Need some help with my 6.4

I just recently bought a 2008 6.4 and completely over hauled the engine. I honed all the cylinders, new rings, replaced the lifters, new rocker assemblies, all new cam crank and rod bearings, new oil cooler, hpp replaced, turbos have 1500 miles on them, performed an egr *** ******, installed minimaxx h and s with custom 300hp tune, studded the heads. After doing all of this my tuner was set to defuel at 1450 and my boost would max out at 49 psi. I ran the truck easy for a good 500 plus miles and then decided to do a few pulls. I am now going to be pulling the engine back apart because of a horrible knocking/squealing in what sounds like the bottom end. Is 49 psi too much for stock springs? What else should I do before putting this thing back together? The truck was running awsome with no noises or drive ability issues. Should i have waited longer before I did a few pulls? Not new to the Ford diesels, just kinda new to upgrading them. Thanks in advance, any informant is greatly appreciated.

nope, it should be fine well over 50 psi but if you had the thing apart you really should have done stage 1 springs , and push rods for reliability. something isn't right . hopefully you put HD pistons i it while you were there.

No I replaced a couple pistons with own, re-ringed them all, and used stock valve springs and push rods. I think I am going to bore the motor .020 and possibly get HD ceramic coated pistons, along with springs and push rods. I'm assuming the rods are pretty strong? Also going to look into getting a new set of injectors, what would you recommend the highest to go with a stock hpp? Thanks again for any advice.

Ricky88 said:

No I replaced a couple pistons with own, re-ringed them all, and used stock valve springs and push rods. I think I am going to bore the motor .020 and possibly get HD ceramic coated pistons, along with springs and push rods. I'm assuming the rods are pretty strong? Also going to look into getting a new set of injectors, what would you recommend the highest to go with a stock hpp? Thanks again for any advice.

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not sounding rude but search feature is your best friend.


with that being said, hd pistons for sure.
rods are strong yes.
injectors stock unless running dual fuelers, been proven about 98% of the time that not even a 15% (unsure if they are still made) nozzle will hold rp, so if you do 30's and run a stock hpfp and then lower the pw to maintain rail pressure you have not gained anything, 650ish is the max for stock fuel (depending on dyno)



lots of good info in the aftermarket section and a lot of quality "builds" etc so reading them will answer a lot of your questions.

Ricky88 said:

No I replaced a couple pistons with own, re-ringed them all, and used stock valve springs and push rods. I think I am going to bore the motor .020 and possibly get HD ceramic coated pistons, along with springs and push rods. I'm assuming the rods are pretty strong? Also going to look into getting a new set of injectors, what would you recommend the highest to go with a stock hpp? Thanks again for any advice.

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wise move, let me know if we can help , we sell all those things .

If you stay stock rods grab some arp bolts for them

Can you verify that the noise is coming from inside the motor? I don't know how many times I've seen converter bolts not get tightened and back out causing a terrible sound when they start rubbing on stuff.

I'd check the outside of the motor quick and see if the noise could be coming from a belt, pulley, loose bolt, something random rubbing, etc....