eastmentCTD600

I realize that stiffer valve springs are required if you wish to spin the Cummins past the 3200 redline; however, I was curious if anyone has needed to install valve spring due to increased manifold pressure (boost)?

Thinking about twins next month, specifically ATS A5k/HE351 for the price and my power/towing goal (~500 HP, ~1000TQ, tow 10k with low EGT). Price is a bit steep but manageable. I would expect boost pressures between 45 and 60 psi with only the Quadzilla Xzillarader II (100 HP added on power level 4).

Question is, at what boost pressure does one require stiffer valve springs? 50 psi? 75 psi? 100 psi? not a problem/not necessary?

Please advise.

Spooler

Yes, you will need springs when you reach around 45-50 psi of boost pressure. You will start to push open the valves.

eastmentCTD600

Spooler,

Any suggestions on what/where to purchase?

Spooler

Get them from where or if you want to buy a cam from. Hamilton or F1 will work fine. Be careful, to much spring pressure will wear out a cam. The two above will be fine.

Bankdude

Interesting. Is the wear gradual or rapid and are there any signs in advance to watch for? I imagine the subsequent failure is catastrophic.

Spooler

Gradual wear. It will take some time. Just use the springs of the cam vendor you are using. If you have issues, then you are using his stuff and that won't be a problem.

kawi600

Are the third gen motors a flat tappet like the older motors? If you dont have a cat or DPF you could add some zinc additive to help with cam and tappet wear from valvetrain upgrades.
Ive got an aftermarket cam and springs and it wiped a lobe last year since I never used the ZDDP additive. Even the old spec oils have reduced ZDDP content thanks to the morons at the EPA.
If youre concerned at all you could also just get oil analysis to look for wear metals too.

Bankdude

Thanks guys. Appreciate the heads up and the solution.