Oil filter comparison

[I6V8]

Hi, '89 325is owner here. I'm in the middle of an oil change and just pulled the Napa Gold filter off. Here's a picture with an original BMW filter on the bottom.

Not sure I'm loving the smaller diameter holes (flow) and there doesn't seem to be a backflow stop diaphragm. Bought it directly from a large, established parts supplier.

Can anyone confirm this is how the OE filters are made? Are the Napa Golds possibly a better design?

[roguetoaster]

The shape or size of the holes probably doesn't matter as long as it hits the flow spec required. I've never seen a flow rate spec for M20s, but I'm sure someone has. Even if you did, you'd have to find the spec on the filter from the actual manufacturer, not just by the label on the can since filters can be a mishmash of manufacturers/specs to be resold by whomever.

You could certainly argue about feature sets and how beneficial they are, but to most of us, we're changing the can long before any of those things really become an issue.

As to backflow, does it matter in a stock M20 orientation?

[TobyB]

heh... that lower filter... heh heh... looks like a Wix.

The Botch Made in USA filters were Wix, back before they Chinesiumed them. They weren't bad, either...

Napa's 'best quality' parts are usually pretty decent, but as always, it's not a bad idea to check...

t
cuts filters apart when he can find his filter- cutter- aparter tool

[I6V8]

Not sure if it matters but my filter orientation isn't 100% stock, car came with an elbow adapter.

Anyway, I used the filter and it ran fine after. I'll just listen for unusual cold start noises next time.

Reason this gave me pause: years ago, a couple of German old school master techs told me that BMW underdimensioned the oil passages in M20 and especially M40s resulting in premature camshaft wear. I bet this was at least partially caused by people running 20W-50 oil in freezing cold weather causing poor cold start flow to the journals. Probably not an issue here in SoCal now but having a backflow stop in the filter just makes sense to me in general.

[packratbimmer]

I use WIX. I think we need to make sure there is a check valve in the filter.

[digger]

Reason this gave me pause: years ago, a couple of German old school master techs told me that BMW underdimensioned the oil passages in M20 and especially M40s resulting in premature camshaft wear. I bet this was at least partially caused by people running 20W-50 oil in freezing cold weather causing poor cold start flow to the journals. Probably not an issue here in SoCal now but having a backflow stop in the filter just makes sense to me in general.

Metric mechanic add a restrictor to the cam sprayer to minimize the oil being pumped to the head so they probably arent too small

https://metricmechanic.com/wp-content/uploads/2016/07/M20-Engine-Booklet.pdf

i always use the OE filter, this avoids the potential low quality / cost cutting issues that are a risk with aftermarket companies. You pay an extra $10-15 but false economy cheaping out on filters IMO

[I6V8]

Metric mechanic add a restrictor to the cam sprayer to minimize the oil being pumped to the head so they probably arent too small

https://metricmechanic.com/wp-content/uploads/2016/07/M20-Engine-Booklet.pdf

i always use the OE filter, this avoids the potential low quality / cost cutting issues that are a risk with aftermarket companies. You pay an extra $10-15 but false economy cheaping out on filters IMO

Same, I never cheap out on fluids and filters. Perhaps the OE filter has a check valve but is just designed differently?

Either way, so far no issues to report except one hot start where the oil pressure lamp stayed on for an extra second. That said, my VDO sensor triggers at 11or so PSI (vs OE at 7 or 8 if IIRC). Cold start and warm up noises sound exactly same.