Mike Murphy

andy-gts

hope this clarifies what we know
​​​​​​Viscosity_Graph.jpg

Mike Murphy

Petza914

I drain it hot and let it drain for an hour. This gets more oil out and leaves a coating of oil on the walls for the restart, which doesn't happen if you drain it cold. I also prefill the oil filter before installing it to build oil pressure as soon as possible.

Speedtoys

My point is you're not aware of what a multigrade is, or how what the numbers mean. (Which I posted)

Its a 20 at 0C, and a 50 a5 100C. Clear?

PS: Glass in my 80 is not cracked.

hacker-pschorr

This is one of those cases where whatever makes you feel the best after the job is done is the correct answer.

It really doesn't matter, getting "most" of the oil out is going to be just fine. All these "tricks" to get that one last drop isn't going to extend the life of your engine. The only way to get every single last drop out would be to run a solvent through the system & that would destroy the motor.

These cars hold an absurd amount of oil compared to modern engines. My 6 liter Yukon XL holds 6 quarts and has a filter the size of a tuna can. These engines easily last 250-300k miles and most are run 10k-20k miles between oil changes.
My sister ran her Yukon with less than 4 quarts in the system for over a year - long story how I determined that - this was 100k miles ago, still running fine. I think she gets the oil changes based on lunar calendars.

Change it on some interval, use a good filter & the proper weight oil and a new crush washer, you'll be fine. No need to over think this.

On that note....why are we still using disposable crush washers? The rest of the planet figured out how to use a rubber seal that is reusable.....

mark kibort

Why do you think im not aware of what a Multigrde is, or what the numbers mean. the oil flows according to the viscosity number... it acts like a 50 weight when hot and acts like a 20 weight when cold. this doesnt mean that it can flow faster when hot vs cold... do YOU understand why this is... you heat up 20-50 weight oil and pour it out of a restricted container.. then do it cold... which will flow faster????? clear???

and thanks for the info about the glas....ill have to figure out how to get out there with a glass guy.. probably just have one meet me out there to remove and install in the race car a the same time! THX!!!

I used to just make sure i got the threads to the last one..... lift up the drain pan to meet the drain hole and quickly remove. no gloves, no mess and then just lower the pan to fit the arc of the flow . its an art form.. now, i just drain cold and leave it for 15mins also by jacking up the passenger side to tilt the engine. i get more out that way i suppose.



Its interesting, that you get the kinematic flow rates on the graph what backs up what Jeff is thinking.. BUT, in reality, related to flow, warm oil always flows faster than cold oil, near regardless of the SAE viscosity numbers. (between 10 and 60 weight) . two different concepts and characteristics.

this makes sense, but it seems to be confusing to many, i agree!
How does it leave more of a coating on the walls for restart? that doesnt make sense vs draining and restarting cold. the only difference between cold and warm restart is that the engine is cold or warm. the engine doesnt know its missing oil in the sump pan ether way. yes, i always fill the filter before i install to avoid that momentary lapse in pressure.

KenRudd

^^^^^One of the reasons I buy so much stuff from Roger- Crush washer taped to every single oil filter. Its a small thing, but still.

GT6ixer

+1!

Speedtoys

I suppose you could machine the oil pan to accept that if you wanted to. Then you could likely use it 2 or 3 times, tops.

But if you used an O ring with no modifications, it too would be a one use item as it would be destroyed first torquing down.

hacker-pschorr

I didn't say O-Ring, go change the oil on most domestic vehicles.
Most never replace them, unless damaged. Except for my truck, since I'm a paranoid 928 owner.

Speedtoys

^^ You are correct.

is there a specific lip that the crush washer sit in now, or a big flat step?

hacker-pschorr

Thank you for your approval!

mark kibort

So, you dont agree that a 20-50 flows faster when hot vs cold?

GregBBRD

I train my guys to allow the oil to drain until there are only slow drips coming out. The percentage of old oil left is so small compared to the total volume, it's inconsequential.

And if the old oil is so terrible that every tiny bit needs to be removed, the engine probably needs to come apart, anyway.