YD25 D40 D22 R51 Duplex Timing Chain Conversion Kit

timing chain website thumb
 Watch Our Timing Chain Install Video


The original yd25 engine had a double row fuel pump chain. The euro 3 and euro 4 yd25 engine use a single row fuel pump chain however the engine still kept double row thickness sprockets and guides. Our duplex chain kit replaces the failing parts [lower chain sprockets and guides] reinstating Nissan's original duplex design. As seen in the workshop manual page below.

  oem duplex  when timing chain problems started  
 Workshop manual showing both chains duplex  Genuine Nissan Crank Sprockets and Chains Double vs Single row  


Duplex chain kit options German Iwis or Genuine Nissan chains

YD25 duplex timming chain conversion iwis kit    YD25 duplex timming chain conversion genuine kit 
 Iwis duplex chain kit    Genuine duplex chain kit


The kit includes:

·         Duplex fuel pump sprocket
·         Duplex 4340 crankshaft sprocket (Australian made)
·         Duplex 4140 vacuum pump sprocket (Australian made by YD25.com.au with local and international registered designs and patents pending)
·         Duplex fuel pump drive chain (genuine Nissan Japan or Iwis Germany)
·         Duplex camshaft drive chain (genuine Nissan)
·         Cam chain tensioner (genuine Nissan, plus an Australian made fail-safe component)
·         Fuel pump chain tensioner (genuine Nissan)
·         Seven quality chain guides 4 (genuine Nissan)
·         Crankshaft oil seal (genuine Nissan)
·         Camshaft shaft sprockets upon request
·         Oil pump o rings
·         Scissor gear tool (Australian made)
·         Free hire of harmonic balancer tools (Australian retail customers only)
·         Step by step installation guide and free telephone or email support
·         Five year, 100,000km chain and sprocket warranty conditional upon vacuum pump  and fuel pump sprockets being in perfect alignment.

We are so confident in the quality of our chains and sprockets that we offer a five year, 100,000km chain and sprocket warranty. This is five times the industry standardCorrect chain running alignment between the vac pump and fuel pump sprocket is curctial for chain longevity. This can only be achieved with our flat faced vacuum pump sprocket.
See video here to check Evidence that the vehicle has been serviced according to Nissan guidelines will be required to support a warranty claim. The warranty covers premature wear to chains and sprockets. Damage as a result of incorrect installation by anyone apart from us, other parts failing causing chain and sprocket damage or continuing to drive the vehicle when there is an unusual noise coming from the motor rather than having it repaired will not be covered by our warranty. All other timing chain components are covered by a 12mth 20,000kms warranty.

We offer clients a choice between genuine Nissan and German Iwis chains.  Iwis chains cannot be used with genuine or aftermarket sprockets (other than ours) due to differences in pitch and width.  We supply Australian made sprockets manufactured to suit the pitch and width of each chain.  The Iwis chain we offer is used in many European high performance vehicles. For example, a 60 link Iwis chain, with its highly polished low friction link plates, is used as an upgrade for the primary timing chain for the Lamborghini Murcielago SV. Our fuel pump drive chain is a 94 link version of the one used for the Lamborghini.

yd25 iwis fuel pump drive chain   yd25s nissan camshaft drive chain   yd25s nissan fuel pump drive chain  
 YD25 Iwis duplex fuel pump chain    YD25 Nissan duplex fuel pump chain    YD25 Nissan duplex cam chain  

Before deciding which chains to supply in our kit we undertook extensive testing of the German Iwis chain and aftermarket fuel pump chains with the following colour combinations: yellow-yellow, yellow-orange, yellow-silver, silver-silver, blue-blue, blue-tan, blue-white, and blue-bronze.  We saw no need to test the genuine Nissan chain.  We subjected each chain to in vehicle testing comprising 400 hours engine running time.  The results showed that the aftermarket chains (all of which had harder pins than the Iwis chain) had wear to the pins and bushings ranging from 3.0mm to 4.5mm while the Iwis chain had the least wear at 0.5mm.  These results do not support claims that harder pins lead to longer chain life.  Aftermarket chains are easily identified by plain packaging and the absence of manufacturer stamp, name or logo. The photos below show pin wear.

Chain pin1   Chain pin2   Chain pin3   Chain pin4 

Some aftermarket sprockets do not correctly mesh with a genuine Nissan chain.  The sprockets below are wrapped with a Nissan duplex fuel pump drive chain. The poor fitting chain wrap on the aftermarket sprockets will cause rapid chain wear and imminent chain failure. The YD25 sprockets fit perfectly thus guaranteeing maximum chain and sprocket life.

after market crank shaft oversize sprocket   after market fuel pump oversize sprocket   YD25 crank shaft sprocket chain wrap   YD25 fuel pump sprocket chain wrap   YD25 vacum pump chain wrap
 after market crank shaft oversize
   after market fuel pump oversize
  YD25 crank shaft sprocket
chain wrap
  YD25 fuel pump sprocket
chain wrap
  YD25 vacuum pump
chain wrap

Original factory YD25 crankshaft and vacuum pump sprockets and some of the aftermarket sprockets that we know of are made from SMF4040 carbon steel. The process of manufacture is Powder Metallurgy Sintered Metal. The later YD25 engines with common rail injection require higher fuel pressures which place the crankshaft sprocket under higher loads than earlier engines. Higher loads mean more wear to carbon steel sprockets.  To handle these higher loads we manufacture our crankshaft sprocket from billet 4340 high tensile steel and our vacuum pump sprocket from billet 4140 high tensile steel.  Both sprockets are nitride hardened.  While carbon steel sprockets can be manufactured for a fraction of the cost of a fully machined high tensile steel sprocket, our aim is to provide a high quality sprocket backed by a five year, 100,000km warranty.  Our Brisbane based sprocket manufacturing partner has over 50 years experience in sprocket design and manufacture.  Every YD25 sprocket is subject to a stringent quality assurance process before leaving the factory.  

Upgrading to duplex

Our timing chain kit is a conversion kit. All competitor's kits are modification kits.

Conversion kit

With our kit to convert the vac pump to duplex simply remove the single row sprocket and replace it with our duplex sprocket. It is that simple.

Modification kit

The process is not that simple with our competitor's modification kit. The vacuum pump is fitted with modified internal parts. To achieve this most workshops go through the following steps.

1.      Removal of the engine from the car.

2.      Remove the fuel pump from the engine.

3.      Remove the vacuum pump from the engine.

4.      Dis-assemble the vacuum pump.

5.      Fit modified vacuum pump shaft to the vacuum pump housing.

6.      Assemble the vacuum pump.

7.      Fit duplex sprocket to the vacuum pump shaft.

8.      Refit the vacuum pump to the engine.

9.      Refit the fuel pump to the engine.

Due to the limited space in which to remove the fuel pump and vacuum pump with the engine in the car, the engine is usually removed when fitting a modification kit.  Owners need to be aware that fitting a modification kit the vacuum pump and fuel pump sealing surfaces are disturbed with the potential for ingress of grit on the o-ring seals which significantly increases the potential for oil leaks.  Dis-assembly of the vacuum pump can also damage internal components and casing (which are a non-serviceable items) requiring a complete pump replacement.

Only YD25.com.au and our resellers can offer a conversion kit which is a quick and simple bolt on replacement sprocket for the YD25ddti engine that takes just minutes to fit.

YD25 original vacuum pump sprocket   YD25 original vacuum pump shaft   YD25s vacuum pump sprocket   YD25 vacuum pump shaft
 OEM simplex vac sprocket    vac sprocket removed    yd25 duplex sprocket fitted    

Buyers be aware. It has come to our attention that there are people that are copying our vac pump sprockets. These sprockets are made in UK Europe and Asia. Some have USA branded names.  On closer inspection, you will see that the copies are of poor quality compared to our parts. Be aware that some people selling these kits are stating the chains are German. We can assure you that their chains are not from IWIS of Germany. If you purchase one of these counterfeit yd25 chain kits, you can expect 40,000 kms service life. We have had several people who have purchased these counterfeit parts contacting us wanting replacement parts.  Our duplex chains are designed to operate with our precision made sprockets and components.  We are sorry to advise these people that we cannot supply parts to mix and match with other incompatible duplex chain kits. Should you find your car has been fitted with a counterfeit duplex chain, we can certainly help out you with our duplex chain conversion kit. We have been supplying the same kit for 9 years with over 12, 000 sold in Australia.


counterfeit2      counterfeit1
 Genuine yd25 vacuum pump sprocket our part    Counterfeit vacuum pump sprocket


The YD25.com.au kit includes genuine Japanese Tsubaki tensioners in their original Nissan packaging. These are the best available. The top tensioner is supplied with an additional fail safe component designed and manufactured by us. When new chains and guides are fitted, the fail safe component only allows the tensioner to back off 1.0mm. Without the fail safe, the tensioner can back off 7.0 to 8.0 mm which, when combined with 3.0 to 4.0mm of wear to the chain, can result in the chain jumping teeth.   We have tested aftermarket tensioners and found high valve failure rates. These tensioners come in plastic bags or white boxes with no manufacturer stamp, name or logo. Failed aftermarket tensioners have cost some owners their engine.

Don’t risk it!

yd25 tsubaki japan tensioner btm    yd25 tsubaki japan tensioner top
 YD25 Fuel pump chain tensioner  YD25 Cam chain tensioner

Special Tools
A scissor gear tool is included in each kit to assist installers maintain the pretension between the scissor gear and the idler gear during removal and installation.  Failure to maintain the pretension and timing will cause vibrations putting undue stress on the engine's internal components.

We offer free hire on the harmonic balancer tools for Australian retail customers. These tools are essential to loosen, remove and re-torque the harmonic balancer.  For those wishing to take advantage of this offer, a security deposit of $230 AUD (including a non-refundable charge of $25 AUD to cover freight one way) is required.  $205 AUD will be refunded on return of the tools in good condition.

 trans.gifWe at YD25.com.au hope you have found this information useful. 

For more information please submit your query using our online form or contact us directly on (+61) (0) 424 034 935.




Last updated June 2020


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