Article on cam failures in Car Craft

[ThikStik]

I hope this hasnt already been posted...anyway, its in March CC in the "Whats Your Problem" tech section. It may hold the answer as to why so many of us and other brands engines are wiping lobes. I personally have never seen it happen so much.
In the article, a guy wrote in about a wiped cam after 20k miles on his 302 Ford. The assembly was done by a good builder. Comp/Crane actually admits that something is going on out there. They think that the reduction of zinc in oils is the cause. It is being ruduced because OEM's dont want it in the crankcase where it is fouling o2sensors and cats. I also bet they dont care now because cars have roller cams now. Anyway, it seems like the cam manufacturers are aware of the problem, but they stopped short of recommending a certain oil. A lube ingineer from Quaker state recommends using race oil.
IMO we are seeing durability , not break in failures. So many are getting 5-20k miles before a failure. Not a quicker failure that would indicate bad break ins. And I know of alot of other brands that guys are losing cams on. I never lost a cam before my GN, and treat it better than all my Pontiacs. My first car was a 72 Pontiac Safari with a 400 and 92k miles that never had had an oil change. I told my Dad not to buy it. I maintained it for 50k miles and not 1 lobe failed. Yes they were worn, but never wiped. Somn is up guys!
I also know the the EPA is on the move to remove phosphors from oil...that can only bode bad for flat tappets.

Any vendor wanna make money on a flat tappet additive?

 

[ronbuick]

You need to stay away from oils that have the starburst symbol on them, that would be 5-20, 5-30 and 10-30 oils, use imho 5-40, 15-40 etc. type oils

Ron

 

[Ormand]

You need to stay away from oils that have the starburst symbol on them

That would be running against the manufacturers recommendations- GM, along with other manufacturers, has tested this oil and found it to provide better wear protection. Here's what GM says:
"All GM gasoline vehicles benefit from using Starburst engine oils over non-Starburst oils"
The oil standard was developed by the US and Japanese companies working together,not just GM. The starburst signifies that the oil complys with the "International Lubrication Standardization and Approval Committee", and is preferred by the manufactures, both here and in Japan. (Don't know what happened to the Europeans)

 

[ronbuick]

When was that article published??

Ron

 

[ThikStik]

It was/is in latest (march) Car Craft.

 

[Ed Valvo]

Racing oils do have a lot more zinc and zinc does affect 02 sensors. Diesel oils have a lot of zinc as does racing oils to prevent metal to metal contact. Acts like a cushion. Problem with racing oils, there is less detergent to keep the engine clean.

 

[QUIP'6']

anybody ever try lucas oils they cling to metal and stays there

 

[VadersV6]

A little moly should help. Get Royal Purple. I used it in my cobra for 5 years, and beat the ever loving **** out of it, even when the engine was really cold. Not the slightests bit of damage...even after having 600hp and a blower for 5 months. After 8-10,000 miles when I would change it, the oil still looked clean. Seems like its less prone to burn. Yes, oil does burn. Ask anyone from Kuwait :smile:

 

[GN87Mike]

I heard last year that the oil companies were reducing the EP additives to help the catalytic converters starting with the API-SL oils if I remember correctly. I started mixing (2) quarts Mobile 1 10-40 V-Twin 4 cycle motor cycle oil with the remainder 5-30 Mobile 1 at oil changes. The motor cycle oils still have the zinc because they don't have the issue with converters. The recommendation I believe came from a Mobile 1 engineer. I also wonder if you could add some GM EOS and gain the zinc also.

Mike

 

[Marc87GN]

This is one persons opinion and unless many other oil companies come up with the similar findings, it remains just that. I can't take credit for this comment made by Steve on Turbobuicks, but I agree with it. Why is it that all of these failures are happening in engines that had machine work? I think we would be foolish to think that all machinists are created equal and know all of the nuances of every particular engine.

If it was the oil, I believe we would have seen this occurring in engines from the factory and that hasn't been the case. He said a good builder built it. That doesn't mean it was machined perfectly for what went in it. I have a hard time believe that all machinists have the expertise to machine any particular block properly for every aftermarket part or application. I believe it's more hit or miss and when you look at the number of misses in aggregate, it appears ugly. Like was mentioned on the other board, I would blame machinists and/or aftermarket part matching before I blamed the oil. I would like to see how many bone stock engines have wiped cams vs machined blocks with aftermarket cams using the available oils. I'm new to GNs, but I'm far from new to working on cars, I lived mustangs for years and I didn't hear of thrust bearing failures or wiped cams until I came to the TR community. This is just my opinion.

 

[chevyII]

How can a machinist do something wrong to a block that would wipe a cam, let alone after 8-10,000 miles? The cam is lubricated by the rods if they are put in backwards it wont make it around the block. I would pay money to see a cam wipe after that many miles that was caused by machining. Only other thing could be the valve springs but there usually bought as a package.

 

[Marc87GN]

How can a machinist do something wrong to a block that would wipe a cam, let alone after 8-10,000 miles? The cam is lubricated by the rods if they are put in backwards it wont make it around the block. I would pay money to see a cam wipe after that many miles that was caused by machining. Only other thing could be the valve springs but there usually bought as a package.

I apologize, the comments were related to the thrust beaing failures. That was what we were discussing related to machining. My mistake. It's been a long day. It just seems odd that factory engines go on for well over 100K miles when properly maintained, but aftermarket cam setups die an early death after building. How can it be related to oils that have been used for years in factory cars with high mileage and still no wiped cams. It said that the engine was built and then the cam wiped.

 

[QUIP'6']

This is one persons opinion and unless many other oil companies come up with the similar findings, it remains just that. I can't take credit for this comment made by Steve on Turbobuicks, but I agree with it. Why is it that all of these failures are happening in engines that had machine work? I think we would be foolish to think that all machinists are created equal and know all of the nuances of every particular engine.

If it was the oil, I believe we would have seen this occurring in engines from the factory and that hasn't been the case. He said a good builder built it. That doesn't mean it was machined perfectly for what went in it. I have a hard time believe that all machinists have the expertise to machine any particular block properly for every aftermarket part or application. I believe it's more hit or miss and when you look at the number of misses in aggregate, it appears ugly. Like was mentioned on the other board, I would blame machinists and/or aftermarket part matching before I blamed the oil. I would like to see how many bone stock engines have wiped cams vs machined blocks with aftermarket cams using the available oils. I'm new to GNs, but I'm far from new to working on cars, I lived mustangs for years and I didn't hear of thrust bearing failures or wiped cams until I came to the TR community. This is just my opinion.

could it be that the factory motors are already broken in and the cams are tempered. these motors are 18yrs old maybe these rebuilt motors dont last because the oil is breaking them down some people are getting 10 to 30,000 miles on after market cams. that could equal 65,000 to 150,000 before the change in oil properties. some people are stating that there factory cams are wiping out 70,80,90 and over 100,000 could this be from people buying cheap oil?

 

[Marc87GN]

could it be that the factory motors are already broken in and the cams are tempered. these motors are 18yrs old maybe these rebuilt motors dont last because the oil is breaking them down some people are getting 10 to 30,000 miles on after market cams. that could equal 65,000 to 150,000 before the change in oil properties. some people are stating that there factory cams are wiping out 70,80,90 and over 100,000 could this be from people buying cheap oil?

I'm sure we could all bang our heads on the numerous number of factors. could be the way the car is maintained, driven, oil, etc or the combination. Usually when we are building engines and adding aftermarket cams, it is not to go slower or make less power. This additional abuse could be adding to the short life span. It could be something simple, like you said, cheap all .

 

[WHEEZER]

Most of the wiping on our ars occur on the # 3 exhaust lobe. The lifter is not centered perfectly on the cam lobe due to design. To *help* correct this flaw engineers put a bit of reverse taper on that lobe to help spin the lifter in the bore, after all, if the lifter cannot spin there is a "pounding" on the lobe resulting in damage. The only cam other than GM OE that has the correct reverse taper on that particular lobe is made by Erson. Many make the mistake of using a spring with too high a pressure also as previously mentioned.Correct valve train geomentry during assembly is a must on our engines. Some people have been known to use "tired" springs for break-in then later install the right ones. Correct pre-load, along with good common sense break-in procedures will help with less wipeage and longer bumpstick life. When doing a re-build go ahead and pony up for a roller and be done with it....I will the next time.

 

[Jerryl]

See link in sig.

 

[WHEEZER]

See link in sig.

Good thread.

 

[VadersV6]

Wipeouts arent restricted to the #3 lobe. Its the most common, but not all the time. I made the point of proper hardening and tempering some time back. If there is the slightest difference of hardness between the cam and the lifter, things will go wrong. Of course there are/used to be additives in the oil to buffer these issues, but if the tempering was done properly, you would need the additives. Same goes for valve seats. You used to need lead to keep the valve seats and valves from cracking, but after coming up with seats which had the right hardness/temper, lead was no longer needed. Motors arent wiping from the factory because they have roller cams and ultra high tolerances/extremely clean and climate controlled assembly rooms and machine shops these days. Plus metallurgy has come a LONGGGG way since 1987. Most of the aftermarket cams arent made with much of a QC program in mind.
What I dont get, is why they dont just make the lobe offset when they make the cam?..cause they're making them from off the shelf cores and they dont want to have to bother with making new molds.

 

[Bens87tr]

If it was the oil, I believe we would have seen this occurring in engines from the factory and that hasn't been the case.

Mark,
I think this may be one of the points being brought up. The oil has changed . Lower zinc / more wear, but better emissions ??

 

[VadersV6]

Like I said above, I would give this a try. I beat the hell out of that car, and the oil looked almost new when I'd drain it 10,000 miles later. My cousin uses it in his 5.0 and he noticed the same thing. I just read this page on their site, and they talk about royal purple's ability to resist oil oxidation..I saw it first hand. Also look at the film strength numbers and how it micro-polished surfaces...which I think probably has more to do with the moly filling the nooks and crannies of the surface.

http://www.royalpurple.com/techi/whyrpi.html