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V8 into Light-weight

V8-ing by John Craddock, to a'Light Weight' Land Rover

The military Air Portable or 'lightweight' Land Rover has always proved popular in 'civvy' street, especially when subjected to the Rover V8 engine conversion. John Craddock looks at the correct procedure for fitting this engine and offers some down to earth advice for would be owners.

You'd be forgiven for thinking that the V8 engine transplant into Air Portable Series 2a and 3 Land Rovers is hardly hot news - it isn't. But you'd be surprised how often the plight of some owners contemplating such a conversion or caught with severe problems in the middle of doing so comes to our attention.

In fact, hardly a week goes by without some-one relating a tale of woe about fitting the Range rover or SD1 engine to a Land Rover - either the conversion kit doesn't work properly, or the prop shaft angles are too acute, or most commonly the fitting is so poor that he resale value of the Land Rover in question has plummeted to new lows.

All of which is quite distressing because Lightweight prices are soaring at the moment and supply could be starting - albeit temporarily - to dry up. But there is hope, and if you follow what I tell you from here on in, you should have no problems whatsoever with this conversion.

A few words of warning first. Most of you will know that the V8 engine in car (SD1, 3500, Coupe) or Range Rover form is a particularly clever unit. It's low stressed and designed primarily for high torque output rather than outright bhp (although the latter can be quickly increased to almost 250bhp with a camshaft change!) The torque output, which varies enormously thanks to the wide range of compression ratios used for the engine, is usually in the range of 200lbft@3000rpm, enough to make the gearbox in most lightweights quake in its casing. But both the gearbox and the rear axle can be made to live quite happily with the V8 through one, simple and cost free modification - the owners driving habits!

Off-road, when in four wheel drive, the problem of gearbox layshaft and rear axle breakage doesn't usually raise it's ugly head, since the torque and power output is split between the two axles, and a fair degree of it is wasted in non-friction wheel spin. On-road, with high grip road surfaces and two wheel drive, you can do a lot of mechanical damage through stupid moves like dropping the clutch at the traffic lights for a race with Porches or XR3's and Golf GTis. This sort of driving technique is a total waste of time with the V8 conversion. You've got nothing to prove and all you'll get is lots of expense because your gearbox and eventually the rear axle will give up on you. Enough said?

Assuming that you already have a Lightweight, and that you have sourced a useable V8 engine.... (in carburettor form only please - even if you can get hold of a Range Rover Efi engine, don't use it for the reasons I've outlined) ...you still have to choose the right conversion kit.

Let me make the choice for you, and recommend now manufactured and marketed by Mercia 4x4 Engineering of Cannock (full address and telephone number at the end of this article).

Developed by Rob Slater. Its a superb kit, well thought out and engineered, and at around 155 +VAT, excellent value.

With the kit, you get the flywheel housing adapter plate which is already drilled, tapped and dowel matched, and oil filter conversion plate, a set of revised engine brackets in MIG welded steel, and a spigot bush conversion plate, complete with bush.

What makes it so good is the thought that's gone into its design. The flywheel housing adapter for example is is one of the nicest castings I've seen in a long while and extremely accurate, and the same can be said of the oil filter conversion plate.

This again is machined and then evacuated of oxygen deposits by vacuum before sealing with silicon. After that, porosity is not a problem!

The principle advantage of the kit, apart from the ease with which it all fits first time round, is that the oil filter plate re-sites the oil filter well away from the chassis, allowing the new engine mounts to sit the engine level in the bay.

Other conversion kits often don't do this, leaving the nose of the V8 some 4 inches higher than the tail and making the front prop shaft operate at some bizarre angles. Reliability is subsequently compromised from the word go!

You still have to source a number of items yourself for this conversion though.

These are Range Rover exhaust manifolds, engine mount rubber blocks, electric fan (Kenlow or similar), clutch disc and pressure plate, and I'm afraid you'll have to fabricate a suitable exhaust system for yourself. But there again, that's half the fun of it all! The bulkhead also has to be modified, by sectioning the foot-well sides and re-welding. 2.25" has to be taken from the n/s foot-well and 1.25" from the o/s.

To start the conversion, remove the existing Land Rover engine, exhaust front section, battery carrier and radiator. You'll be left with empty engine bay which no doubt could do with a power wash down - it makes life a lot cleaner and pleasant when you're working in there.

 You'll also be able to thoroughly inspect the bulkhead, prior to modification, for corrosion too, and I would strongly recommend that any faults are repaired before you put the engine back. If the foot-wells and door pillars have suffered from rot, it would be worth replacing the bulkhead altogether with a new one. They're not that expensive and it makes modification straight forward too.

The bulkhead should be marked in the same way as the one we've shown in the photo's. The spot-welded overlap seam on the inner side panel of the foot-well can be drilled and unpicked, and the surplus area cut away. Use the overlap seam to link the foot-well section again and either gas weld or MIG weld it back together for a neat and water tight join. A careful application of mastic sealer will also tidy up the join and the 'repair' should be repainted on the inside and outside of the foot-well. The later point is important if you want to prevent the foot-well rusting badly.

Turning attention to the engine, the revised engine mounts and the oil filter conversion plate are simple enough to fit.

For the oil filter plate, first remove the radiator fan, and the oil pump base plate. fit the new oil filter conversion casting, and refit the oil pump base plate to it. It's as simple as that!

At the rear of the engine, you will have to modify the crankshaft tail to fit the new spigot plate and bush. the crankshaft tail should be marked exactly 0.25" from it's end and this section cut off. Any remaining flywheel bush should also be removed. The conversion plate will then fit into the flywheel using the new bolts supplied with the kit.

If you are using a Rover car V8 and flywheel, use the following clutch components:

Series2a Air Portable
Land Rover 9" clutch disc GPC1358 (Borg & Beck HB1358). 9" pressure plate Borg & Beck 45692/71 (Austin FX4 Taxi)
NB: Flywheel will require one extra dowel.

Series 3 Air Portable
Rover 3500s 9.5" Clutch disc Borg & Beck HB2347. Pressure plate Borg & Beck HE2854 (1968 Jaguar MkII 3.8). NB: Flywheel modification required. Thrust pad centre on clutch must be enlarged to give clearance over clutch withdrawal sleeve.

If you are using Range Rover engine and flywheel, use the following components:

Series2a Air Portable
Land Rover drive plate and pressure plate. Use 9.5" diaphragm pressure plate and disc (IIa type)

Series 3 Air Portable Original Land Rover 9.5" clutch assembly.
NB: Flywheel needs drilling and tapping for these clutch units.
You'll find that with these units the gearbox will line and bolt up easily and the engine can be installed in the engine bay. Check that the clearance you have created by modifying the bulkhead is sufficient - if not, then repeat the procedure. The remainder of the conversion is plain sailing. The radiator can be refitted and linked to a Kenlow fan, and suitable linkages for the V8's carburettors are not difficult to fabricate. The radiator itself can be linked to the engine using Range Rover hoses and little trimming.

The exhaust is really a mater of personal preference.
I would suggest that the original V8 down pipes are fitted and linked to a cut down Series 3 V8 LWB system.
That way their back pressure rating of the silencers is correct for the engine and you stand more than a fighting chance of gaining suitable ground clearance for serious off-road work.

As with any conversion, you should allow some settling-in time for small problems to make themselves known before you dissapear into the wilderness in search of really tricky lanes and the like.

Time spent on the carburettor linkage alone will pay dividends in terms of smooth action and control.

If you have any problems regarding the conversion, talk to Rob Slater direct on 05435 71754, or pop round to see him in person at:
Mercia 4x4 Engineering, Unit 11, Cannock Industrial Centre, Walkmill Lane, Bridgetown, Cannock, Staffordshire.

Items such as radiator hoses, clutch assemblies (Land Rover only), bulkheads, exhaust components and manifolds, engines and even suitable Lightweights, you'll find at:
John Craddock Limited, 70-76 North Street, Bridgetown, Cannock, Staffordshire. Tel 05434 77207/5408

Convenient, isn't it? Happy Converting.

Comment (By Teflon)

A more practical and detailed 'How to' article than the Robert Irvings one; This is probably the better article to use as your guide to actually doing the job of fitting a V8 to a Series Land Rover, rather than contemplating all the things you need to think about. As such, there is little I can say about it or add to it. But....

A lot of the problems encountered in a RV8 conversion were circumvented by JC very succinctly by using the Rob Slater conversion kit, in it's entirety. I have no idea whether this kit is still available. Conversions & Precision still offer V8 adapter plates, and LRO Forum user Integer-Spin has been threatening to make some up if any-one wants for a couple of years; However; from the Forum's, most people that undertake this conversion these days tend to use second hand conversions kits or parts, often of dubious origin. Consequently, the old bug-bears of exhausts; oil filters and engine mounts frequently crop up on the Q&A boards!

A certain 'Trialist' and Hybrid Builder I know, advocated the use of the infamous 101FC oil filter housing, denying that they are 'rare as rocking horse do-da' by pointing out he has six of them in his garage........ They ARE rare as rocking horse Do-Da, he just goes to inordinate lengths to find them! A lot of people then poo-poo the use of remote filter adapters, on the basis that they result in lower oil pressure, and expound at length how the Rover V8 does NOT like low oil pressure, and the contention rages......

So, my tuppence worth: It's a 'feature' of the Rover / Buick sub-small block V8 that it has a low pressure lubrication system. It accounts for a lot of anomalies with the engine; Like how it gums up, and carries on running; and why they can go for years with the oil light flickering on and off, even at speeds above tick-over!

BUT, while the RV8 is a LOW pressure lubed engine, it is not a NO-Pressure lubed engine! And they DO like a decent oil pressure, even if they CAN live without it. So; take a tired,  late life RV8 out of a Rangie or SD1 saloon (or in & out of various vehicles, as is more common these days!), add a remote filter kit, and the consequent oil pressure loss can be enough to give the engine a hard time; it WONT run very well on splash lubrication, it does need a BIT of pressure to shove the oil into the journals.

So, the 'bad' reputation of remote filter kits, I suspect is significantly acquired from such kits being fitted to engines that are past their best and don't have all the oil pressure they should to begin with, the remote filter accelerating the demise.

The alternative, apart from a 101 filter housing, is to site the engine higher, for filter clearance; and or use a smaller filter; I have a feeling that the filter from a Renault 14 was commonly used, as it was smaller and screwed straight on the standard mount.

Echoing Craddock's comments; NEITHER solution, to my mind is particularly useful. Mounting the engine higher, and tilting it from front to back, causes a myriad of consequential problems; particularly around gearbox alignment, and prop-shaft angles; bulkhead clearance, brake servo clearance, exhaust manifold clearance and exhaust routing, as well as at the front with regard to the alternator, water pump, cooling fan and radiator.

AND! Ultimately, it doesn't particularly solve anything with the lubrication system, just moves the problems about. Tilting the engine, means that the oil will be sitting lower and further back in the tilted sump, to start with; Then the smaller filter, if used, wont flow the same quantity of oil as a larger one, so will still give some lube pressure loss; and being smaller, as it filters, it will give more pressure loss, more quickly, until the relief by-pass opens and it stops filtering altogether, rather defeating the object.

Some people live with these issues, and change filters more frequently, do oil changes more often, and are more contentious of their oil level.... But to my mind, these are difficulties you are making for yourself by not doing the job right in the first place, and its spoiling the boat for a hapeth of tar job.

The engine should be mounted as low and level as it can be; and THAT should be the starting point; get that right and you wont have any where near as many problems later on. Mounting the motor as comfortably as you can, will avoid a lot of the consequential niggles; To do so, you WILL have to use a remote filter kit, which means added cost and the oil pressure 'problem'; BUT, Rover V8 in decent shape SHOULD cope with the small pressure loss of a remote kit pretty easily, and that small loss if likely to be less than that from a half clogged undersize filter, or curious inclination of the engine.

So, I advise a remote or re-sited filter kit, and if you are worried that your RV8 wont take the pressure drop..... find and cure the problem, NOT the symptom! 

RV8's are notorious for 'the black death' and that robbing oil pressure & gumming up tappets, wearing rocker shafts and making the engines run poorly. IF you have low oil pressure to begin with; it's a PRETTY good indication of a tired engine; which begs the question; why go to all the lengths and expense of a conversion to fit an engine that's on it's last legs?

Choose a decent engine to begin with, or BEFORE you put the motor into your lovingly prepared engine bay; do some renovation work to it. You DON'T need to do a full tear down, though it may be useful; but pulling the sump, timing cover; the cam, tappets and rocker gear, de-sludging as much as you can get access to, and putting it back together with new timing chain; and a properly fettled or new oil pump, properly primed, and you SHOULD avoid any oil pressure problem, whether you choose to use a remote filter kit or not.

Another note on the remote oil filter; cooling. Lots of people complain of RV8's overheating, especially in converted engines. As both Irving's and Craddock, comment, standard Series Radiator is 'adequate'; HD 4-Core Series Radiator, better, or you CAN with a little engine-uity adapt Range Rover or P6 radiators.

As a note, I did some careful measuring up, when I was planning to convert Wheezil; And a Standard Range Rover Radiator, WILL fit between the Series inner wings; but, the RR rad is a 'cross-flow' type, and mounts top and bottom, where the Series one is a vertical drain rad, and mounts on the sides. RR rad is about 2/3 the thickness and not quite so tall though, and would make a bit more room for electric fan(s) or auxilliary oil coolers if needed, BUT a bit of tin bashing and met-fab would be needed to the radiator panel.

Any way, most 'cooling faults' on RV8's are not to do with the cooling system, or lack of fans; they tend to be tired engines with tired cooling systems; badly set up ignitions and carburetion, or blown head-gaskets. BUT, it's often forgotten, that the oil system takes a lot of heat out of the more inaccessible parts on the engine, and carries heat away from the hotter bits where the it couldn't escape through natural conduction, like the bearings, and pistons.

Gummed up engines, with poor oil circulation obviously aren't going to get the full, if any benefit of any oil cooling, so again, good reason to pay a bit of attention to initial condition; BUT, IF you go for a remote filter kit, very easy to plumb a seven or nine row in line oil cooler into the lines; or even the 'Military' specification 'in front of Rad' oil cooler. And again, that little precaution, to my mind is a useful one.

The only bit of Mr Craddock's advice in the article I can really criticise, is the comment; "If the foot-wells and door pillars have suffered from rot, it would be worth replacing the bulkhead altogether with a new one. They're not that expensive and it makes modification straight forward too."

Series III bulkheads are no longer cheap or readily available; and from a lot of comments on the Forum's about trying to adapt 90/110 or Defender bulkheads to fit series Landies; it might be almost impossible to source a 'good' replacement bulkhead. However; it's a 'usual suspect' in the Series Land-Rover's line up of 'faults', and there aren't many out there with bulkheads that aren't patched and plated to begin with.

Modifying the footwells is the one bit of tin-bashing that most other conversions don't need, and used to be the main reason people opted for other conversions to avoid the met-fab work the V8 needed.

My opinion on that is that chances are, when you come to look at it; you're bulkhead will probably need or benefit from attention ANYWAY; and given the difficulty of procuring a replacement, or adapting a later coiler bulkhead, which has it's own myriad of consequential problems, PERSONALLY, I would look at the Bulkhead as a mini-project in it's own right, and put restoring it on the jobs list above doing a V8 conversion; BUT with the idea that while refurbing it, I would mod the foot-wells as directed for V8 conversion, so I could do that conversion, later, without so much grief.

On that topic; I don't usually recommend people getting all enthusiastic with MIG welders. The hardware is far to easily available....... the skill to use it unfortunately NOT! Lots and LOTS of people get the great idea when they get into 'classic' cars about buying a MIG welder, and doing their own structural and body work........ and an alarmingly high proportion of amateur 'restorations' consequently end up with more holes in them than the tin worm ate, or with very poorly aligned panels, doors, and even wheels!

That caution mentioned; When it comes to Series bulkheads; It's possibly a necessary evil. You CAN buy professionally refurbished and even galvanised bulkheads, but at around 500 they are prohibitively expensive. And if you intend to mod the footwells as well?

Modifying a coiler bulkhead, then starts to look attractive, but that brings probably as much work one way or another, as the Series pedal box wont fit, the brake servo is in a different place, and various other detail differences exist. Making a coiler bulkhead serviceable on a Series, will mean either stripping out lots of series stuff to fit coiler parts, which brings us back into the realms of Hybrid Hassle, OR demands cutting out metal, grafting in Series sections and or..... some scratch fabrication. Personally I don't think it's worth it.

Basically, there doesn't seem to be ANY cheap AND easy way to a decent series bulkhead; so at some point you will have to accept the pain or expense of doing something fairly serious, and to my mind, retaining a series bulkhead is probably the BEST starting point. You may be able to buy a reasonably good second hand coiler bulkhead reasonably cheaply; but at the end of the day it will still be 'old metal', you are bashing about. So start with your Series bulkhead, and accept that you'll just have to do a bit more to it.

Starting point, would be to get it off the vehicle, and preferably get it to a commercial sand blaster, with express instruction to be pretty hard on it! If there's not much left after they have done......... well at least you KNOW you haven't got a lot to work with! But hopefully you'll at least have a skeleton to work to.

Paddocks & Craddocks both list bulkhead repair sections; and a complete set, including door pillars, corner sections and footwells, are about 200ish. A competent professional welder, will probably charge about as much again to weld them all together, so all in, not a huge saving over the 'refurbished' bulkheads you see advertised; BUT, you'll probably get the V8 footwell mods done into the price rather than on top.

And at that sort of price and that sort of effort; you can see why I suggest that refurbishing the bulkhead is a job done before a V8 conversion, as a project in it's own right. But done; done right; and done once, it shouldn't be something you have to worry about again, for a very long time.

Any way; with best part of 200 worth of welding to make just the bulkhead 'good', very enticing to consider getting that 'Mig-Mate' out of the Machine Mart catalogue and having a go at DIYing it! And to be honest, With an engine conversion, and the need to make up nadgery engine mounts, adapt exhaust systems and make up lots of associated hangers and brackets and other odd's and ends..... it is an idea that DOES have merit.

But, you HAVE been warned; getting the kit is easy; it just takes money; using it, is a little more difficult, and using it well, and importantly, well enough to start contemplating structural or cosmetic welds rather than 'functional' ones on not so critical bits of iron-mongery, something FEW can achieve without LOTS and LOTS of practice.

But the choice is yours. Personally, I have a welder, but even so I'd try and find a more competent bloke to use it for me on the critical bits.


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