Flat tappet wear, need a new oil

[kevm14]

My father-in-law has an older Chevy truck with a Chevy 292 (inline 6) that he rebuilt about 4 years ago. He put a cam a little hotter than stock in it, and I think valve springs that may have been stiffer than necessary at the RPMs he was running. He's probably put about 6000 miles on it since then and done maybe 3 oil changes. I think he ran something like Castrol GTX 10W-30 on break-in and after having a ring sealing problem (tight ring gap, no relation to oil), he switched to Supertech, probably 10W-30.

The ring problem got bad enough that he tore it apart to rebuild and when he did, he noticed some excessive cam scuffing wear from the flat tappet lifters (they are hydraulic). He estimates maybe something like 10 thousandths, based on comparing the current lift to the cam card.

After he talked to someone in the hot rod industry about this, he learned all about ZDP, API SM and all that fun stuff. My solution, if it were my project, would be to seek out a competent cam re-grinder to fix the wear problem (292 cams are very hard to come by) and have the cam lobe surfaces hardened so he can switch to roller lifters, and not worry about this anymore (and free up a few HP in the process).

But assuming he stays with flat lifters, what oil should he run? He goes have a cat (a modern, high flow variety), and though emissions is not a legal concern, it is an ethical one, so I don't know if an off-road high-ZDP oil is the right answer. What oils would do a good job for lifter-to-cam contact? One of the HDEOs for diesels like Rotella T (regular or synthetic)? How about German Castrol? Something off the shelf would be more desirable than a boutique brand.

 

[Gary Allan]

Quote:
He goes have a cat (a modern, high flow variety), and though emissions is not a legal concern, it is an ethical one, so I don't know if an off-road high-ZDP oil is the right answer.


Cats existed and had very long lives with high zinc/phos add levels. Many lived beyond the chassis to 15 years+ without failure. No ethics involved. How much mileage can possibly be put on this engine/cat combo in practical terms ..and how much does a cat refresh (if in doubt) cost compared to the work performed on the cam regrind and tear downs to date?

 

[Robenstein]

A HDEO will work fine in that application. Kendall's GT1 20w50 conventional has higher levels of zinc, but that is the only grade that does. It has around 1200ppm of zinc to protect non roller cams. There is also Valvoline's VR1 line. All are under around 4 bucks a quart.

 

[daman]

Any HDEO will do the job, pick one.

 

[d00df00d]

Originally Posted By: kevm14
But assuming he stays with flat lifters, what oil should he run? He goes have a cat (a modern, high flow variety), and though emissions is not a legal concern, it is an ethical one, so I don't know if an off-road high-ZDP oil is the right answer. What oils would do a good job for lifter-to-cam contact? One of the HDEOs for diesels like Rotella T (regular or synthetic)? How about German Castrol? Something off the shelf would be more desirable than a boutique brand.

German Castrol would be good.

As I understand, Royal Purple's oils are made with flat tappets in mind, at least to some extent. They are definitely popular with the muscle car crowd. I would consider them, too.

 

[Leo]

Agreed. Any good HDEO will do the job. No synthetic required here.

 

[d00df00d]

Not all HDEOs have elevated levels of ZDDP, though, right?

 

[kevm14]

Well I guess this is the underlying question: is ZDP content (and I don't mean more is better) the biggest factor in determining an oil's ability to protect against lifter-to-cam wear? Is the average API SM oil (especially a conventional one) really inadequate? His cam wear suggests it is. Even if an SM/GF-4 oil "should" be adequate this application certainly differs from a modern engine.

I will concede on the emissions point, as the primary concern in this application is engine longevity.

 

[Robenstein]

The local machine shop has seen a lot of cam failures on older non roller engines since the reduction. Without an additive to take the place of the lost zinc, the cams are dying and/or the lifters are dishing out.

I used to run nothing but Castrol or Pennzoil 20w50 back in the mid 90's. Now I wouldnt put it in any of my small or big block cars.

At the local wal mart they have Rotella 2.5 gallon jugs for 20 dollars. Hard to beat that.

 

[ARCOgraphite]

Jonn Deere +50 oils have high ZDDP, as do the torque guard series as does most all lawn equipment oil like briggs and stratton and MTD oils. No need for silly 20w-50 oil. Also check Marine 4 stroke oils as another cheaper source - most are API SJ spec. I'm currently running MTD OEM-737-0303 5w-30 with good results - though i do not have a VOA on the oil yet. JD also makes a break-in oil as does Joe Gibbs Racing. On the Mobil front - the M1 Racing 4T synthetic has the most zddp you can put in oil without galling and pitting issues. But thats 9 bucks a qt.

 

[ARCOgraphite]

Was the cam run in properly per the cam manufacturer (usually with light valve spring tension) and slathered with assy lube?

 

[addyguy]

Since you're in the Northeast, you will most likely be able to find Brad-Penn oils - their 'Penngrade 1 High-Performance oils' have lots of ZDDP that you need, and it comes in a 10W-30.

 

[d00df00d]

Originally Posted By: kevm14
Well I guess this is the underlying question: is ZDP content (and I don't mean more is better) the biggest factor in determining an oil's ability to protect against lifter-to-cam wear?

Not at all. It's just the most common way to get the job done.


Originally Posted By: kevm14
Is the average API SM oil (especially a conventional one) really inadequate? His cam wear suggests it is. Even if an SM/GF-4 oil "should" be adequate this application certainly differs from a modern engine.

Tough to say, just because the range of API SM oils includes everyday dinos and high-dollar synthetics.

 

[Quest]

Regardless of what sort of high ZDDP/low ZDDP oil he's gonna use in this new motor, make absolutely certain that he follows the camshaft manufacturer's direction RE: properly breaking in the camshaft.

Fail to heed this advice will land you premature/excessive cam lobe wear further down the road, regardless of how much ZDDP you have in your oil (post break-in).

Q.

 

[d00df00d]

Indeed.

 

[m37charlie]

Aim for a Zn/P level of ~1600ppm. The Supertech could have been as low as 600ppm, or even a bit lower. The GTX might have been a bit higher, maybe ~800ppm.
John Deere Plus 50 CI4+ oil (NOT their Plus 50 II CJ4 oil) is about 1550ppm. Available in 0W40, 10W30, 15W40.
Alternatively, one can add ZDDPlus or Redline Breakin Additive.
The concentrations are available, do the math very carefully.
Too much Zn/P can cause severe tappet wear (as little as 2000ppm)
Reference available to all doubters.

Charlie

 

[rclint]

I know this is a oil forum, however from my research done many of the "oil" related problems were shown by cam vendors, retailers. I myself think the blame may be with the metallurgy with the cam, spring, etc related parts. I looked around one time when researching this, and found documentation on the internet (from cam manufactures I forget which one) that inferior metal/metals were being used causing these problems, then the blame conveniently was pointed at the slightly lower ZDDP.

 

[Quest]

Originally Posted By: rclint
I know this is a oil forum, however from my research done many of the "oil" related problems were shown by cam vendors, retailers. I myself think the blame may be with the metallurgy with the cam, spring, etc related parts. I looked around one time when researching this, and found documentation on the internet (from cam manufactures I forget which one) that inferior metal/metals were being used causing these problems, then the blame conveniently was pointed at the slightly lower ZDDP.


Fundamentally agreed.

Truth of the matter is that no matter how hard we try, we simply cannot have the same engine service and break-in environment like auto manufacturers do, citing the differences between an original factory cylinderwall honing pattern and consistency, variable-load break-in procedures for all fresh-off-the-assembly engines vs rebuilt engine break-ins, etc., which plays a crucial role in determining the longevity of the engine down the service life.

Aside from metallurgy, induction hardening, quality of castings, etc. for a good quality camshaft; the other decisive factor that plays a very crucial role is the phosphate coating on the cam and how it gets broken-in during the first 10secs on the new engine block. This is the time when the cam lobes and their mating surface (rollar cam, bucket shims, hydraulic lifter buckets, etc.) experienced tremendous load wear when there's little to no additives or very little lubricant to provide the borderline surface lubrication as the coating on the cam lobe wears ......

Once the camshaft and the cam lobe+ other mating surface wear pattern is properly established, it (camshaft) takes very little ZDDP to maintain proper service life and exhibits little wear further down the road

Aftermarket is just aftermarket and rebuilders typically don't pay too much attention or they play down the importance of properly breaking in a valvetrain. That's where most of the urban myths, half-arsh truths and house-wifeys tales came into play and rebuilders typically lay casual blame to ZDDP part.

My 2c's worth.

Q.

 

[Jaymus]

Well... in this same train of thought, maybe people are pointing fingers at the engine builder(s) because it's more convenient than blaming the oil.

Always looking at this subject from both sides.

 

[aquariuscsm]

If you need some serious zinc,here`s an email I got back from Pennzoil asking about their Pennzoil GT 25W50:

I have a question about Pennzoil Racing 25W50. I`m currently using Valvoline VR1 20W50 in my 1996 Nissan 300ZX. I`ve always been a Pennzoil yellow bottle oil fan,but started using the VR1 because I`d rather have the added wear protection versus the EPA/CAFE requirements. Can Pennzoil`s Racing 25W50 be used in my car,which is my daily driver that gets driven the way a sports car`s meant to be driven? I change my oil every 3 months regardless of mileage.

Thank you for your inquiry. Yes, this formulation would be equivalent to, or better than, the Valvoline formulation which you are currently using. The Pennzoil25W-50 Racing Oil, stock # 3623, contains approximately 1800 ppm ofZDDP anti wear additives. Best Regards,Technical Service- RM