Did we ruin our engine? This is what an oil analysis test revealed

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Update by Tom Suddard to the Porsche Cayman project car
Aug 8, 2023 | Porsche, Oil, Cayman, Porsche Cayman, Engine Oil, Oil Analysis, LN Engineering, Driven Racing Oil, SPEEDiagnostix

Whelp, we did it: My wife and I bought a broken Cayman in Seattle, Washington, and then drove it all the way home to Florida in fourth gear. Washington, Oregon, Idaho, Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Louisiana, Mississippi, Alabama and Florida: As we learned, these are all states that can be driven across in a Porsche screaming at 4100 rpm.

(If you’re interested in the finer details of our trip, you can follow along in the live thread we kept while we were on the road.)

Now that the car is home, I found myself interested in a much more expensive detail: Had we ruined the car driving it that far without the top two gears?

Particularly, I was worried about the health of the engine. I’ll be honest here: Modern cars are amazing, and I had little doubt that a used Porsche could scream across the country without exploding. But I was still curious, and lots of people on the internet told me it would surely blow up. So it’s time to find out what really happened inside the Cayman’s engine, and an easy way to do that is oil analysis.

Before we left Seattle I mailed a sample of the Cayman’s old mystery oil off to SPEEDiagnostix, an oil analysis company recommended by our Porsche friends at LN Engineering (and included a kit in their generous care package for this trip).

For $69.95, SPEEDiagnostix will analyze your oil sample and tell you everything there is to know about it, including how well the oil is working, what pieces of your engine are floating around in it, and what you might change to get a better result next time.

After draining the mystery oil, I poured in a fresh fill of Driven Racing Oil DI40. Why this oil? It was also in our care package from LN Engineering, but came well-reviewed from the oil analysis folks, too.

Those initial results came back while we were halfway through our trip. Viscosity was slightly below grade, which they noted was typical for Mobil 1, as was the measured additive package and oxidation value. But “all other results are within normal ranges.” So I had our baseline: When the Porsche left Seattle, it had a perfectly good engine with no issues.

But what about after more than 4000 miles at 4100 rpm? I took a fresh sample, packaged it up in the prepaid SPEEDiagnostix box, and paced back and forth across the shop for a few days while I waited for the results. That little bottle would either prove I’d made a $15,000 mistake or prove that you really don’t need 5th and 6th gear to drive across America.

Then the email came. The results didn’t just show healthy oil. It showed healthier oil than the first sample, with “fantastic” single-digit numbers on all wear metals. In short, my Cayman shrugged off the abuse with a smile on its face, even if it was screaming the whole time.

So we didn’t blow it up.

What’s next for the Porsche?

Well, it’s time to stop procrastinating and pull that broken transmission out. We’ll do that in the next installment.

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bobzilla
bobzilla MegaDork
8/8/23 9:01 a.m.

You know you have your own Oil Analysis guy here..... Just sayin'. 

BA5
BA5 GRM+ Memberand HalfDork
8/8/23 10:05 a.m.

One of the longevity tests manufacturers do is to just run the engines at redline and full load for weeks on end. I think it'll be ok.

bobzilla
bobzilla MegaDork
8/8/23 10:41 a.m.

Why this oil? It was also in our care package from LN Engineering, but came well-reviewed from the oil analysis folks, too.

I mean, the founder of the lab is also the developer of the oil so I would be shocked if they were critical of it. 

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
8/8/23 10:59 a.m.

Bob, I didn't realize you were an oil analyst. What do you think of the results? And was I correct in going into this with the assumption that this would be no big deal, anyway?

 

bobzilla
bobzilla MegaDork
8/8/23 11:20 a.m.

In reply to Tom Suddard :

There report is a bit hard for me to read. Not sure why they add all the wear metals together. Kinda odd but maybe that's their thing. I do know they use a different method for their elementals. It's an older out dated method that's being bright back with new technology and equipment. 
 

as for the results themselves the appear normal. There is always wear in an engine. It's the amount you need to watch. Keep in mind sampling procedures (how you obtained the sample) can have the largest effect on results. There's a lot of variables in play. That sample wouldn't concern me. If you were truly worried I'd continue to sample to monitor the trend to make sure it's fine. But barring any known issue I wouldn't be worried about running an engine for extended time at higher rpms. 
 

edit: although I think maybe I should raise my prices if they are charging $70 per sample

t321sg
t321sg New Reader
8/8/23 1:22 p.m.

You said it was mystery oil that you drove across country - but the initial analysis referred to Mobil 1. So does the lab believe it was Mobil 1 in the engine when you bought it and drove it across country?

j_tso
j_tso Dork
8/8/23 1:24 p.m.
bobzilla said:

You know you have your own Oil Analysis guy here..... Just sayin'. 

Bob is the oil guy...?

bobzilla
bobzilla MegaDork
8/8/23 1:26 p.m.

In reply to t321sg :

There's no real way for the lab to answer that question. Additives can be similar but be sold as different oils using a different base stock. The way its supposed to work is you work from the information on what the oil is supposed to be. When you start looking at the sheer volume of oils out there trying to work backwards is just not something you can do reliably nor cheaply. 

bobzilla
bobzilla MegaDork
8/8/23 1:27 p.m.
j_tso said:
bobzilla said:

You know you have your own Oil Analysis guy here..... Just sayin'. 

Bob is the oil guy...?

Not that guy, but kinda

 

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
8/8/23 1:29 p.m.
t321sg said:

You said it was mystery oil that you drove across country - but the initial analysis referred to Mobil 1. So does the lab believe it was Mobil 1 in the engine when you bought it and drove it across country?

We drained mystery oil out of the car before driving cross-country, then drove across country on the Driven DI40.

Bob's correct--there's no easy way to tell what was in the car when we purchased it. But given the dealer service history and the lab's observations, we suspect it was Mobil 1

Andy Hollis
Andy Hollis
8/8/23 2:01 p.m.

The race engineer in me says this test proves that you should run the car closer to redline constantly.  All this longer gearing stuff might save some fuel but it's KILLING your engines.

bobzilla
bobzilla MegaDork
8/8/23 2:03 p.m.

In reply to Andy Hollis :

Interesting fun fact.... the new forte with the spoolie boi runs 80mph at about 3400rpms. That's also about where it gets fantastic fuel economy, hovering around 40mpg. When I drive to work and short-shift and keep the revs low, I get 37.

z31maniac
z31maniac MegaDork
8/8/23 2:08 p.m.
Andy Hollis said:

The race engineer in me says this test proves that you should run the car closer to redline constantly.  All this longer gearing stuff might save some fuel but it's KILLING your engines.

I'm a firm believer in a few hard pulls to redline every time the car is driven (assuming you wait until everything is up to temp). For instance, went to grab lunch today on the way back is a long on-ramp back on to the Turnpike. 1st-4th to redline in each gear, before slowing back down to just above the speed limit as I merge.

jstecz
jstecz New Reader
8/8/23 4:12 p.m.

4100 RPM?   That's an normal highway cruise for a Miata driver.   :)

 

jstecz
jstecz New Reader
8/8/23 4:12 p.m.

4100 RPM?   That's an normal highway cruise for a Miata driver.   :)

 

bobzilla
bobzilla MegaDork
8/8/23 4:43 p.m.

In reply to jstecz :

Pretty sure that's where the wifes first gen manual RAV4 ran at highway speeds. The engine was fine, but the cats weren't happy after 30 hours of straight running.

Bfrance
Bfrance GRM+ Memberand New Reader
8/9/23 12:14 p.m.

This is AWESOME, Tom!  

I'm  eventually going to make my own P-Car purchase, so it's super cool to read about your adventure!

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/9/23 12:59 p.m.
jstecz said:

4100 RPM?   That's an normal highway cruise for a Miata driver.   :)

 

jstecz

Exactly, we have proven that a 10 year old Cayman is the equal of a 34 year old Miata.

Snrub
Snrub Dork
8/9/23 3:04 p.m.

S1 RX-8s (NC Miata platform ;) ) do around 4k at 80mph. They get better fuel economy at 55-60mph, which is probably expected for multiple reasons.

fearlesfil
fearlesfil New Reader
8/9/23 4:26 p.m.

Back in '77-'80 I drove 400 miles round trip Yuma to Phoenix every other weekend, mostly at 90 MPH. In a '70 Mustang (Corvette Yellow) with a 351 Cleveland 4V, FMX automatic (no OD), and 3.00 gears, 4,000 RPM cruise was normal. Never had an engine issue.

Unless you include the one time: A fan belt came off, taking the other two with it, and the transmission fluid lines for good measure, near the Barry M. Goldwater Air Force Range south of Gila Bend. I had to leave the car on the side of I-8 and came back the next day with two friends, parts/ tools. We had just finished fixing it when a deafening explosion right above our heads sent us all to the deck. I looked up to see an F-15's tail, just 50 feet off of the deck, high-tailing (low-tailing?) it for the bombing range after "buzzing" us. Guess he saw three jar-heads standing around a yellow car and just couldn't resist. I can imagine him calling "tally-ho!" as he spotted us on his way out of Luke AFB. Bad-ass cool!

fearlesfil
fearlesfil New Reader
8/9/23 4:42 p.m.

In reply to bobzilla :

Engines have their best BSFC (brake specific fuel consumption) at their torque peak. I suspect at 80 MPH you are nearer that RPM, and the turbo is probably helping out some at that point too. So long as you are below the point when boost crosses the threshold to when the computer starts retarding timing and/or enriching the mixture, the turbo can make the engine more efficient.

 

Berck
Berck Reader
8/9/23 7:04 p.m.

I'm going to posit that the following are both true: (1) you didn't ruin your engine and (2) this oil test isn't particularly meaningful by itself.

Aside from catastrophic failures that you'd notice anyway, you're not going to get much of anything from a single oil analysis.  I do them on most of my cars as well as my airplane. They are useful, but not especially useful in a vacuum.  The way they are useful is when you do them regularly, collect trends, and then notice unusual data that you can't correlate with a change in usage.

50 hours after I bought my airplane, I changed the oil.  Here's the oil analysis:

Taken by itself it's hard to say much from it.  The most value is that compared to the provided averages from the same engine, aluminum and chrome are high.  You'll note that the comments on it are concerned, but not alarmist.  The oil filter told a much clearer story--it was completely full of metal.  We took the airplane out of service and sent off the engine for an overhaul before even getting the oil report back.  On disassembly it was clear that the camshaft and tappets had ground themselves into oblivion.

This is a best-case scenario for a one-off report like this.  In your case, there are no averages from similar vehicles.  Worse, driving cross-country with few heat cycles over those 4,500 miles is likely completely different usage from the total unknown "baseline" of the oil that was in the car when you bought it.  Maybe you did cause excessive wear and have no idea because you don't have anything to compare it to?  I don't think you do, and I'd be seriously shocked if driving across the country at 4,000rpm did in that fancy engine did real damage.

Mostly I just want to caution against using single reports like this to pronounce an engine "healthy".  At most you can pronounce it, "not obviously destroyed."

 

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/9/23 8:19 p.m.

I once did an oil sample on a 3.0 Toyota engine and discovered large chunks of piston in it. No external lab was required to come to a conclusion. And by "oil sample", I mean "I was draining the oil and piston parts came out".

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/9/23 8:59 p.m.
bobzilla said:

In reply to Andy Hollis :

Interesting fun fact.... the new forte with the spoolie boi runs 80mph at about 3400rpms. That's also about where it gets fantastic fuel economy, hovering around 40mpg. When I drive to work and short-shift and keep the revs low, I get 37.

I put 4.78 gears in an '85 RX-7 with 205/60-13 tires and with the engine spinning 5000rpm down the highway, I was getting 32mpg.

(before you ask, yes that is after correcting the odometer.  it was over "40"mpg before correction)

On the other hand, when I had my T-bird, I drove for a week without using 3rd gear because I was thinking about dropping the 2.77 gears in favor of 4.56 gears and wanted to see what it was like to drive.  It was something like 4000 at highway speeds.  Oddly enough a 429ci pushrod engine does NOT respond well economy-wise to spinning that fast.

 

(i didn't go with the 4.56s)

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/9/23 9:04 p.m.
Keith Tanner said:
jstecz said:

4100 RPM?   That's an normal highway cruise for a Miata driver.   :)

 

jstecz

Exactly, we have proven that a 10 year old Cayman is the equal of a 34 year old Miata.

It is my understanding that one could buy a 34 year old Miata in the same condition for the same price, so yes this is true smiley

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/9/23 10:58 p.m.
Pete. (l33t FS) said:
Keith Tanner said:
jstecz said:

4100 RPM?   That's an normal highway cruise for a Miata driver.   :)

 

jstecz

Exactly, we have proven that a 10 year old Cayman is the equal of a 34 year old Miata.

It is my understanding that one could buy a 34 year old Miata in the same condition for the same price, so yes this is true smiley

And that's why :)

MyMiatas
MyMiatas HalfDork
8/9/23 11:12 p.m.
bobzilla said:

In reply to jstecz :

Pretty sure that's where the wifes first gen manual RAV4 ran at highway speeds. The engine was fine, but the cats weren't happy after 30 hours of straight running.

I have heard of Squirrel powered cars but Cats powering a car for 30 hrs! Way too lazy for that. ;0)

CrashDummy
CrashDummy Reader
8/10/23 7:51 a.m.

I'm not really understanding why you'd think extended running at 4,100rpm would be harmful. This car should be able to handle extended track driving at near-redline. Why would it care about highway cruising at a slightly elevated RPM? 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/10/23 8:30 a.m.
CrashDummy said:

I'm not really understanding why you'd think extended running at 4,100rpm would be harmful. This car should be able to handle extended track driving at near-redline. Why would it care about highway cruising at a slightly elevated RPM? 

All of the this.

 

Any engine that can't handle 4000rpm on end deserves to die.

The uncharitable part of me says yes, even Diesels smiley  but let's speak in the context of sporting vehicles here.

 

All the same, there is gut feeling, and then there is testing and proof one way or the other.  Gut feelings are fine but keep in mind that your gut is full of E36 M3 smiley so I do appreciate the approach taken with the before and after testing.

What I am curious about is if the Driven oil is API rated.  There are two points to this: if you use non API oil, or whatever the OE specifies ( be it API, ACEA, or manufacturer specific) then you are asking for a warranty denial.  This has happened when people used a certain brand of oil without certifications, the warranty was denied, and rightfully so.  Without certification it could be Wesson in a pretty square bottle.  The other point, somewhat related, is I know they make Driven for old flat-tappet pushrod engines and "American Iron" racers swear by the stuff, even more than the old Brad Penn racing oil.  If this is the same stuff, the high levels of zinc-phosphate compounds needed for the heavy point friction surfaces in a flat tappet pushrod engine are not really needed for a modern engine and can be detrimental to catalyst and oxygen sensor life.  Which is why the API specs pulled those compounds out in the last few decades.

Slippery
Slippery GRM+ Memberand PowerDork
8/10/23 8:45 a.m.
Pete. (l33t FS) said:

What I am curious about is if the Driven oil is API rated.  There are two points to this: if you use non API oil, or whatever the OE specifies ( be it API, ACEA, or manufacturer specific) then you are asking for a warranty denial.  This has happened when people used a certain brand of oil without certifications, the warranty was denied, and rightfully so.  Without certification it could be Wesson in a pretty square bottle.  The other point, somewhat related, is I know they make Driven for old flat-tappet pushrod engines and "American Iron" racers swear by the stuff, even more than the old Brad Penn racing oil.  If this is the same stuff, the high zinc-phosphate compounds needed for the high point friction surfaces in a flat tappet pushrod engine are not really needed for a modern engine and can be detrimental to catalyst and oxygen sensor life.  Which is why the API specs pulled those compounds out in the last few decades.

From their website:

"DRIVEN DI Series Racing Oils are formulated for High Performance Engines/Racing applications only. This engine oil will NOT MEET any current API or OEM Engine Oil Specifications. "

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/10/23 8:55 a.m.

In reply to Slippery :

I was actually going back to get the oil model to search for myself when you posted that smiley

Basically, this oil is great for heavy performance use, but do not use in anything covered under warranty.  Which is fine, for "us", since I like to believe that we're all adults here, and we'd respect that if we went outside the spec for warranty then we'd accept that a warranty claim would be denied.  Or we race old crapcans whose warranty expired five owners ago, one or the other smiley

 

I still maintain that the six cylinder boxer wasn't screaming, it was singing, but I wasn't there for it.  Unfortunately

bobzilla
bobzilla MegaDork
8/10/23 8:55 a.m.

In reply to Pete. (l33t FS) :

According to the results, it has a bit more than normal ZDDP, but not excessive. 100-200ppm over a SN rated wally world synthetic oil, but less than say Redline or Motul. 

Milburn Emery
Milburn Emery New Reader
8/10/23 11:14 a.m.

I use Blackstone for my MB

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
8/10/23 12:11 p.m.
CrashDummy said:

I'm not really understanding why you'd think extended running at 4,100rpm would be harmful. This car should be able to handle extended track driving at near-redline. Why would it care about highway cruising at a slightly elevated RPM? 

Oh I totally agree (and I wrote in the article that I wasn't worried), but some of the comments were much less confident. I figured I should investigate.

 

Flynlow (FS)
Flynlow (FS) Dork
8/11/23 9:20 a.m.
bobzilla said:

In reply to Pete. (l33t FS) :

According to the results, it has a bit more than normal ZDDP, but not excessive. 100-200ppm over a SN rated wally world synthetic oil, but less than say Redline or Motul. 

Mobil 1's factory fill Porsche oil is ~1000ppm Zn:

EDIT: hyperlink to the sheet isn't working, if you click "Zinc and Phos" on the right side of the page, it's there:

https://www.mobil.com/en/lubricants/for-personal-vehicles/our-products/products/mobil-1-fs-0w-40

bobzilla
bobzilla MegaDork
8/21/23 9:21 a.m.

In reply to Flynlow (FS) :

Manufacturer specific fluids will always be different depending on needs. 

CrustyRedXpress
CrustyRedXpress GRM+ Memberand Dork
8/21/23 12:50 p.m.

Sounds like a cool trip-glad the engine made it. 

Begs the question though-what is the most GRM Porsche engine swap?

LS? K-swap? Audi 2.7T? 

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