• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

P400 tare-down findings

Twisted Steel Performance

Twisted Steel Performance

Anything worth doing is worth overdoing.
Vendor
Messages
4,126
Reaction score
8,058
Location
Pauline, SC
I have a customer's P400 in for checking and rebuilding.

Reason for tare down, this motor had a db2 installed and suffered 3 runaways for various reasons, not good putting it mildly ...

I had this motor in 35K miles ago for a partial build. The crank was not removed, I only went as far as removing pistons & heads.

Due to unfortunate things I have it back after 35K miles, today I took it down 100% and so far nothing broken or cracked, BUT a good inspection has not been done yet.

The block will be at the machine shop tomorrow for some work.

What I did fine was disturbing, the inside of the motor had a very heavy black film covering everything, It looks like the motor wasn't breathing, or held heavy fumes internally. I found 2 different brands of cam bearings had been installed and 1 was delamanating it seems, these were factory installed....

The main bearings, LOL, they looked to have 200K miles on them, one was showing heavy ware to the copper, the others were close to that, all with 35K miles.

The rod bearings were coated, they look good compared to the mains...

Another bad spot was the HS rockers, about 3/4 of them were flat spotted where they sit on the valves and were no longer moving on the shaft... they also had a heavy film of soot covering them, so sooty air was inside the motor because oil does not flow around the outside of the rockers... The problem with the rockers worries me, I have mot seen a set go bad like this before..

The case crank bore showed signs that the bearings had been chattering in the case...

The block is going to get measured and the crank will get magnafluxed ...

More pics tomorrow...

peters taredown 001.JPG
peters taredown 002.JPG
peters taredown 003.JPG
peters taredown 006.JPG
peters taredown 007.JPG
peters taredown 004.JPGpeters taredown 005.JPG
 
Last edited:
Will L. said:
Has me wondering if something got caught in the roller to stop it spinning. Tiny nick on the right side.
Click to expand...

3/4 of them ?

The inside of the motor looked like it had 200k miles on it, I think oil filtering went wrong and got loaded with soot, timing not right, cold weather, etc all played into it... A few of the rockers won't spin on the shaft, I'll take them apart and find out more. I'll also call HS, but my guess is they will blame it on dirty oil..

More to come...
 
On a side note for anyone that doesn't believe bearing coating provide any protection, looking at these main bearings beside the rod bearings would not believe they came from the same motor, this was a crate motor from the start, copper showing on mains and nearly no ware on rods... Coating does help...
 
Twisted Steel Performance said:
and for a while ran veggie fuel till
Click to expand...

:facepalm: :facepalm: :facepalm:

My experience with alternate fuel was very expensive. I have said many times a bad injection system will take the diesel engine with it. I would suspect the alternate fuel wasn't burning well or they got hold of peanut or other oil that simply gums the works up.

What was the oil change interval? Although with carbon stuck rings it doesn't matter as the blowby would dump soot in the oil.

Engine overspeed alone could be why there is bearing damage.

Flat spotting the roller rockers... Did this engine have a stretched out timing chain hammering them?

Fuel contaminated engine oil is another possible problem to add to the mess. I experienced an oil failure when I ran B99. The UOA did not flag B99 oil contamination as fuel. My oil should have been going out of grade thick, but, it was a grade thinner and a quart or two higher on the stick. DPF equipped Duramax. The Low Oil Pressure Stop Engine Alarm had come on and an oil change solved the problem. The DPF regen post injection was the cause and alternate (B99) fuel does not evaporate back out of the engine oil like #2 diesel will.

Injection system problems they had could have alternative fuel contaminated the oil and not evaporated back out.
 
The oil was drained before he shipped it here so nothing to send in...

He does have a bypass filter system, I think he still used a 5K oil change interval..

Timing gears not a chain.

They stopped making them because the military went to a different motor, no other reason..

The owner used alternate fuels for some time when fuel went to 6$ plus in price then went back to diesel...

I'm not going to lay blame on anyone, I'm interested in finding the root cause of things I found to better myself. I have shown these motors are very dirty from the factory, I made the mistake back then to not take it all the way apart and start from scratch, that won't happen again.. At this point I believe the alternate fuels along with IP problems caused the majority of trouble..

I'll be posting other things I find when I get parts cleaned up more...
 
Any other oil additives that the owner does not want to fess-up to? Or, more than 5K interval oil changes?

Although, agree that the run-away might have done the damage. And then the 2 more only added to the injury.

Agree with WW that veggie oil does not belong in an engine that anybody wants to keep. Read enough about that stuff to get to the point where the only good use for it in home application is a substitute / additive for heating the house with oil.

FWIW, my P400's oil analysis did not support more than a 3K oil change interval (metals) up until the time I got rid of the Burb. IIRC, the engine had ~20K miles on it by that time and still came back with needing a shorter change interval. And this was with a remote AMSOIL dual bypass filter setup. In a brief E-mail chat with the manufacturer, the metal content was normal and would settle down as the engine broke-in.
 
Twisted Steel Performance said:
The oil was drained before he shipped it here so nothing to send in...

He does have a bypass filter system, I think he still used a 5K oil change interval..

Timing gears not a chain.

They stopped making them because the military went to a different motor, no other reason.
Click to expand...
Or maybe the military went to a different motor because the P400 had issues impacting longevity?
 
Big T said:
Or maybe the military went to a different motor because the P400 had issues impacting longevity?
Click to expand...
Military turned down the P-400 over environmental / economical standards. Can’t argue the impact of having better economy from a logistical resupply/sustainment standpoint but, have a hard time with the ‘can’t win if you’re not “super green” too.’

Waiting for the results of the tear down and analysis before condemning this P-400. I miss the old emoji’s, need the ‘eating popcorn’ guy right about now.
 
Wow- 3/4 of the rollers- didn’t realize that. Definitely some grit had to be in the oil.

As to the engine over speed from run away causing all the damage- I don’t see that. Harland Sharp makes roller rockers for engines that are racing at 7-8k rpm or higher for extended periods of time. They are not perfect, we seen the errors they made when the first 6.5 ones were made. But all these bearings add up to some tom foolery in that oil. The high rpm of runaway generally has a loss of unbalance and throws a rod as failure point.
But the way stronger rod design, the bedplate holding the crank in nice and secure could definitely have helped it from going grenade mode.

I do recall back around turn of the century the fuel company I worked for was experimenting with bio fuels and learning the lesson the hard way with peanut oil is the base for their biofuel. The test runners was the city bus system- CAT bus (Citizen Area Transit). They ended up having to buy all new engines for all the buses. This actually occurred at a point I wasn’t working for them yet and was no longer working as a private company for them either. When they mentioned bio fuel to me as private company and they were my customer- I warned them of peanut oil having already been familiar in the diy world of it: Guess I got the polite brush off because they had their own fuel engineers so they figured they were onto a secret sauce no one else had figured out. By time I hired on there was a new engineer replacing the old one- hmm. When the alternative fuels conversation came up later, they thought I was reading from their secret findings report talking about problems of peanut oil. It would be interesting to find out where this guy was getting his cooking oil from.
Diy bio fuel can definitely be ran for hundreds of thousands of miles without damage. But has to be done right and oil samples along with fuel samples to the lab is part of the requirement. Personally. I am more fond of black diesel than bio.
But the used motor oil has to be cleaned up fully. Proper centrifugal cleaning will get brand new oil cleaner than it was in the new bottle. People think pouring it through cloth and a couple fuel filters is enough and wonder why they experience problems. SMH

Hoping the best for this guys p400. Be sad to see it become a parts engine, not that I wouldn’t donate to the cause…
 
The block is at the shop, they will cook it to get it clean, then on the CNC and laser measure all the areas I want measured, if all is good it will get decked and o-ring groves cut. I have 3 p blocks there getting the same services, and I'll be making a video of the process hopefully in a couple weeks..
 
JayTheCPA said:
FWIW, my P400's oil analysis did not support more than a 3K oil change interval (metals) up until the time I got rid of the Burb.
Click to expand...

Gapless rings should allow the engine oil interval to go longer although soot not metals was the limiting factor I would run into.

Will L. said:
The high rpm of runaway generally has a loss of unbalance and throws a rod as failure point.
Click to expand...

Small difference between runaway to failure and overspeed. If the engine doesn't pop a rod it can have serious bearing damage from it. Aircraft engines are well known for procedures for overspeed conditions that include look for metal in oil screens.

Given the stuck rings and other wear ... Oil failure/contamination is a contender. But why just one problem... 🤔

Twisted Steel Performance said:
I'm interested in finding the root cause
Click to expand...

I would suggest cylinder wear info can help determine if fuel washing was a problem like that 1992 project of mine where the fire went out in some cylinders. The alternate fuel being the suspect not injection system.
 
WarWagon said:
Small difference between runaway to failure and overspeed. If the engine doesn't pop a rod it can have serious bearing damage from it. Aircraft engines are well known for procedures for overspeed conditions that include look for metal in oil screens.

Given the stuck rings and other wear ... Oil failure/contamination is a contender. But why just one problem... 🤔



I would suggest cylinder wear info can help determine if fuel washing was a problem like that 1992 project of mine where the fire went out in some cylinders. The alternate fuel being the suspect not injection system.
Click to expand...
I have no problem with that idea except those roller rockers survive 10,000 rpm in other engines without flat spotting. If multiple stop spinning like that the huge volumes of contamination had to occur in the oil. And bearing wear wouldn’t do that is the bearing material is the best part of the bearing and I don’t see multiple hug chunks missing in those bearings that would get stuck in a lot of them. A couple- ok.
 
You must log in or register to reply here.
Back
Top