 |
|
So for the first time in six years of tracking my car my oil light started to come on at Cmp this past weekend. Started Sunday in turns 1 and 3 for the most part. Checked level and it was at full mark. Only change was I had added a quart of Restore about a month ago prior too a. I’d event. Wondering if that had some effect
NevEr had the issue before. No crank scrapped or baffled oil pan all stock
What was the car doing when the (7psi) OP light came on? What kind of oil?
Don’t add crap to your oil. A lot of careful work went into creating the additive package of your oil. No sense pissing in it.
There’s some disagreement on this, but IMO “Full” is about 1 qt not enough.
As to what the car was doing, I was trying to het in front of cars in font of me and keep you behind me! Mainly came on in turn 1 and 3 the left handers.
Running 20-50w oil. I had thrown in a van of the restore when I was chasing my weak motor problem.
Funny I had never had the light come on before in 6 years of racing. Guess i’ll change the oil and overfill the next time.
What were the rpms when this was occuring? If the rpms were low because you were shifting then it’s no big deal. If you were under load you damaged your bearings. No way around it, and it will only get worse. Bearings with surface damage have a harder time maintaining the “hydroscopic wedge” necessary for lubrication.
What kind of 20W50?
I’m the oil and lubrication whackjob here, so you’ll want to also get 2nd opinions. That being said, I’d buy a crankscraper and drop your pan. Actually, being obsessed and all, I’d also get an additional layer of baffling by buying a Poore or Metric Mechanic oil pan, or get the baffle from TC Motorspots.
And buy coated rod bearings and new rod bolts.
Then I’d drop the pan and inspect rod bearings 4-6. If they look fine, put them back in. But chances are you’ll be replacing your rod bearings…you’ve been running that motor hard with no real oil control measures…replacing those bearings is inevitable. All you can really hope for is that your crank bearings have survived. If you have a bad rod bearing, you might as will pull #6 main and look at it too.
The scraper will need some work with a grinder and some test fitting. The I-J scraper doesn’t fit very well out of the box, especially around the oil pump. The teflon version will require less work.
If a main bearing is bad, it’s time to start thinking about an engine swap or rebuild.
None of this is particularly hard. You just need an engine hoist. A half day to pull everything apart, then put the scraper in with some goobage to cure over-night. Then 2hrs the next day to button everything back up.
Any thoughts on why this would have started? Never had the light come on before in 6 years of racing. Engine has 204k and has never been opened beyond valve cover gasket!
How much of the inspection items can be done with engine in the car? Not really up for engine R&R in the garage.
Thanks.
Keith
[/quote]smithk3933 wrote:
[quote]Any thoughts on why this would have started? Never had the light come on before in 6 years of racing. Engine has 204k and has never been opened beyond valve cover gasket!
How much of the inspection items can be done with engine in the car? Not really up for engine R&R in the garage.
Thanks.
Keith[/quote]
What kind of rpms was the engine running when the oil light came on?
There’s a bunch of variables that go into OP, so it’s not Infantry simple. But there’s one clear truth…for all practical purposes there’s only one wear item in OP and that’s bearing gap.
OP is pump pressure minus resistance to flow. Obviously pump pressure is a matter of engine RPM, but resistance to flow is trickier.
Resistance to flow is a matter of the visc of the oil at temp, and the retriction to flow provided by the engine.
Restriction to flow. The oil has 3 routes, IIRC. To the galley, to the head, and to the oil pump’s intermediate shaft. A fair amount of oil goes to the head and the intermediate shaft, so a 20% loss of OP is probably a 50% increase in oil flow thru the bearings. The relationship between bearing gap and oil flow is a little tricky. A particle gouge in a bearing will reduce film thickness yet not reduce flow restriction. Reduced film thickness can lead to accelerated wear tho. Normal wear not only reduces flow restriction, but also wear accelerates because the worn bearings allow the crank to move off axis. The bottom line is that it’s a wear item and once it starts going it goes faster.
Viscosity. Oils are all different and you have to look deeper then the xWx weight band that it’s labeled. For example M1 15W50, a decent but not terrific oil, has a 100degC visc of 18-19 and Brad Penn 20W50, a terrific oil, has a 100degC visc of ~24 IIRC correctly. A thin oil Redline (20W50 100deg Visc 17) is going to run at a lower pressure then a thick oil (Brad Penn 20W50). Thin oils will drop pressure in worn bearings before thick oils.
There’s also the issue of the oil’s anti-wear properties. Most modern oils don’t have much in the way of anti-wear in their additive package. But smart oil choices will include the kind of anti-wear additives that allow bearings to better ride out an occasional light scuff. Anti-wear isn’t just for cams and rockers, it plays a role everywhere.
So what caused the OP light to flash? The combo of oil choice, oil level, wear state of the bearings, engine rpm, precise g load, and lack of oil control measures around the pump pickup.