Red Oil Pressure Light comes on when idling (right after rod bearing replacement)

[MTiz]

Quick update: FCP Euro is more than willing to do a warranty swap with stock clearance bearings, meaning I can save some money on that end. However, their BMW Catalog Manager does not believe the additional clearance bearings would cause me to have low pressure at idle. He believes an o-ring on the oil pickup tube could have gotten nicked during installation.

Unfortunately, there's no way of knowing without tearing the car apart again so that's coming up in the near future. What a nightmare.

[ClevoCapri]

If you put some heavy oil in it like a 20w50 and the oil light stays off at idle. It would be a fair indicator that the bearing clearance increase has upset the engine. I would be replacing with the correct size either way.

[heinzboehmer]

I think I'm just going to buy a car cover and park it until I can save up to do the rod bearings again.

...might see a white M3 on marketplace soon

Oooor your could get all the parts new from FCP for free and do your first project on the car. Take your time, rent a tech angle and you should be good. Bearings sound really daunting but are actually very straightforward.

[sapote]

So stay away from extra clearance bearings?

Why deviate from the factory spec? I'm sure the designers had spent many hours testing to arrive at the spec. I see no reasons to increase the clearance.

[sapote]

You could raise the idle rpm. What rpm does the low pressure light turn off at?

Not good, as higher idle rpm will eat the tranny R , 1st (and 2nd if SMG) fast. For longer synchro life run low idle rpm.

[MTiz]

I think I'm just going to buy a car cover and park it until I can save up to do the rod bearings again.

...might see a white M3 on marketplace soon

[BMWahba]

So stay away from extra clearance bearings?

[Icecream]

If I was to choose between running an engine at low oil pressure or normal, I would choose normal.

Not arguing that this is an ideal solution, but may allow the op some time to save up for another rod bearing job.

I think either way a rod bearing job is likely in the op’s near future. But if planning to run it, I would raise the idle to prevent damage to there rest of the engine internals.

I really think that is asking for trouble. We don’t know why the pressure is low for certain. If it were mine, it would be coming apart immediately, as much as it sucks.

[eacmen]

Am I the only one that thinks this is a bad idea?

If I was to choose between running an engine at low oil pressure or normal, I would choose normal.

Not arguing that this is an ideal solution, but may allow the op some time to save up for another rod bearing job.

I think either way a rod bearing job is likely in the op’s near future. But if planning to run it, I would raise the idle to prevent damage to there rest of the engine internals.

[Slideways]

I'm not sure which o-ring you're referencing. Everything that came in this kit: https://www.fcpeuro.com/products/bmw...-1124783440kt1 was done though, do you see what you're mentioning listed?

Admittedly I ordered the first kit that FCP said would fit my car and didn't find out about the larger clearances until today. However, I don't believe the larger clearances would cause me to lose pressure at low idle but the article that eacmen posted makes it seem like a possibility. It appears that this would be a non-issue on track cars use to seeing high RPMs all the time, but on my street driven car it's causing me this headache. I'm seriously regretting everything at this point

Unfortunately, it is not included, but it is strongly suggested to replace it. I'm not sure why FCP suggested two pointless items in that kit, one being the oil pan cover and the other being the dipstick tube seal (both can be reused), and they left out one of the critical o-rings.

My guess is the extra clearance is causing the low oil pressure at idle issue since it is the only aftermarket spec part.

Number 9 -

[heinzboehmer]

Am I the only one that thinks this is a bad idea?

Yeah if the loss in oil pressure is actually coming from the increased clearance in the bearings then I wouldn't want to be running my engine like that. The oil film thickness is probably the most important bit in the rod bearings. If it's not what it was designed to be then the bearings will wear faster.

Any bored mechanical engineers/people with experience designing systems like these want to run the calculations to see how much 0.025mm of extra clearance will affect the pressure lol?

[Icecream]

That's not a bad idea. The low-pressure light turns off at 1000-1100 RPMs

Am I the only one that thinks this is a bad idea?

[eacmen]

That's not a bad idea. The low-pressure light turns off at 1000-1100 RPMs

I don’t think that’s crazy high. I’ve raised my idle rpm on the last car to 1150 since it had a lightweight flywheel and chattered like mad.

Requires modification to a couple tables in the DME.

[MTiz]

You could raise the idle rpm. What rpm does the low pressure light turn off at?

That's not a bad idea. The low-pressure light turns off at 1000-1100 RPMs

[eacmen]

I'm not sure which o-ring you're referencing. Everything that came in this kit: https://www.fcpeuro.com/products/bmw...-1124783440kt1 was done though, do you see what you're mentioning listed?

Admittedly I ordered the first kit that FCP said would fit my car and didn't find out about the larger clearances until today. However, I don't believe the larger clearances would cause me to lose pressure at low idle but the article that eacmen posted makes it seem like a possibility. It appears that this would be a non-issue on track cars use to seeing high RPMs all the time, but on my street driven car it's causing me this headache. I'm seriously regretting everything at this point

You could raise the idle rpm. What rpm does the low pressure light turn off at?