Cold Start Oil Pressure / Fuel Pump Shutoff Switch

[blckstrm]

My latest Blackstone analysis came back a little worse than my previous couple, likely due to a change in my duty cycle.

With 214k miles on the clock, I've been working to cut down short trips / cold starts, but I'd been thinking about what else I could do when I stumbled across this video of a short drive in the PTG E36 M3 race car.


https://www.youtube.com/watch?v=Cn-4zpNI74Y

I like the idea of a switch to interrupt power to the fuel pump and let the car crank to build oil pressure. Plus, it would be a nice security measure - not that I've ever had any trouble.

There are several factory switchplates I could replace with a simple, blank OEM-looking switch.

I haven't dug into the wiring details, but have enough friends with track cars I'm sure I can sort it out.

But has anyone ever done / tried this? Any thoughts?

[samy01]

once i had to leave my car parked in a garage for one month, and when i came back to start it, i unplugged the fuel pump relay to let the starter turn the engine to get some oil pressure before i start it. i had to let the starter run for about 10-15 sec until the oil lamp turned off.

personally i wouldn't do it, because i wouldn't want to let my battery and starter work that hard because of this.

in warm climate this might be a solution to a "cold start" but if we're really talking about cold starts like -4°F/-20°C then the "oil pressure build up delay" is one part of the problem, the other thing is, the oil is still very cold and not ideally lubricating all the necessary stuff, no matter if you first cranked it with the fuel pump off.

well yeah you can do it if you want, but i wouldn't want to toast my starter because of this

[blckstrm]

once i had to leave my car parked in a garage for one month, and when i came back to start it, i unplugged the fuel pump relay to let the starter turn the engine to get some oil pressure before i start it. i had to let the starter run for about 10-15 sec until the oil lamp turned off.

personally i wouldn't do it, because i wouldn't want to let my battery and starter work that hard because of this.

in warm climate this might be a solution to a "cold start" but if we're really talking about cold starts like -4°F/-20°C then the "oil pressure build up delay" is one part of the problem, the other thing is, the oil is still very cold and not ideally lubricating all the necessary stuff, no matter if you first cranked it with the fuel pump off.

well yeah you can do it if you want, but i wouldn't want to toast my starter because of this

I'm aware of the tradeoffs.

A new starter is a lot easier and faster than rod bearings, and free (I replaced my original at 206k, got a lifetime warranty one from one of the auto parts stores. So a new one would be free). My current battery is nine years old, so I'm not particularly worried about "excessive" battery drain either.

I'm in Texas, so no temperature issues.

So, I DO understand the tradeoffs. But I was curious to hear from anyone who's done this if there's any crazy weird side effects or things to watch out for.

[Eric93se]

Replacing those small o-rings in the oil filter housing cap regularly is good practice to keep oil in the housing and top end.

[shogun]

The worst is if the oil filter drains, there were some probs on E32 and E34 with M30 engines and also M60 oil filter housings, that the check valve did not work anymore and then all oil went to to the oil sump, then of course when new starting it took a longer time to get the fluid into circulation. M30 oil filter housing was modified. Here a thread http://www.mye28.com/viewtopic.php?t=103046
Symptoms:
• Oil pressure light abruptly began taking nine to ten seconds to go off upon cold starting.
• Dreaded"chime" for low oil pressure. When restarting after short runs the light goes out very quickly.
http://www.bmwe34.net/E34main/Trouble/OilCanister.htm

Are there similar probs with E36 oil filter housings?

[Eric93se]

Not for the E36, shogun ! thankfully. But I do wonder how much does drain. Like I was saying there are small o-rings that should get replaced once and a while, the M52 and S52 have 2 very small o-rings, the M50 I think has one o-ring. The M50's o-ring comes with some oil filter packages I believe (not sure).

Oil pressure lite came in handy for them!

[blckstrm]

Not for the E36, shogun ! thankfully. But I do wonder how much does drain. Like I was saying there are small o-rings that should get replaced once and a while, the M52 and S52 have 2 very small o-rings, the M50 I think has one o-ring. The M50's o-ring comes with some oil filter packages I believe (not sure).

Oil pressure lite came in handy for them!

Yes, new o-rings come in the filter packages - small one for the bottom, big one for the cap, and new crush washers for the filter bolt and drain plug.

Even then, I do get a little bit of seepage from the cover sometimes. I crank it couple more (WOW - 20 ft-lbs!) and it usually subsides. I've loosened and rotated the cap a time or two, and that seems to take care of that.

But yeah, as Eric said it's not really an issue with the E36.

I've just got a lot of miles. I generally have great oil reports, but the recent change in my driving cycle has me doubling the number of cold starts:

1. Run the kids to school in the morning, shut it off to walk them in.
2. Start it back up when it's still not very warm.
3. It cools off while I get cleaned up, and then another cold start to drive to work.

I didn't realize how hard this was on the car until I got my latest oil report, which has lead me to change my routine a little to mitigate some of the extra wear.

I've started leaving it idling for a few minutes while I walk the kids to the front of the school, eliminating one extra start - plus then its warmer (and stays warmer) while I get cleaned up so that second morning start isn't as cold.

I bought the car to drive, so it's not like I'm going to get something else to keep the miles off it (it's got 214k on it - seriously, NOW I'm supposed to start taking easy? That's about 10 years too late).

I just want to do something to mitigate the impact of those cold starts, and this seems like a good idea.

I have a friend converting a Spec3 car to a GTS2 car with help from a crazed former NASCAR / OEM engineer, and when I brought it up with my buddy he said the engineer had JUST suggested the same thing to him. So in principle I know it's a sound recommendation.

I'd just the cautious type.

Usually for our cars someone has already done anything you can think of. I was just looking for some feedback from someone who's done this in case there are any hidden issues with doing this on our platform.

(hidden issues. I'm aware of the extra wear on the starter and possibly the battery. As I said earlier, those are both more easily replaced than rod or main bearings, rings, or wrist pins).

[shogun]

Good hint, thanks. On the M30 engines that was a real problem, in addition the oil spray pipe banjo bolts got lose and the oil pump itself caused also probs with oil pressure. For example many use cross drilled banjo bolts which one member of the forum sells for the M30 and M70 engines.
"The cam/rocker arm oil spray bar bolts have a history of loosening on the m30 big-6 and the m70 V-12 BMW engines, causing reduced or loss of lubrication which leads to premature wear/failure of the cam lobes, rocker arms, valve stems. BMW issued a "fix" with a revised bolt with a patch of Tuflok® nylon thread locker applied to them but even when used and installed under the best conditions, they too can loosen on their own before the next valve clearance adjustment is due. Put your mind at ease and solve the problem once and for all by using banjo bolts with cross-drilled heads, and safety tie wire": http://www.nmia.com/~dgnrg/banjo.htm
I also found lose banjo bolts in my M70 E32, luckily early enough to avoid more damages. I made such clips based on the drawing and pics here
http://s273.photobucket.com/user/kibokojoe/media/banjoboltbracketdrawing4.jpg.html?sort=3&o=144
http://s273.photobucket.com/user/kibokojoe/media/bracketforbanjoboltsidephoto.jpg.html?sort=3&o=145
http://s273.photobucket.com/user/kibokojoe/media/bracketforbanjoboltmounted.jpg.html?sort=3&o=146
http://s273.photobucket.com/user/kibokojoe/media/bracketforbanjobolt.jpg.html?sort=3&o=147


1. Run the kids to school in the morning, shut it off to walk them in.
2. Start it back up when it's still not very warm.
3. It cools off while I get cleaned up, and then another cold start to drive to work.

that is just a average car user profile, do not worry.

[blckstrm]

that is just a average car user profile, do not worry.

I know - but the average car also isn't being asked to do summer track days in Texas at that kind of mileage!

And I am very NOT interested in "upgrading" ... uh ... pretty much ever. I'll keep her until they outlaw vehicles that run on fossil fuels, and even then I'll probably sneak out at night!

[shogun]

Maybe just change oil and filter more often, if you are worried. Or/and like the people in cold climate do, buy an engine pre-heater for cold climate, examples
https://www.wolverineheater.com/Oil-and-Transmission-Heaters-Car-Light-Truck-s/1814.htm
http://phillipsandtemro.com/wp-content/uploads/2017/01/2016-Zerostart-Catalog1.pdf#page=83

[flyfishvt]

I don't see the need to build up,oil pressure before it starts the way OP is describing. Our oil pumps create pressure as soon as the engine cranks. The pump is directly connected to the crank with a chain drive. Unless your car has been sitting for a very long time without being started there is more than enough residual oil coating the surfaces to protect it for the first few cranks. If this wasn't true there wouldn't be any e36s over 100,000 miles.

[Nanniepoo]

Aye, I fired up my E36 after sitting for 10 months. No lights or warnings.

[Mike WW]

1. A coating of oil stays in the bearings and pistons for years, so a start isn't really dry.
2. The engine will start anyway, it's got residual pressure in the fuel system so it will start and run for a little while at least. It's possible it might die if it take a really long time for the light to go off, then it's going to have to crank for a while as it builds up fuel pressure.

I vote no.

[FiberFast]

You can buy a pressurized resivoir that injects oil into the engine before starting.