11 March 2023
The best option for a worn or damaged engine may be a straight replacement. Alisdair Cusick shows how a brand-new 2.4 engine is fitted to a Defender
Need to know
Time: 6 hours.
Cost: See below.
Difficulty: 5 out of 5
Models: 2.4-litre Puma-engined Defenders (2.2 version is similar).
Tools needed: Spanners, sockets, fuel clip pliers, impact gun, engine stand, engine crane, pry bar, hub removal tool, stud extractor.
Parts & costs: 2.4 Puma stripped engine, DA1182, £4062; Various fixings, seals, pipes and ancillaries
• Use the right tool, for the right job
• Always be fire-safe in the workshop
• Use the correctly rated lifting and support equipment
• If in doubt, get an expert to do the job.
Thanks to: Ian Baughan and IRB Developments for his help with this feature. Visit: irbdevelopments.com
We could be forgiven for thinking of the Puma Defender engines as modern diesels. The reality now is they were simply the latest technology back in 2007; a long time ago now, and all Puma Defenders will now have seen many operating hours.
They are, on the whole, a reliable and well-suited engine for the Defender. As you would expect after more than a decade’s use, some are at the point where they’re starting to have issues in areas such as injectors, turbocharger and Exhaust Gas Recirculation (EGR), all of which are repairable by swapping the parts for fully-functioning units so the engine can operate to spec again. Any engine has an intended operating zone where it is designed to cope with normal temperatures and pressures.
But anything that prevents proper lubrication or allows excess heat will cause that operating bubble to be exceeded, and damage to components occurs quickly. What do you do if your engine develops more serious problems, such as crankshaft issues, or is run low on oil after excessive timing cover oil leaks?
Rather than fit a rebuilt engine of unknown quality or workmanship, there is the option of fitting a brand-new crated Puma engine. The 2.4 powerplant comprising cylinder block, cylinder head, rocker cover, inner timing cover, camshaft and crank gear is known in the trade as a ‘stripped’ engine, to which the ancillaries need to be mounted. Many (but not all) of the engine ancillaries from your failed Puma can be reused and built onto the new stripped engine. For example: the sump is a Ford Transit-spec part, so a Defender sump is required with its recess for propshaft clearance. Many ancillaries can be swapped straight over, but there are some critical parts that should be simply renewed, and some that you have options with.
If something has moving parts, then it may be best to replace it, but sensors and pipework can all usually be reused. A new turbo oil feed pipe should be fitted to ensure no contaminants are carried into the delicate turbo oil system, and a new alternator is recommended because it’s difficult to replace when the engine is in the car, but also consider the fuel pump for the same reason.
Careful consideration should be given to why the original engine failed before deciding which parts are safe to re-use, particularly if you want the benefit of the two-year warranty on the engine. An over-fuelling injector that caused a piston to hole obviously means new injectors are needed, but consider fuel pump and auxiliary belt tensioners, too. It might mean a larger parts bill, but give thought to what corners can be cut and what is a false economy, given you have a brand-new engine out of the car.
That is the problem faced by the recent LRM cover car of Chris McCormack. His ex-utility 2010 2.4-litre Puma had only done 86,000 miles, but it had developed a terminal knock. The common culprits were investigated and worked through: injectors, timing chain, etc and various remedies tried, but the knock persisted.
Further investigation meant removing the head and, with that, an open-ended question over escalating costs to diagnose and subsequently cure any issues found.
The engine has now been removed from Chris’ Defender, and Ian Baughan of IRB Developments takes us through the first steps in the process of swapping it for the new engine: it’s a steady day’s work. The old engine is still fully ‘dressed’, out of the car on an engine stand next to the new one, so Ian starts by removing and assessing the ancillary components from the old engine, ready to fit on the new motor.
If you haven’t done engine work before, here are LRM Technical’s five golden rules:
1. Work Cleanly: Work in a clean space, with plenty of room to work on, and store, the parts.
2. Understand the task: Do your homework and work from a workshop manual, following the procedures exactly.
3. Take pictures: When stripping anything, take lots of photographs and make notes as you go. They’re useful to refer back to if you get stuck.
4. Where is it? Store removed ancillaries or systems in separate trays. Put bolts back in ancillaries you remove so you know what went where.
5. Don’t rush: Engines work on tolerances, so many settings can be critical. Work steadily and accurately, checking as you go. Rushing means mistakes happen.
Removing and assessing parts from the old engine
First step: Pete Fogg of IRB Developments starts by removing the fan. The correct narrow spanner is needed, and sometimes a hefty tap helps free it on the right-handed thread.
Idle work: Slacken the idler to release tension on the ancillary belt, then undo the idler and remove the belt. Bin the belt, but possibly reuse the idler if serviceable.
Step by step: Unbolt the alternator. Refit the bolts into anything you remove, and have a container for removed parts. You then know what is where, and with the correct fixings.
Pumps, plural, off: Remove the rear hose, then unbolt the water and vacuum pump. Below that, unbolt the power steering pump. Again, consider the condition of these when deciding upon reusing.
More pulleys: Unbolt the engine lifting eye bracket, then the large pulley and tensioner assembly. It could possibly be reused, but it’s best to replace it.
Crankshaft pulley: Unbolt the coolant feed pipe in the middle of the timing cover, ease it out of the block, then unbolt the crankshaft pulley: it can be reused.
Brackets and mounts: Unbolt the pulley on the air-con bracket, then remove the bracket itself, and the engine mounts each side. These will be reused, after restoration.
Break the seal: The timing cover comes off. With the fixings removed, a pry bar breaks the RTV sealant’s grip. Don’t worry about damaging the faces, all will be renewed anyway.
Oil ancillaries: Unbolt the turbo oil drain and remove. Pull the dipstick cover out of the block. Inspect the dipstick pipe: if it is corroded near the base, replace it rather than reuse it.
Bin it: Unbolt the banjos and remove the turbo oil feed pipe. Always renew this feed pipe, to prevent contaminants damaging any new turbo – and thus preserve the new engine’s warranty.
Turbo next: Unbolt the turbo and remove it. The fixings should release okay. If they’re tight or seized, undo a touch, then tighten and repeat, which should ease them free.
Six-sided socket time: Unbolt the exhaust manifold. The same trick as for the turbo fixings might be needed. These were shocked free with the impact gun. Don’t round the heads off!
Fuel system next: At the top now, unbolt the five fuel rail feeds: four cylinder feeds plus one common rail feed pipe. Officially these should be replaced, though they’re usually reusable.
Easy does it: Carefully pull off the clips for the spill return pipes. Don’t break them, don’t lose them. Lift the pipes out of the injector tops and leave out of the way for now.
Injectors: Number the injectors if reusing them: the ECU knows which goes where. Undo the bolts on the fixing clamps and discard the bolts – these are single-use stretch bolts.
Fuel feeds: Unclip the spill return from the pump and remove the pipes. Unbolt the main fuel feed pipe from the pump to the common rail, and remove the location P-clips.
Will they, won’t they? Remove the injectors, which usually come out easily in a Puma, with just steady wiggling. Carbon build-up on nozzles, or heavy corrosion, might make them reluctant to move.
EGR system: Unbolt and remove the pipe connecting the EGR valve to the exhaust manifold. We’ll be reusing this. Vapour blasting will make it as-new, quickly and affordably.
EGR pipework: Working at the rear of the block, undo the various water feeds to the EGR cooler and remove the cooler. Inspect the EGR: it can soot up, causing running issues.
What did we say? Unbolt the inlet manifold and remove. This is caked with crud inside from the EGR system. We’ll clean it out in the parts washer, but it will take a while.
Common rail: Unbolt the common rail. We’ll reuse it, but store carefully to avoid contaminants entering. It operates at very high pressure – up to 1800 bar at the injectors.
Water works: Unbolt the water inlet manifold and the pipe feed to the oil cooler. Again, these aluminium alloy parts will be reused. After being vapour-blasted, they’ll look new.
Harness: Remove the glow plug harness then unbolt this mounting bracket. We’ll replace the harness with a new one, but reuse the bracket, which has an earth point on.
Fuel pump: To remove the fuel pump we first remove the sprocket. A special tool will lock the sprocket while releasing, but an impact gun usually shocks the bolts off.
Puller needed: The fuel pump sprocket hub is now revealed. A special tool is needed to remove it – it’s nothing more than a small puller, but it’s essential for the job.
Considering whether to replace or reuse
Out it comes: The fuel pump can now be unbolted and removed. Because of the work involved in changing it with the engine in the vehicle, it’s worth renewing it now.
Definitely replace: The turbo, turbo feed pipe and the water pump aren’t going to be reused. Fitting new replacements is sensible, and is best practice to preserve the engine’s warranty.
Think about it: The tensioners, fuel pump and injectors can be reused, but consider carefully the condition and causes of any issues in the original engine. It may be better just to replace them.
Make good: Ancillaries such as sensors can be reused, but might need cleaning, like this filthy Manifold Absolute Pressure (MAP) sensor. Removing the EGR gunk will ensure it reads correctly again.
Reuse pile: All these parts will be refreshed. Vapour-blasting will remove dirt and corrosion, meaning the new engine will look the part without needing to replace them all.
Dress them ready: Some parts, such as the exhaust manifold, will need preparing before reuse. Here, we’re removing the studs so we can replace them. A stud extractor usually works, but not always. We’ll cover this issue soon.
Part two of this engine series sees us dress the new stripped engine with ancillaries, set the timing and get it all ready to crane into the vehicle. Along the way we’ll refresh some parts to better than new condition, so the engine doesn’t just work well, it looks great, too.
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