Flat Tappets: Observed Failures

[delirious]

Originally Posted By: ka9mnx
Originally Posted By: JeepWJ19
My flat tappet 4.0 has had some pretty loud lifter tick on cold starts regardless of ambient temperature. It's been like this for the past 60k miles I've had it. If it was a failure attributed to SN oils, I'd have a hard time believing it'd still be running to this day. JMO


Since you are OK with Mobil 1 I would try the 10w30 HM Mobil 1. I think that may quiet down the 4.0 It has worked wonders on my 4.9 "tractor motor"! Anyways, I think your 4.0 calls for 10w30 and it would be fine in your Winters. I know some are using 10w-40 but I wouldn't do that.


I'm already using Mobil 1 High Mileage. Nothing quiets the loud lifter tick. Have tried Pennzoil Conventional and Pennzoil High Mileage 5w30 to 10w40. Have tried Rotella 5w40, have tried Mobil 1 High Mileage 5w30 to 10w40 and it just keeps happening. I've gotten used to it lol.

 

[thescreensavers]

My 4.0s valvtrain in my XJ is very quiet..At first I was using T5 but that became harder to find so I switch to Maxlife and I literally have zero noise cold or hot makes no difference.

 

[caprice_2nv]

If a 1983 Chevy 305 (from the era of soft cams) has gone 230k miles, the cam is not likely to be a problem no matter what oil I use correct? I have been using EOS, or other zddp additives for the 8 years I've had it as extra insurance but I'm thinking it's not needed.

My other engine is a 76 Oldsmobile 350 and Oldsmobile was not known for cam failures like Chevy was.

 

[jeepman3071]

I've run Pennzoil conventional in my Jeep 4.0 for some time now, and have returned used oil analysis with single digit iron wear numbers.

I've run oils with higher ZDDP including Quaker State Defy, Rotella, Mobil 1 High Mileage, etc. All of them ran noticeably louder and the Rotella caused a cold start tick.

 

[John_Dude]

I've put 60k miles (now at 160k) on my escort zx2, which has the zetec DOHC with flat non-hydraulic tappets. I've used API sn oils the whole 60k and the engine seems fine, buckets and lobes don't look abnormally worn. For the last 25k miles I've run Castrol magnatec, which has polarized esters which coat the valve train for cold starts. These engines are notoriously noisy on cold starts, with magnatec I get no valve train rattle on cold starts. I can't adjust the valve clearances because it uses solid buckets, so I'm hoping the magnatec slows down valve train wear. I would think the lack of cold start noise indicates less wear occuring.

It had cold start rattle from 100k miles, so did my other zx2's with similar mileage. Too bad they stopped using shims after the first model year.

 

[riklyn]

I had a lobe failure on my 4.0 Jeep TJ @ approx 50,000 miles. Bought it at 40,000 and don't know what was in it before, but I was using synthetic 10w30 when failure occurred. I use Rotella now. Don't know if it makes a difference, but can't hurt.

For what it's worth, I worked for and retired from Chrysler and owned many 4.0 vehicles, including a 2000 GC that had close to 300,00 miles on it when it left my family. All on conventional oils with a lot of wal mart cheap oil changes and never an issue.

 

[turtlevette]

Originally Posted By: OVERKILL
Originally Posted By: turtlevette
Now. I wonder. How much sliding do roller lifters do. There has to be some.

How much sliding do the needle bearings within the roller lifter do? I would think ep and anti wear additives are still important in a roller cam system.



AW? Sure, EP? I don't think so, since most oils aren't dosed like a gear lube. I've handled a good number of high mileage roller lifters and none of them have had any real wear in the roller area, nor did they have play that would indicate wear in the needles. These were OEM Ford roller lifters from SBF's for the most part run on typical PCMO's.

I think you'd be more likely to see sliding in valvetrains with marginal spring pressure where you are near-float and the roller skids across the lobe face rather than rolling, which it would otherwise do with sufficient pressure on it.


I wonder how much study has been done on roller valve trains. I would think they would Normally be in hydrodynamic mode so you have no metal to metal contact. You have the fluid friction which would turn the roller, but I seriously doubt the speed is equal to the cam speed.

I'm going to disagree and say high performance valve trains with lots of spring pressure would benefit from ep type additives which would be needed on the ramp when you lose hydrodynamic lubrication.

 

[OVERKILL]

Originally Posted By: turtlevette
Originally Posted By: OVERKILL
Originally Posted By: turtlevette
Now. I wonder. How much sliding do roller lifters do. There has to be some.

How much sliding do the needle bearings within the roller lifter do? I would think ep and anti wear additives are still important in a roller cam system.



AW? Sure, EP? I don't think so, since most oils aren't dosed like a gear lube. I've handled a good number of high mileage roller lifters and none of them have had any real wear in the roller area, nor did they have play that would indicate wear in the needles. These were OEM Ford roller lifters from SBF's for the most part run on typical PCMO's.

I think you'd be more likely to see sliding in valvetrains with marginal spring pressure where you are near-float and the roller skids across the lobe face rather than rolling, which it would otherwise do with sufficient pressure on it.


I wonder how much study has been done on roller valve trains. I would think they would Normally be in hydrodynamic mode so you have no metal to metal contact. You have the fluid friction which would turn the roller, but I seriously doubt the speed is equal to the cam speed.

I'm going to disagree and say high performance valve trains with lots of spring pressure would benefit from ep type additives which would be needed on the ramp when you lose hydrodynamic lubrication.



You are welcome to disagree, I'm simply stating my experience with what is being discussed. From what I've seen in the SBF scene, back when I was more actively engaged, oil was not a concern in camshaft/lifter wear with roller engines. It was far more about keeping the bearings separated and so the focus was more on necessary viscosity. I don't remember any of the guys with high revving high spring pressure roller setups ever being worried, nor do I recall any failures that were of that nature. You'd see the odd dogbone failure with the factory setup and then the lifter going sideways and wiping itself and the lobe out, and we saw some of the less expensive rollers fail with the pin coming out of them. But the OEM Ford lifters and the high quality aftermarket link-bar offerings, this was never an issue.

I'm sure there was quite a bit of study work done on the development of roller valve trains, most of it in the 70's and 80's when they were working on making them mainstream.

If there was a need for EP additives in PCMO's to protect roller valvetrains, I'm sure there would be evidence demonstrating that. From what I've seen, there isn't, and the primary draw of roller valvetrains in high performance builds is the ability to run a more aggressive lobe profile while maintaining streetability and durability. I've built a few reasonably high revving 302's with both stock and link-bar roller lifters with the necessary springs to support 7K operation and it is the springs that give out and need to be replaced when these are used as street mills. Tear-down has never shown camshaft or lifter wear issues when high quality parts are used.

I simply don't see evidence of the scenario you are alluding to being benefited by the inclusion of EP additives actually existing. That may be because the AW additives like ZDDP are sufficient at that interface and thus, EP additives, like what one would see in a gear lube or grease, are simply unnecessary as the forces experienced, even with elevated spring pressures on the narrow roller/lobe interface, are not sufficient to warrant it

 

[Ducked]

Originally Posted By: ka9mnx
Originally Posted By: BrocLuno
Originally Posted By: Ducked
Originally Posted By: ka9mnx


Most cam failures in the 90's was later discovered to be with inferior camshaft and lifter materials and hardening. Present day failures are attributed to import lifters.


Ah, So if that's true, IOW there were failures, and there still are.

Doesn't entirely fit the "non-issue" line you came in with,


OK, cam and lifter failures are two different things. Obviously they relate to each other, but they come from different causes.

Most cam failures are caused by incorrect heat treating of wrong alloy selection and then poor surface hardening. The big failures (by numbers) were/are GM and Comp. Both were attributed to soft cores.

Lifters failures are related to one of three factors. Lifter face hardness, lifter face radial geometry, and poor bore fit. So something like the Delphi or Johnson lifters were well made and held to very tight tolerances. Then along came the off-shore copies ...

So the Aussies had/have to buy OEM lifters from the USA when GM and Ford were still building cars down under. Lifters were an expensive import item for the hot-rod community. So they got good at regrinding the faces and reusing them. Same quality metal throughout. They claim to be able to get three re-grinds and are still selling known good USA lifters as re-grinds around the world with decent results.

A cam will fail by wearing the nose off, usually through spalling. A lifter will fail by cupping or failing to spin. If a lifter skids (not spinning) it will die quickly. It's prolly dead in 100 Revolutions of the cam lobe, but if it starts spinning again, it'll limp along for a while. But the death knell is set.

The way you know which is which is by looking at the carnage. If the cam is flattened, but the lifter is mostly intact, you have a soft core /hardness issue. If the lifter is cupped or oddly worn, but the cam lobe looks about right, you have a bad lifter.

OEM spring pressures, even say Z-28 springs will not really stress a cam/lifter combo. But you start getting past say .550~.580 lift on a BBC (fairly mild hot cam) and say 350#s over the nose to control valve float above 5,000 RPM and you are goinna stress the materials. If they are not right, it'll die. >1,000 PPM ZDDP is mandatory as the spring pressures go up. Above these numbers and things just go sideways quicker, if not all correct.

Comp lost a lot of cam/lifter sets and did everything they could to blame the end user. Howards and Crower have had very, very few failures. Howard's offers a 5-year warranty if you buy their whole kit and follow instructions. Comp wouldn't do that if you paid them ...

Ford and Chrysler have had few cam/lifters failures running even their most aggressive factory grinds. Practically none of their daily driver combos have failed. And this is with average Joe doing spotty maintenance, etc. GM has not been so fortunate ...

So we need to know exactly what scenario you are interested in? I still will not buy much from Comp (mostly just rockers) and their other brands like Lunati. Howards or Crower - no question about their reliability as far as I'm concerned.

Oil pressure does not fix this. 60 PSI at 6,500 is plenty, more than enough. Bad oil and bad metallurgy will get you every time. It's up to the builder to get things right. Break-in right. Pop the valve covers and make sure every push rod is spinning as it should after initial fire-up. No start stop, or herky jerky allowed. It's either right, or shut it down and fix it ...

Cam on shim/bucket is a type of flat tappet. But not the traditional push-rod configuration that had all the issues ... OHC engines have different lube strategies and lighter valve trains, so they have milder spring pressures (no need to control as much inertia). Push-rod engines have cam lobes lubed by sling oil off the crank. Hit and miss at best ...



Thanks BrocLuno. I was going to reply to Ducked that it wasn't an oil problem but you said it all!


Yes, thanks for the extensive answer, which I'll re-read more carefully when I have time.

However, "wasn't an oil problem" doesn't seem to exclude the possibility that an optimal oil selection could to some extent mitigate deficiencies in metallurgy or design.

 

[Garak]

I've had several failures, all on SJ and older oils.

 

[Building3]

It seems that no one has had a real documented flat tappet/cam failure on an older engine either rebuilt or original when using the newer SM and SM oils for regular oil changes. So I guess the major oil companies are correct, SN oils are backward compatible and there's no reason to look for unique or boutique oils to solve a problem that does not exist.

 

[emmett442]

I had a cam failure on my '99 Eldorado with the 4.6 Northstar.


Last year of the flat tappet setup. 2000 MY went roller.

 

[FCD]

Originally Posted By: Building3
It seems that no one has had a real documented flat tappet/cam failure on an older engine either rebuilt or original when using the newer SM and SM oils for regular oil changes. So I guess the major oil companies are correct, SN oils are backward compatible and there's no reason to look for unique or boutique oils to solve a problem that does not exist.

Wrong

 

[Building3]

emmitt442: how many miles on your Cadillac and what oil did you use? Did it happen after SM/SN was introduced?

 

[Building3]

FordCapriDriver: So you have examples to share with type of engine, miles and oil used? This is the purpose of this post.

 

[BrocLuno]

AS I said earlier, there are reasons for FT cam/lifter failures. By being careful on parts selection, I can say I have never had a cam/lifter failure. But I have had friends that have had one go away. Chevrolet every time. One was a lifter failure (cupped), one was a cam failure (flat lobe). Both within 20,000 miles of engine build. And they were both running Valvoline VR1 which is stout oil and pre SN.

However, they were running aftermarket cams, springs, lifters, etc. (Comp & Lunati). Oil can kill a motor. But usually not a name brand well respected oil like M1 or Chevron Supreme, etc.

 

[Garak]

Originally Posted By: Building3
It seems that no one has had a real documented flat tappet/cam failure on an older engine either rebuilt or original when using the newer SM and SM oils for regular oil changes.

We've certainly heard anecdotes with some high pressure applications. But, the guys running an ordinary, low output flat tappet application don't exactly need to seek out a racing oil, to say the least. As I'm sure BrocLuno can confirm, a proper break in even on a lower output application after a rebuild can save a lot of grief down the road with lower phosphorus oils.

 

[Ducked]

Originally Posted By: Building3
It seems that no one has had a real documented flat tappet/cam failure on an older engine either rebuilt or original when using the newer SM and SM oils for regular oil changes. So I guess the major oil companies are correct, SN oils are backward compatible and there's no reason to look for unique or boutique oils to solve a problem that does not exist.


How many people who run flat tappet engines for significant mileages on new oils do you think you reached with this thread?

I'd suggest not many, so your sample size is probably too low to draw any conclusion.

I run a flat tappet engine but I can still get SJ oil and I don't do significant mileages. When I got the car it had a lot of metal in the oil.

I can't draw any conclusion either.

 

[Shannow]

Originally Posted By: Ducked
Originally Posted By: Building3
It seems that no one has had a real documented flat tappet/cam failure on an older engine either rebuilt or original when using the newer SM and SM oils for regular oil changes. So I guess the major oil companies are correct, SN oils are backward compatible and there's no reason to look for unique or boutique oils to solve a problem that does not exist.


How many people who run flat tappet engines for significant mileages on new oils do you think you reached with this thread?


I've lost a cam and lifters on "modern" oil back in the day...Mobil 1 15W50 in 1994, and seen a bunch of others in my then circle of rev-heads.

Limiting it to SN...nope, not me.

 

[Garak]

Originally Posted By: Ducked
I'd suggest not many, so your sample size is probably too low to draw any conclusion.

I'd definitely agree with that. Of course, even if we did have a load of people complaining that SN/GF-5 cost them some cam lobes, we never know if that's really the case. Substandard parts? Improper break in? Coincidence? Or, really due to the lower phosphorus?