NISSAN YD25DDTi

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There are an increasing number of reports of lower timing chain failures in Australian released Nissan YD25DDTi engines. The primary (lower) timing chain and gears are a simplex (single row) design, while t

he secondary (upper) timing chains and gears are a duplex (double row) design. The simplex chains are stretching and ultimately falling, leading to major engine component failure, including valve and piston crown contact and dam

age. It is advisable to replace the simplex timing chains and tensioners before 80,000kms.

Typically the timing chain guides and the vacuum pump timing chain sprocket and shaft are found to be heavily damaged and/or worn as well.

 

Excellent Reviews

“The experience we had with Southside Cylinder Heads at 10/547 Kessels Road, Macgregor, was without doubt first class. Nathan and his team are very professional in every sense of the word. Their attention to detail and standard of work was amazing. Technically our vehicle has never sounded better. Southside Cylinder Heads kept us informed and consulted throughout the process. Then there was the after-service care and the follow-up call. There are mechanical workshops out there and then there is Southside Cylinder Heads. Absolutely recommended.”

Antonio Pires

Warning on the use of Hylomar!

Most of the head gasket designs available for aftermarket use can be classified into two general categories – Composite and Steel (MLS).  Typically composite head gaskets have a steel core, usually perforated, with softer facing materials (graphite or aramid fiber) bonded on each side.  Until recently steel head gaskets consisted of four to six layers of steel bound together by a variety of mechanical methods however the trend now is for fewer layers with three or two layers not uncommon and even a single layer now in use on some applications.  Also common to these head gaskets is an impervious silicone coating or viton rubber sealant bonded to the outer layers, a key characteristic in the ability of the gasket to “cold seal”.

Gasket

 Generally speaking, almost all aftermarket head gaskets (both composite and MLS) are designed to be used without additional chemical sealants (i.e. hylomar).  The use of an additional chemical sealant on gaskets not designed for it will actually do more harm than good and affect the gaskets ability to seal.

The use of additional chemical sealants such as hylomar can affect the head gaskets ability to:

  • Cold-seal, the ability of the gasket to seal coolant until the engine is first started.
  • Cold Flow, the characteristics of the coating material to creep as the gasket is loaded (clamped), to seal small scratches and imperfections on the head and block surfaces.
  • Reduce the shearing forces that are applied to gasket sealing surfaces by thermal expansion of the cylinder head and block
  • The added thickness of an applied sealant on a head gasket can cause uneven loading and or a loss of torque retension.
  • The use of an additional sealer may also cause relaxation when temperature is introduced

Some chemical sealants may also react with the gaskets silicone coating, causing the gasket to deteriorate, and in some cases can cause the deterioration of the chemical sealer itself.

The vast majority of gaskets supplied by Southside Cylinder Heads will not require any additional sealants and the use of such products is not recommended, and may void the head gasket’s warranty.  Please read the gasket fitting instructions before fitting your next head gasket, or simply give us a call if you are unsure if your head gasket requires an additional sealant.

A Basic Guide to Engine Valve Failure

Auto-Engine-Valves-320x200

Engine Valves

The valves in your cylinder head are a vital component of your engine and undergo enormous stresses, opening and closing up to 2500 times every minute under normal operating conditions. When one or more of these valves are damaged, the result can be anything from reduced power and poor fuel consumption, to complete engine failure.  The two most common types of valve failure are bent/broken valves and burnt valves.

Bent Valves

The most common failure of valves is bending or breaking as a result of contact with the pistons. The valves contacting the top of a piston is due to incorrect engine synchronization caused by timing chain/belt breakage and incorrect fitting of new belts and chains. If you suspect your engine may have bent or broken valves, it is crucial not to attempt to start the engine as this may result in more costly damage being caused to the cylinder head, pistons and cylinder bores.

The bent valves above are a result of a fatigued timing belt that has broken. Your timing belt doesn’t last forever and needs to be replaced according to the manufacturer’s service guidelines. Replacing your timing belt is cheap insurance against costly engine damage.

Burnt valvesValve-Piston-Diagram

The other common type of valve failure is valve burn, or burnt valves. Essentially this is caused by combustion gases escaping between the valve and valve seat when they are not sealing correctly. The hot combustion gases are forced past the valve which starts to burn away the edge of the valve, progressively getting worse the longer it is left without being rectified. Normally this type of failure affects the exhaust valves only, but it can also damage the intake valves.

A burnt valve will cause issues with your vehicle’s performance and fuel consumption. Rough idle, reduced power, backfiring, and misfire are all symptoms of valve burn. If your engine is showing symptoms like these, we recommend you get your car checked by a trusted mechanic, as continual driving with a burnt valve will cause more damage to your engine, and will in turn cost more to repair in the long run.


Possible causes of burnt valves are:

Bent-Valves-Caused-By-A-Broken-Timing-Belt-320x200

Bent valves caused by broken timing belt

  • Excessive localized heat
  • Combustion gases escaping past the valve and concentrated at only one point
  • Irregular valve sealing with cylinder head valve seat. Carbon residues generated by irregular combustion (poor mixture) will appear at the seat region and will jeopardize the sealing between the valve and its seat
  • Deficient refrigeration is another factor, due to partial obstruction of the cylinder head cooling.  As a consequence, the valve is cooled inadequately
  • Incorrect valve clearance can jeopardize the valve sealing and also cause this type of failure
  • Running a dry fuel such as L.P.G resulting in inadequate lubrication of the valve seat, causing the valv
    A-Valve-Starting-To-Burn4

    A Valve Starting To Burn

    e seat to fail and consequently, the valves

To help prevent this type of failure, there are a few things you can do. Maintain a clean, efficient cooling system so the engine does not run too hot,  use good quality fuels to help prevent carbon build up on the valve seats, and have your mechanic regularly check the valve clearances are within specifications.

If your vehicle is using an aftermarket L.P.G fuel system, you must check that the engine is L.P.G compatible (most are NOT). In the event your engine is running L.P.G but is not L.P.G compatible, valve failure is imminent. It will generally be less costly to have your cylinder head removed and modified for L.P.G before the valves start to burn, rather than wait until the damage is done. Once the L.P.G modifications are complete, it will be safe to use

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Burnt Exhaust Valve

the L.P.G without damaging your engine.

The Damage That A Lack Of Servicing Can Cause

You may think that having your vehicle regularly serviced is not essential however the following situation that one of our customers found themselves in may cause you to reconsider!

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The piston rings are full of carbon deposits which caused low engine compression

The customer came to us earlier in the year wanting a service on his Hyundai Getz – it had done 51,000 kms & its last service was 30,000 kms ago. While carrying out the service we found that it had low compression due to the rings on the pistons being full of carbon deposits as highlighted in the picture below.

This damage was a direct result of the vehicle not having had an oil change in 30,000 kms. As a result, the engine had to be fully dismantled, cleaned and rectified costing the customer in excess of $4,000.00. Had more regular servicing been carried out on the vehicle this damage would not have occurred and the customer would only have been up for the cost of a service – a much less costly exercise!

Has it been a while since your last service? Even though you might not have experienced any repercussions yet it is most often the case that damage is already being done to your vehicle’s essential components. Don’t keep putting it off until it’s too late!

welding repair to cylinder head

Brisbane’s Best Established in 1977

Southside Cylinder Head Service Owner/Operator’s have been servicing the motor welding repair to cylinder headvehicle trade and retail client since 1957.

Making Southside Cylinder Head Service one of Brisbane’s longest serving engine reconditioning businesses and one of the most experienced in engine cylinder head diagnostics, servicing and repairs.

fast service and delivery from southside cylinder heads

Fast Turn Around, Convenient Delivery

fast service and delivery from southside cylinder headsWe offer FAST turn around of your cylinder heads. We keep a large stock of exchange heads making sure you receive the cylinder in the shortest possible time. SSCH offer a pick & delivery service in most Brisbane suburbs & a fast, reliable courier service to all areas of south east Queensland, the Gold Coast & beyond.

Brisbane's quality cylinder head service specialists

What to Expect from Southside Cylinder Heads

Brisbane’s Southside Cylinder Head Service offers world best practiceBrisbane's quality cylinder head service specialists and are one of Australia’s and Brisbane’s best choices for fast, reliable & quality workmanship. Our friendly and talented automotive technicians and engine builders are highly capable mechanics and have extensive experience in the reconditioning, repairing and diagnosis of cylinder heads from a wide range of engine types and take pride in their work.

 

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Welcome to Southside Cylinder Head Services

Where we GUARANTEE a Hassle Free, Profitable and Risk Free solution to independent Automotive Mechanics who require Cylinder Head Repairs.

We are recognized by the automotive industry as having the most lucrative profit assistance program for mechanics.