Premature cam failure, ZDDP issue??

[Taylor]

Currently a discusion on another forum im a member of.

I spent the weekend changing a f**ked cam in a friends stroked engine. Fellow is a young guy who works at the machine shop where I get my engines built - the owner asked me to help him. I get some free machining out of the deal, so I was cool with it, as the owner was busy and needed help.

Anyhow, story is:

98' NVH block, 93 HO head. KB 10:1 pistons on 4.0L rods. 12 counterweight crank. Comp 68-232-4 cam with Magnum 360 beehive springs.

The engine was properly broken in (guy works in an engine shop, so we assume this anyhow) and ran well for 1500 miles - then it dropped the #6 intake lobe out of the blue one day while cruising at highway speed.

Normally we would blame Comp and get all [censored] at them. However, this is the 6th cam in the last 3 months to fail from this shop, cams were various brands. We have done oil analysis and hardness tests on the failed cams and discovered that it isn't actually the cams that are causing the failing - it is an oil issue.

All the cams that failed are flat tappet cams in high performance engines. Apparently due to dropping zinc content in engine oils - flat tappet cam failure is becoming more and more common, especially in engines running higher lift cams and higher spring pressures. The 4.0L is of course a flat tappet engine, and a stroked 4.0L is (in my books) a performance engine.

 

[Taylor]

I have done a lot on this subject.
Start here.
http://www.lnengineering.com/oil.html

Castrol makes a Syntec oil for "older" vehicles. It is made with plenty of ZDDP.

http://www.castrol.com/castrol/gener...tentId=7032644

As do many other companies. Brad Penn, Redline, Royal Purple, Joe Gibbs.
Add Kendall 20w-50 GT-1 to the list. But only 20w-50 GT-1. The "lighter" grades do not have the addivtives.

Brad Penn 20w-50 is repackaged GT-1. Use a filter that has a anti drain back valve such as the Mobil 1. Which is also a very effective filter micron wise.

GM EOS which is forifed with ZDDP
http://www.gmpartsdirect.com/results...partnumber=EOS

1. GMSPO realigned there marketing. EOS along with many other products are now labeled AC/Delco. Still the same stuff. Only a change in the dye color.
2. Diesel is high in detergents. IMHO anything after CI is too watered down in the ZDDP. SH for conventional oils. Overall good stuff in a gas engine.
3. VR-1 is a ND oil. It also lacks many of the stabilizers and moisture inhibitors of street oil. Not the best choice for a street engine.

 

[Taylor]

I used Kohler engine oil with GM EOS in my sbc383.

Needs some zinc.

 

[Taylor]

I can guarantee it was installed with the proper assembly lube - the engine was assembled in the best engine shop I know of. High standards.

 

[Taylor]

1. Viscosity is measured by a drip standard that is set by API standards. This way a advertised weight will be consistent across the temperature range AND the various brands.

2/3. Again to meet API standards an engine oil is subjected to various load, wear, thermal etc tests. With different base stocks and additives oil can be "formulated" to meet most any standard. This is not to say that some oils are better then others, they are. But to meet an API rating an oil has to at least meet the new standard.
Guess what drives the new standard ? The manufactures of the engines to begin with. As pointed out, the primary reason for reducing ZDDP was because of cat convertor poisoning. Then factor in the fact that modern engines are running a roller cam. The roller cam allows for modified cam profiles that enhance engine performance. The list goes on........

4. Total [censored]. While I cannot disagree that the newer oils have advanced formulations. That doesn't make them right for EVERY application. Just because an oil meets a SJ API standard doesn't mean that it meets an SH standard. Each API standard has specific demands that an oil must achieve.
Take the reduction in ZDDP as an example. The old SH oil has enough ZDDP in it to keep a flat tappet cam alive. But a new SJ doesn't, does it ? Logic would dictate that SJ is better then SH. IN API OIL STANDARDS IT DOESN'T WORK THAT WAY.
Take Kendall GT-1 20w-50 as an example. While it meets SM API standards it also has a high level of ZDDP in it. So if that is the case then how did Kendall meet SM with a load of ZDDP ? Kendall formulated the oil with a base stock and additives that meets both standards.

5. Boron and chromium have been but two of the anti wear agents of late. While I will not go so far to say that there MIGHT be a new API standard that works well will flat tappet engines. We are not there yet. At this time using a ZDDP rich oil is the only way to keep our hot rod engines alive.

7. EOS is garbage ?? Did you know that Crane cam and Comp cam asm. lube is EOS repackaged ? Did our expert read the chemical make up of EOS ? If EOS is garbage then how come thousands of flat tappet engines are staying alive with the addition of EOS to the engine oil ?
Why does GM offer EOS ? As an asm lube and and engine break in lube. Why, because it has a formulation that minimizes the scuff between moving metal at extreme pressures and heats.

 

[Taylor]

Quote:
Originally Posted by Unka-Boo
Couple things that come to mind:

Is the same person installing all the "bad" cams?

Are the cams and lifters from the same manufacturer?
( I've seen cams go flat because of different hardness between cam/lifter )

Are you matching the springs to the cam?
( Seat pressure, open pressure...yada yada....it can get a little sketchy if you're using a cam from manufacturer "A" and a spring from "B"...)

You said yes to break in lube, but what about break in itself? Are they varying RPMs, or just holding say @ 2000 for 20 min?

Are the pushrods the correct length?
( Verified with an adjustable "dummy"??)
1) Yes. And has been for forty years. Builds all the rod motors worth owning where I live.

2) No. Half were cam kits, half were mismatched. We ran Rockwell hardness tests on the cratered cams - it wasn't a hardness issue.

3) It's not our first rodeo - we always run conservative springs in an effort to avoid these issues.

4) We always do 1800 RPM for 20 minutes. Then 100 miles of varying.

5) Yes, pushrods are the right length. See 1 above.

 

[Taylor]

Quote:
AERA (Engine Rebuilders Association) #TB2333 dated March 2006. "The current engine oils used by engine manufacturers in new car production are not applicable for inital flat tappet camshaft break-in. Those oils are less desirable than older formulations which have better wear additives than the current SM category oils." "There have been numerous reports of premature flat tappet camshaft failure. This has been an issue of late and not just with one brand or type of camshaft. In almost every case, the hardness or the taper of the lobe is suspected, yet most of the time that is not the problem. This growing trend is due to factors that are unrelated to camshaft manufacture or quality. Changes in today's oil products and advanced internal engine design have contributed to harsher environment for the camshaft and a potential for failure during break-in."

 

[MolaKule]

Quote:
All the cams that failed are flat tappet cams in high performance engines. Apparently due to dropping zinc content in engine oils - flat tappet cam failure is becoming more and more common, especially in engines running higher lift cams and higher spring pressures. The 4.0L is of course a flat tappet engine, and a stroked 4.0L is (in my books) a performance engine.


I am glad you said, "apparently" or maybe you should have said "alledgedly" since I am not convinced all these cam failures are due to the oil, except where the wrong viscosity or wrong API rated oil was used.

Too many variables and not enough data. I would still like to see a measurement of a new cam verses the so-called failed cam; what were the profile measurements before and after?

 

[Gary Allan]

Start adding more ZDDP and see if the incidence of failures evaporates. Hardly conclusive ..but highly suggestive.


..but ..why in the world would anyone need ultra-high spring rates on a stroked 4.0 where there is absolutely no need for it? Just what rpm range can one possibly operate it in that would require that level of tension?

If I ever get to play on my 4.0 ..it will be with the 4.2 crank ..and having the head machined for Jessel 1.7:1 rollers (maybe just getting Yella Terra)..and that's it. That's the only alteration needed to contour to the 450 Mopar factory performance cam while retaining emissions standards. The profile is almost identical ..overlap and all.

 

[Taylor]

none of this i what ive said im arguing it wasnt the oil and getting heavily flamed

 

[SHOZ]

I use the GM stuff in my Flat tappet Fords. 1 oz per oil change.

 

[Taylor]

u want ZDDP use crane cams superlube, i posted a VOA a while back. but back on topic...

 

[Taylor]

I don't - but I can tell you that it was "barely" worn. A casual glance would not have picked it out, and the lifter surface was not worn at all.

 

[Taylor]

We actually run about 30% less spring rate than Comp specifies for the 68-232-4 cam. We build FA and high compression 4.0L engines - higher clamping force is necessary.

 

[Leo]

Originally Posted By: Taylor

Take Kendall GT-1 20w-50 as an example. While it meets SM API standards it also has a high level of ZDDP in it. So if that is the case then how did Kendall meet SM with a load of ZDDP ? Kendall formulated the oil with a base stock and additives that meets both standards.


I believe the ZDDP limits imposed on API SM formulations are only restricted certain viscosity ranges, no? I think there are no restrictions on 40wts and above...

 

[Taylor]

I know there are differences for different weights, not sure about 40wts and above

 

[Colt45ws]

15W40 or 5W40 synthetic HDEO? If it fails with that stuff the problem is somewhere else.

 

[Taylor]

i think the bent pushrod proves this...

 

[Taylor]

I had just assumed that when the lobe wore to a certain point, the pushrod was able to jump out of place and be damaged.

It IS possible that proper break-in was skipped. I am sure the first 20 minutes was done right, then proper oil added with additive (I was there) - BUT the next 500 miles he was on his own.

We dumbed down the springs specified for the particular cam as well.

Maybe it was Chinese parts, but Comp is generally good stuff.

The stuck valve theory might be possible, except we always open up the 4.0L guides to allow for thermal expansion beyond factory spec.

 

[Taylor]

ZDDP is a cheap antiwear additive used to save parts from an inferior base stock. A good oil can be low ZDDP an dlow SAPS and still perform well in service (not for break-in, though).... You're right, Rotella and all "diesel" oils have gone to low ZDDP for EPA07 diesel needs. That's the API CJ4 stuff.

Jeeps are the only "modern" engines using flat tappets, so we have unique needs. Rather than play chemist, find and use oils that are actually tested for flat tappet engine wear. That's ONLY ACEA now. ACEA A3 is a good choice.

Even still, that's not enough for break-in, and there needs to be a lot of antiwear additives present on that break-in and a bigh windage cloud, since lobes are splash lubricated. That means RPM is your friend, but not to the point of valve float.