2 Litre Mods

[101RRS]

Hi Everyone,

I have bought a late 2 litre engine to go into my station wagon - for starters will need a new carby, dizzy.

I am assuming the engine will need as a minimum, valve grind, bearings and rings - most likely more.

So - given I am going to have to do major reconditioning I am looking for suggestions to improve overall performance.

First up some givens - I want to use an original carby - maybe jetted for more oompf, I will use an original dissy and will use an original exhaust manifold.

Aim - more power and torque but not at the expense of a peakier torque curve - ideally more torque but still coming in at low revs.

Performance mods for consideration:
1. Head work and bigger valves - convert to ULP
2. Better cam grind.
3. Boring the engine - take out to max oversize or actually overbore?
4. Increase compression ratio from the 6.?? to 8.?? - shave head or different pistons?? Would the conrods - bottom end take it?
5. Bottom end - would another landie crank fit - to stoke it out a bit?
6. Given the contraints of a standard bigger jetted carb and standard exhaust manifold - could consider extractors if they could be easily made - would fuelling be an issue with a modded engine.

Any other suggestions - everyone has ideas on how to mod engines - and thoughts accepted - but would like to hear from people who have actually modded the 2 litre petrol engine and what they did and how did it go.

Thanks

Garry

[chazza]

"Head work and bigger valves - convert to ULP"

I don't think you will need to modify the seats or valves for ULP. The original seats are very hard apparently and were made in the days when petrol was very poor quality.

In fact I don't know of any car that hasn't had hardened seats fitted that needed them after the withdrawal of leaded petrol,

Cheers Charlie

[alexmassey]

I run ULP in my 53 no problems at all. Which has a 2L.

It loves British Petroleum 95.....

Tho today it got 91 as it was 93.3 c per L Yepeee!!!! I wonder if we will see 89.9 again!

[JDNSW]

Hi Everyone,

I have bought a late 2 litre engine to go into my station wagon - for starters will need a new carby, dizzy.

I am assuming the engine will need as a minimum, valve grind, bearings and rings - most likely more.

So - given I am going to have to do major reconditioning I am looking for suggestions to improve overall performance.

First up some givens - I want to use an original carby - maybe jetted for more oompf, I will use an original dissy and will use an original exhaust manifold.

Aim - more power and torque but not at the expense of a peakier torque curve - ideally more torque but still coming in at low revs.

Performance mods for consideration:
1. Head work and bigger valves - convert to ULP

I doubt there is room for larger valves. If there is might be worth doing.

2. Better cam grind.

Needs an expert, which I am not

3. Boring the engine - take out to max oversize or actually overbore?

I don't think you can safely go more than the max oversize. What you can do will also be limited by available pistons.

4. Increase compression ratio from the 6.?? to 8.?? - shave head or different pistons?? Would the conrods - bottom end take it?

It would have to be new pistons - there is no combustion chamber in the head - the bottom of it is flat. Bottom end should take it as long as you don't increase maximum revs.

5. Bottom end - would another landie crank fit - to stoke it out a bit?

Can't think of anything that would fit.

6. Given the contraints of a standard bigger jetted carb and standard exhaust manifold - could consider extractors if they could be easily made - would fuelling be an issue with a modded engine.

This engine is limited primarily by breathing - but you want to keep the manifolds! Larger diameter exhaust is likely to help, but remember that freeing up breathing, while it is likely to increase maximum power, would also make the engine less flexible and less driveable.

Any other suggestions - everyone has ideas on how to mod engines - and thoughts accepted - but would like to hear from people who have actually modded the 2 litre petrol engine and what they did and how did it go.

Thanks

Garry

This engine has been out of production for fifty years, so most of the people who would have known how to modify it are dead. The similar six stayed in production for another twenty years, so perhaps you might find more useful information on it. I suspect that the biggest improvements you could make to power would be to increase the compression ratio, and to fit twin carburetters. But the second would be quite a job, and is likely to reduce flexibility.

John

[slug_burner]

If breathing is a problem, why not go for a turbo? I suspect that this is all a bit mute as most doing up series ones are trying to restore back to original as possible. If you want to get more power and are prepared to make mods why keep the same engine? Just drop a modern 4 cylinder into it! Turbo diesel. Some bloke near Ballarat stuck a 200 Tdi into his 86" I think he is pretty happy that it has more power that he needs to use.

[series1buff]

Garry

You might consider a contemporary Rover 6 cyl saloon motor ..I've seen at least two LWB series 1's with them fitted ...the drawback is the fitting.. from memory , they cut a section of the bulkhead out or some radical thing .

I don't think you can do much with the original motor ... If it was a easy option to make it produce more bhp or torque.. then plenty of people in the UK would be 'hotting up' motors, but you never hear of it . You can use the Series 3 F head pistons . Apparently, the Rover 6 cyl pistons will increase the compression slightly, by about 5% or something like that. You could also polish the inlet and exhaust ports in the head/block ..would it make much difference ?

Mike

[101RRS]

Getting off track a little with talk of turbos and 6 cylinders etc.

I have to rebuild a 2 litre (this is a given) and I am just after advice as to what mods I might be able to do while the engine is pulled down to improve perfromance.

Certainly on outwards appearance I want the engine to appear standard - hence the original carby and dixxy requirement and no other add ons.

Seems to go is to bore to max oversize and clean up the head.

Cheers

Garry

[JDNSW]

Getting off track a little with talk of turbos and 6 cylinders etc.

I have to rebuild a 2 litre (this is a given) and I am just after advice as to what mods I might be able to do while the engine is pulled down to improve perfromance.

Certainly on outwards appearance I want the engine to appear standard - hence the original carby and dixxy requirement and no other add ons.

Seems to go is to bore to max oversize and clean up the head.

Cheers

Garry

If you can locate high compression pistons, it would help. Series1buff suggested that six cylinder Series 3 pistons will fit and increase the compression a little.

John

[rover-56]

The 2 litre engine responds surprisingly well to power modifications, it is a crossflow design which has been strangled in order to achieve low speed torque.
You can replace the inlet manifold and carb with a 4 branch design manifold fed by a 2 barrel progressive Weber carburettor, and replace the exhaust manifold with a similar 4 branch 2 into 1 header, and the result is amazing. Even with the standard camshaft.
It will spin easily to 5000 rpm and is a delight to drive.
I drove my little '56 in this condition for 15 years and loved it.

There is a downside though, sustained engine speeds over 4000 rpm will cost you a camshaft and followers. The chrome facing on the followers quickly comes off, and that is the end of the camshaft.

It is also very noisy above 3500 rpm. even though I balanced the engine.


If you want to retain the original look of the engine, you can polish the roughnes out of the inlet ports, and make sure the ports line up smoothly.

The same with the exhaust manifold, although that is not as important as the inlet, a free flowing muffler will help.

Increasing the compression ratio will definately help, there is enough metal on the top of the block above the piston top savailable to machine, I think there is about 1 mm available to remove, and you can use a steel shim gasket instead of the copper composite one.

Experimenting with carb jetting and venturi size can give benefits too, remember the engine was designed to run most of the time at 2000 rpm and full throttle, although you may lose some low speed torque.

Good luck,
Terry

[Fourgearsticks]

Usually cleaning up and enlarging ports gives you more power but less torque.

[101RRS]

Terry - thanks for the information - all good stuff - the sort of thing I was looking for.

Cheers

Garry

[chazza]

The 2 litre engine responds surprisingly well to power modifications, it is a crossflow design which has been strangled in order to achieve low speed torque.
You can replace the inlet manifold and carb with a 4 branch design manifold fed by a 2 barrel progressive Weber carburettor, and replace the exhaust manifold with a similar 4 branch 2 into 1 header, and the result is amazing.

I bead blasted my 1600cc manifold last week and had a good look at it last night. The design of the branches is atrocious, with the centre branches having to change direction several times before the gas can reach the cylinder. There is also an incredibly small inlet hole just below the carburettor, which is as Terry described and restricts gas flow into the engine.

In contrast, the porting in the cylinder head is very good with no obvious narrowing, although I haven't tested it yet.

Out of interest Terry; what make of inlet manifold did you use and where did it come from? I would think a free-flowing inlet manifold, even with the same carburettor and exhaust manifold, would make a huge difference to performance.

[series1buff]

Doesn't the coolant exit the head via the inlet manifold ..might be tricky if you want to try another inlet manifold...setting it up
Mike

[chazza]

Doesn't the coolant exit the head via the inlet manifold ..might be tricky if you want to try another inlet manifold...setting it up
Mike

Indeed it does!

I was thinking about it the other day; the water jacket on the manifold seems excessively large, compared to more modern cars that also employ this feature. Areas of Oz such as where I live, probably don't need the water-heating feature at all but in any case a new manifold could be designed with a different water jacket and branches. A cobber of mine who is a mechanic well-versed in cars of this vintage, suspects that the water-heated manifold was favoured in very cold climates running on the low-octane petrol of the 1950's. Or alternatively; it might be possible to have the water exit from the head into a casting which is then connected by hose to the short pipe at the thermostat housing. This would enable a pattern-maker to concentrate on a simpler pattern which is only concerned with gas flow.

I think I could make the manifold pattern but my knowledge of modern core-box making and core sands is non-existent, which hampers me completely :(

Any pattern-makers out there who can give me some advice?

[series1buff]

Indeed it does!

A cobber of mine who is a mechanic well-versed in cars of this vintage, suspects that the water-heated manifold was favoured in very cold climates running on the low-octane petrol of the 1950's.

yes that's true ... apparently there was also a fuel available called POWER KEROSENE ... older tractors used it . It was different to normal household kero..how I dont know . During WW2 some car owners fitted pre heating devices to the inlet manifold ..to heat up the kero as petrol was very hard to buy, legally anyway . Kero was illegal as a car fuel as there was no tax on it ..but some did try it . You would start on petrol....then change over to kero after the motor warmed up.

[JDNSW]

yes that's true ... apparently there was also a fuel available called POWER KEROSENE ... older tractors used it . It was different to normal household kero..how I dont know . During WW2 some car owners fitted pre heating devices to the inlet manifold ..to heat up the kero as petrol was very hard to buy, legally anyway . Kero was illegal as a car fuel as there was no tax on it ..but some did try it . You would start on petrol....then change over to kero after the motor warmed up.

Power kerosine was the normal fuel for most tractors until probably the late fifties when diesel started to take over. As stated, start and warm up on petrol, then change to kerosene. It has not much to do with lighting kerosene, being more volatile than that but less so than petrol (hence the need for a hot spot manifold. Most tractors using it were designed with an exhaust heated hot spot on the manifold, often running a lot hotter than is usual with petrol engines.

The reason that the Rover engine uses coolant to heat the manifold is that it is effectively a crossflow head, so the exhaust is on the other side, and it is easier to pipe water round than it is to pipe exhaust round. Similar manifold heating systems were used in contemporary Peugot and Citroen engines with crossflow heads. Modern crossflow engines with fuel injection can get away without it because the port injection makes icing almost impossible and inadequate vaporisation is dealt with when cold by the ecu adjusting mixture to compensate, and any unburnt fuel heats up the catalytic converter.

I would be careful about making the intake too free - while this will certainly increase the maximum power, it will also move it to higher rpm and make the power and torque peaks more pronounced, which while it may improve the maximum speed, will not improve the driveability.

John

[Aaron IIA]

Indeed it does!

I was thinking about it the other day; the water jacket on the manifold seems excessively large, compared to more modern cars that also employ this feature. Areas of Oz such as where I live, probably don't need the water-heating feature at all but in any case a new manifold could be designed with a different water jacket and branches. A cobber of mine who is a mechanic well-versed in cars of this vintage, suspects that the water-heated manifold was favoured in very cold climates running on the low-octane petrol of the 1950's. Or alternatively; it might be possible to have the water exit from the head into a casting which is then connected by hose to the short pipe at the thermostat housing. This would enable a pattern-maker to concentrate on a simpler pattern which is only concerned with gas flow.

I think I could make the manifold pattern but my knowledge of modern core-box making and core sands is non-existent, which hampers me completely :(

Any pattern-makers out there who can give me some advice?

This may be possible. The thermostat housing on my 1600 must have corroded through, as the previous owner removed it and replaced it with a piece of plate and pipe. The engine runs well even though the water heating has been removed. This is probably because it does not get cold enough to need heating.

Aaron.

[chazza]

Ah, quite interesting!
On my car the back of the thermostat housing had corroded through leaving a nasty big hole for the water to flow through. :eek:

Thanks for the reply John. I know bugger all about torque and driveability compared to gas flow through the head. Looking at my collection of 2 1/4 litre manifolds, it appears that they are not nearly as restricted and the branches are more sensibly shaped compared to the S1 engines. Can you reccomend any reading on the subject? In the meantime I have researched modern moulding sands and have the germ of an idea for making a substitute. Incidentally, increasing the maximium speed doesn't interest me but making the thing more fuel efficient and a bit nippier at lower speeds does,

Cheers Charlie

[JDNSW]

........
Thanks for the reply John. I know bugger all about torque and driveability compared to gas flow through the head. Looking at my collection of 2 1/4 litre manifolds, it appears that they are not nearly as restricted and the branches are more sensibly shaped compared to the S1 engines. Can you reccomend any reading on the subject? .....

Not really - my knowledge comes from reading lots of bit and pieces plus experience over the last forty-five years - the nearest thing to a reference I can think of is the only book I have on the subject - "The Modern High Speed Internal Combustion Engine", Ricardo & Clyde, 3rd Edn. 1941. At least this is probably the book that the designer of that engine used! It is difficult to compare the manifolds of the 2.25 and the 2.0 engines because the combustion chamber shape and the gas flow within the head are quite different.

When you improve the overall flow of gas into the engine, you enable more mixture to get into the engine, particularly at higher speeds, which will increase power at higher engine speeds, but make little difference at low engine speed, since there the resistance to flow is proportional to the square of the gas velocity. This has the effect of more power at higher rpm, but since there is no difference at low speed the power is more "peaky". A further problem is that unless the improved flow is very well thought out, the mixture to different cylinders may be different at all speeds, leading to rough running and reduced torque at low speeds. Not so much a problem with four cylinders, but particularly with sixes, the pulsing effect (think of tuned exhausts) can really cause problems for getting even mixture to each cylinder. This is where the advantage of multiple carburetters comes in, as well as allowing more mixture, it sidesteps the "getting it even" problem.

In the case of the 2.0 litre engine I suspect a well engineered two carburetter manifold might improve both maximum power and low down torque.

John

[series1buff]

Ah, quite interesting!
and a bit nippier at lower speeds does,

Cheers Charlie

hi charlie ,

They already are quite nippy at lower speeds..like taking off at traffic lights .
Up to about 25-30 mph...going through the gears, the low rev torque peak is very noticeable and they accelerate very respectably .. not sluggish at all .
Mind you, the motor will only perform like that ,if its up to the specs e.g., 135 psi in each cylinder.
Mike

[chazza]

hi charlie ,

They already are quite nippy at lower speeds..like taking off at traffic lights .
Up to about 25-30 mph...going through the gears, the low rev torque peak is very noticeable and they accelerate very respectably .. not sluggish at all .
Mind you, the motor will only perform like that ,if its up to the specs e.g., 135 psi in each cylinder.
Mike

Thanks Mike,

I will hurry up and wait until mine is a runner :D

Cheers Charlie

[rover-56]

Pics as required:)