Tuesday, October 29, 2013

Should You Rebuild or Replace Your Land Rover V8?

That is the question facing more and more Discovery II owners as their engines age.  Land Rover’s Buick-designed aluminum V8 engines were never paragons of reliability; engines in the last P38 Range Rover and Discovery II models are arguably their worst.

There are three common failure modes.  Most common is the overheating failure, where the engine consumes coolant for a while and then overheats whenever it’s driven. Sometimes people fail to catch this in time, and the engine is driven till seizure.

Land Rover V8 with block failure behind the liner.  Coolant scours the piston clean
I've got several articles on liner failure online.  Here is the latest one.  This story explains the process in detail.

The next failure starts with oil pressure loss. The post-1998 oil pump is integrated into the front cover, and it’s prone to wear out over 100,000 miles.  If the pump merely wears you get low oil pressure, and a light at idle.  That can actually be fixed with a new front cover.  However, it’s often accompanied by worn main and rod bearings.  We’ve also seen the thrust faces break off the center mains, and either of those failures will necessitate engine overhaul.  If the pump actually fractures internally you can get total loss of pressure, and engine failure if the warning light is ignored.

The gear in this oil pump broke into pieces

The final failure is unacceptable motor knocking.  Sometimes this comes from lifters or rocker shafts but more often the noise is deeper inside - in the pistons.  We’ve also heard heavy noises from the lower end. The piston skirts wear and the motor starts knocking, first when cold and then all the time.  There’s no cure for this short of complete overhaul.

The only cure for excess piston skirt clearance is new pistons

It’s said that the production tooling had worn out but Rover continued to use it.  However it happened, the result was a series of engines whose internal clearances were at the wear limits before they even left the factory.  Internal balancing was abandoned to save costs, and finish quality dropped. Internal stress increased as the rated power was raised; first in 1999 and again in 2003.  The final straw was extra heat from leaner running; these motors were beyond their limits to achieve post-1997 emission compliance. 

Where the engines in older Rover models often went 200,000 miles or more, these final series motors seldom hit that mark. Most fail by 120,000 miles and a few don’t even reach 60,000. They seem to have gotten worse with age.

So what do you do about it?

Over the last decade, used Land Rover values have fallen and repair costs have risen.   Short block engines cost just $1,000 in 2004; by 2013 they were $6,000+ if you could find them. Long blocks - with the oil pump and heads - are closer to $8,000 Even so, the repair decision remains easy on a Defender, where vehicle values are usually above $50,000 and holding.  No sensible person would scrap a Defender for mere engine failure.  The situation is different for Range Rovers and Discoveries because those vehicles may be worth less than $10,000, and total repair costs can easily exceed that number.

If you’ve got a Rover whose engine is on its way out you basically have three choices:
  • Scrap the truck;    
  • Install a used motor;
  • Rebuild your motor, or buy a rebuilt motor.
Some people will read this and ask, what about a different motor, a Chevy or Toyota conversion?  If you've got an old Rover, and you live in a place that does not have emission testing, that is an option. Unfortunately most 2000-newer Rovers in America are subject to emission test, many through the OBD port, and an engine conversion will not work for them.  Your conversion options are mostly applicable to 1995-older trucks without OBD II.  It's also worth noting that a high quality engine conversion is often 100+ hours of work, so there is no cost savings to this route if you pay to have the work done.

If the Discovery is “just a car” to you, the scrapyard option may look attractive; people in that position tend to move on to other brands of car.  Major repairs are what separate the serious enthusiasts from the weekend dilettantes.  The weasels get a can of gas and a match, and get ten grand from the insurance company.  A few good men take their own ten grand, and do a proper repair.  Then they go out and burn the gas, chasing action through backwoods and beaches. 

If you are dedicated to Land Rover, and like the separate frame/live axle design of these trucks, you know there is no present-day equivalent.  As an off-road platform the built-up Discovery II outperforms the Defender in many situations, with vasty improved civility and much greater family acceptability.  If you agree with all this, and your truck is in good shape otherwise, the most sensible option may well be repair.

That leaves you with a choice of engines.  I’m often asked about used motors for these trucks, and I am never in favor of that idea.  The reason:  any used motor you find is going to be 10 years old at least.  If its not worn out, it’s going to be well on the way.  Worst of all, any used motor is going to retain all the design flaws the motor you have now has, and it may blow up a month or two after installation.  When I look at the cost of used motors and the effort it takes to put them in I think you’d be nuts to choose that route.

If you’re still thinking about that notion, just remember that your late-series Land Rover V8 was a fatally flawed design.  What sense does it make to put another flawed motor in your rig?

To me, the only option that makes sense is the fitment of a flange-liner motor with a new front cover; one where the late series design deficiencies have been addressed.  That is the solution that leads to long term reliability.

I’ve written several articles about the use of flanged liners to fix overheating in these engines.  When that technique is combined with new pistons and an updated front cover, and the motor is blueprinted and balanced you end up with a rugged and smooth running engine that will last a long time. 

A rebuilt Rover engine, ready to install
Robison Service has been rebuilding engines like that for several years; it’s the only way we do Land Rover V8 motors now.  Other companies in the UK and the USA are offering engines with various combinations of parts and technology.  In my opinion that is the way to go.

There are still a few “old style” short blocks in the market with the original Land Rover tube liners.  I suggest avoiding those motors as they have all the flaws of the original engines.

Now for the final question:  What will it cost:

A set of pistons, flanged liners, bearings, and other parts to rebuild a short block will run a bit more than $2,000.  The machine work to rebuild a short block is substantial.  Here is what we do in our shop:
  • ·      Tank clean and bead blast the block
  • ·      Remove the old liners and check for cracks
  • ·      Repair the cracks
  • ·      Check the block for straightness, corrosion, and other damage
  • ·      Machine the block to accept flanged liners, and install the liners
  • ·      Bore liners to match the new pistons
  • ·      Rebuild crank and rods
  • ·      Line bore block if needed; deck cylinder head surfaces;
  • ·      Balance rotating mass
  • ·      Assemble short block
We can change displacement from 4.0 to 4.6, or something a bit larger.  Upgrade costs can be anything from $1,200 up.  Other shops may follow different steps, or a subset of these steps.  Not all blocks are rebuildable; a few are too damaged from overheating.  Expect the total cost for a rebuilt short block to be in the $5,000-6,500 range; more for custom work.  You can rebuild the block you have (that's what we do most of the time) or you can buy an exchange block, already built.  

Then you get into the rest of the job . . . 

Add a couple thousand more to rebuild the heads, replace the front cover and take care of the other rebuilding work.  That gives you what rebuilders call a "long block" - a complete motor less the covers, accessories, brackets, hoses and wiring.  Those too can be purchased or made.

A wise owner looks at the ancillary items – things that should be attended to when the motor is out. New water pump, hoses, motor mounts are just a few possibilities.  You may need a radiator, or AC work, or a steering box and lines.  Those costs should be added in for a first-rate job.  You should also consider cosmetics - do you care how the engine bay looks?  If you do, this is the time to refinish or re-plate under hood pieces while they are all out and apart.  The change may be striking:

A restored D90 engine bay
Finally there is the labor to do the job; expect this work to consume 30-40 hours at whatever labor rate prevails in your area; more if you get into detailing or custom work.  Jobs like this typically cost $11-14,000 in my part of the country, as of fall 2013.

It’s expensive, for sure, but it’s the only repair that’s going to last.  If you have a Rover V8 and you want to preserve it I suggest giving this plan serious consideration.

1995 Range Rover Classic atop Killington Mountain
Note:  The advice in this article applies to any 1987-newer Land Rover with V8 engine.  If you have a pre-1999 engine you may not need the flanged liners but the rest of the job is essentially the same.  Owners of older cars should also consider a diesel conversion, something that is not possible for those of us with newer vehicles in states where emission testing is a requirement.

John Elder Robison is the founder of J E Robison Service, independent Land Rover specialists in Springfield Massachusetts.  John has been part of the Land Rover community for 26 years; since the marque’s 1987 return to North America.


Andrew price said...

What do you think about fitting a 4.4 Leyland p76 motor in a 88 classic

Andrew price said...

What do you think about fitting a 4.4 Leyland p76 motor in a 88 classic

John Elder Robison said...

You must be Down Under. The P76 motor is not found in North America and it would not meet emissions rules in most states here.

If you have an older truck and you didn't have catalyst and emission worries the P76 is an excellent choice if properly rebuilt.

gsmac said...

What about other engine alternatives that could be shoehorned into place - perhaps a nice beefy diesel?

John Elder Robison said...

If you have an older Rover diesel and other engine conversions are a possibility. For the folks in the USA with late model trucks the emission rules generally prevent those swaps.

Simon said...


How do you repair the cracks you may find in the block?

Lefty McStinky said...

I am interested in this engine and the 215 Buick Olds engine it is derived from for experimental aircraft use, but this doesn't make it sound attractive.

I bought a Disco with some body damage and parted it out for the axles and transfer case for a Series swap/conversion. The engine seems to be in good shape but because of a minor fire in the wiring wasn't running.

My guess for thiose in environazi states is that one could do a Buick 3800 swap if the ECM could be replaced with the GM one and reflashed. Diesel or CNG conversions might be possible too.

Alice Estman said...

very interesting knowledge about land rover spare parts .thanks for sharing such a informative post

leslie ramos said...

Can you recommend a shop in the Northern CA Area?