Why did my valve hit my piston?

ford141 · May 20, 2014

So, just so I'm clear, when you mention an underlying problem....

VGT problems?
valve-piston clearance?

Anything else I should be looking into? Sounds like valve springs is a band aid on a bigger issue at the power/mod level that I'm at.

B585Ford · May 20, 2014

ford141 said:
So, just so I'm clear, when you mention an underlying problem....

VGT problems?
valve-piston clearance?

Anything else I should be looking into? Sounds like valve springs is a band aid on a bigger issue at the power/mod level that I'm at.

I agree and based on you throwing a code on Mild I believe the WG is a bandaid. Do you know what your EBP was when you threw the codes?

Morgan@Midwest Diesel & Auto · May 21, 2014

Springs and pushrods would be the absolute minimum and the
I would be considering a gate. Stock size chargers can't get rid if the drive pressure that a large race tune can create.

Let me know it there is anything I can do to help.

Morgan@Midwest Diesel & Auto · May 21, 2014

And make sure all your sensors are working.

Fwiw we see a lot of these like this and most are way worse.

weekendwarriorfsw32 · May 21, 2014

I wonder if this is a unlaying reason to why pistons crack in a 6.4 so much.

dsberman94 · May 21, 2014

I've got a pic of upgraded and stock valve springs. Tried to combat this issue before it even had a chance to happen. Ended up selling the truck but the pic is below. The taller spring was the upgraded one it was taller and noticeable stronger than the stock spring, which is the shorter and noticeably softer one.

B585Ford · May 21, 2014

To clarify, I am not stating the a WG wouldn't be worth considering. I wish I had done one on my old setup to keep EBP in check (and I now do have one). If you get a WG dialed in right, you can have it open before EBP gets so high that robs peak power. It can also take some of the strain off the valvetrain by keeping the EBPs lower. The only disadvantages IMO are they can be tricky to get dialed in and it is one more part that can fail.
My point from before was that if you are throwing a code on "Mild" there almost has to be an issue. Mild should not be putting out enough fuel to cause EBP problems high enough to trigger a code and limp mode. Again, I would like to know what your EBPs were when you threw the code. Since you did throw that code multiple times, I think it is a VGT issue...not necessarily the turbo itself, but as someone mentioned earlier and you replaced it, the EBP sensor could have been the issue.

B585Ford · May 21, 2014

weekendwarriorfsw32 said:
I wonder if this is a unlaying reason to why pistons crack in a 6.4 so much.

I still vote heat and crappy design of piston are the biggest contributors although I am sure kissing the piston may be a factor in a quite a number of cracked pistons. I came to that conclusion because at least so far, you don't hear of many cracked modified pistons (delipped factory or IH). Very few guys with a tuner only/small build monitor EBP so there may be a lot more floating valves on relatively stock trucks than people realize.

weekendwarriorfsw32 · May 21, 2014

Thats what I thought to but I had a 6.4 with International coated pistons go 15k ish and crack another piston.

B585Ford said:
I still vote heat and crappy design of piston are the biggest contributors although I am sure kissing the piston may be a factor in a quite a number of cracked pistons. I came to that conclusion because at least so far, you don't hear of many cracked modified pistons (delipped factory or IH). Very few guys with a tuner only/small build monitor EBP so there may be a lot more floating valves on relatively stock trucks than people realize.

B585Ford · May 21, 2014

weekendwarriorfsw32 said:
Thats what I thought to but I had a 6.4 with International coated pistons go 15k ish and crack another piston.

I am sure there are others out there but yours and Kinds are the only 2 I know of so far. Based on the pics, I think Kinds was a manufacturering flaw. Was your IH pistons the ones that got exposed to 2000 degrees for about 30 seconds when you popped an IC boot or was that the stockers? Do you know of any more moddrd pistons that cracked? Who knows, but with time we might starting seeing more pistons crack and it turns out to be valve related.

Jonnydime · May 21, 2014

ford141 said:
It has a new EBP sensor now (little late). I do have a full EGR/DPF delete, 4" turbo back, S&B, and No Limit CAC.

I'm going to pull the VGT apart to make sure everything is OK, although it feels very free.

If I do valve springs do I also need to upgrade the pushrods? What springs should I be running with essentially a stock motor with an H&S?

Once you delete the egr you do not have any EBP relief as the factory egr kinda works as a wastegate. Even if tuning turns it off at high back pressure the egr will open and relieve pressure.

ford141 · May 21, 2014

The EGR was only turned off with the H&S but was still there up until about a month ago when I did the No Limit CAC pipe since I had the truck apart for accident repairs. But the gaskets were already leaking and I only drove it about 20 miles with the EGR deleted fully before I tore it down to this point. Didn't tow with it or run it hard during that 20 miles, only drove it home and back to the shop.

Unfortunately I did not monitor ebp when it threw the code. That was my dumb fault.

So this is what I'm looking at right now to remedy this problem:

1. Replace cracked piston with factory stocker.

2. Valve spring/pushrod upgrade.

3. Wastegate

I'd really like to upgrade the pistons while I'm in there, but I honestly don't plan to run this motor hard. I'm 100% sure that my cracked piston is due to valve contact. If I remedy the valve contact with springs and a wg, I'm thinking it will live a very happy life for a long time while I have it.

Morgan, I will be in touch, but I have to save some money first. I didn't budget this much into my head gasket repair job.

sootie · May 21, 2014

some pistons crack with no warning, no excessive heat, good tuning and no valve contact. ticking time bomb imo.

B585Ford · May 21, 2014

Jonnydime said:
Once you delete the egr you do not have any EBP relief as the factory egr kinda works as a wastegate. Even if tuning turns it off at high back pressure the egr will open and relieve pressure.

Most race tunes turn off the EGR if it isn't already deleted so whether it is deleted or not is irrevelent to EBP on most of the hotter tunes.

B585Ford · May 21, 2014

sootie said:
some pistons crack with no warning, no excessive heat, good tuning and no valve contact. ticking time bomb imo.

:whs: Since you are going through Morgan, check out the prices on pistons from him. Obviously pistons aren't cheap, but Morgan's prices on them are pretty reasonable IMO. I would highly suggest doing pistons if you can do without your truck a little longer while you save a little more money.

ford141 · May 21, 2014

B585Ford said:
:whs: Since you are going through Morgan, check out the prices on pistons from him. Obviously pistons aren't cheap, but Morgan's prices on them are pretty reasonable IMO. I would highly suggest doing pistons if you can do without your truck a little longer while you save a little more money.

Grrrr... Ok. Hmmmm, I'll look around the shop to see what else I can sell...

B585Ford · May 21, 2014

I know it sucks....you may very well never have an issue with originals, but as Sootie said, some seam to crack w/o a good explanation or warning...as mentioned earlier, it may be heat and chitty design, it may be sticky injectors that leak, it may be kissing the piston, it may be certain batches, etc....they do tend to be hit and miss. If I ever have even a remote reason to be in that deep, I am definitely doing them. You will already be there so that is my reasoning. Again, you may be fine w/o ever doing them.

johnp115 · May 21, 2014

If i ever found myself in that deep i would do pistons no matter what. Even if i had to pull extra money from somewhere or wait a little longer. Like said, they seem to be a hit or miss. And since one is already cracked, i wouldnt feel too confident in the others. Even if its only because of valve contact.

ford141 · May 21, 2014

I have some parts trucks sitting out in the field that I'm going to scrap for some extra cash.... Anybody looking for a late '50s Mercedes 219 restoration project? Anybody?

How can I find out factory tolerance specs for this motor? I.e. piston protrusion, head thickness, cylinder bore tolerance, etc? I need to measure the head to see just how much has been taken off of them to this point, and I also want to check everything else to make sure my tolerances are good before I start buying more parts.