OIL CHANGE AFTER BREAKIN

[Neil Bardsley]

I think you need to consider what type of driving you do and in what temperature? Pre summer most of my driving is relatively short and the engine rarely got up to 90/100c. For this type of driving I was happy to use a 5/30 good synthetic. As most of the wear happens on startup and while the oil is still cold. Now summer is here I'm using 10/40. I have a lot more confidence it can run better at higher, extended temperatures than a mineral.

You don't worry about cam wear and low ZDDP? I don't know of a synthetic in those viscosities with enough ZDDP
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Please read Richard Mitchell's book "Which Oil" he has a section on ZDPP

[Martin Benade]

Since I don’t have the book does he make a case for less ZDDP?

[Jay Darlington]

I used Mobil 1 synthetic 10/30 in my Vee race engines most of my racing years. I never suffered bearing failure or significant wear over 20 plus race weekends on each engine, but the engines were pampered, never used for short journeys and multiple starts. Just a lot of time above 6k rpm and they sometimes got very hot.
No ZDDP but of course relatively very short time between rebuilds
There is a school of thought that leans toward high flow oil lubrication rather than high pressure and belief that 10/30 will of course flow more easily. I am going to stay with more ZDDP and thicker synthetic oil for my 356 engines.

David, about your more flow and less pressure. as a kid just out of high school i worked in a lumber mill, most of the time i was a forklift driver. the old forklifts were powered by a Continental flathead six. when i would start the engine in the morning cold it might have 10# oil pressure, 30wt oil. as it warmed up to operating temp it would go to zero and the needle wouldn't move. i mentioned this to the mechanic, so he puts a new mechanical gauge right in the block fitting for oil pressure. still zero pressure, these engines were old when i started and we ran the heck out of them. in an 8 hour shift they would be to the floor half the time. lifting a load 4 units high was a full throttle blast. these engines NEVER failed and ran for years after i was gone. no oil pressure but reasonable circulation.
Jay D.

[Brian R Adams]

Since I don’t have the book does he make a case for less ZDDP?

Yes, Neil, why be coy about it? Edify us. That's why we're discussing here, not in a bookstore.
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[David Jones]

Jay, they must have had oil pressure otherwise there would be no circulation. Maybe the gauge was positioned where it saw very little pressure. I bought a BMW 1800 Ti a very long time ago for very little money because it had a bad rod bearing. I fixed it and was concerned to find that it had less oil pressure than I expected, this was on the factory installed oil pressure gauge. I discovered after a little research that the oil pressure was actually not low but because of where it was taken at the end of the overhead camshaft it measured oil pressure at the lowest point in the lubrication path. Still not sure in my mind if that was the right way to design it but one knew if you had any oil pressure at all you must have a lot more at the crank bearings.

[Ron LaDow]

10/30 unless it is a special formulation will also not have nearly enough ZDDP. Before you put any oil in your 356 engine check the MSDS for ZDDP level. Below 1200 ppm is not considered sufficient.

David, what sort of data do you have on this? I've yet to have problems (stock, or near stock open valve spring pressure on Elgin cams).

[Ron LaDow]

I think you want to run dino oil til rings fully seated/broken in.

Back when you could pick up the phone and talk to those who knew ("Hi, this is Fred" at Carillo Rods), the owner of Red Line (headquartered across the bay at the time) advised me to use dino-oil for break-in. His stuff was too slippery to allow the break-in process. If someone is advising you to buy something other than his product for a specific purpose, it carries some weight.

[Ron LaDow]

i have a full flow system with a spin on filter.
Jay D.

Sorry, missed this.
Hope you kept the bypass as it turns out to be a valuable addition: https://www.912bbs.org/forum/ams/oil-fi ... matters.4/
Still, last engine build got changed at 100, 500, 1,000 and then annually (not often hitting 4,000/yr anymore). But you'll love pulling the dipstick out at 3,000 and still being able to SEE THE DIPSTICK!

[Neil Bardsley]

Since I don’t have the book does he make a case for less ZDDP?

Yes, Neil, why be coy about it? Edify us. That's why we're discussing here, not in a bookstore.
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Well my knowledge isn't the same as Richard's so his reasoning in the book is better but in summary modern synthetic oils are much more slippery than mineral oil with ZDPP.

[Harlan Halsey]

ZDDP is a unique molecule which has the property of maintaining lubrication under high pressure such as between 356 cam lobes and the nearly flat followers. There is no substitute! Since it was added to all engine oils at around 1300 PPM after some time in the 1920s, our 356s were designed for it. No one knows what the minimum effective concentration is. I would guess that there is some margin below 1300, but whether that number is 1,000 or 800, no one knows because no testing for the lower limit has been done. There has been enough experience to know that the lower limit is not 0.

[Brian R Adams]

ZDDP is a unique molecule which has the property of maintaining lubrication under high pressure such as between 356 cam lobes and the nearly flat followers. There is no substitute! Since it was added to all engine oils at around 1300 PPM after some time in the 1920s, our 356s were designed for it. No one knows what the minimum effective concentration is. I would guess that there is some margin below 1300, but whether that number is 1,000 or 800, no one knows because no testing for the lower limit has been done. There has been enough experience to know that the lower limit is not 0.

That interpretation is where I hang my hat. And yet ... Obviously many of us have stopped using ZDDP-rich oil (either willfully or inadvertently) but I am not aware of a rash of cam lobe destruction. That doesn't mean cams aren't wearing down faster than they should, but it's curious that there's no indication of such a trend in the scuttlebutt here, unless I've missed it.
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[David Jones]

Brian, I can recount one known instance of cam lobe failure on a Vee Engine but it was due to incompatibility of surface treatment between lobes and lifters. Oil was Mobil 1 10/30 syn as on all the Vee engines I built. This was an anomaly, engine ran about 1 hour before it lost significant power and oil pressure. Cam lobes were worn down a large amount.
I never had issues with lack of ZDDP on race engines but they did not go through what I would assess as severe service like a street engine. It is probable that a street engine on Mobil 1 10/30 synthetic would not see any significant wear either but there is no real difference in cost between a synthetic with or without ZDDP so I will err on the side of safety and continue to use the oil with 1200 ppm of ZDDP.

[Neil Bardsley]

Ps after I got my type 4 engine back from a rebuild I changed to synthetic and was advised to switch back to mineral for the first 1000 miles. Which I did.

[Wes Bender]

For the reasons Harlan states in his post #40, I use an oil with ZDDP in all of my engines that don't have roller lifters. The only exception to this is during the initial break-in period when I use a 30 wt non-detergent oil. Might be old school and YMMV, but it's worked for me. I've never had a come-back, but then I'm my own customer and I always cut myself some slack..... I'm not as experienced as many on here. I've only rebuilt 3 Porsche 356 engines.

[Jay Darlington]

Wes,me too the same as you, old school as it gets.
Jay D.