Hamilton Cams Cummins 24V 103lb Valve Springs | 1998.5+ Cummins 5.9L / 6.7L

Stock 24v springs have 78-82lbs of seat pressure at 1.380″. If you are over 35psi(boost or drive pressure), stock springs do not fully control the valvetrain. Intake and exhaust valves can be blown open by boost and exhaust drive pressure which allows reversion. Reversion can hurt your power potential by allowing exhaust gasses to enter the cylinder on the intake stroke. Inert gasses in the exhaust, when re-introduced into the cylinder shield the fuel particles from oxygen in the cylinder. This does a few things that negatively affect power. It increases the time delay from start of injection to start of combustion, it decreases the maximum pressure and maximum temperature reached in the cylinder and it increases the total time needed to completely burn the available fuel. Correct valve spring pressure is a very important piece of power production. Hamilton springs solve this problem.

Nose pressure has been lowered from 220lb to 180lb recently. Watch out for other companies that have nose pressures over 250lb. Your cam will have a shorter life with high rate springs. Don’t just ask what seat pressure is when you are shopping for springs, ask what the pressure is on the nose(1.031″ with OEM cams or .958″ with the 188-220) Lately we have seen a few cams damaged when customers run cheaper aftermarket springs from other shops. We only offer warranty on our cams with our cams if you run our springs and tappets. These springs are great to 4500 rpm. Over that the #110 springs are necessary. Over 4500 rpm with #103 springs you will see broken or cracked retainers due to float and harsh valve actuation.

*tool steel retainers are not included but can be purchased separately.