Project P38: Service Time: Filters, fluids, fix-its & plugs

First things first with our new, auction purchased Project P38 V8 car – get it on a ramp, cross fingers, have a good look, diagnose/fix some of the (ever-growing!) electrical and mechanical P38 ‘idiosyncrasies’ and give it a darn good basic service of fancy filters, fluids & plugs.

And, as with all the project cars I’ve owned over the years, I took Project P38 V8 to Dave Green at Henstead Motors in Beccles, Suffolk. Dave is a master engine builder, welder, spanner man, fix-it guru and a great, car-loving bloke besides. He set up Henstead Motors in 1986, has worked on pretty much every car job imaginable and is, as you say, ‘da man who can.’ And his cheerful chief technician Simon Mills also happens to be a Range Rover nut (who’s built various chopped Bobtails), which is extra helpful with the quirky P38.

On the ramp, first impressions were surprisingly solid. I could certainly see why it passed its last MOT with no advisories. Sure, there’s a bit of dirt, rust and corrosion, but not a lot and – crucially – not in “the bad places.” In fact, the only negative things found were: 1. Very minor play in the nearside front drop link to the anti-roll bar, explaining the tiny knocking noising. 2. Minor oil leak from one of the rocker cover gaskets (as expected for 109K). Jobs for the ‘to do’ list, not today.

Dave also ran the diagnostics computer, and we all placed bets on the number of fault codes: Dave, 20. Simon, 10. Me, 15. Actual, just two! One we cleared, about ‘mixture adaptation in bank 2’ (the one with the leaky gaskets) and one we couldn’t clear – ‘pressure regulator monitoring short or open circuit’ in the transmission, which could explain why the gearbox only works in ‘D’ – not 1-2-3-4 and why there’s no Sport/Manual mode. Again, a job for the ‘to do’ list!

We had less luck in the short timescale (with no quick fixes available) sorting the admittedly pretty long list of electrical issues – no erratic dash odometer reading, no electric windows/sunroof/mirror control, erratic radio control, no motorway cruise/sport mode for the gearbox, sagging offside air springs, blah, blah, blah! So, they too are on the ‘to do’ list. It  looks like we’ll have to wait to be able to open the sunroof or windows (it’s quirky and amusing opening a door to pay and collect at the drive-in/toll booths), or even listen to tunes, or hear the V8 burble against hedgerows. Never mind. Best things come… and all that.

The main aim of the day was to drop the engine, gearbox, transfer box and differentials oils and replace with the much-revered-in-motorsport Ravenol brand, swap the standard paper air filter for an upgraded K&N (and fit a K&N high performance oil filter) and install some new NGK spark plugs, specifically designed for use with LPG engines. And that all went swimmingly. No really, it did…

Ravenol engine & transmission oils:

It goes without saying that quality engine, gear and transmission oils radically improve any car – but especially an older vehicle, like Project P38, with its burly 4.6-litre V8 and old school auto gearbox desperately in need of some new lifeblood (it was all filthy, especially the gear oil, loaded with sludge).

I’ve lost count of the amount of engineers and technicians in motorsport arenas who’ve told me to spend decent money of decent fluids to extend the life of engines and transmissions, not to mention up their efficiency. And, having heard great things in the world of motorsport (rallying in particular) about Ravenol oils – especially from two top, hard-to-please experts, Roy Millington (engine builder supreme & now Ravenol supplier) and Stuart Newbie (rally car builder) – I selected them. The fact that Stuart recently stripped a rally car gearbox down after a full, hard season and said he could have sold the components as new says a lot I think. Impressive.

Despite being a name few here in the UK may have heard of, Ravenol are big in their home country of Germany (I’ve seen them well used in the Nürburgring pits) and have been making quality oils and fluids since 1946 in Werther, Northern Germany. The Ravensberger Schmierstoffvertrieb GmbH (Ravenol for short) currently supply over 80 countries worldwide, making them one of the largest independent oil and lubricant manufacturers in Germany. They specialize in developing and manufacturing high performance oils and lubricants for the automotive, motorsport, motorcycle and marine market. So they should be more than capable of working in the humble, old Project P38.

Ravenol has a really excellent, extensive range of engine and transmission oils, additives and sundries on their online shop and were super fast at delivery, even all the way from Germany (Teutonic efficiency see!); I’ve waited longer for UK-based parts before now!

Their sales team also offered superb, expert advice over the phone and via email too. They recommended a full synthetic, low friction Ravenol VMO 5w40 for the V8, designed to offer excellent cold start characteristics and ensure optimal lubrication in the cold running phase, adding: “Some companies’ lists do say that a 10w40 semi synthetic would be OK, but with an LPG conversion like you have on Project P38, they do tend to run hotter than on petrol, and the full synth 5w40 will cope better with the excessive heat, as well as offering a slight benefit in fuel economy.”

Expected benefits of the new 5w40 engine oil are: Improved fuel economy in part load and full power operation, excellent wear protection and high viscosity index even under high-speed operation, exceptional cold starting characteristics, a safe lubricant film at high operating temperatures, low evaporative tendency (so lower oil consumption, which is currently quite extensive), no deposits in combustion chambers, in the piston ring zone and valves (due to superb detergent and dispersant additive package) and extended oil change intervals. Sounds great, and the Ravenol VMO 5w40 synthetic engine oil costs £10.49 for one litre and £45.99 for five. We used, well, a lot!

For the differential oil, Ravenol again recommended a full synthetic – VSG 75w90 gear oil – offering exceptional levels of protection against wear, a stable effective lubricating film even under high loads, very high levels of protection against corrosion and foam formation, improved fuel economy capability even during short distances in low outside temperatures, excellent cold flow behaviour (promoting improved gearshift efficiency), a very high oxidation resistance (preventing oil thickening and deposits) and extremely high shear stability (ensuring ‘stay-in-grade’ capability)… all over extended change intervals. Sweet! The Ravenol VSG 75w90 synthetic gear/transmission oil costs £13.99 (1L) and £54.99 (5L). We used two litres in each diff: Greedy beggers!

The range of Automatic Transmission Fluids (ATF) Ravenol offer is second to none, with over 30 in stock. And they are one of the few companies who do actually offer ZF-spec ATFs, suited to many Land Rovers. So, for the Project P38’s ZF4HP22 auto box, the guys recommended their 6HP fluid, which covers the ZF 6-speed ‘boxes, but is also backwards compatible with all ZF 4 (like mine) and 5-speed ones too. It is produced with a blend of hydrocrack oils and synthetics with special additives and inhibitors to ensure smooth and reliable operation of ZF high performance automatic transmissions.

Claimed benefits include a very good lubricating ability even at low temperatures, high, stable viscosity index, very low pour point, exceptional protection against corrosion and foam formation, good balanced coefficient of friction, compatibility with all types of sealing materials and non ferrous components, a high thermal and oxidation stability, excellent cooling abilities and crucially, low evaporation losses. In short, it’s the dog’s balls of auto oil…

The Ravenol ATF 6HP synthetic auto gearbox oil costs £12.99 (1L) and £49.99 (5L). We used four litres in the gearbox. So, the total spent on Project P38 V8 Ravenol service fluids was £150.97, and we have plenty left-over for topping-up. Find out more about Ravenol or order online at:

K&N Air & Oil Filters:

The first thing I do with any new car is bin the standard, restrictive, flimsy, flawed paper air filter in favour of a high flow, cotton gauze, excellent filtration, washable, re-useable, 1,000,000 mile guaranteed, economical (50,00 miles before first clean required) and sexy K&N panel air filter: “The World’s best air filter.” Never replace your air filter again, and gain power and efficiency: It’s a total no brainer.

Designed to simply slot straight into the manufacturer-designed, cold-air-fed airbox (and not upset the electronics via the air flow meter signal), these motorsport tried and tested panel replacement filters offer a virtually unrestricted air flow, with superb filtration – making engine breathing more efficient, raising power and torque (typically between one and five bhp) and improving fuel economy. They even usually add a nicer intake sound, which is certainly the case on Project P38 (part No. 33-2788 MSRP). And at just £40.27 + VAT (£48.32), fitting, forgetting and enjoying a K&N air filter isn’t even really a decision, it’s just common sense.

What many folk do not realise with K&N filters is that they also do oil filters – for cars, SUV’s, motorbikes and marine applications. They are great value – with the PS-2004 MSRP model for Project P38 costing just £5.49 plus VAT (£6.58) and they offer them in Premium ‘wrench off’ canister or Pro Series form, as fitted here.

The Pro Series Canister Automotive Oil Filters from K&N are specially designed for professional installers and service providers. Their high flow design aims to improve engine performance by reducing oil filter restriction. K&N say: “Our Pro Series Oil Filters have a fluted canister shape so they can be removed with a traditional oil filter wrench commonly available to commercial installers. These Pro Series oil filters provide outstanding filtration and engine protection throughout their service life. They are engineered to handle all grades of synthetic, conventional and blended motor oils. The pleated media provides high capacity making them suitable for extended oil change intervals when used in accordance with the vehicle and motor oil manufacturers recommendation.” They offer a high-flow, low restriction design, rolled threads, fluted shape for traditional oil filter wrenches and come with anti-drainback valves (where applicable) or PSI relief valves (where applicable).

The K&N oil filters are designed to offer maximum flow and filtration (trapping 99% of harmful contaminants), are heavy duty (suiting the P38), easy to fit/remove (suiting Henstead) and are suited to high oil pressures (likely!) and all types of modern synthetic oils (like our new Ravenol). Filter perfection. Find out more at

NGK LPG Laserline Spark Plugs:

A spark plug, is a spark plug – aiming to deliver the ignition system current to the combustion chamber – right? Wrong.

Bad plugs, worn, plugs or the wrong plugs often lead to engine detonation (knocking, or pinking), where the combustion occurs outside the envelope of the normal combustion front, causing damage to the pistons, or beyond. And old, poorly-fitted choked up plugs – as the poor old P38 had fitted, two of which were so loose they were blowing back and were covered in oil – will lead to a massive reduction in power, not to mention potential running/starting issues, which were starting to be evident. Given how badly the old plugs were installed (finger tight) and how gunked-up they were, it’s a miracle the P38 was still firing all eight really.

Also, the standard (NGK) plugs fitted to the P38 were designed with petrol combustion in mind, not LPG, as Project P38 runs mostly. LPG runs hotter than petrol, has a nasty habit of finding any weakness in ignition system, requires a larger voltage and is more suited to a single ground (not multi) electrode top – so, a switch to LPG specific plugs was called for.

NGK, who have been designing and manufacturing spark plugs since the 1930s, recently introduced these LPG Laserline plugs (LPG2, model No.1497 for P38) – offering a new range of plugs (covering over 90% of the LPG market) designed specifically for gas powered engines, like ours.

Unbelievably, up until the Laserline release in mid-2010, the LPG-specific plug has been a previously untapped market, which NGK Spark Plugs has now filled, by popular demand, due to the rising number of vehicles (especially Land Rovers) making use of cheaper LPG fuel and tax prices.

The aim of the LPG LaserLine plugs is to make servicing not only easier, but also more reliable. More importantly, these plugs are designed to be better suited to the combustion process of LPG, which is a very different beast from the combustion of petrol – with the gas/air mixture being more difficult to ignite, then far hotter.

The plugs are designed to increase ignition voltage, reduce stress on ignition coils (reducing the risk of their failure) and offering a higher operational temperature range, more suited to the higher temperatures the gas/air mixture burns at. Conventional electrode and housing materials corrode more quickly in this harsh combustion environment and the spark plug also has to dissipate more heat. Prior to the release of NGK’ LPG Laserline, the best solution was to change from standard spark plugs to precious metal spark plugs with a different heat range and to adjust the spark gap. But this was never a great alternative, requiring specialist set-up.

Now, it’s easy: The trick Laserline plugs come with a double precious metal design, with an Iridium-tipped, Copper-cored centre electrode and Platinum tip in the ground electrode – providing maximum resistance to gap growth and a reliable ignition, throughout the service life. They are also laser welded for strength, further reducing the risk of corrosion. And, they are super easy to install with a preset spark gap – eliminating the need for common gap setting faults. Perfect.

Furthermore, NGK claim they offer enhanced ignition, thanks to the shape of the electrode facilitating optimum ignition advance on the flame front – giving peak performance, and better fuel efficiency. Win, win, win!

Each NGK LPG Laserline plug RRP is £20.74, plus VAT (£24.88), so cost £199 for all eight for the P38. Find out more about NGK at:


So, how is Project P38 V8 feeling post service No.1 – fluids, filters, fix-its and plugs – then? Fighting fit, and ready for green lane battle, that’s how. The difference pre to post service is staggering. On first ignition, the old girl sounded completely different – not fluffy and wheezy, but roaring into life, then idling – ney purring – beautifully.

And out on the road, there was a marked improvement in throttle response, a far better low, mid and top end pull, much smoother engine and transmission operation and far, far less engine and transmission NVH too.

The combination of better quality, fresh oils in the engine and transmission, more free-flowing, cleaner air and oil filters and proper ignition control from the spark plugs has really revitalized the P38. It’s quite remarkable by how much. These are all products well chosen and time well spent, so thanks Ravenol, NGK, K&N and Henstead Motors. A fine first service, done!


Dave Green @ Henstead Motors/Motorsport (01502-714177 & – Service, fix-its & spannering skills

Dave & Brian @ Ravenol Oils: – Engine, gearbox, transfer box & differential oils

Don @ K&N Filters: – Air & Oil filters

Andy & Tim @ NGK Spark Plugs: – LPG Laserline Spark Plugs

Gerry Bucke and team at Adrian Flux Insurance: Tel: 0800 369 8590

IMG_0237IMG_0231Screen Shot 2014-01-15 at 12.23.41Ravenol engineNGK SP Logo PMS[1]Adrian Flux Logo New Style - Blue