Oil temp and skid plate, the saga continues

#21

When speaking to a well known spec e30 engine builder last year he explained or at least I remember him saying that he installs a choke/reducer in the oil supply galleries to the head. He stated that too much oil is pumped to the head during high rpm…

I completely forgot about this conversation until Ranger’s post. I doubt that this type of mod is spec legal.

HMMMMMM, maybe we can restart a thinner vs heavier oil debate. You know, my thinner oil drains back to the pan faster but my heavier oil protects my bearings better :stuck_out_tongue:

#22

Ranger wrote:

[quote] That is to say when you rev up to high rpm the pump is pulling more oil, but there is a lag in how fast oil returns.

I think that what is happening is the oil level is dropping below the sensor. Then the sensor is exposed to the hot air inside of engine which come from combustion blow by past the rings.

So I’m thinking that it’s not just the left turn that causes oil starvation, but the combination of temporary low oil level due to sustained high rpm, and the left turn.

Any other theories on why my OT would show this behavior?[/quote]

I think your observtions make sense.

The questions now become a) how to confirm? and b) what to do about it?

Wouldn’t a little over fill (say 1 qt) confirm and solve?

Is 1 qt overfull too much?

Don

#23

A 1 qt overfill won’t hurt anything.

#24

donstevens wrote:

[quote]Ranger wrote:

[quote] That is to say when you rev up to high rpm the pump is pulling more oil, but there is a lag in how fast oil returns.

I think that what is happening is the oil level is dropping below the sensor. Then the sensor is exposed to the hot air inside of engine which come from combustion blow by past the rings.

So I’m thinking that it’s not just the left turn that causes oil starvation, but the combination of temporary low oil level due to sustained high rpm, and the left turn.

Any other theories on why my OT would show this behavior?[/quote]

I think your observtions make sense.

The questions now become a) how to confirm? and b) what to do about it?

Wouldn’t a little over fill (say 1 qt) confirm and solve?

Is 1 qt overfull too much?

Don[/quote]
I’ve been running a quart over since the death of engine #1, so that’s not going to make this symptom go away. This strikes me as an interesting characteristic, but not anything to really worry about. As long as the oil comes back down into the pan fast enough that the pump pickup stays submerged, it’s hard to care.

Re. reducing oil to the head. Metric Mechanic puts a restrictor in the head’s oiling tube on those M20’s that are set up to rev high. They do not do this on motors that retain the OEM rev limit. One of the things I learned when I was researching the idea of oil pumps that flowed more, is that additional oil is likely to just go to the head and therefore not be a helova lot of use.

#25

The oil capacity of the M20 (stock pan) is 4.5 qts and I get up to the max line on both of our cars with 5 qts. So you +1 qts people are actually running with 6 qts of oil? Just wondering.

#26

Re. oil capacity. The spec for the 325e and the 325is is the same. But the e has no oil cooler. So I’d guess that the spec was set early for non-oil cooler cars and never changed. I figure that the oil capacity of an oil cooler equipped car is probably 5qts, vs. 4.5, which syncs with what you’ve (Julio) found.

Re. 6qts. Roger that.

Subject change: Lighter oil. I ran this weekend with Brad Penn 15W40 to see what OP’s would be. BP makes thick oil. All of their oils are on the thick edge of the XwX band. Therefore a BP 15W40 is almost as thick at 100deg C as a light weight xW50 like Redline. BP 20W50 is a helova lot thicker (24 vs. 18) then Mobil1. Valvoline VR1 is in the middle.

The result of my experiment with a very thick 40 weight oil was the OP’s were a bit on the low side even tho OT’s were low. OP’s were low enough that I’m going to put heavier oil in before the next event.

The OP was around 50psi@6k rpm and OT was 160-170deg.