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BigJ

6cyl SWB?

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Anyone ever heard of a straight six engine in a SWB? I drove a LWB with one years ago and was impressed with how smooth and torquey the engine was.

Is the 6 - cyl bulkhead different to the 4 pot?

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Yes, I’ve had two in the past (one in an 80) and have got one in an 88 2a.

Lovely engine, suits it really well

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Yes, it's got the gearbox shifted quite a way back, so the bulkhead is different.

I don't know if there were any swb 6 pots.  The rear prop would have been quite short.

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I’ve one in S1 86 inch, really sweet engine, but a tight fit.

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1 hour ago, Jeremy1 said:

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How difficult was it to fit? Any major mods required like moving the gearbox or chopping the 4 pot bulkhead?

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They were originally only fitted to LWB. It's an adaptation of a P4 engine, essentially detuned. They are lovely, sound great but realistically give very little extra power. Parts are scarce (water pump for example cannot be replaced, refurbishment only) and maintenance is more complicated. They also have a habit of overheating. Top mpg regardless of how you drive is 17 but mainly in the region of 14. The bulkhead (more similar in shape to a Defender) is different with a shorter gearbox tunnel. Annoyingly, you can no longer buy the gaiter for that tunnel either. I did a nut and bolt rebuild of one. Many of these models were subject to Perkins engine conversions because of the extra room or indeed great for TDi conversions - not that I'm an advocate for this. You'll struggle to find an original model. However, when I last looked, there were plenty of unused 2.6 engines around...

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In the 1970s someone I knew fitted the 3-litre IOE six from a Rover P5 into a SWB 'station-wagon' SIII - it involved a bit of messing-about to accomodate one of the twin-SUs [which wanted to live where the brake master-cylinder/servo had already claimed residence], the engine needed to sit a bit high to give sump clearance and and the radiator needed moving forwards but the result was rather smooth-and-fast nice.

You started off in 2nd. 3rd was good for 65MPH, and had loads of mid-range torque, brilliant for A-road-overtaking. You ran out of revs in 4th well before you ran out of power. Biggest problem was the brakes: even with 1-ton 109-inch drums they smoked/faded horribly if you were driving fast for any time.

If they'd worked out a safe brake solution and fitted Range-Rover 3.54 diffs I really think a factory version of the 3-litre IOE engine and a SWB SIII could have found a niche in the 1970s LR product-range.

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Thanks for the replies, shame that parts for the engine are so hard to come by now.

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Mine was built by the Rumsey brothers several years ago. The gearbox is in normal 4cyl position so no need to modify bulkhead.

Drives beautifully, no overheating problems (nor in previous ones, nor my 109 6 cylinder, nor my forward control 6 cylinder!). Parts are out there, I’ve not had any issues yet.

Nice period conversion, (especially the 3.0 version!), sounds lovely!

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Mine started out as 6cyl but when it needed work it made much more sense to drop the V8 in - more power, more economical (no, really!) and much easier parts-wise. Shame as I did like the six.

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12 minutes ago, Jeremy1 said:

Mine was built by the Rumsey brothers several years ago. The gearbox is in normal 4cyl position so no need to modify bulkhead.

Drives beautifully, no overheating problems (nor in previous ones, nor my 109 6 cylinder, nor my forward control 6 cylinder!). Parts are out there, I’ve not had any issues yet.

Nice period conversion, (especially the 3.0 version!), sounds lovely!

Interesting. With the gearbox staying put did you need to move the radiator forward? Likewise for the engine mounts, do they need cutting off the 4 pot chassis and moving?

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5 hours ago, Tanuki said:

In the 1970s someone I knew fitted the 3-litre IOE six from a Rover P5 into a SWB 'station-wagon' SIII - it involved a bit of messing-about to accomodate one of the twin-SUs [which wanted to live where the brake master-cylinder/servo had already claimed residence], the engine needed to sit a bit high to give sump clearance and and the radiator needed moving forwards but the result was rather smooth-and-fast nice.

You started off in 2nd. 3rd was good for 65MPH, and had loads of mid-range torque, brilliant for A-road-overtaking. You ran out of revs in 4th well before you ran out of power. Biggest problem was the brakes: even with 1-ton 109-inch drums they smoked/faded horribly if you were driving fast for any time.

If they'd worked out a safe brake solution and fitted Range-Rover 3.54 diffs I really think a factory version of the 3-litre IOE engine and a SWB SIII could have found a niche in the 1970s LR product-range.

Totally agree, mine went like stink as it has the Weslake head, braking was always the issue and you “bailed” before it stopped pulling. 

Jeremy1 has seen mine and makes a great period conversion and well worth spending the time doing - you’ll never stop smiling once done.

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I’ve just managed to get my hands on a 3.0 Rover P5 engine, the 130 bhp version. I’ll rebuild it and put it to one side for when the restoration starts.:)

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Mmmm, when I bought my last 2a swb for restoration a good 10 years ago now it sported a 6 cyl bulkhead with a 2.25D engine and I always wondered why, maybe the po had a plan that never materialised I don't know but with the 6 cyl bulkhead being fitted it took up a lot of room aspecially around the bellhousing area as it just looked like someone had grafted a cover between the bulkhead and gear lever, the hi / lo lever's couldn't work properly due to fouling on something, anyway at the time I planned on using my then newly recon'd 2.25P engine out of my S3 I had for the restoration of the 2a with inc buying and restoring a 4 cyl petrol bulkhead then later converted it to a 200tdi :)

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Posted (edited)
5 hours ago, Cornish Rattler said:

Mmmm, when I bought my last 2a swb for restoration a good 10 years ago now it sported a 6 cyl bulkhead with a 2.25D engine and I always wondered why, maybe the po had a plan that never materialised I don't know but with the 6 cyl bulkhead being fitted it took up a lot of room aspecially around the bellhousing area as it just looked like someone had grafted a cover between the bulkhead and gear lever, the hi / lo lever's couldn't work properly due to fouling on something, anyway at the time I planned on using my then newly recon'd 2.25P engine out of my S3 I had for the restoration of the 2a with inc buying and restoring a 4 cyl petrol bulkhead then later converted it to a 200tdi :)

I believe that by fitting the 6 cylinder bellhousing the engine mounts will need to be pushed forward a few inches which may involve using an electric fan which is no big drama. Battery and air filter holder will need repositioning slightly too and of course the exhaust dealt with. I think from what I’ve read the existing bulkhead will still work as the engine will be further forward but I need to get my tape out to check for sure. The engine I have was cheap so if it doesn’t look like it’s doable then I’ll just keep the four pot and flog the 6 for spares.

If I can make it work then I should end up with a nice period conversion but we’ll see.

Edited by BigJ

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6 hours ago, BigJ said:

I believe that by fitting the 6 cylinder bellhousing the engine mounts will need to be pushed forward a few inches which may involve using an electric fan which is no big drama. Battery and air filter holder will need repositioning slightly too and of course the exhaust dealt with. I think from what I’ve read the existing bulkhead will still work as the engine will be further forward but I need to get my tape out to check for sure. The engine I have was cheap so if it doesn’t look like it’s doable then I’ll just keep the four pot and flog the 6 for spares.

If I can make it work then I should end up with a nice period conversion but we’ll see.

Yeah they sound really good the 6cyl's I always fancied one over a V8 but the 3ltr engine from the P5B rover

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I’ve another question on this is anyone can help?

If I needed to replace my 4 cyl bulkhead as part of the rebuild, could I fit a 6 cylinder one with the correct cutouts etc along with the 6 cylinder floor and tunnel to my SWB?

If so would the gearbox then sit further back and mean that I would need to reposition the gearbox mounts and modify the two props? Would the rear prop end up being too short to function correctly? All this on the assumption the new engine would sit on the existing engine mounts.

One reason for asking is that the engine weighs 300kg which is 100kg above that of the 4 pot so keeping the weight distribution as even as possible and not too far forward would be helpful.

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Does it really have to be the Rover 6 ? I have seen a 110 with a BMW straight 6, seems to be a South African model. Looked real tidy under the bonnet and sounded great. The BMW doesn't weigh that much more than the Rover 4 but has at least twice the power.

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1 hour ago, AV8R said:

Does it really have to be the Rover 6 ? I have seen a 110 with a BMW straight 6, seems to be a South African model. Looked real tidy under the bonnet and sounded great. The BMW doesn't weigh that much more than the Rover 4 but has at least twice the power.

I think it was the fact that it’s a period engine and one that performs well in addition to needing minimal fabrication that swayed to for me. At 130bhp and bags of torque I think it will be on the limit of the Series gearbox as it is but anything more than that I might have been looking at a gearbox upgrade too.

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My father fitted the 3ltr version of the 6 into one of his SWB's when I was growing up in the 1970's. It was great,very smooth and excellent for towing, he ran a tree surgery business,so large trailer loads of dead elm were common.

I don't know where the overheating bit comes from for the 2.6 six comes from,my brother and his girlfriend recently did a 45,000km lap of Australia in a 109 six,including plenty of low range work in sand etc.Overheating was never a problem, they are now in Burma,making their way back to the UK. Nice engine if you treat it sensibly and look after it.

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11 hours ago, BigJ said:

I think it was the fact that it’s a period engine and one that performs well in addition to needing minimal fabrication that swayed to for me. At 130bhp and bags of torque I think it will be on the limit of the Series gearbox as it is but anything more than that I might have been looking at a gearbox upgrade too.

I've converted mine to a 200tdi fitted Def / Disco 1 3.54 diffs will be having the gearbox uprated once son's wedding is out of the way in May and hopfully get an o/d as I recon with the tdi engine already having the pump tweaked by ( p.o. ) and a new 300tdi turbo, no power steering and no fixed fan it should be around 130 bhp I guess once it all done :)

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11 hours ago, Ally V8 said:

My father fitted the 3ltr version of the 6 into one of his SWB's when I was growing up in the 1970's. It was great,very smooth and excellent for towing, he ran a tree surgery business,so large trailer loads of dead elm were common.

I don't know where the overheating bit comes from for the 2.6 six comes from,my brother and his girlfriend recently did a 45,000km lap of Australia in a 109 six,including plenty of low range work in sand etc.Overheating was never a problem, they are now in Burma,making their way back to the UK. Nice engine if you treat it sensibly and look after it.

Think back then when the 6 pot LWB first came out the radiators was to small like a lot of other B.L. cars of that eara but since then radiators have got better so the problem was solved :)

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On 11/03/2018 at 8:57 AM, BigJ said:

If I needed to replace my 4 cyl bulkhead as part of the rebuild, could I fit a 6 cylinder one with the correct cutouts etc along with the 6 cylinder floor and tunnel to my SWB?

If so would the gearbox then sit further back and mean that I would need to reposition the gearbox mounts and modify the two props? Would the rear prop end up being too short to function correctly? All this on the assumption the new engine would sit on the existing engine mounts.

Changing the bulkhead won't change where your engine + box sit, that's what engine + transmission mounts are for :P and yes it was *all* different on the 6cyl.

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Overheating can be an issue, but this is not due to the engine but usually poor radiators. Make sure yours is in good condition (not full of c**p) and then use goood quality coolant at the right mix. 

The 4cyl gearbox is fine, but treat it with respect. If you drop the clutch and floor it - inevitably it will be wrecked after a few thousand miles. 

To get all to fit I moved the engine mounts forward, removed the engine fan and went electric, tbh I only ever needed it on hot days in traffic.

If all tuned right, the engine runs like a sewing machine - really quiet and really smooth, they can tick over as low as 600rpm, though mine was around 900. 

With plenty of power, you’ll have real,fun, though watch the right foot as half shafts can quickly need replacing!

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