increase in MPG - I passed my test in a petrol SIIA, then we had a diesel SIII - the IIA is a superior vehicle IMO.

V8 would probably offer same or better mpg than an 2.25 petrol. But you get much better performance and a better soundtrack.

The.downside.of.a v8 is the.additional cost of consumables such as spark plugs and leads and if the carbs need balancing, it can be a nightmare if you dont know what you are doing. Replacing a standard 2.25 with a v8 isnt as straightforward as some peeps make out.

Col

also the issue of space in a 2a

Colthebrummie said:

The.downside.of.a v8 is the.additional cost of consumables such as spark plugs and leads and if the carbs need balancing, it can be a nightmare if you dont know what you are doing. Replacing a standard 2.25 with a v8 isnt as straightforward as some peeps make out.

Col

Click to expand...

You can't be serious can you?? Extra cost of plugs and leads.... even if you are doing big mileages (which I highly doubt in a Series), you are probably talking 10 years use or more between changing such items. A set of V8 leads are £20-30, so over 10 years likely about £1.50 more a year to run in this regard, compared to a 4 pot!

As for swapping in a V8. Not 100% straight forward, but in the realms of engine swaps pretty easy. It also isn't a 100% direct swap for a 2.5Nad from a 2.25p either....

kermit_rr said:

also the issue of space in a 2a

Click to expand...

Not really. People have been stuffing the Rover V8 into Series models for around 50 years.... including the factory with the Stage 1.

300bhp/ton said:

Not really. People have been stuffing the Rover V8 into Series models for around 50 years.... including the factory with the Stage 1.

Click to expand...

Yes but not in the 2 a, you'll have to push the radiator forward

kermit_rr said:

Yes but not in the 2 a, you'll have to push the radiator forward

Click to expand...

Only if you want too. But you don't have too.

People put RV8's into 80" Series 1's without changing the bodywork.

If you replace the petrol engine with a diesel, be careful that you don’t get stung for the ULEZ or whatever it’s called as you live in London. Personally, I’d stick with the petrol but get it rebuilt. Power upgrades from ACR are available which will let it keep up with traffic.

300bhp/ton said:

You can't be serious can you?? Extra cost of plugs and leads.... even if you are doing big mileages (which I highly doubt in a Series), you are probably talking 10 years use or more between changing such items. A set of V8 leads are £20-30, so over 10 years likely about £1.50 more a year to run in this regard, compared to a 4 pot!

As for swapping in a V8. Not 100% straight forward, but in the realms of engine swaps pretty easy. It also isn't a 100% direct swap for a 2.5Nad from a 2.25p either....

Click to expand...

Well you may be right but I doubt very if much that the spark plugs will last ten years in such an old engine unless you can keep the timing spot on and internal engine wear is negligable. I remember cars of the 70's needing new plugs almost every year. As for the engine swap, Ive never tried putting a v8 into a series but I have heard how others have had to move engine mounts, get an adapter plate for the gearbox, which are now pretty hard to find, and all sorts of other problems but as I say, I havent done it.so Im no expert.

Col

300bhp/ton said:

People put RV8's into 80" Series 1's without changing the bodywork.

Click to expand...

Used to happen a lot when I first had Land Rovers back in the 80s.
Series Ones were available for a few hundred quid, and people used to get an old V8 and put them in to go trialing.
I imagine most have now been removed, due to the prices Series Ones fetch.

Never seen the attraction of V8s myself, the basic concept is not well suited to losing heat, and they take up a lot of room under the bonnet, so make servicing more difficult.

Turboman said:

Used to happen a lot when I first had Land Rovers back in the 80s.
Series Ones were available for a few hundred quid, and people used to get an old V8 and put them in to go trialing.
I imagine most have now been removed, due to the prices Series Ones fetch.

Never seen the attraction of V8s myself, the basic concept is not well suited to losing heat, and they take up a lot of room under the bonnet, so make servicing more difficult.

Click to expand...

I do suspect some have been reverted, although it would only make sense if you are selling...

This is a friends 80, it has a 3.5 RV8 in it. Absolutely lovely....


Room in the engine bay is less, but tbh better than most modernish (1980's onwards) cars. Visually you wouldn't know it was a V8. But it burbles along with a wonderful soundtrack. It also has enough power to drive with modern traffic. The original 1.6 or 2.0 litre engines where slow even in the 1950s.

It's no worse on fuel than the original engine, just a lot nicer to drive. And I think that is the crux of it. If you have it only as an investment or don't plan to drive it. The 4 pot engines are fine. But something with more power is a lot nicer.

The 80 gets used as a pub car (roof off) during the summer and goes green laning regularly.

This is a family members, also running a 3.5 RV8 and retains the standard bonnet and front panel.



As for swapping in a V8, yes there are a few things to do. And finding the adapter ring might be more difficult these days, although in a 109 you could also easily fit a 5 speed gearbox too. My personal preference would be to stick with a 4 speed though, as it'll make it stay more in character. An LT-95 could be used and will bolt straight to a V8.

Or look at other engines. I personally was very keen to fit a 2.0 T-Series to my 88. But sadly had to sell the vehicle before getting that far. Although the T-Series is a bit of a rare beast these days. More torque than a 2.25p and more power than a Tdi. Plus smooth and refined.

There is of course a Tdi swap, which makes much more sense than a 2.5Nad. But do be warned, the Tdi is less refined than the indirect injection diesels. It would go well and be pretty fugal on fuel. But they are very noisy. I had a 200Tdi in my 88 and it served a good purpose, also managed 43mpg on one laning trip with it. But it was LOUD, no matter what I did. Way less refined than a Tdi 90/110. Had I kept the vehicle it would have gone back to petrol power one way or another.

Personally I doubt any LR engine swap would seriously impact the value of a 109 currently. And as long as you keep the original engine, you could always convert it back should prices dictate it to be financially rewarding. But if you plan to use the vehicle, then having something that goes well is a real bonus.

The ACR stuff for the 2.25p is interesting, but it is pricey. Do really make any difference to outputs you'll spend as much or more than swapping in a V8.