Update:
Lots to report.
I found that the P0171 & P0174 were due to leaking injector seals (which were installed during the rebuild new from REINZ master gasket set). I replaced them with GM injector seals which were just a tad meatier and fit much more snug.
Fixed that issue.


Sadly, I ended up pulling the intake (SAI is a pita) after finding the valve cover bolts were so loose that I thought I had the wrong size socket on them.
I personally had put them on and know they were tight. The gaskets must have deflected with the heat cycles and were weeping oil on the back corners. I replaced the gaskets with a spare set (that actually fit better!) I had and tightened the bolts really well this time. I also sprayed the gaskets (both sides) with copper spray gasket prior to installing them.

While the valve covers were removed, I checked the ARP head studs torque. I re-torqued them all to 72ft/lbs. Some moved, some didn't.

With the intake off, I checked the back of the heads and valley pan, they were dry.
Great majority of oil seepage was directly from the head gasket seem/edges.
Oil is definitely seeping from them. Turns out, as I research this problem, Cometic headgaskets are well documented for leaking.
Let me google that for you
SO, until I have time to pull the heads, I'll just keep topping it off and enjoy anti-rust coating the Rover is developing under the chassis.

Since the rebuild, the motor has always sounded like a diesel when starting up. It clears up when warm, after about 5 minutes of driving.
I've installed a sandwich plate to feed the SunPro cluster's oil pressure gauge. Its reading 55-60psi oil pressure on a cold motor pretty quickly after ignition. 20-40psi while driving (2-3Krpms), and 10ish at hot idle.
Motor is quiet after warming up, so I guess it's just a Rover thing?

I've since also rebuilt a 4.0 motor for a neighbor's D2 and his sounds the same way after startup. His didn't clear up after warming up but has a tap/clatter located in the back lower of the motor -in the area crank/main bearings. The noise has me worried enough to pull the pan. Nothing obvious and it looks beautifully clean inside.
I'll check more into it tomorrow. If nothing shows up, I'll refill with 15/40 Shell Rotella T instead of 10/30. Not convinced thats the problem though. 30 to 40 weight oil isn't a but jump in viscosity and the bearings and motor is practically new.
Back story on that one:
His was instantly overheating. It had a warped block on the passenger side. One cylinder on that side had been previously top-hat sleeved and was lower than the deck (strange?). Both heads were warped. All were sent to the machine shop. I installed a Crower cam and new lifters.
Its been about 50 miles after the rebuild and it's making a piston slap sound on the back 2 cylinders (7/8) on a hot motor. Can't be heard in the cabin but audible outside.
No oil pressure gauge on this one and I don't have the adapter for our shops oil pressure gauge to test it. The pump is new, as are the bearings, the crank was within standard specs as were the rods. I installed standard bearings.
The block was decked and honed (just to deglaze the cylinders). The heads were flattened and the valves and their seats touched up. Everything checked out according to the machinist.
I reassembled with a new oil pump, timing chain, new piston rings (end gaps checked in the cylinders and were great) water pump, every seal/gasket/bolt new for the internals. I also used ARP studs and cometic gaskets. I pinned the sleeve s too. Coated and packed near everything with assembly lube. Broken in with Royal Purple break in oil for 1/2 hr at 2-3Krpms. Starts, runs, and drives great, just the bottom end is too noisy for a nearly new engine.
On the Cometic gaskets, I used Copper Spray gasket on them and the block, and the heads hoping the curtail any leaks they might exhibit. Did little good as they are also leaking in the same way mine are.

That is all for now

 

After mush inquiry on the forum, I went 25-50-75...then 88 ft. lb.

Seems to be just fine, as I have no intention of going back in to re-torque.

 

Yesterday I pulled down the pan.
Removed it today and found nothing of consequence. No metal in pan (only 70 miles fresh oil & filter after break in oil was swapped out). No play in bearings.
All rods have on average 0.26mm of clearance.
Spec is: Connecting rod clearance = 0.15 to 0.36 mm (0.006 to 0.014 in) (page 40 of RAVE Engine Overhaul)
All bearing caps were tight, as were main bearings.
We rotated the assembly and saw no play in any parts of the rotating assembly.
Cylinder bores were clean and crosshatching was untouched.

Starter is properly torqued and tight.
Torque converter bolts were treated with blue threadlocker during assembly and remain tight.
Oil pick up had it's O-ring and was sealed properly.

After finding nothing, the pan was replaced (after being washed & dried, along with the nearly new oil pan gasket).

Filled with 15W40 Shell Rotella T and a new oil filter (filled prior to threading on).
Oil light went out very quickly after starting. Motor was quiet until warm.
Once warm, the noise returned. I've used a stethoscope, long screwdriver, and wooden dowel I still can't determine the source. Seems to be in the block, not the pan or heads.
Sounds like piston slap. Goes away when revved, returns at idle.
Pretty frustrated and I need to get this back to my neighbor. Just not comfortable with the sound. May run like this forever but ya never know.

 

Loose sleeve. Put an inline thermostat in.

 

Sleeves were all pinned after the block was decked.
180°F thermostat already installed during the rebuild.

 

I've read that shorting out the spark to each cylinder individually should show which cylinder the problems on if it's piston slap.
I'll try that today and see what I come up with.

 

Pistons slap when cold. When hot they wouldn't make noise. If you are sure the sleeve isn't moving, I would think it was a lifter problem. Being that the oil thins out when hot. Check the oil pressure, some of these ancient oil pressure switches have mushed springs and turn the light off at 3 or 4 pounds. The wire grounding test will only check for a bad rod bearing.

 

Any chance the noise is related to a cracked or damaged flex plate?

 

We've narrowed down the sound to cylinder # 5 with a stethoscope. It's sounding like a bad lifter (which were new).
We'll pull the valve covers tomorrow. Praying it's something simple.

 

You could have wiped the cam out. Check the lobes. Wont miss at idle but will miss at high load/rpm. Will make a ticking sound at idle.