Low oil pressure/metal in oil
So, I have used my car about 10k miles in 10 years, the last 4 years as my only car, year round.
Car has total of 35k original miles.
It has never given a bit of trouble except the oil light has always come on at hot idle in drive.
For about 8 years this didn't bother me. Whenever I saw the light I gave a tiny bit of gas to slightly raise the idle until the light went out. (or if it was really stubborn, I would put it in neutral with a/c on, which did the same). But usually just a slight touch on the gas would put the light out, leaving it in drive.
2 years ago I saw for the first time, metal shavings on the oil dipstick just routinely checking the oil. Tiny tiny bits of metal in the oil, not shavings per se, but more like I was looking at metallic grey paint, but the metal flakes were even smaller than they are in metallic paint. Barely visible but visible. This scared me.
I took the oil all out, took the filter apart, (the old filter style with 7 bits and pieces to assemble) and realized that someone years ago had put the filter in without one of the bits. I forget which. I think it was missing the cone shaped gasket that goes on the spring.
I saw lots of metal dust in the filter can. Cleaned it out, put new filter, new oil, hoped this wouldn't happen anymore.
Well, after about 1,000 miles I see more metal on the stick. Did the oil change and filter again. This has gone on 3 times for 3k miles. Plus I have to assume that it was happening during the first 8k miles I used the car, I just was not looking carefully for metal filings.
But now the oil light is a little more readily able to come on and I have to put the gas on a little more, to make it go off. (now, in hot traffic, at a red light, I must raise the idle to 800 or 900 to make the light go off.). Clearly it is getting worse.
I have started changing oil and filter every 500 miles, and will switch to a SSii oil filter pedestal to make that easier. I thought maybe the ssii oil filter might be more effective straining out metal. maybe that is not true, any ideas? One interesting thing is that I will use genuine Bentley oil filters, because I checked the specs of the oil filters that interchange with that, and they all have vastly different specs. Some have blowoff valves at 15psi, some 30psi, some 40psi, they can not all be correct!!!! I believe the oil pump itself has a blowoff valve at 40psi, so if you also had a filter with that same pressure valve, that would mean your oil pump could quit serving oil before the filter bypassed. VERY VERY BAD!!! A bypass of 15psi would likely also be bad, as high rpm might demand more than 15psi to the mains.
I figure that I have 3 choices. (I won't decide which choice until I speak with 2 or 3 real RR mechanics)
Choice #1 (my favourite choice)
Get all new main and rod bearings, and a new oil pump, and put all these in myself. Engine in situ. (Rod bearings as usual, and For main bearings, I will roll the main bearings in place with Crank in situ, as is done in diesel ships where the crankshaft weighs 200 tonnes).
Choice #1 will cost about $1700 in parts, and special tools. (2 RR spanners for crank nuts, and an engine hoist)
Choice #2 Order a rebuilt engine from Florida, for $7k (plus $1500 core charge + shipping, and I will not send back my core). I would save my core engine, because it shares the chassis number and the car is a ragtop of some value although it falls about $400,000 behind it's competition, the 280se 3.5, which not long ago had same value as the RR.
Choice #3 Have a mechanic rebuild what is there. This will cost about $30k, and I can't imagine I would do it.
Does anyone have any opinions? This car works for a living. It has been my only transport for many years and needs to continue as such. I do not ever intend to sell it. It has been the most reliable car I have ever owned. Has never FTP in 10 yrs. Still drives like a new car, even with almost no oil pressure and metal in the oil.
IF I did decide to do choice #2, and use the cheap rebuilt engine, I would save my own engine and someday rebuild it myself (the correct and thorough way, if the block is not ruined) and put it back in. I can not do that now because I have no shop, and no garage. The repair will be done in a friends driveway or a rented garage if I can find one.
And I have a couple questions...
1. Are these shavings likely just bearings wearing out on account of almost no oil pressure at idle and low pressure other times? Or is the cam and lifters coming apart too?
2. What about the cam? There are no bearings at all there...
My thinking is, if it still runs like new after 10k miles of this, with near nil pressure at idle, etc, the situation can only be improved by all new mains and big end rod bearings, and new pump. I was hoping, if some damage came already to the cam or lifters, it couldn't be too bad now given the motor is dead silent and has full power. and that damage would stop occurring once my new pump and bearings were in they could only raise pressure.
3. Since the cause is essentially a mystery, what are the odds that the original owner or his driver overheated it bad and dimensionally messed up the block? Would new bearings even fit without shimming the mains?
Another idea was to use a used motor but unless there was an easy way to put in a motor from the late 1980s or newer I won't be interested in that. It is my only car. Any used shadow i motor has 50 year old liner seals, and if the car is so bad they are selling the motor, it probably was not a well looked after motor. Wish someone had a shadow that was hit in rear with a good motor I could buy...
The shadow knows...
Use your PMC for mental therapy. I replaced my psychiatrist with a PMC. Thirty minutes of driving per day is more effective than doctors and drugs.
Last edited by spiritofx; 05-15-2019 at 12:28 AM.