yd25.com.au

At YD25.com.au we build YD25 Navara reconditioned exchange engines.  

Drivers Side View	Passenger Side View	Front View

 

Video guide on how to assemble Engine

Make  Sure you watch our Step By Step YD25 Assembling Video

 

Cylinder Block

The deck is machined and the bores are measured. If the bores are within standard specifications they are given a very light hone. If the bores are outside standard specification they are bored oversize. The main bearing caps and the crankshaft tunnel are checked for alignment. If outside of standard specifications the caps and block are machined then precision line bored. The oil gallery welsh plugs and ball bearings are removed allowing total cleaning of the oil gallery system. Oil gallery ball bearings are replaced with BSP tapped bungs. New oil gallery welsh plugs are fitted.

Engine block is honed and decked		Engine block tunnel is line bored or line honed		Block and crank oil galleries are bunged

original balls in oil gallery		galleries are cleaned with a drill bit		threads are taped		bungs are fitted

  

 
Crankshaft
Crankshaft journals are measured and if within standard specification they are given a very light polish. If the journals are outside standard specification they are reground under size.
The ball bearings in the oil galleries are removed to allow thorough cleaning of the oil galleries. The end is tapped and fitted with grub screws.

original ball in oil gallery		ball is removed		galleries are cleaned with a drill bit		threads are taped		bungs are fitted

 

Balanced Pistons and Conrods

Conrods are resized and balanced as well as the pistons and gudgeon pin. Because our engines are balanced the balance shaft assembly is not required. No balance shaft adds to the reliability, power, and fuel economy.

conrod little end unbalanced vs balanced		conrod big end unbalanced vs balanced		balanced pistons

 

Bearings
We have seen major issues with bearings included in most YD25 engine rebuild kits. We have found that Taiho bearings for mains, big ends, and thrust are the best and for gudgeon pin bushes Genuine is best. We have tested these bearings in our D22 Drag car making 400hp and 50psi boost 

Trimatal bearings the best for the job		Nissan gudgeon bush best for the job

 

Piston Rings
Most other engine assemblers use after-market piston rings. The issue with these rings is that the rings have too much end gap. This results in excessive blow by. Fitting genuine rings ensures end gaps are to Nissan specifications.

Cylinder Head  
All engines are fitted with new cylinder head Castings, genuine valves, washers, springs, lifter buckets, and collets retainers.

Valve train gear		Camshaft side of head	Engine block side of head

Included extras 
Our reconditioned exchange engines are assembled as bare long engines (block and head assembled with head torqued). Engines come in a package with a full gasket kit, double-row timing chain kit, oil pump, and vacuum pump bearing.  

Gasket kit	Duplex Timing Chain Kit	Oil Pump	Vacuum Pump Bearing

 

Video guide on how to assemble engine

Our reconditioned exchange engines are assembled as bare long engines (block and head assembled with head torqued), you will need to watch our video to make sure you assemble the rest of the engine properly as shown below.

Drivers side view		Passenger side view		Front end view

 

Make  Sure you watch our Step By Step YD25 Assembling Video

 

Recommended Coolant System Upgrades 

With our reconditioned engines, we rectify all the weak points of the engine however for maximum reliability we highly recommend the following parts be fitted at the same time.  Failure to replace these parts often results in an engine overheat.

Upgraded heater hose kit for d40 and R51		EGR delete pipe kit		Radiator top tank

 

Warranty

We warrant our engines for a period of 12 months or 20,000 kms (which ever comes first).  The timing chains and sprockets are warranted for 5 years or 100,000 kms (which ever comes first). Only full synthetic oil 5w 30 must be used.  Using any other engine oil voids warranty. Catch cans voids warranty. Driving to destruction voids all warranty claims. Coolant loss resulting in over heating voids all warranty claims. Warped cylinder heads, gouging in cylinder head is evidence of extreme over heating.   YD25 is not responsible for any issues as a result of poor engine installation procedures by installers. All cooling system rubber hoses thermostat oil cooler must be replaced. Radiator cores and heater cores in YD25 vehicles are isolated from the body by Nissan. Connecting a multi meter to the engine block and radiator core or heater core shows voltage. Earthing or grounding the radiator core or heater core rapidly increases corrosion and electrolysis. Earthing or grounding the radiator or heater core voids warranty. Incorrect coolants and mixed coolants voids warranty. Only new denso injectors are to be fitted.

 

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

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

Last updated 31 June 2020