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P400 in the Burb install
- Thread starter spdgofast
- Start date
n8in8or
I never met a project I didn’t like
I’m glad to hear you’re finally on what sounds like a path forward, even though you need to yank it. What are the chances one of the valves in the #2 cylinder was hanging open when the engine was dormant and the humidity in Florida rusted the valve and or seat so now it won’t seal?
Regarding the difference in #2 between the 2 pumps I have 2 thoughts: 1. Were both pumps timed the same? I don’t mean by the line on the front cover, but by a Ferret or luminosity probe. With the lower compression of that cylinder it’s not generating as much heat so that along with a timing issue could make it more difficult for that cylinder to light (at least when the engine is cold). 2. Again with the lower compression, the Conestoga pump is putting out more fuel at idle and could actually be snuffing the flame out - almost like running rich in a gassr.
Either way, it seems like too much of a coincidence for that cylinder to have low compression and it’s also acting funny. I’m glad Chris was able to use his experience to get you over that hump. I have no idea about that cam key.......
Peter, all 6.2 valves aren't larger, only a certain few years were.. The ones in question are .125thou or 1/8" bigger thus allowing more flow through the heads.. My set also have the bigger valves, and I went one step further with the unshrouding around the seat area..
DieselAmateur
She ain't revved 'til the rods are thrown...
Thanks for the lesson, learn something new every day here 
1/8" seems pretty significant, wonder why it wasn't kept that way if it indeed gives better performance? Out of curiosity, which years specifically had the larger valves?
I remember from one of Chris' threads on P400 heads that the valves are noticeably different in the seating area, didn't think other valves would interchange so easily.
@spdgofast sorry the engine is giving you so much trouble, hope this is rock bottom and it can only go up from here!
1/8" seems pretty significant, wonder why it wasn't kept that way if it indeed gives better performance? Out of curiosity, which years specifically had the larger valves?
I remember from one of Chris' threads on P400 heads that the valves are noticeably different in the seating area, didn't think other valves would interchange so easily.
@spdgofast sorry the engine is giving you so much trouble, hope this is rock bottom and it can only go up from here!
FellowTraveler
Well-Known Member
I an w/the IFS but in 2wd for shakedown now building a full manual Dodge 47RH/48 4x4 hybrid transmission using a Dodge NP241 DLD front case and a GM NP 241c rear case so far its looking like I will not have to move the IFS x-member from the stock location.
I was going to lower the front IFS diff 2" but that required grinding off lots of reinforcement on the IFS case on drivers side so I'm going to shave upper rightside IFS case in the area of the top 3 bolts it is real close to the Cummins oil pan edge.
82-87 6.2's... The valves were canted slightly different in the heads...
And the p400 heads do have more metal under the seats and are able to safely have the bigger seats installed, other heads I won't even attempt it...
So your conversion is on a 4x4 with IFS you just haven't completed the T case and drive shaft configuration yet, correct?
I had a 12 valve Cummins from a 96 5spd manual with the 215HP pump that I was going to install before I went with the P400, I didn't want the added expense of a built 48RE trans with a stand alone computer and a 271 T case which I figured would be like 8 to 10 k plus the engine mods and install, you know how that hindsight is right? 20/20 I still think the shit would be a 06 Cummins EFI live 5.9 twin turbo 48RE and a 271 t case. But then a fully deleted 6.7 with the same setup would work. It's a freaking viscous cycle! If I could only win the Lotto and get all of this shit done!
FellowTraveler
Well-Known Member
Yes to your question.
Since I started with a 47RH which I had already owned from my Ram Cummins I was concerned about the 4L80e braking ability so I built the 47RH hybrid using all 48RE components that fit too include all 6 pinion planets etc....this Dodge series transmission is perhaps the easiest to work on and costs for building are greatly reduced by doing it yourself more like 2.5 to 3k drag racing add another 3k to that figure. Yes there is a DIY learning curve with the valve bodies and the many variations from full manual to simple control or expensive track controllers. I don't race my diesel if I want speed I jump on my Busa for the Adrenalin rush it always gives.
My full manual valve body is the only way to combine both the 47RH/48RE components so they work the shifter has a thumb switch to shut off lockup when downshifting "no shutdown say goodby to trans..."
A word on the stock input intermeadiate and output shafts they are claimed to generally good too 450 HP level that's crazy torque and that is what breaks thing quickly behind any Cummins.
Well Dave what has been done to this project sense we last talked ??
Hey Chris, as soon as I can get caught up on the $ making mechanical projects I have on my plate I will be digging out the Burb from the shop mess I have built around it and pulling the engine and then pulling the heads and asses the issue and see what I can afford to get done. I sure hope we get a long and late winter down here, my shop doesn't have A/C so it just sucks working on a Topside creeper when it's 80 + degrees.
Alright guys, I have not posted in a few months so I'll let you know where I'm at. While battling a couple of performance injection pumps last fall I discovered that the guy that did my head work as far as the valve seat modification for the larger 6.2 valves did a very shitty job. Learn a lesson from my mistake, I will never install a motor before doing a leak down test and run compression before installing the engine, no matter how good a reputation the builder or machinist has. Since I was forced to remove the engine to redo the valve seats I am now rebuilding a P400 with 119 miles on it. So I have enlisted the help of Chris with Twisted Steel Performance to work his magic on my heads and my pistons. I will also be having the rotating assembly balanced by a local engine builder. I also intend on installing a complete new set of Total Seal rings. Since the engine is apart I will be installing all new bearings on the bottom end. Which brings me to a question I ask you guys, should I use the stock GM main bearings or go with something like Clevite main bearings? Since the rod bearings are I believe specific to the P400 I will be using GEP rod bearings. This damn truck has seemed to be the bottomless money pit from hell but hopefully I will end up with a nice running engine. (one would think right) So feel free to give me opinions on main bearings for the build.
ak diesel driver
6.5 driver
Don't know if the p400 is the same as the GM blocks but the GM bearings are select fit. Chris would probably know
Will L.
Well-Known Member
I know the cam bearings that failed me were stamped GM. GM probably just puts out to bid and whatever is lowest....
Clevite and king has had good reports. I bought clevites.
Idk if p400 is select fit. Wouldn’t surprise me.
Gep doesn’t balance anything and doesn’t align hone either.
As long as I am spending your cash, it’s easy to say have the machine shop balance your lower assembly and align hone it too. Get them the bearing specs before bringing parts. They can get the holes straight as possible and hopefully get it to one bearing size like a normal engine.
GEP just followed GM on most stuff and the GM guys just make me shake my head about how they did these engines on some stuff.
Clevite and king has had good reports. I bought clevites.
Idk if p400 is select fit. Wouldn’t surprise me.
Gep doesn’t balance anything and doesn’t align hone either.
As long as I am spending your cash, it’s easy to say have the machine shop balance your lower assembly and align hone it too. Get them the bearing specs before bringing parts. They can get the holes straight as possible and hopefully get it to one bearing size like a normal engine.
GEP just followed GM on most stuff and the GM guys just make me shake my head about how they did these engines on some stuff.
Yes the mains & rods are select fit, and the P400 rods are specific to that motor, the mains are not..
And this is not the only motor that select fits bearings, many others are just like it due to assembly line production ...
I can get what ever bearings are needed..
And this is not the only motor that select fits bearings, many others are just like it due to assembly line production ...
I can get what ever bearings are needed..
denata
Well-Known Member
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Is it a custom head? Are guides and saddles installed? Is it made from an ordinary head or is it a new type?
The p400 heads are a different casting, i have a thread here that shows the differences. Same on the outside, different on the inside.
denata
Well-Known Member
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Will L.
Well-Known Member
If there is anyway you can afford it, get a set of p400 heads.
Far less likely to crack, flows better, etc.
that is not one I would try fixing.
Far less likely to crack, flows better, etc.
that is not one I would try fixing.