Another What Oil do u use thread

[lfalzarano]

Right decision.


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[Paul Workman]

Originally Posted by XfireZ51

Always an interesting topic. I would agree w Hans in that thread, that the seat and spring pressures our motors experience(a benefit of 4v OHC architecture) don’t reach what the LS/LT motors need to run for the in-block cam setup to breathe as well. So the need for ZDDP not as great and I think we have examples of being able to “get away with” lower ZDDP content.

Dom, You may be correct, but I'd argue that the LT5 spring/seat specs of the motor hasn't changed. So, where's the justification/evidence to suggest that lesser (ZDDP) than what was originally "spec'ed" (i.e., API SG, SH) is acceptable?

And, in the case of using cams with a modified lift and lift rate profile, isn't it reasonable to assume the lubricity of the oil would (if anything) need to be increased - certainly NOT decreased?

The wear on the LT5 lifter is insidious. Making matters worse, it isn't easy to collect lifter wear data w/o at least perhaps removing the cams to access/measure lifter wear (using a depth micrometer). Removing and re-phasing the cams means pulling the motor to do so, all to facilitate making the lifter wear assessment(s). So, w/o taking the trouble to pull the engine periodically to gauge the wear progression on the lifters, do we really want to imply reducing ZDDP with ZERO on so little (or none) comparison of wear data to go on?

You may very well be correct in saying LESS ZDDP may be OK, at least in certain circumstances (not everyone drives the same way). But, to do so would be in spite of supporting evidence and not because of it.

[ZWILD1]

On my first 91 Z I used either Red Line full synthetic or the Mobile 1 15W50 during the summer. That car I drove a bit during the winter later on in it's life and I would use a lower viscosity Mobile 1 during the winter months. On my current car I use what the previous owner used and that is Amsoil recommended by Marc Haibeck. I couldn't find it local so I went on line to Amsoil and joined their preferred customer account. It saves me a bunch on the cost. I now use their products in our cars and even my John Deere and ATV .

[XfireZ51]

Originally Posted by Paul Workman

Dom, You may be correct, but I'd argue that the LT5 spring/seat specs of the motor hasn't changed. So, where's the justification/evidence to suggest that lesser (ZDDP) than what was originally "spec'ed" (i.e., API SG, SH) is acceptable?

And, in the case of using cams with a modified lift and lift rate profile, isn't it reasonable to assume the lubricity of the oil would (if anything) need to be increased - certainly NOT decreased?

The wear on the LT5 lifter is insidious. Making matters worse, it isn't easy to collect lifter wear data w/o at least perhaps removing the cams to access/measure lifter wear (using a depth micrometer). Removing and re-phasing the cams means pulling the motor to do so, all to facilitate making the lifter wear assessment(s). So, w/o taking the trouble to pull the engine periodically to gauge the wear progression on the lifters, do we really want to imply reducing ZDDP with ZERO on so little (or none) comparison of wear data to go on?

You may very well be correct in saying LESS ZDDP may be OK, at least in certain circumstances (not everyone drives the same way). But, to do so would be in spite of supporting evidence and not because of it.

Paul,

The ZDDP in the Mobil1 15W-40 is 1200 Zinc/1300 Phosphorous. Both Pete and I have seen my cams numerous times in the recent past including last winter. Lifters and lobes look like new and they have been installed 4 years ago and have about 20k on them. The Mobil1 15W-40 is specified for race motors and flat tappet cams.
I’ll keep u posted if I have any problems.

[SBAquaLT5]

I'll throw more fuel on the fire..



What are you guys seeing for "hot" idle oil pressure? With Amsoil 10W40 at 200F Oil Temp I'm seeing 39PSI idle, and 65PSI at 2000RPM. Granted these gauges are not 100% accurate, that seems high. GM service manual says minimum oil pressure at idle should not be below 12 PSI.



I know everyone likes Haibeck's Amsoil 10W40 for ZDDP, but has anyone looked into 5W40 weight? Seems like a good compromise for quicker oil flow on cold starts. Thinking of writing Marc about that.

[Paul Workman]

Originally Posted by XfireZ51

Paul,

The ZDDP in the Mobil1 15W-40 is 1200 Zinc/1300 Phosphorous. Both Pete and I have seen my cams numerous times in the recent past including last winter. Lifters and lobes look like new and they have been installed 4 years ago and have about 20k on them. The Mobil1 15W-40 is specified for race motors and flat tappet cams.
I’ll keep u posted if I have any problems.

Yup! We're in "violent agreement" again, Dom. I wuz taking exception to implications which may have been left adrift in the statements in post #7.

Left un-checked, it seemed to me some would be left with the impression that because of the reduced spring/seat tension of the LT5 (compared to pushrod motors) that the ZDDP level could be reduced or less than the 1200/1300 ppm originally specified for the LT5.

The fact IS, some receding from the "1200/1300" spec might work for some driving conditions, e.g., those whose LT5s seldom see much track or drag strip duty, i.e., some 60% of ZR-1 drivers (according to a "who has hit the rev limiter (on their cars)" post - some years back. However, who among us is qualified to guarantee that reducing ZDDP to "X/Y" ppm is OK...OK w/o a spec of test data to support such a reduction. (Generally speaking: sometimes it is better to not pick a fight with "factory specs" , especially when it results in little more than reducing the margin for error in favor of some arbitrary and capricious but more economical "solution"...was my point: all present thread contributors excepted.)

[Karl]

I just had Blackstone labs analyize my last seasons Mobile 1 and the zinc content reads 750ppm versus their advertised 900ppm.

Although I have never had a problem with the oil and I drive my car aggressively whenever I can I am officially dropping Mobile 1 for amsoil z-rod 10w/30.

No need to worry Mobil 1 I may still use your product in my Prius....

Btw they said my engine oil analysis was great and my motor shows no wear, contaminants, or problems!

[Dynomite]

Post 3 - LT5/ZR-1 Fluids



Amsoil 10w-40 Recommendation/Analysis

Amsoil 10w-40

[Top Toy]

I started using Amsoil Z-Rod a few years ago because 1). Has high ZDDP content 2). Has extra corrosion inhibitors to protect an infrequently run motor and 3) Comes closest (10W-30) to the viscosity originally spec'd by GM for our motors. This oil is formulated specifically for flat tappet, high performance engines that may sit idle for extended periods of time. Works for me.

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[XfireZ51]

Paul,

Pete is currently “refurbing” my motor. I can tell u that after about 2 years of using the Mobil 1 10W-40 High Mileage, the cam lobes and tappets are in very good shape. No wear shown. And we know that the 10W-40 has a ZDDP spec lower than what we consider adequate for protecting our flat tappets.
These are Pete’s cam regrinds. So just a data point for the discussion.
More recently, ie last summer, I have switched to the Mobil 1 15W-50 which does have a 1200+ spec for ZDDP.