Booztd 3

iTrader: (5)

Everyone

The last few months my rig has been complaining about low oil pressure at idle. Its gotten worse with the colder ambients and most recently developed a tick/knock


I need this thing for daily duties and a friend had a 60k mile LM7 sitting around so over the last few days I swapped them out and got the truck back on the road.

I tore down the engine today expecting to find a roached rod/main bearing but after complete disassembly I'm not seeing anything stand out. I'm curious if it could be a lifter but I'm not really sure how to determine if they're bad.



Cam bearings were all in tact and didnt see anything crazy on the cam. This particular journal I noticed it had some odd wear but I highly doubt this was the source of the noise. The journal feels smooth



Mains from front to back







Some pitting on the main cap #1 but nothing (I would assume) to cause my noise



Crank from front to back









Every rod bearing was in-tact with no grooves detected by my finger nail. Without question none of them had spun. The bearing locating tabs were in 100% shape as proof. There is also no blue-ing on the crankshaft to indicate a loss of lubrication.

I rolled every lifter over by hand and didnt feel any flat spots or binding in the rolling action. The L33 had ~175k on it so most of the bearing/journal wear I would assume is normal.

Scratching my head a little at this point.....

Thoughts welcome, advice appreciated

cobalt964

have you checked the small end of the rods? could be a lifter too.

Booztd 3

iTrader: (5)

Not many AFA guys in here huh?

FWIW I got it figured out tonight. Just took a little closer of an eye than I was expecting to use.

I examined the rockers much more closely this time and found two that had worn and consequent push rod wear. This added more slop to the combo and produced the wear. I may be able to chalk this up to a failing oil pump giving me low oil pressure in combination with maybe some lifters taking a dump.


Here is one in decent shape



You can see the wear on this one



Here is the 2nd one (I found only two like this among all cylinders) next to a good one



You can see the worn push rod compared to a good push rod. There is an obvious difference the length.



I think I'll reassemble this L33 and put some good parts in it and sell it as a long block

spy2520

iTrader: (3)

I've heard of the pressure relief valve in the pump sticking and causing a low oil pressure condition. Its possible it only affected the newer engines, but maybe something to look in to.

RonSSNova

iTrader: (3)

My L33 had a couple like that too. Although I bought just the engine for my turbo project.
Got a photo of the piston skirts?
Mine were a bit scuffed.

JaxMustang50

iTrader: (1)

Same thing here with my L33. Ron, what did you end up doing about it?
I'm a bit torn as to weather or not to tear into the whole thing and "freshen" it or just replace the pushrods and worn rockers.

RonSSNova

iTrader: (3)

I lightly smoothed the scuffed pistons with 1200 grit and used them. Reused the bearings too.

Because I was adding a turbo I replaced the cam lifters pushrods etc with new. Along with a new oil pump.

Mine came from a wrecking yard, so I don't know it's history.

I'd actually like to have a spare engine, just in case. I like the L33.

Ron