Engine oil (for european cars)

[spork2367]

Originally Posted by grahambehan

Thanks for your input

Since contact pressure is the main driving force in terms of film shear and therefore wear, it is very iimportant.

It's important, but even if the film shear strength isn't exceeded, the engine still experiences wear. This isn't a question of immediate engine failure, it's about long term wear.

The LT5 has some advantages with respect to retention of lubrication at star up since it has an iron to iron contact at the cam to tappet interface.

You would be surprised at the amount of oil retention at this area even after years of standing idle.

I've torn apart dozens of old junkyard engines, including several LT5's that sat on pallets for years. So I'm pretty aware of how much oil is retained and where. The fact is, while that provides protection against oxidation, it provides very little protection against scuffing that occurs prior to full oil pressure/flow. That is one of the primary reasons zddp, zdtp, and molybdenum were added to engine oil.

If the oil film is broken down at a bearing interface it is due to poor design or operating outside design parameters, so I understand placing as many band aid as possible.

There are dozens of real world conditions that lead to a breakdown of the hydrodynamic load capacity of an engine oiling system. Cold starts, excessively cold engine oil, imperfections (within spec) of cam grinds, imperfections in engine bearings, contaminates in engine oil, short term oil starvation due to g-forces, to name a few. Obviously we would like to make the oiling system as robust as possible. Especially for a vehicle that has limited replacement parts. High zddp oil is much cheaper than a set of cams.

The original question was pertaining to the use of a certain oil in a stock LT5 with 25 k miles, in the context of the question the answer is yes.

In that sense, he could use Italian walmart oil and his engine isn't going to fail due to oil

Now if we wish to discuss modified engines, extreme use or other extenuating circumstances, then the answer may be different.

At the end of day there are many opinions, all I have is facts having evaluated and reported on most of the lt5 engines following many very arduous durability tests that led us to release for production in 1990 and 1993 MY.

Graham

I'm in no way questioning your knowledge of the LT5. You've likely forgotten more about the LT5 than I've ever known/will know.

That being said, I work for a aircraft piston engine manufacturer that has produced flat tappet engines for 90 years. I manage quality, including our reliability engineer. There is a reason we recommend zddp additive for every engine we produce. There is a reason we use molybdenum assembly lube when building engines. There is a reason we spent millions of dollars perfecting DLC coating on our lifter faces. Engines wear regardless of whether design parameters are exceeded. They wear regardless of the performance level of the engine. We have a lab that exceeds that of most tier one automotive manufacturing facilities. We have done our due diligence on cam/tappet wear.

The fact is, the engine oil specified for the LT5 that was produced after 1996 has less zddp than the engine oil produced prior to that. Will an LT5 run with lower zddp content oil fail immediately...no. Will it fail after 200,000 miles...no. (at least not due to oil). But all else being equal, an engine that has been run with high zddp oil, over time, will show measurably less wear than one run with low zddp oil. That is based on 90 years of reliability data, not my opinion as a shade tree mechanic.

[Ccmano]

Wait... wait... I need more
H

[grahambehan]

Thanks again for your input.
So yes we agree that an lt5 is capable of 200k miles plus.
Yes Walmart does have good oil, that's were I get Mobil 1 from too.

So as we developed the Lt5 we did see many failures of virtually every major part of the engine, this resulted in material, design and manufacturing changes, as happens in most development programs.

With the exception of cold start, although the are various strategies for that, I would suggest that the balance of your wear comments are design and manufacturing issues, eg cam irregularities even though within tolerance.

DLC is a great aid, although sometimes a little finicky to perfect, I spent a fair amount of time with Argonne Labs back in the day doing just that.

I am in absolute agreement with you some mechanisms within some engines under certain operating conditions not only benefit from, but also need heavy amounts of additives.

Although having examined/measured lots of LT5 engines following 200K miles and other durability tests I will stand by my original statement.

Btw I have always found all engine designs interesting, given there differing design criteria, depending on application, also their longevity of use.

Graham.

[Dynomite]

Originally Posted by grahambehan

...........Although having examined/measured lots of LT5 engines following 200K miles and other durability tests I will stand by my original statement.

Graham.

I assume your examinations included the Chain Guides/Facings........
At 200K miles inspections, what is your assessment of the durability of Chain Guide Facings?

I know this may depend on the oil used and oil change mileage....Lets not debate that for the moment
What were the engine oils used and what was the oil change mileage (in general).
I am assuming for a well maintained LT5 it is easily a 200K mile engine......

Thank you for your very informative discussions

And thank you spork2367 for your technical Analysis

[Paul Workman]

Originally Posted by spork2367

I'm in no way questioning your knowledge of the LT5. You've likely forgotten more about the LT5 than I've ever known/will know.

That being said, I work for a aircraft piston engine manufacturer that has produced flat tappet engines for 90 years. I manage quality, including our reliability engineer. There is a reason we recommend zddp additive for every engine we produce. There is a reason we use molybdenum assembly lube when building engines. There is a reason we spent millions of dollars perfecting DLC coating on our lifter faces. Engines wear regardless of whether design parameters are exceeded. They wear regardless of the performance level of the engine. We have a lab that exceeds that of most tier one automotive manufacturing facilities. We have done our due diligence on cam/tappet wear.

The fact is, the engine oil specified for the LT5 that was produced after 1996 has less zddp than the engine oil produced prior to that. Will an LT5 run with lower zddp content oil fail immediately...no. Will it fail after 200,000 miles...no. (at least not due to oil). But all else being equal, an engine that has been run with high zddp oil, over time, will show measurably less wear than one run with low zddp oil. That is based on 90 years of reliability data, not my opinion as a shade tree mechanic.

Cut n pasted this in my ZR-1 LUBRICATION file!

[Dynomite]

Originally Posted by Paul Workman

Cut n pasted this in my ZR-1 LUBRICATION file!

The Discussion was very Credible from all participants and is now in Post 6 of "Solutions" The Importance of ZDDP Debate under ENGINE LUBRICATION SYSTEM

[1977CamaroZ28]

Hello to everybody!

I can't put more technical information about the best LT5 oil, but I think I can help Max76 with the special problems to find good oils in Europe for our beloved ZR-1's.

Here in Spain, we have a specialists in ZR-1 with a big repair shop, members of ZR-1 Net Registry too. They recommended me to use Mobil 1 5W30 or 5W50 depending on the way you use the car. Normal/Tourist use (5W30) or hard use including track days or hard mountain/highway drive (5W50).

Since 2.014 I'm using Mobil 1 5W50 with a very low oil consumption and I'm very confident on it. I use to drive 4.000 kilometers (2500 miles) per year and I change the oil every 18 months and the oil comes so clear similar to new.

My Zr-1 has 79.000 kilometers (49.000 miles).

All the best from Spain to all the ZR-1 community!!

Marcos Gil.
1.990 ZR-1
#2342#

[grahambehan]

Originally Posted by Dynomite

I assume your examinations included the Chain Guides/Facings........
At 200K miles inspections, what is your assessment of the durability of Chain Guide Facings?

I know this may depend on the oil used and oil change mileage....Lets not debate that for the moment
What were the engine oils used and what was the oil change mileage (in general).
I am assuming for a well maintained LT5 it is easily a 200K mile engine......

Thank you for your very informative discussions

And thank you spork2367 for your technical Analysis

Sorry for the delay in answering this, had stuff to do today, plus, since I am not one for generalizing or conjecture, I had to find my Franklin planner from 89 thru 91.
I may not answer the questions in order, but here we go.

At the end of both the 150k, 200k, and 400 hour durability test they were, quite frankly surprisingly good. The 200 hour test engines however showed deeper wear patterns, but were still serviceable.

Early/ 90 my sign off testing was done on 10-30 sg mineral based oil and the latter on 5-30sh M1.
Now oil change intervals on the cars were 5k, although oil was added prior to changes, after all they were LT5's.

As to the dyno engines, I have some notes that say 20 hours of Corp durability, but I need to find more info on that re the later engines to give a definitive answer.

I have included some images, which show higher wear in terms of measured groove depth and surface discoloration than the tests I have commented on and one image of something different.

As always ask any questions and I will endeavor to answer them

Graham

[max76]

Originally Posted by 1977CamaroZ28

Hello to everybody!

I can't put more technical information about the best LT5 oil, but I think I can help Max76 with the special problems to find good oils in Europe for our beloved ZR-1's.

Here in Spain, we have a specialists in ZR-1 with a big repair shop, members of ZR-1 Net Registry too. They recommended me to use Mobil 1 5W30 or 5W50 depending on the way you use the car. Normal/Tourist use (5W30) or hard use including track days or hard mountain/highway drive (5W50).

Since 2.014 I'm using Mobil 1 5W50 with a very low oil consumption and I'm very confident on it. I use to drive 4.000 kilometers (2500 miles) per year and I change the oil every 18 months and the oil comes so clear similar to new.

My Zr-1 has 79.000 kilometers (49.000 miles).

All the best from Spain to all the ZR-1 community!!

Marcos Gil.
1.990 ZR-1
#2342#

Hi 1977CamaroZ28,
yes...i know, i can use the mobi1 5w30...but there's also an other oil available in europe that i think it's better than mobil, it's the Liqui Moly MoS2 10w40...Now i must decide what to do, use Liqui Moly oil or use Mobil1 with add the ceramic power liquid anti friction treatment...
I ues the car like turist...old turist!!!! :-) :-)