I'm the third owner of my 98 D1. When I got it, it needed a head gasket job, and once my indie mechanic opened it up, it was revealed that the PO had really abused the engine and the poor thing was sludged to hell, starved for oil, and likely had 10k mile oil changes (if that). Upon removal of the oil pan (needed timing gears/chain as well, so front cover had to come off), there was a good bit of metal shavings found, allegedly from the main bearings. My mechanic told me that it would probably be a bit cheaper to just buy a whole used replacement engine rather than to order main bearings to spec. As I could barely afford the head gasket job, we crossed our fingers and buttoned the engine back up. All seemed to be well after the reassembly, nothing knocked and the engine ran cooler than ever.

Fast forward five months, and I began to notice an occasional, slight lower-end knock upon startup, only for a few seconds. It would then go away completely at all other times, idle and rev, hot and cold. I mentioned it to my mechanic and he recommended upping my oil viscosity to see if it remedied the problem in the short term. As I'd only done about 2000 miles since the last change (rotella 15w40), I planned on waiting until my next change to take any action. Fast forward another few weeks, and I've got the knock on almost every startup, it's much heavier, and lasts for about 3-4 seconds. I'm absolutely paranoid I'm going to nuke my engine, but I'm getting a whole lot of opinions from many directions, and then of course there's the reality of what I can afford to do. How much would you guys expect a run-of-the-mill main bearing job to go for? Is my mechanic just lazy, not wanting to measure each journal and order bearings? I'd call myself an intermediate-level backyard mechanic, should I attempt it myself? I've seen write-ups for D2's on here, but not D1's. One write-up for a D2 even had a guy putting stock bearings on a high-mileage engine... https://landroverforums.com/forum/di...p-48197/page4/

 

Pretty common practice to replace shells without machine work. Measure a journal. If your getting rod knock now it won't take much to spin a bearing under load and then you can toss the crank in the bin. Try finding a straight (within spec) used 4.0 crank. If you one day go all in pick up a 4.6 crank.

 

Before I did my complete engine rebuild I replaced the main and rod bearings with the motor in place. I used the write up on the D2 as they are basically the same rotating assembly. The difference is the oil pick-up tube comes from the front cover on Bosch motors and comes from the middle of the block on GEMS motors. I was able to roll the mains off with the crank in place. I used standard (not oversized) bearings that were about $80 for both main and rod bearings from partsgeek.com. It isn't hard but it is time consuming and you have to make sure the caps and bearings are put back in the right place and in the right direction.
You got to start by pulling off the pan and seeing whats in there.

 

i dont have an answer, but i laughed when you said you're paranoid about damaging the engine! I'm like a hypochondriac when it comes to engine noises. I always think it's the worst!

 

Same here.