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I think it means any hope of me getting another 6th place season trophy are gone…
But anyway, after driving M20 powered cars for years on the street and the track, I got to see the first oil light today…
Have any of you guys who have had bottem end failures had the light flash before it grenaded?
The light comes on at idle with the engine warm, I guess I need to get a mechanical gauge and test, then maybe change the oil pump and see if that makes a difference.
Any suggestions appreciated.
Al
It would not be unknown for this to be a bad oil pressure switch… Substituting a gage will tell you if there’s really an issue and how bad it is.
The engine I used to have in my car had a pretty badly worn bottom end and could only hold 5psi at idle when hot. A couple of bottles of STP on top of Castrol 20w50 allowed it to survive some 12 DE events (including last year at RA when the temps were over 100F).
On my car, the light would come on during hard right handers (think T1 at Road Atlanta). It turned out that the thin unprotected wire running from the sender down below had a pretty large bare spot and was shorting against the block during those types of turns. Check the continuity before scrapping hopes of more rusty metal for the trophy cabinet that you can contract tetnus from.
Yep, I moved the wire around to make sure it was not shorted…what worries me is how it is coming on at idle and goes out with the throttle blip, just like you would expect a low pressure problem to show. Not real sure about the STP…if I was gonna drive it just on the street or local DE’s I would do it, skerd to drive it to Atlanta and “hopefully” drive home.
with straight 50 weight racing oil and STP it would prolly go 100k on the street…
Al
You really need to know what the oil pressure is doing. The OE sensor trips at 7psi, if it is working correctly. It doesn’t take too much wear in the bottom end and oil pump to cause the pressure to dip to that or below on a hot engine at idle. What’s more important is what the pressure does in the 5-6k range.
STP’s main purpose is to increase the viscosity of the oil. It certainly won’t hurt a race engine and may be enough to eliminate the worrisome flash of the light at idle on an aged engine.
hmm…I think I will try it…the STP, but I dont think I will drive the car down. As I said in my original post, I have been running M20’s forever, and this is the first time I have seen an oil light. My original spec e30 engine did every mid a race, half SE races plus an enduro or 2. When I had an engine builder look at the bearings, he said they had less than a weekend left, could not believe it was not knocking…but no oil light. If I was at VIR I would run it and look for the light at Oak Tree
Al
so I pull off the highway and get a bottle of STP, the light had been coming on every time I put it in neutral…put the STP in drive a few miles and test, the light does not come on, drive the 20 miles to Travis’ house, no light. I just cant bring myself to drive a ticking timebomb all the way to etlanner…when i get back I will do some test with a real gauge, the engine has 15/40 rotella in it now with STP, when I drain that I will try straight 50 racing with a preheater. I am also gonna test the rotella at the catapillar lab and see if there is any metal. I may change the oil pump before I run the 50 weight…
Al
Since one bottle of STP appears to have eliminated the light, if would be a reasonable to say that the sensor or the pressure is right on the edge of bringing the light on. One bottle doesn’t do a lot in terms of increasing oil viscosity.
I’d suggest switching to 20w50 (Castrol GTX) for this weekend. You don’t need a preheater. Simply cranking the engine and allowing it idle long enough for the engine to reach normal temp (maybe 10 minutes?) before flogging it should work fine. 20w50 might be enough thicker than 15w40 when hot to eliminate the light, and if not there’s STP.
If I remember correctly, 20w50 is the factory recommendation for this engine unless ambient temp will be very low.
I have the same issue with my race car whenever I put in anything other than 20-50. Once I put the right oil in, the oil light stopped flickering.
Yep, I did the 15/40 Rotella cause the temp, also the Rotella I used has the zinc additive I think we need. I drive the car on the street so if it is gonna be real cold I put a halogen work light pointed at the oil pan and turn it on 15 mins before I start it up. I am gonna test it when I get back from Road A, probably will try an oil pump change. There is a Mid A race at VIR the end of Feb, I may be back from CO by then and could run it that weekend, 4 miles fom home…
Al
You could try 15W50 Mobil-1. The 15W synthetic will flow much better cold than Castrol 20w. Plus the synthetic gives a little better film strength in the bearings durring long corners when the pump may be sucking air. For the $40 worth of oil it may give you some piece of mind.
Don