Seth 2500HD

It's alive....however I'm disappointed. Only 35 psi at idle, and pressure varies by 5 psi (about a 3-5 sec. ocsillation). Only goes to 40 at 2k rpm. This is the dash gage however, so I'll slap the mechanical back on after some break-in runs.

Mod to t-stat is keeping temps about 10* cooler, so im satisfied with that.

This is interesting - on 3rd start, ses light comes on, and its b1s1 o2 sens - no activity. Scanner sees slight flux in voltage around .3xx. Heres the catch - all the o2's are very calm. Especially compared to before rebuild, they bounced all over the place......thoughts?

I do have photos - ill upload a highlight reel in the next few days....

PowellSixO

Is the 35 psi hot idle or cold idle? What weight oil are you running? What are you running for exhaust? Headers? Cats? Not cats? What injectors are you running?

Seth 2500HD

35 is when its hot. Not a whole lot of difference from cold. Has cats. No headers. 10w-40. Stock injectors.

FFDP

iTrader: (2)

35 hot sounds fine, I'd expect 50 cold or around that. Under a heavy load I'm sure it'll reach 60+.

If the o2 sensor has that code I'd be checking it. They are suppose to bounce all over the place once it's somewhat warmed up and not running in open loop anymore. They will bounce lean and rich of stoich if working like normal, which in mv is like 450-500mv. Anywhere from .100 to .900 when switching is pretty much what you will always see.

Seth 2500HD

Ok. I'm going to record the data tomorrow and see. I did have another look and they were more lively this last time i fired it up (except for b1s1). I havent done the break-in yet - ran out of daylight again...hopefully i havent ran it too much just sitting (i was oscillating the throttle to 2500). Another interesting thing, the hour meter reset - so it shows ive ran it .8 hours - i think thats a bit of an exaggeration. How did it reset the hours btw??? But it reads 80% oil life left...lol. I dont know what to think of that oil life thing - i think ill stick to a reg. Schedule.

Im now also getting p0300.....that would match up with a bad o2 sensor from what ive heard.

Seth 2500HD

Quick update -
Break-in complete. Did 30-50mph in 3rd about 30 times. Did a few wot to 60 mph, up to 5k rpm. Highest oil press. Was 60 psi. At 2k rpm it varies 35-45. Cruising. No leaks.
Cleared dtc codes, they never came back. All o2s dancing (still calmer than before rebuild)
Have a sound from top of motor - sounds a bit like a diesel, very subtle.

PowellSixO

60 psi at WOT is what my lq4 runs. It sits around 35 at a hot idle, and 40 at a cold idle. I'm not much help when it comes to the O2's. Can you post a video of the sound coming from the motor? Is it valve train noise? How much preload are you running on your lifters. Are you running new lifters? If so did you soak them in oil before installing?


Maybe you could give a quick list of what actually made it into the engine. It's hard to pick out from the previous posts, what you actually installed.

Cam-
Lifters-
Springs-
Installed spring height-
Push Rod length-
Lifter preload-
Pistons-

Seth 2500HD

Tsp low lift 212/218, w/ LS6 springs
sealed power hyperteutic flat top pistons.
Reused lifters - they were kept in order and installed back where they came out.
Didn't measure preload / installed height - figured not necessary since there was no drastic change. I did check for play at rockers in case of collapsed lifter - didn't find any. Error in judgement not to check?


I'll get a video this evening for it - heading to countryside where it'll be quiet enough..

PowellSixO

The reason I ask, is because you will get valve train noise if you don't put the correct preload on the lifters. They're sloppy and have lots of room for different length push rods, but they tend to be quieter around a preload of .060-.080". I believe you can run as much as .100" of preload. But like I said .060-.080" is usually recommended. So yes, it is recommended to check for the correct push rod length. 7.400" is the stock length pushrod, and most aftermarket cams have smaller base circle which usually results in a longer push rod, but not always. So with your 7.425" pr's you should be ok. But measuring is the only way to know for sure. But with a bigger cam than stock, some noise is expected. I'm curious to hear the video.

PowellSixO

Did you listen to the video I posted of my truck idling? Does it sound different than my truck? My pushrods are 7.400" and I am running .075-.080" of preload.