Oil experts: synthetic or non-synthetic in E30 for track?

[rumatt]

When I got the E30, I immediately changed the oil, and used non-synthetic oil. I've read that switching to synthetic on a high mileage engine can quickly speed up leaks and oil consumption, often making problems occur suddenly.

I was thinking of changing the oil again before the my track event next week. Would you just stick with a "decent" non-synthetic oil??? Would you go directly with the manual's recommendation, or a bit heavier?

[rumatt]

Thanks. WTF is dino juice though? Is that geek-talk for oil (non-synthetic)?

How long do you go between changes? (in terms of miles and/or track events?)

[rumatt]

About 5000 miles, or after I had added 5 quarts. :devcool:

Too bad the oil filter on these cars is underneath. Otherwise, you would never need to drain the oil. Just keep adding a quart every month or so, and change the filter occasionally. :)

[Jason C]

About 5000 miles, or after I had added 5 quarts. :devcool:

Too bad the oil filter on these cars is underneath. Otherwise, you would never need to drain the oil. Just keep adding a quart every month or so, and change the filter occasionally. :)

Since when does having an oil filter underneath prevent you from changing it alone? :?

[TD]

About 5000 miles, or after I had added 5 quarts. :devcool:

Too bad the oil filter on these cars is underneath. Otherwise, you would never need to drain the oil. Just keep adding a quart every month or so, and change the filter occasionally. :)

Since when does having an oil filter underneath prevent you from changing it alone? :?

Um, I think he's referring to the fact that, if you're adding 5 qts in 5K miles, you essentially have all new oil in the car and don't need to change it - except for the filter.

It was kind of a joke.

Unless I misread Matt.

[bren]

Synthetic oil isn't going to "cause" any problems but since it flows better it will find every bad seal and make unknown issues obvious.

I would use something like Castrol Syntec Blend.

[rumatt]

Since when does having an oil filter underneath prevent you from changing it alone? :?

Um, I think he's referring to the fact that, if you're adding 5 qts in 5K miles, you essentially have all new oil in the car and don't need to change it - except for the filter.


You're both correct. C.M was saying that you can still change just the filter, even though it's underneath.

But if you're as slow as I am, you'd lose a quart or two of oil when trying to swap it.

[rumatt]

Synthetic oil isn't going to "cause" any problems but since it flows better it will find every bad seal and make unknown issues obvious.
Yeah, that's what I meant.


I would use something like Castrol Syntec Blend.

hmmm. I've read an awful lot of stories of cars started drinking synthetic (or pouring it out through cracks like a watering can).

[SCA]

In a M20 I'd stick with dino. In my S14 I run Redline 15w50 as did the 1st owner.

[Rob]

You're both correct. C.M was saying that you can still change just the filter, even though it's underneath.

But if you're as slow as I am, you'd lose a quart or two of oil when trying to swap it.

The Captain thinks there is a valve that shuts off the flow when you change the filter. He's going to experiment before I do. If he claims he changed a bottom mounted filter without loosing half the oil in the car, I will try it as well.

The BMW up top filter design is awesome. My oil extractor is in the attic now. :cry: I suppose I should sell it, but you never know when another BMW might show up in the driveway.

[Roadstergal]

The race dudes use synth. I'd try it, and if you're leaking or burning - fix the leak or burn. ;) The car will run better for it.

[Jason C]

You're both correct. C.M was saying that you can still change just the filter, even though it's underneath.

But if you're as slow as I am, you'd lose a quart or two of oil when trying to swap it.

The Captain thinks there is a valve that shuts off the flow when you change the filter. He's going to experiment before I do. If he claims he changed a bottom mounted filter without loosing half the oil in the car, I will try it as well.

I'll know for sure by this saturday. :eeps:

[Jason C]

The race dudes use synth. I'd try it, and if you're leaking or burning - fix the leak or burn. ;) The car will run better for it.

I like her line of thinking. :thumbup:

[rumatt]

Took my car to an independent BMW shop for a pre-track inspection. It wasn't strictly necessary, but since I just recently bought the car, and I don't have much experience, so I figured it was worth it.

Overall they said the car is in awesome shape, and I'm good to go. But he noticed it took too many cranks to start, and replaced the "main relay" :? and now he said it idles better and starts right up. W00T!

Total bill: $25.00. They felt bad because they kept the car for 3 full days, and weren't particularly responsive about calling me back, so they didn't charge anything for the 30-40 minutes labor. :shock:

[Jason C]

But he noticed it took too many cranks to start, and replaced the "main relay" :? and now he said it idles better and starts right up. W00T!

Starting system or fuel system related relay? I'd have guessed starting, except that he mentioned car characteristics at idle which has nothing to do with a starter relay IIRC.

[rumatt]

Starting system or fuel system related relay? I'd have guessed starting, except that he mentioned car charicteristics at idle which has nothing to do with a starter relay IIRC.

Must be fuel system relay. He said "bad main relay, the one that runs the engine computer and fuel [something or other]". Just just kept saying "main relay". :dunno:

Oh, and he tighened a hose clamp somewhere... so maybe that's what did it.

[Roadstergal]

It's just called the main relay. There's nothing seperate for the starting system. It's responsible for the ECU for both starting and running. There are three principal relays - main, fuel pump, and the third, which is rarely a problem and I can never remember what it's for. O2 sensor or something random like that.

It usually either works or doesn't, though. Getting rid of a vacuum leak would help the idle and start. It doesn't take much of a vacuum leak to affect the idle - pull the oil dipstick out with the engine running sometime...

Speaking of, put a fresh O-ring at the base of the dipstick. A dipstick vacuum leak can cause a really annoying-to-diagnose small and variable idle roughness.

[Jason C]

It's just called the main relay. There's nothing seperate for the starting system. It's responsible for the ECU for both starting and running. There are three principal relays - main, fuel pump, and the third, which is rarely a problem and I can never remember what it's for. O2 sensor or something random like that.

I didn't know E30's combined starter and fuel relays into one unit. :dunno:

BTW, O2 sensors are hardly "something random." :tongue:

[Roadstergal]

I didn't know E30's combined starter and fuel relays into one unit. :dunno:

There are three principal relays - main, fuel pump, and the third

;)


BTW, O2 sensors are hardly "something random." :tongue:

:P

[Doug]

I tried Mobil One, and my car drank it in no time.

I now stick to 20/50 dino juice, and even with a leaky head gasket, it takes about a thousand miles for my car to burn a quart.

YMMV

I'm with Stuka, if it's not a newly rebuilt motor stick to non-synthetic or you'll go through the stuff like crap through a goose. Racers rebuild the motors fairly regularly, some yearly or more.

[rumatt]

Thanks for the input guys (and gal).

[Jason C]

Regarding the filter changes, I went back and thought about it some more yesterday. I don't know how I missed something this obvious, but here's something to ponder:

If a low oil filter placement would let all the oil in the sump out when the filter is removed, why do those cars still have drain plugs? :P





The reason the oil doesn't just spill out of the holes in the block where you put the filter is this: Oil is stored in the sump ('cept for porkchop boy) and stays there until it is sucked into the pickup tube, up into the oil pump, and then going back out to the oil filter, finally getting distributed to important areas like the valvetrain, main bearings, etc. With the engine off and the pump not circulating, how is the oil going to-

a) Defy gravity by going up through the pickup tube unassisted.
b) Go to the pump.
c) Push against the pump vanes/rotors/gears/etc, which meshes with the oil pump shaft, which is probably splined to the camshaft.
d) Go back down and create a big mess.

Unless you're tracking the car, don't just dump that hi-tech expensive shit out at 5k. :twisted:

With full synthetics, filter change and top-off is good enough at 5000. But make sure you fill up the new oil filter with as much oil as you can before you screw it back onto the car. Those with angled/vertical filter mounting can fill it up, then pour it back to the oil bottle using a funnel. I'll post something in the appropriate forum if anyone wants to know why to do this.

[Rob]

Do you really think the five second pressure delay caused by not filling the filter up will cause dammage?

[Jason C]

Do you really think the five second pressure delay caused by not filling the filter up will cause dammage?

It's not as simple as you make it sound. ;)

ADDED: Ask any engine rebuilder what he thinks about a 5-second delay of oil getting to the main bearing journals.

[Rob]

I wasn't trying to make it sound simpler than it is - with the filter empty, the pump has to fill the filter before the oil can get to wherever it is sprayed. By my best guess, that takes about 5 seconds on the V b/c that's how long the EMERGENCY oil pressure light was lit up on the dash when I didn't fill the filter.

If it will cause damage, I will start filling it. I guess I am asking a simple question - is it worth the time, irritation and mess to fill a new filter before installing it? I WILL spill some of the oil. It's as inevitable as the sun coming up tomorrow.

[Jason C]

I wasn't trying to make it sound simpler than it is - with the filter empty, the pump has to fill the filter before the oil can get to wherever it is sprayed. By my best guess, that takes about 5 seconds on the V b/c that's how long the EMERGENCY oil pressure light was lit up on the dash when I didn't fill the filter.

If it will cause damage, I will start filling it. I guess I am asking a simple question - is it worth the time, irritation and mess to fill a new filter before installing it? I WILL spill some of the oil. It's as inevitable as the sun coming up tomorrow.

Er, " time, irritation and mess"??? Geez, it's an oil filter. Hold it steady while installing it. :)

You have that CTS-V, right? It has a horizontal filter surface, doesn't it? That's the best-case scenario already! Be happy that you don't have an S2000 where it's mounted damn near vertical on the block.

I'll start up a thread in the appropriate forum. :tongue:

[Pinecone]

Also cars use positive displacement oil pumps, so nothing flows through unless they are turning or are VERY worn.

Yes, that 5 seconds is bad, but there is still oil in the bearings from teh last time. The real killer is the first start up of a new engine.

But for best engine life, put in an Accusump and turn the valve off before shutdown and on before engine start, it pre-oils the engine.

If the engine doesn't leak the synthetic, it will give the best protection to your engine. If it does leak, yo have seal problems and will have to rebuilt is pretty soon anyway.