I'm hoping the loss of power was the ignition system breaking down as the coil tower burnt on the distributor cap - the connector wasn't seated properly and burnt the corner off the tower from arcing. If so, I may have gotten lucky because when I looked down at the gauges when power faded, there was no oil pressure - yet there was plenty a mile or so before. Some of the pressure loss could have been from the engine slowing down on compression braking with no ignition.

No chance on the tight ring end gap idea. I set the top ring gap at .018", 2nd ring at .020" and all oil rails had a minimum of .010".... all individually fitted for each cylinder @ 1" down the bore and square.

I don't think anything ever seized..... even at the hottest temperature, the engine would still turn over, though not as fast as when cool. I attribute at least a part of that to the combination of ignition timing and a hot engine.

When the 3.0L engine is right - and with good lifters - there's absolutely no lifter tap. The newer lifters have a 3mm oil passage that seems to help. If yours are collapsing with good pressure, I'd suggest replacing them if the engine has good life left in it.

I thought about the tight gear end clearance when I packed the pump with the thicker assembly lube, but I figured if the cranksahft bearings can clear it, so would the oil pump.

I think (hope) the problem will be found in the oil pump. If the relief valve is open, there would seem to be too little oil flow..... which would transfer friction heat to the oil that did manage to circulate. I'm sure some damage has been done - I just hope not too much.

I'm tempted to pull the girdle for a look-see while I have the pan off, but that could open another can of worms. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Frank

The ignition should well be the power loss.
It does not take much of a chip in the relief to put a big hurt on the oil pressure on some engines.

Some worms need to be looked at. If that one bearing is uneven or is running tight now would be the time to know.

Yes, but the flip side is losing a bearing shell location when the girdle comes down - and/or not being able to see the installation of the girdle wrt the thrust bearings and possible damage on re-install. I'm really leery of that. <img src="/forums/images/graemlins/baby.gif" alt="" />

Frank

You glue the thrust bearings in with grease! Actually you can use a real glue to hold them to the girdle, a spot of super glue can do it but way back when I worked on MGs I just used a paste grease to hold bearings in.
It would be nice to see if a bearing is running hot and scrape it or try a different shell if needed.
This all depends if you find a chip in the relief valve.

Yes, I do that - wheel bearing grease or assembly lube works well.

In the old days of small blocks, I did rebuilds in-frame with complete main bearing replacements, but you could get enough crankshaft slack clearance to roll the new half-shell around the journal.... not sure I want to try that on a 3.0L.... those mains can be tough to seat.

Frank

You would only need to inspect the lower shells, the uppers are not loaded. I would try to keep the crank up snug for an inspection so a shell or thrust ring does not drop.
The rear seal and the pump may be enough to hold it. Maybe a wedge under the ring gear.

I might try it, but I hate to replace the lower half of a bearing without also replaceing the top half.

On the engine stand, I take extra care to set the girdle so the crankshaft bears equally on both the upper and lower thrust bearing halves to get sufficient end play - I suppose I could still do that in-frame with some careful prying.

Frank

If you find a bad bearing then you need to replace both shells.
If they are fine then you just put it back together. With prying and tapping you can get the girdle to set in place.

There are certainly some worms. A pan full of metal and 3 of 4 main bearings spun:




Now the question is whether my failure to heed ARP's advice and align hone the main bores caused it - or if the oil pump failed and caused the bearings to spin. Chicken or egg....... I guess it doesn't really matter since I'm gonna need a new barnyard.

I removed the relief valve from the pump - found no debris at all.... but the plunger/piston above the spring hangs in the bore..... sorta sticky.

Who was it that said "When you find yourself up to your arse in alligators, it's no time to wonder who drained the swamp".

My guess is that the relief valve hung open and starved the bearings - otherwise, I think I would have seen higher pressure after the bearings spun.

Back to the engine stand it goes for another full rebuild - after I find time to remove it and take the block for align honing - and yes, a new OE oil pump will go back in.

Frank

Nasty stuff <img src="/forums/images/graemlins/barf.gif" alt="" /> Makes me sick to see that, what with all the care you've taken and time spent on doing it right.... Damn shame. If I can help, call me <img src="/forums/images/graemlins/cheers.gif" alt="" />

PS: Thanks for the advice today. I pray one of the possibilties you and Eddy offered will do the tricksky <img src="/forums/images/graemlins/baby.gif" alt="" />