Z20 engine lower sump gasket  - the one that goes between the alloy sump and the lower steel sump pan 

When upping the boost on a standard type engine , sometimes its a good idea to pull the compression back a little bit. This can be done easily with a thicker headgasket as one way of doing it without having your pistons machined. Going thicker in headgasket size is only a solution for a certain amount , if you end off needing a ludicrously thick gasket to get the compression you want then its probably time to start thinking about other options. The problem when you go too thick on the head gasket can be reliability. This area at the very top of the cylinder is where a lot of the really high pressure energy is made – its often a weak point on some engines prior to increasing the thickness. Increasing the thickness increases the surface area the chamber sees pressure over , meaning that the gas can now actually get more force into blowing the gasket out.

 

If building your engine from the onset for really high boost then we would recommend you ask about piston machining being involved in your build. If you maybe already have you engine built but are having some slight detonation issues then the RnD gasket could be ideal for you. Usually the heavier detonation on a z20 will always be around the outer ring of the piston , usually around the exhaust valve side.

The z20 engine tends to have quite a tight squish band . The standard tolerance of piston protrusion is 0.4mm , its acceptable to skim the block a few thou so piston protrusions can easily get into the 0.45mm area without piston correction. The standard headgasket is 1.1mm thick , the cylinder head is flat and has no recess for the piston. This leaves us with an area around the top of the piston that will come within 0.65mm of the head ( about 0.025" ) just turning the engine over by hand , a little closer maybe at 7000RPM . The RnD gasket is 1.6mm thick , this immediately bumps 0.5mm onto this size giving us 1.15mm ( about 0.045 ) - this size is certainly better for running more boost , if you have built a few engines for high boost then you will maybe still also think that this is still tight!

The 1.6 mm gasket is the thickest gasket we recommend for the Z20 engines for high boost reliability..

The RnD gasket has no rivets installed - do not mix up the gasket layers 

We also offer custom machining of z20 pistons via post

Custom machining on pistons available on new pistons £95 inc VAT set of 4 pistons.

We also have some developed Wossner Pistons arriving into 2020 , please get in touch if you are unsure what you need

We strongly recommend the use of ARP headstuds , we only use this in all our engines.

CNC machined and fully anodised aluminium, a simple item but made to a high standard.

Sometimes the OE oil level sensor is not required on the Z20 engine. This little bung slips in place and uses the same clip that you find in the stock bottom end gasket kits.

Comes supplied with orange O ring ready to fit

Aimed at sub ~450-500hp setups, these solid billet aluminium lightweight crank pulleys free up the engine from both inertial weight and parasitic drag from driving the alternator as fast (and A/C if you are retaining that). On setups below the 450hp region we have used these for years with no problems, and you can really feel the benefit on something fairly standard -> 350hpish, as the alternator and A/C add quite a lot of drag which soaks up a good bit of the available power.

The Standard pulley weighs just over 1.7kg, these are just 0.44kg. This allows the enigine to rev more freely, helping with downshift rev matching and general low gear accelleration, essentially a lesser but similar effect to lightening the flywheel.

They are also a smaller diameter than the standard pulley, so drive the alternator more slowly. This helps the alternator to survive at high rpm, and reduces the amount of effort required to drive it, so saving you power to go to the wheels instead. They have been sized to still drive the alternator hard enough at idle to keep the battery charged easily, no increased idle speeds are required. Same goes for the A/C Compressor if you elect to retian that.

We offer a few different packages to suit different setups, as listed below;

Under Drive Pulley Only, no belt

Under drive pulley with Billet Tensioner kit and belt - AKA the Air Con Delete kit - This kit requires you to retain the springy tensioner part of your original air con setup

Under drive pulley with belt for direct drive - Best used with an adjustable alternator bracket

Under drive pulley with belt for retaining A/C

For setups that are aiming beyond 450-500hp, we recommend to use a damped pulley (the standard pulley is not a bad option), as crank shaft harmonics can cause problems without the damping. For that setup we can provide the below kit;

Billet Tensioner kit with belt for Standard Crank Pulley

If you already have an underdrive pulley, then you could buy the tensioner pulley kit on it's own;

Billet Tensioner kit only

Billet Tensioner kit + belt to suit our under drive pulley (if you already have the pulley fitted)

Aimed at sub ~450-500hp setups, these solid billet aluminium lightweight crank pulleys free up the engine from both inertial weight and parasitic drag from driving the alternator as fast (and A/C if you are retaining that). On setups below the 450hp region we have used these for years with no problems, and you can really feel the benefit on something fairly standard -> 350hpish, as the alternator and A/C add quite a lot of drag which soaks up a good bit of the available power.

The Standard pulley weighs just over 1.7kg, these are just 0.44kg. This allows the enigine to rev more freely, helping with downshift rev matching and general low gear accelleration, essentially a lesser but similar effect to lightening the flywheel.

They are also a smaller diameter than the standard pulley, so drive the alternator more slowly. This helps the alternator to survive at high rpm, and reduces the amount of effort required to drive it, so saving you power to go to the wheels instead. They have been sized to still drive the alternator hard enough at idle to keep the battery charged easily, no increased idle speeds are required. Same goes for the A/C Compressor if you elect to retian that.

We offer a few different packages to suit different setups, as listed below;

Under Drive Pulley Only, no belt

Under drive pulley with Billet Tensioner kit and belt - AKA the Air Con Delete kit - This kit requires you to retain the springy tensioner part of your original air con setup

Under drive pulley with belt for direct drive - Best used with an adjustable alternator bracket

Under drive pulley with belt for retaining A/C

For setups that are aiming beyond 450-500hp, we recommend to use a damped pulley (the standard pulley is not a bad option), as crank shaft harmonics can cause problems without the damping. For that setup we can provide the below kit;

Billet Tensioner kit with belt for Standard Crank Pulley

If you already have an underdrive pulley, then you could buy the tensioner pulley kit on it's own;

Billet Tensioner kit only

Billet Tensioner kit + belt to suit our under drive pulley (if you already have the pulley fitted)

Aimed at sub ~450-500hp setups, these solid billet aluminium lightweight crank pulleys free up the engine from both inertial weight and parasitic drag from driving the alternator as fast (and A/C if you are retaining that). On setups below the 450hp region we have used these for years with no problems, and you can really feel the benefit on something fairly standard -> 350hpish, as the alternator and A/C add quite a lot of drag which soaks up a good bit of the available power.

The Standard pulley weighs just over 1.7kg, these are just 0.44kg. This allows the enigine to rev more freely, helping with downshift rev matching and general low gear accelleration, essentially a lesser but similar effect to lightening the flywheel.

They are also a smaller diameter than the standard pulley, so drive the alternator more slowly. This helps the alternator to survive at high rpm, and reduces the amount of effort required to drive it, so saving you power to go to the wheels instead. They have been sized to still drive the alternator hard enough at idle to keep the battery charged easily, no increased idle speeds are required. Same goes for the A/C Compressor if you elect to retian that.

We offer a few different packages to suit different setups, as listed below;

Under Drive Pulley Only, no belt

Under drive pulley with Billet Tensioner kit and belt - AKA the Air Con Delete kit - This kit requires you to retain the springy tensioner part of your original air con setup

Under drive pulley with belt for direct drive - Best used with an adjustable alternator bracket

Under drive pulley with belt for retaining A/C

For setups that are aiming beyond 450-500hp, we recommend to use a damped pulley (the standard pulley is not a bad option), as crank shaft harmonics can cause problems without the damping. For that setup we can provide the below kit;

Billet Tensioner kit with belt for Standard Crank Pulley

If you already have an underdrive pulley, then you could buy the tensioner pulley kit on it's own;

Billet Tensioner kit only

Billet Tensioner kit + belt to suit our under drive pulley (if you already have the pulley fitted)

Z20 Billet Steel Bottom End Girdle Kit

The more you push the power onwards in the z20 , the more problems you start to notice , this is another piece of the puzzle to aid solving a problem of the mains caps moving about and twisting under full load.

Machined from a solid lump of steel , steel is stronger and also very close to the same expansion ratio as the standard block – meaning this girdle does not suffer the same fate as the alloy versions – the mis-match in expansion ratios actually make the mains caps move more !

Machining one from aluminium is a lot less demanding than milling one from steel , its less demanding of the machine and a lot less wear on the tooling too , that still does not mean that its the right way to go. Making the mains caps strong and rigid is the foundation of a lasting bottom end.


This is probably one of the only parts we have actually made that is more heavy than the OE version , we normally like to go the other way and make things lighter where we can. In the case of this girdle , we made sure to carry enough weight in the girdle to really make sure its pretty resilient to twisting and moving

Supplied with a bolt kit to hold the standard windage tray and oil pickup pipe – this girdle kit requires no other non standard parts to be used, no extra machine work and is a direct fit to the z20let (balance delete ) z20leh engine
 

This girdle has all the machine work done then as a last process , is ground flat on the faces that mate to the block.

Upwards of 500HP  , making the bottom end solid is proven foundation for things lasting.
 

Billet Steel Cylinder head hollow dowel pair - 

Replace the junky standard ones for some of these , proven to not crush down and allow the head to move so much