It's 2017, let's do the OIL thing, which one

So far no three people have agreed on one oil, what gives

Guess I'll go out to the shop and see what I used last time

 

I used one of these for an oil change, the other to top off during the year. Have no idea which
Image Unavailable, Please Login

 

The cat story may be true but I don't run cats.

 

No this Shell oil is a normal high performance oil.
Shell also recommend the 10W60 Racing for the 308 QV.
See attachment (in Dutch).
Image Unavailable, Please Login

 

I'd go for the Titanium - it's sound cool.

 

Right, why I said I use it in my Boxer and not in my 308QV.

Also, let's be realistic here as this subject has been discussed beyond any other except timing belts. The oils available back in the mid late 70s - mid 80s are not comparable to the oils of today. Personally, I use my cars fairly regularly and they both run very well. I stated, I've used several different viscosities and brands of synthetic oil varying from 10 - 40 to 20 - 50. Decent synthetic oil is not whats so bad for the motor as a lack of use. Change it reularly, put on a new filter and enjoy the car that's my philosophy. Has worked for me for 40+ years of sports car ownership.

 

The last time a thread like this was around I did a little research and found some interesting data is a journal published paper. Wish I had kept it. The results showed that it was not so much that lower ZDDP level do not protect flat tappet engines but rather how long the protection lasts. The protection offered by ZDDP and other additives breaks down over time. The time it takes for the level of protection to drop below that necessary was found to be a function of initial ZDDP concentration. Driving a 1000 miles a year with annual oil changes, the lower ZDDP level didn't seem likely to matter.

 

ah no, seriously.

 

As I said, I can not find the original paper on increasing wear with ZDDP degradation, but here is an abstract from a paper that seems to have a similar theme.

 

Just wanted to add something here. I was ask why I chose Redline 5w-50 on my 308 for many years now and has been running great. According to Redline, this is what's in their synthetic oil, at least the one that I use: Redline has a ZDDP or Zinc level of 1225ppm and Phosporous level of 1375ppm. So I think this should be suitable for older tappet type valvetrain cars like ours. What do you think?
Image Unavailable, Please Login

 

+1

 

I'm running what I was told to, Valvoline Racing 20W-50 with ZDDP.

 

After suffering an engine problem in my track car that I partially attribute to engine oil I did a ton of research on any performance oil I could source fairly easily in the States (ordering from Stateside suppliers is acceptable to me but I don't want to have to import engine oil unless there's a very compelling reason to do so).

From what I could tell, Redline had a clear advantage over every other oil I compared it to. My intended use case is probably fairly different from most people here and I was looking primarily at 10W-40 and 15W-40 oils, but if I were in need of a heavier or lighter grade I'd look at Redline first.

I still use Rotella T Synthetic and Penzoil Ultra Platinum in some cars (mainly out of convenience) but the track car and the Ferrari get Redline. IMO you made a great choice.

 

I was just going to mention that I use Redline myself, both in the engine and transmission.

Regards

 

I posted before, that I don't think the 308 DOHC engine is a flat tappet engine of the old school style that requires higher ZDDP concentrations. Instead, it's like every other double overhead cam engine with the cam acting directly on a shim or bucket - not at all like the old overhead valve engines with the single cam and roller or flat followers.

Why would a 308 need flat tappet oil when every other modern engine using double overhead cams does not? Answer, I don't believe it does. I'd need to see an actual explanation of what constitutes a flat tapped design that requires higher ZDDP, and which engines use that design, before I'd consider ZDDP concentration to be a factor in selecting oil for my 308.

 

Valvoline Premium Conventional 20W-50 in the engine.

I tried synthetics but they caused the car to leak and smoke quite a bit more. So I am sticking with dead dinosaurs.

 

Whatever modern oil you want: Just avoid racing oils like the 10W-60, if possible. Change it often and together with the oil filter: This is the only important thing

Ciao

 

Why avoid the "racing" oils? I think this is nonsense.
Even Shell says that this is the best oil for the 308 QV.
These are normal oils just like the 5w40, but a bit thicker when hot.
The 5w40 is too thin for these old engines.

 

I don't think so, actually: 5W40 has been fine for my 328 GTB during the last 12 years. And the engine does not leak.

Rgds

 

Sorry, "avoid" sense is that the racing oils are not designed to last a long time and maybe without using the car like it often happens for vintage cars, so it can increase the oxidation and corrosion due to acid moisture: This is why every not racing oil is better than every racing oil for vintage cars. Pay attention: I didn't say "it's not good", I just said "The other is better" as todays oils (all, including racing ones) are ten times (or more) better than 1973 oils, when the 308 engine was introduced on the market.

Then I want to add this, as my personal experience: the 10W-60 is even too thick and I had a problem with this oil in my former Countach 5000S, as the pressure was too high and the oil flow was drained by the relief valve when cold.

As said: Use every standard oil you want, XW-40 or XW-50, better if not a racing one. It's like tires issue: the modern ones (all) are ten times better than the old ones, so you can use whatever tire you want, as it's ten times better than the OEM one.

10W-60 can help just in heavy weared engines that no more have the minimum oil pressure due to a too big plays on the crankshafts bearings. In those cases it gives you the illusion it's everything ok as the oil pressure becomes higher, but the problem stays

ciao

 

Shell 10W60 Racing can be used for 10-20K km's.
So perfectly fine for our cars that are not being used every day.
I change my oil and filter every year.

A Countach is a very different car of course (but a fantastic one ).

But just like every other oil thread, everybody has their own opinion.
I just use the opinion of an oil expert (and the Kendall oils laboratory that tested my old 5W40 oil) and Shell company.
They both say 10W60 is the better oil for my 308 QV.

 

I'm not the Shell company, nor an oil expert: I'm just an average mechanical engineer. What I know is that the oil pressure sender measures the oil pressure just after the oil pump. If you have a very thick (hard) oil like the 10W-60, you will have a big pressure loss from the pump to the crankshaft bearings, that is the only point where the pressure value is important. So, what I mean is that the pressure you read on the gauge is not all: A thin oil will loose much less pressure, so the real pressure at the bushings is much closer to the value you read on the oil pressure gauge than with an hard oil. If the oil system has a relief valve set for a 50 oil hot viscosity index, maybe it will open too many times with a 60 hot viscosity oil index. As the 308 was born when the 60 viscosity index oil didn't exist, I'm much worried about that possibility, so I don't want it. I appreciate a lot the extra cold start protection that the 5W oil gives versus the 10W.

I don't want to say that other choices are wrong (as they aren't), but I just wanted to explain the reason why I did mine.

Ciao

 

This ^^

 

Call Shell oil at 800-237-8645 and ask an engineer. In my experience, they are more than happy to talk to you and answer questions. He recommended Shell Rotella T6 for flat tappet engines.

 

I thought most cars had the oil pressure sender near the end of the oil path... On the 911 for example, its ear the cam... So the pressure at the main bearings regardless of reading is much higher than what the gauge reads...

The sender is almost never right after the oil pump, as that pressure location doesn't reflect any useful info. Ie, your bearings could be shot and you would have 100% normal readings...