Almost every diesel engine we come across, has a significantly undersprung valvetrain when it comes to absolute power production. The 1.7 16 valve Isuzu engine doesn’t just fall into this category, it smashes through the roof of what should be allowed to be fitted to an internal combustion engine.

On the oval port engine (oval exhaust ports) the valve spring situation is pretty bleak. They have only 15kg of seat pressure, which is perfectly adequate for sub 1.5 bar (22psi) and 4500rpm operation, however once past this, issues start to arise.

With the stock valve springs, the valve control under high boost and high rpm operation becomes seriously affected. This is not ideal when we are wanting to make the valve events happen at a specific time, and for a specific duration.
Exhaust manifold pressure is one of the key things that makes valve control a problem on highly tuned diesel engines. Put simply, the exhaust valve will not close in time, and it is possible that under high rpm high boost situations (accompanied by high EMP), that the exhaust valve may come into contact with the piston. This will not always result in damage, but it is a situation that is best avoided.
With this valve spring kit, the ability to run at higher performance indexes is achieved, while maintaining the ability to control the valve events decisively and accurately.

This dual spring kit is a high performance upgrade. Suitable for those running increased boost pressure, that are experiencing diminishing returns in power compared to the power you should expect from that particular boost pressure, and for those who are using performance camshafts, which require a greater level of valve control, due to the accelerations of the valve given the ramp rate of the cam. The kit also provides better valve control, after the valve has landed in the seat at a faster closing ramp speed, thus better valve sealing is achieved earlier in the cycle.
The spring kit comes as a set of 32 springs (16 inner and 16 outer) 16 valve spring retainers, 16 valve spring seats, and 32 valve locks. The springs are made from high grade high tensile heat treated steel, designed to work together in harmony for the ultimate in valvetrain modifications. Valve spring retainers are cnc machined for the best possible finish, fitment and strength. Valve locks through hardened for absolute maximum strength and rigidity.

This engines potential is truly epic once a cam and valvespring package has been added, and due to the nature of the solid lifters, high rpm operation and rapid changes in valve lift with high spec cams are done with the utmost ease.

Once performance camshafts are used, you will need this spring kit to allow the extra valve lift from the camshaft, and avoid valvetrain lockout.

All valve springs are made to exact specifications, and are direct replacements for the standard springs.

A running in procedure of 3 heat cycles at light load is required for these spring kits.

For valve lifts above 9mm, shortened valve guides will be required.

If ordering dual valve spring kit, you will be asked about your specific camshaft before we ship your valve spring kit, so that the correct valve spring seats can be provided. This will ensure that the valve springs are within the 1.5 mm to coil bind specification, and ensure the best valve control possible.

It is important that you measure your valve spring installed heights to ensure you do not run into coil bind, as this will cause premature failure of the valve springs.

All spring kits come with 12 months warranty.