P7100 Spring for Cummins Injection Pump 3K/4K Governor Springs 12V 5.9L 1994-1998

Best upgrade for little money. Do this before you do anything else, not multiple things at once. Installed in a f-800 5.9l industrial Cummins motor tow truck that used to top out about 65. Did 3k kit leave out small spring, now 75 with ease. Will recommend to others and would buy again if or when we have another truck with this 5.9l motor.

Springs are great quality; I was very skeptical because of the price but have no regrets. Install was relatively easy, Power Driven Diesel has a great video for swapping these out that I recommend watching. I will emphasis BE CAREFUL when removing the old springs so you don't drop the shims into the AFC housing and have to sweat bullets while trying to fish them out with a small magnetic pickup (ask me how I know). I'm only running the 3k on my truck as I don't have upgraded valve springs and this definitely made a noticeable difference in my low & upper end power band.

This spring set helped bumping up my 12 valve top rpms from 2200 to 3000 (smallest spring not installed). Also the gas pedal has a quicker response, love this mod!

I left all the 3 shrims with the 4gsk even if somebody says you have to left any. I had preload set on 0,8 mm on one side and 0,4 mm on the other. I set them both on 0,8 mm or 4 click. Someone says it's between 1 - 1,2 mm. Be careful.

Worked like they should. As always govenor springs really wake up the ole 12 valve Cummins.

Great Quality Springs, was leery because of the price being so low. Still took the chance and bought them fully recommend these to anyone.

Works great. Great price

Perfect application for the performance I needed! Great buy!