My Pete rebuild

[Nostalgic]

(12-27-2019 )Rawze Wrote:  unless at some point in its past someone was trying out some wacky settings perhaps, and it happened all at once, then took its toll later on?.

I'm pretty sure you have everything that it's ever run on, and the last cal, the only thing I changed was to roll back the OFC tables to the previous table.

I have always noticed a haze at idle, and at times it seems on the rich side.


One thing I have found odd (I've only pulled the front 3 so far), is that the rings have spun since I dropped in the pistons. I know for a fact that I offset them 180 degrees, but yet #2 and #1 had the gaps nearly on top of each other on the exhaust side. #3 was still offest, but the top ring gap was over the wrist pin.

I'm curious what rings are in the new kit, because according to qs, 792xxxx should have a smaller gap on 2nd ring.

[Nostalgic]

(12-27-2019 )Rawze Wrote:  Was the engine really tight to turn by hand before tearing it down?

Just on compression - same as when I was over.

[Unilevers]

honestly it looks like slightly too much timing and a incomplete burn. Are they the right pistons? Is it a wacky compression ratio? IPD came out with some ISX pistons that they were testing at lower compression did some of those sneak in there? there are many different pistons designs for certain applications now. Is it the right piston and liner combo?

honestly you would be ok at 7-8 degrees BTDC under load and still not be quite where that spray pattern is, and you say your down in the 2-3's? Something aint right there.

[Magard]

Dang that fuel shadow is awful high looking, completely out of the bowl. 871 must be awful forgiving for the main bearings to look that good.

[Rawze]

(12-27-2019 )Unilevers Wrote:  honestly it looks like slightly too much timing and a incomplete burn. Are they the right pistons? Is it a wacky compression ratio? IPD came out with some ISX pistons that they were testing at lower compression did some of those sneak in there? there are many different pistons designs for certain applications now. Is it the right piston and liner combo?

honestly you would be ok at 7-8 degrees BTDC under load and still not be quite where that spray pattern is, and you say your down in the 2-3's? Something aint right there.

It is in fact down in the 2's and 3's with no master offset.

What is the injector part# stamped on the side of the injector(s)?? -and where did they come from?

I would recommend that you bring that thing down here after it is back together so I can do some testing of the injection timing to see if its audible break-over points are at the right degrees offset(s) during idle. - That would tell me for sure if something was wacky or not. - I can only do that by sound unfortunately, as I know exactly what to listen for.


And your positive that the #4 wedge was in the injector cam, and the #6 was in the valve cam? -- AND that the crank pin position was absolutely correct? and it was not slipped into the wrong place when assembling that thing? - these things are critical, as any error mechanically results in a much larger (2x amplified) SOI error.


I know you were not expecting to see this, but did you happen to wedge it again before tear down to see if anything had slipped?

--- it just does not add up.

Also, still I think you should have taken me up on my offer to do it here. Maybe a second set of eyes would have found something more significant?.

[tree98]

What does the combustion chamber of the head look like compared to an OEM head (if you still have the old head) maybe that's where the compression ratio was changed?

[Rawze]

(12-27-2019 )tree98 Wrote:  What does the combustion chamber of the head look like compared to an OEM head (if you still have the old head) maybe that's where the compression ratio was changed?

the bottom of the head is flat. - However, recessed valves because the head was re-machined can change the compression ratio by quite a bit (lowering it).


Compression change would happen if that piston bowl design is different. I am also pretty sure that whatever aftermarket company that makes them, does not want to get sued for copying a piston design ... There has to be some differences, and that crown looks too tall for an ISX unless it is a small tier engine (the lower 400hp tier), or a 2350, but it is hard to tell in the pics.

Also the compression ratio can be changed by the TDC point of the piston (distance between wrist pin and crown) and/or the position of the top ring on the piston too.

an aftermarket or incorrect valve camshaft can significantly change the compression ratio too.

[Nostalgic]

(12-27-2019 )Rawze Wrote:  What is the injector part# stamped on the side of the injector(s)?? -and where did they come from?

Injectors are 4954434PX from Hunter Peterbilt.

Quote:I know you were not expecting to see this, but did you happen to wedge it again before tear down to see if anything had slipped?

I dropped 4 in injector, and 6 in valve cam before tear down. I didn't insert the pin, but the insert pin mark lined up.

Quote:Also, still I think you should have taken me up on my offer to do it here. Maybe a second set of eyes would have found something more significant?.

I was hoping to connect with Mommaburt, but he never replied to my message? Not sure if he's connected to the new shop that opened up next door or not...

[Nostalgic]

On a cold start, once it dropped out of warm up mode and idle would drop, a lot of times, it sounded labored. Not all of the time, but a lot. When it was labored sounding, I would have a vacuum at the intake again.

Is it possible that there's a issue with the actuator that didn't show with your tester?

Would the mist of oil being pushed through the CAC be enough to cause the deposits?

Either way, I picked up a new actuator and turbo from Cummins, and I'll have to clean my CAC of sludge before things go back together.