Non-BMW Stuff on a BMW Forum
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Think about it this way, there is roughly one square inch of bearing area that a connecting rod journal forces down on. If 60PSI is your maximum oil pressure, that is roughly what the pressure relief valve vents at, then it would only resist 60 pounds of force when combustion happens. If you only have 60 pounds of force you aren't going anywhere. Just from compression pressure say 150PSI x the area of the piston (3.5/2)2 x 3.14 = 9.6 square inches. You end up with a force down of 9.6*150= 1440 pounds, and that is before combustion starts.
Not here to argue anything, but to simply point out that this logic isn't exactly sound.
This would be the case if you were to have the whole surface of the bearing being an oil passage, but it is instead adding oil into the bearing area to provide a fluid film.It's not uncommon to see 6-8psi oil pressure at idle, and if you were to be worried about the direct force acting on it you would never see oil going into the bearing.
But I agree, 20w50 is far too thick for that motor, only M30's seem to need that kind of honey in the summer.
You could add some zinc additive to the oil if desired, I know @snap should have some suggestions in that department.
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All oils are categorized by API standards, and that's the easiest way to determine what oil is "best" or equivalent to OE standards.
At this point in time I would be willing to bet that all oils that you can buy off the shelf are better or equivalent to what was available at the time when these motors were designed. -
All oils are categorized by API standards, and that's the easiest way to determine what oil is "best" or equivalent to OE standards.
At this point in time I would be willing to bet that all oils that you can buy off the shelf are better or equivalent to what was available at the time when these motors were designed.You're probably right. Which is why part of me says I'm entirely overthinking this and go to Walmart and just get some gtx 10w40 and you'll be fine.
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People that post on www.bobistheoilguy.com are insane and will fight to the death about how Castrol doesnt have enough ZDDP for their 1998 Duratec V6, meanwhile an Amsoil dealer lies in wait to go in for a sale.
Stick to the owners manual unless extreme circumstances dictate otherwise (racing/heavy modifications).
This was the only photo I could find from the E30 owners manual and its hard to read, but 20w-50 is good for all but our coldest months and 15w-40 is good for all but maybe an extremely hot summer day sitting in stop and go traffic. Pick a good 40/50 weight oil. Just dont get down into the 30 weight oils
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People that post on www.bobistheoilguy.com are insane and will fight to the death about how Castrol doesnt have enough ZDDP for their 1998 Duratec V6, meanwhile an Amsoil dealer lies in wait to go in for a sale.
Stick to the owners manual unless extreme circumstances dictate otherwise (racing/heavy modifications).
This was the only photo I could find from the E30 owners manual and its hard to read, but 20w-50 is good for all but our coldest months and 15w-40 is good for all but maybe an extremely hot summer day sitting in stop and go traffic. Pick a good 40/50 weight oil. Just dont get down into the 30 weight oils
And if it wasn't for it being pretty noisy at startup, it seems the 20w50 would be fine; but the engine was pretty rattly as it warmed up for a few minutes then it was great. I'll pick up some 10w40 and see how that works.
Thanks for your help!
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Snap is right about the bob site, massive amount of detail and oil loyalties as religion battles. Fun reading if you have the time. If you go to R3v you'll also see e30 oil debates, and Ranger on the spece30 site has spent more time than is healthy on oil issues, zinc contents, and more on his way down the rabbit hole.
You can do a Blackstone oil analysis to get a baseline on your engine, and follow up to see the wear effects of your oil choices.
When I was street driving the 325i it was dino 20w-50 summer, and fall to spring 10w-40. Racing it now with 190k on the m20 engine using 20w-50, changed every few events. All good per Blackstone.
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Back on the ground! Hopefully for a while this time. One of the tie rod securing nuts was frozen, so it got new tie rods. Oil is drained out and new stuff goes in tomorrow. Fixed the hood ground strap. Getting the lights finished. Pretty excited.
Now my standard question. How would I go about aligning this bumper?
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So I started it up tonight after putting in the new oil; Liqui Moly 10w40 with the friction additive. Anyway, noise was still there when I started it up. See the video:
After a few minutes it was gone and sounds like this:
I did a valve adjustment when I put it back together. Thoughts??? Opinions?
Going to start it in the morning to see if it sounds any better.
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Not here to argue anything, but to simply point out that this logic isn't exactly sound.
This would be the case if you were to have the whole surface of the bearing being an oil passage, but it is instead adding oil into the bearing area to provide a fluid film.It's not uncommon to see 6-8psi oil pressure at idle, and if you were to be worried about the direct force acting on it you would never see oil going into the bearing.
But I agree, 20w50 is far too thick for that motor, only M30's seem to need that kind of honey in the summer.
You could add some zinc additive to the oil if desired, I know @snap should have some suggestions in that department.
I was illustrating that the logic of oil pressure being what prevents metal contact is ridiculous. Maybe that wasn't clear.
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I'm not an engine guy so others with more experience will weigh in but what method did you use to adjust your valves, and what settings did you use? The m20 even when healthy will sound a bit like a sewing machine but your does not sound right.
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I'm not an engine guy so others with more experience will weigh in but what method did you use to adjust your valves, and what settings did you use? The m20 even when healthy will sound a bit like a sewing machine but your does not sound right.
Using a .010 feeler gauge in between the eccentric and the valve. I guess with the engine cold I can double check them. When its warm it sounds good. Just the first couple mins of that cold start.
I think I'll readjust the valves to the slightly tighter clearance that that post says and go from there.
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If it turns out to be not valves/rockers, then maybe it's an oil pressure on startup issue? Some oil filters have drain back issues, stock Mann/Mahle are better choices. What happens with your oil pressure light on startup? Granted the light doesn't tell you much compared to an actual gauge but if it is staying on for a bit that could be an indicator. It should go off a second or two after startup.
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If it turns out to be not valves/rockers, then maybe it's an oil pressure on startup issue? Some oil filters have drain back issues, stock Mann/Mahle are better choices. What happens with your oil pressure light on startup? Granted the light doesn't tell you much compared to an actual gauge but if it is staying on for a bit that could be an indicator. It should go off a second or two after startup.
I had a Mann filter in at first and this one now is a Bosche. So I don't think it's a filter.
Oil pressure was my thought and why I went to the thinner oil. My only hope is that there was still some thick stuff left and now that the new oil has made it's way around the block, that it will start up and sound great this morning.
I haven't looked for the oil pressure light, but I didnt see any dash lights on.
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Back on the ground! Hopefully for a while this time. One of the tie rod securing nuts was frozen, so it got new tie rods. Oil is drained out and new stuff goes in tomorrow. Fixed the hood ground strap. Getting the lights finished. Pretty excited.
Now my standard question. How would I go about aligning this bumper?
I LOVE how this car looks. What are the wheels?
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I LOVE how this car looks. What are the wheels?
They're RS reps made by ESM. They make a lot of bbs reps and they're pretty cheap/affordable.
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The oil pressure light should come on when you turn the key to run before starting the engine. If the switch is failed open or the bulb is burned out it will never come on.
I'll double check that it comes on.
Otherwise any other ideas about the noise?
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