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Old 4th January 2011, 01:36   #9
Robson Rover Repair
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Default CHAPTER 09 - Overview and common faults for the 1.8 engines

1.8 and 1.8T specific engine details / faults / common servicing costs


A history of the K series engine

The K-Series engine is a series of engines built by Powertrain Ltd, a sister company of MG Rover. The engine was built in two forms: a straight-four cylinder, available with SOHC (single cam) and DOHC (twin cam), ranging from a 1.1 L to 1.8 L.

The K-Series was introduced in 1988 by Rover Group as a powerplant for the Rover 200 car. It was revolutionary in that it was the first volume production implementation of the low pressure sand casting technique. This works by injecting liquid aluminium into an upturned sand mould from below.

In this way any oxide film always remains on the surface of the casting and is not stirred into the casting structure. This production technology overcame many of the inherent problems of casting aluminium components and consequently permitted lower casting wall thickness and higher strength to weight ratios.

However, the process required the use of heat treated LM25 material which gave the engines a reputation for being fragile. An engine overheat would often result in the material becoming annealed and rendering the components scrap.

The aluminium engine blocks were fitted with spun cast iron cylinder liners that were initially manufactured by GKN's Sheepbridge Stokes of Chesterfield, but replaced by spun cast iron liners made by Goetze after some seminal research conducted by Charles Bernstein at Longbridge, which proved influential even to Ducati for their race engines.

Unfortunately a large number of aftermarket and replacement engines, (the so called "VHPD"s" very high performance derivative as used in the 187 bhp lotus elise) were built with the old substandard GKNs by Minister, Lotus and PTP well after the Goetze liner's introduction to the production line in 2000.

Engine size and capacity history

The engine was introduced initially in 1.1 L single overhead cam and 1.4 L dual overhead cam versions. The engines were held together as a sandwich of components by long through-bolts which held the engine under compression, though this construction is not unknown in early lightweight fighter engines from the First World War.

It had also been used in motorcycle engines and Triumph Car's "Sabrina" race engine. As the Honda engines became obsolescent and were phased out, but well before the BMW takeover, an enlargement of the K Series design to 1.6 and 1.8 litres was carried out. This was done by using larger diameter cylinder liners and also increasing the stroke. The change required a block redesign with the removal of the cylinder block's top deck and a change from "wet" liners to "damp" liners.

The plastic throttle body fitted to the engine until 2001 was manufactured by the SU Carburettor company - they also included aluminium and larger sized bodies.

The two types of head that were bolted to the common four-cylinder block were designated K8 (8 valves) and K16 (16 valves). A later head design also incorporated a Rover-designed Variable Valve Control (VVC) unit (derived from an expired AP patent). This allowed more power to be developed without compromising low-speed torque and flexibility.

The VVC system constantly alters the inlet cam period, resulting in a remarkably flexible drive - the torque curve of a VVC K-series engine is virtually flat throughout the rev range and power climbs steadily with no fall-off whatsoever until the rev limiter kicks in at 7,200 rpm

The Rover 75 was never fitted with the VVC engine, instead receiving the turbo application instead.

The 1.8 Head Gasket problems and explanation in detail

Head gasket failure on the 1.8 and 1.8T engines typically occurs around 30,000 miles, and thus the majority of high mile 1.8/1.8T engines will almost certainly have had ''a head gasket repair'' done at some stage. If done correctly, then we have multiple members whose cars have done into the 100,000 of thousands of miles!!!

When purchasing a 1.8/1.8T ask if the head gasket was done. If it was done, ask for the receipts as often people cheat and simply pour a tank of "Radweld or K seal" into the engine coolant tank which will temporarily cure the car, often enough for you to have driven the car away and it fail a week or two later. Its a dirty trick in the second hand market, HOWEVER some people have reported it has worked to their advantage curing tiny leaks.

The K-Series engine has gained a reputation for head gasket trouble. This is due to a range of problems including build tolerances, reduced block face stiffness, casting quality and material and cooling system layout. A number of changes were made over the years to improve the condition.

Amongst the first of the changes was the introduction of steel head locating dowels. Early versions of the K Series engine had steel dowels, but these were loose fitting and used as an assembly aid. Plastic dowels were then introduced to prevent head face damage on the assembly line and also as a cost saving. This engine had wet liners and a solid block top deck and was not known for being prone to gasket failure. The plastic dowels were carried forward to the redesigned K series which was then available in 1600 and 1800 capacities by using damp liners and an open block design.

However, it became apparent that this engine had an issue with head gasket failure which was partly due to lack of stiffness in the head/block interface. To help reduce this shuffling, steel dowels were reintroduced, but with a tight fit to fix the head securely to the block face. This reduced one mode of head gasket failure caused by movement between the block and head faces, but was only partly successful because the dowels only helped in their local areas. The gasket itself was also subject to minor improvements to the sealing bead design over the years.

During its later years, the cooling system of some models was also modified by the introduction of a PRT (pressure release thermostat). This allowed increased coolant flow at high engine loads even before high temperatures were reached and reduced the thermal shock the engine saw when a conventional thermostat was first opened. This thermal shock would cause differential expansion across the gasket face causing relative movement between head and block.

A new design of head gasket has been available for several years from Land Rover which can be retro-fitted to all K-Series engines. This is of the MLS (multi layer steel) design. This has now been superseded by a new MLS design that is used in conjunction with higher tensile head bolts and strengthened oil rail (into which the bolts are screwed). A modified tightening method is also used with the new bolts. The effectiveness is yet to be proved.

Destined to be introduced with the Euro IV emissions compliant engine in late 2005 was the MLS gasket and strengthened oil rail. The aim of the latter is to improve engine rigidity. But this was never introduced by MG Rover Group as the company had gone bankrupt by the time of the planned launch.

The N-Series engine (basically the aforementioned Euro IV-compliant K-Series) in the MG TF relaunched by Nanjing Automotive in September 2008, has these modifications as standard.

None Starting / Fuel Filter Syndrome (FFS) / Orange Clip

Common to ALL petrol cars. The fuel must be delivered at the correct pressure or it won't start. You can hear the petrol pumping up (priming) when you start the car with the key in the ignition.

Often the intank fuel pump will "separate" as its of a screw in design, simply the pressure will push it to unscrew. This can be prevented by fitting an orange clip.

Details and part numbers are inside this thread. http://www.the75andztclub.co.uk/foru...ad.php?t=40717

The cars many ECUs checks delivery pressure. If the delivery of fuel to the engine and a untouched filter module without the orange clip isn't diagnosing FFS (nor indeed the lack of it) then a simple fuel pressure bleed caused by a fractionally slackened filter cap will ensure it doesn't start.

White Exhaust Smoke / Inlet Manifold gasket

This can usually be the most obvious sign from a cold engine of head gasket failure, especially when the engine is cold, BUT it can also mean something much simpler but also as concerning as in this case the white smoke wont be oily. Coolant or water vapour leaking from the inlet manifold. After the car reaches running temperature the smoke typically reduces to almost a small amount.

Unburnt fuel can be a cause of white smoke also. Fuelling problem will make smoke billow out and make it judder, and it becomes obvious car is only running on 3 cylinders at times.

The key difference between the Inlet Manifold Gasket failure and the Head Gasket failure (HGF), is the engine will run normally. Number 4 cylinder is a usual suspect for the gasket to leak coolant into. If it was HGF I would expect the cooling system to be pressurizing and the car would not be running right at all.

Don't use any inlet manifold gaskets that aren't genuine ones, always found them to go brittle with heat. The simplist thing is to replace the inlet gasket and have the coolant system bled and engine serviced.

1.8 Turbo specific issues

Not too many issues effecting the 1.8 Turbo specifically.

Overboosting/Underboosting

Obviously with the engine having a turbo fitted you can have issues, and they start around 2500 to 3000rpm, the hesitation is only around 2600 to 2800 under hard acceleration, sort of like a splutter in power then whoosh, your off!

The problem is typicially the black vacume hose where it joins the turbo,, the rubber joining piece at the end can become oversized due to the heat of the turbo and surrounding area.

It has a spring clip around it to maintain the seal, this doesnt work allowing a loss of vacuum and wastegate problems leading to ignition cutting out (ECU safemode) hence the hesitation.

A new set of solenoid vacuum hoses, three of which to replace around £35 and you will be back to normal.

Rough running / M.A.F

If your 1.8 Turbo is running a little "lumpy" or "rough", with revs at idle searching in and around 750 to 900 plus up to 4500 rpm its great but then lacks instead of pulling to 6700rpm then your looking at a M.A.F failure (providing you have checked the hoses above into the turbo).

The arm between the vacuum actuator and the waste gate can seize where it pivots on the waste gate lever. This will cause an over boost, and usually will temporarily cut the ignition to protect the engine giving you a stall or a safe mode activation (where the car runs very slowly).

Again, a simple clean of the pivot and applied a high temp anti seize spray available from your local motorfactors will resolve this providing your actuator hasnt failed outright but the car would display an engine fault light if it does.

Additionally old spark plugs, failing spark leads an incorrect spark plug gapping can create the same or similar feeling.

General servicing costs and maintenance

So if all of that hasnt scared you off then heres the good news now, assuming you have covered all the regular issues listed then actual maintenance of the 1.8 engines is actually quite inexpensive providing you service it when you should. In fact its the cheapest car of the lot to service.

Depending on usage, a 12,000 mile service is perfectly acceptable, some do around 6000 miles if the car is used less frequently, but its up to yourself. Rover specificed 15,000 miles originally or once per year.

The basic oil filters, sparkplugs, engine filters and such are quite cheap, changing everything will cost you no more than £40

Use of the correct coolant is recommended so use O.A.T coolant, which is pink in colour. Save yourself over Halfords prices and buy none-diluted from your local Vauxhaul dealership. 5 litres will cost you about £22 maximum and when you mix it 50:50 gives you 10 litres of coolant.

Use a 10W/40 or 15W/40 oil meeting both ACEA A3 and ACEA B3:96 specifications, and having a viscosity band recommended for the temperature range of your locality.

Last edited by Robson Rover Repair; 3rd September 2011 at 20:35..
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