jadombert

So I've been building my fishing/duck hunting rig for a little over 2 years now and just this past weekend splashed it for the first time. Im running a bone stock 2004 LM4 5.3 that I pulled out of a trailblazer at the junkyard, side swiped and no idea of the mileage. It had a decent mount of sludge but looked to be a running complete motor. I took and am using all of the stuff that came out of the trailblazer in terms of sensors, coils, intake etc. I did the backwoods valve job with some grinding compound, a rubber hose and a drill, had the heads decked to be flat, put new head gaskets and valve seals on it and threw the thing together. Its running 6.0 marine power wet exhaust manifolds, no water pump as it is supplied by the jet pump, and I turned the intake manifold backwards. Compression across all cylinders was and still to this day is 160 psi +/- 5 psi

Im using microsquirt, tuned it for idle in the driveway and splashed it in the water. Im idling around 12.9 AFR, and when its moving staying in the 11's, hard to read a lab top in a boat but I'm working on it. Few issues, it runs cool, I need to limit the pressure to the motor as WFO for a while it only reaches 135 degrees, idles at around 110. I've had in in the water for about two hours now and just before pulling it yesterday it started smoking, a lot.... Driver side cylinder bank, by the looks of the plug it appears to be cylinder 5, I have a decent amount of oil in the intake manifold as well. It smokes immediately after start up heavily, a little at idle, and bad under power.

Im thinking valve guides or a pcv issue? Compression is good and it didn't seem to lose power or make any noises.

G Atsma

You might have broken a ring or two. BTW does it have a thermostat? It would be better for it to run a bit warmer.

jadombert

would a broken ring not show up on my compression check? My cylinders are all within 5psi of each other at 160 psi tested since the smoke started

jadombert

no thermostat, I have a valve that I can limit the flow of water to the engine with. I need to get it adjusted so it holds around 160-170 at idle I think would be the correct temp. Then just watch it and make sure it doesn't climb while under load

G Atsma

An oil ring broken would burn oil, while the compression rings would maintain compression. And/or you might have a defective valve seal or two, even if they were new.

Che70velle

iTrader: (6)

Put some more temp in it and try it. Keep an eye on your oil level (dipstick). If it’s burning oil, oil level is dropping, and if it’s burning a lot, oil level can drop quickly. I’d guess it’s a pvc issue with your readings. Intake gets oil in it quickly and becomes a smokeshow.

jadombert

I will try to get the water valve adjusted first thing, temp might help the valve seals seat better. I highly suspect a PVC valve issue, as the one that came with the motor looks nasty and sounds like a rattle. Will try to report back after I put a pvc and some heat into her.

jadombert

It is only smoking from one cylinder bank(i have true dual exhaust through the transom), which is the only part that worries me.

AINT SKEERED

iTrader: (2)

If its using a PCv I'd go to a catch can first. But I'd say its either a broken oil ring or valve seal as well