REVscene Automotive Forum - Something for people considering an engine swap should read.

I know it looks long, but if you are considering doing an engine swap on your car, you SHOULD read this

Second-hand Japanese engines have been flooding in through Australian import wreckers for many years. Indeed, their amazingly cheap prices have proven a tremendous advantage to anyone who owns - and, especially, modifies - a Japanese car. But despite popular opinion, not all Japanese import engines have done only 30,000 kilometres and are in mint condition. In addition to this, it's common for people wanting to do a conversion to buy a cheap bare engine - but then not be able to afford to do anything with it. Certainly, it's easy to be seduced by a bargain package that only half suits your needs.

In this story, we'll have a look at what type of engine configuration best suits your application and how to check on its health...

For Sale: Engine Only

Bare engines are extraordinarily cheap - and there are good reasons for it. These engines have had their hoses and wires slashed in order to quickly hoist them out of the donor car; all that the buyer receives is the engine and whatever's bolted or screwed into it. As such, an engine-only purchase is most suited to somebody who's simply after a bolt-in replacement for an existing engine; in this case, there shouldn't be any major problems with wiring looms and connections. (But make sure that the donor car is the same make and model - not all same model number engines have the same ancillaries and computer.) In addition, though, some people - especially those who are tuning their cars for maximum power - consider it worthwhile to purchase a bare engine simply as a spare.

We'd advise against buying just a bare engine if you're planning on performing an engine conversion into another body. You'll either have to pay to get a separate computer, loom and any necessary ancillary electronics (such as airflow meter, boost solenoids and igniters) or you'll need to shell out for programmable management. The latter option is fine if you're positive that you want programmable EFI, but - be warned - you'll be up for at least $2000 to get such a system installed and tuned.

Being jammed up against - or beneath - other engines inside shipping containers, it's common for bare engines to get damaged during freight and/or handling. Typical damage includes crushed top-mount intercoolers, broken EFI sensors and cracked cam covers.

Note that bare import engines often come with a transmission still attached - as a 'bonus'.

For Sale: Engine, Trans, Computer and Loom Package

The next step up from a bare engine is an engine package. A package deal typically includes the engine, trans, computer and loom - supposedly "everything" that's needed for a custom engine transplant. Be warned though, you very rarely get all that's required. All too often, these 'package deals' are minus a couple of ancillary items, such as igniters, MAP sensor and many other easy to overlook items. Finding these components - and then getting them at a good price - can be difficult.

Be especially wary of incomplete packages that wreckers say they can get the necessary components for. When extra parts have to be sourced from a different vehicle, you're leaving yourself open to problems with plugs being slightly different, wiring loom variations, gearboxes having the wrong ratios and more. The management computer, for example, may be designed for use with a manual transmission when you might also want it to control an auto trans. There are a million areas where problems can arise.

As before, an engine package can also get knocked around and damaged during freight and handling.

For Sale: Half Cut (Front Clip)

Short of purchasing a complete car and stripping out everything you need, a half-cut is by far the safest way of buying a Japanese import engine. A half cut is - literally - the front end of a vehicle cut from the dashboard forward. (In a the rare mid-engined cars, it comprises the rear half of the car.) This gives you things like the airbox, charcoal canister, fuse box, relays and more. Brakes and suspension are also usually included in the deal.

If you're conducting an engine conversion, this is indeed the best - perhaps only - way to go. With the inclusion of the aforementioned components, you can rest assured that everything you need for the conversion is at hand - except for the fuel pump and anything that's normally found in the rear half of the vehicle. Of course, this is not to say that a swap will be easy though! You'll always need to organise things such as engine and gearbox mounts.

On the other hand, a half-cut may be overkill if you just want a replacement or back-up engine. The extra cost, however, may be offset by the inclusion of many hard to get and expensive parts that only come attached to the body - igniters, boost solenoids, relays and more. Take this on a case-by-case basis.

Inspecting an Import Engine

With just a bare engine or half cut sitting on the wrecker's floor, you may feel unable to thoroughly check its condition. But there are a quite a few checks that can be made.

The first place you should start is with a complete visual external inspection. Take your time to check the engine for any damage from freight, handling or a road accident. AutoSpeed staff have purchased two Liberty RS engines over the years; both were later discovered to have cam sprockets that had been broken in the accident that the donor car had suffered.

Next up, you should check all critical sealing areas for signs of oil and coolant leaks. This should be followed by a good look inside all accessible oil and coolant passages. Excessive oil stains around breather pipes are indicative of combustion blow-by, while signs of "mayonnaise" in the coolant passages is indicative of a blown head gasket; another pointer is deposition in the coolant overflow tank. It's also a good idea to look at the electrical wiring - especially in a half-cut. Check for brittle insulation and deteriorating connectors - these are common in vehicles such as the Nissan 300ZX twin turbo, where under-bonnet heat can be a problem.

Another thing to consider is how well the engine has been looked after while it was running in Japan. It's scary how many cars barely ever get serviced - especially the cheaper cars. Signs of 'cheapo' maintenance include non-genuine parts eg the oil filter, gaskets and sealants, spark plugs and - sometimes - fastening bolts. Also, look for tell-tale signs of removed bolts and fasteners - this will give you a guide to any service interval maintenance or more major repairs. For example, if you look at an engine and see a few intake manifold bolt heads slightly rounded-off, a non-factory sealant that has leaked out between the head and block, and an aftermarket oil filter - steer clear!

As mentioned, don't assume that every engine out of Japan has minimal kilometres.

If you're not buying a half-cut with the odometer still attached, it's advisable to have a look for signs of service interval style maintenance. Most modern engines use a one-time seal or a sticker over the cam cover; if it's been burst then it's likely somebody's changed the timing belt. And there's no reason for that to occur unless the engine has done (depending on the type of vehicle) 50,000km or 100,000km. Importantly, bear in mind the age of the engine; it's unlikely that that a 10 year old Mazda 12A turbo rotary, for example, will have less than 80,000 kilometres on it. Be sceptical if the wrecker makes claims to the contrary.

Beyond a visual check you will need to get some tools out.

Step one will be obvious to many readers - rotate the engine internals using a spanner on the crank pulley. Check for rotation smoothness and, if it doesn't turn at all, don't bother with that particular engine.

After that, we'd remove the sump plug and drain the oil into a bucket. Look closely for any stray metal particles and consider the colour of the oil. About six years ago, one AutoSpeed staffer had a Daihatsu Charade carby turbo engine installed by a wrecker - only to later discover a funny clacking noise from the bottom-end. Inspection of the ex-Japan oil revealed many tiny metal particles that had once belonged to the big-end bearings...