Wiping cam lobes help.

[turbowrenchhead]

I had my first schneider cam warrentied. Now after only 500 miles or so the lobes are going again. I'm running 10w30 Quaker State. The spring seat pressure is at 90 #. I dont know what the h*ll else I can do to keep it from happeing

 

[NASSTY]

Seems like some of these LC2s just reject flat tappet cams,some have good luck with them.But I've seen quite a few that didn't,like mine.I've got a motor w/6k miles and the cam has gone south. My 85 is down for this year.I'm building a garage right now so I won't have the cash for a roller cam for a while.Maybe this winter.I'm not gonna waste my time with another flat tappet. It's not so bad I still have a GN to drive.

 

[Two Lane]

LC2s left the factory with flat tappet hydraulic cams that run forever.

So why do so many aftermarket flat tappet hydraulic cams from high-quality manufacturers using quality components fail?

Somewhat illogical, isn't it?

Is it the cams, or installation errors?
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Got a nice cam ready to go in...AFTER it's been cryo'd AND coated with a lubricant film process from a professional coatings shop.

That's how "spooked" I am about the dozens & dozens of wiped cams reported here on the Board! And even that may not be enough!

Losing a motor due to upgrading a cam would be a nightmare...but evidently very common with these motors!

 

[Nick Micale]

Maybe if there was more follow-up info about "wiped" cams we could possibly establish some reasonable causes?

Seems during the mid-90's there was a terrible rash of aftermarket cams going bad. The consensus then was the cores were not properly heat treated or ground correctly. How accurate this info was I do not know.

The ones that can answer this best is the manufacturers. Don't think I would use a replacement cam unless they gave me a report why the first one failed? This assumes that the manuf. recommendations were followed and their [recommended] lifters/springs used as well.

I am sure we could accomodate a data bank or special forum at TB.com to log information on cam problems. The appropiate and pertinant info would be needed for this to be of value.

Personally, if I had a failure the first thing I would like to know is the surface hardness of the cam. This should be done by someone other than the manufacturer for credibility.

Also, the feedback from the manufacturer concerning the reason for failure and how they handled the situation should be logged as well.

This is a nasty, and expensive, problem we have seen for too long, affecting too many turbo Buick motors. If the factory motors can have stock cams that last 100K+ miles, even running low 11's or so, why cann't the aftermarket cams do as well?

Just my thought for the night, hope it can help.

 

[1badTTA]

Maybe this will throw a little more fuel on the fire.
At 36,062 miles I installed an aftermarket cam from a reputable Buick vendor, within 2,000 miles it had a flat lobe. It was the #1 exhaust lobe. All the other lobes looked good. Me being the cheap bastard that I am, I reinstalled the factory cam with new lifters and haven't had a problem since and have another 12,000 miles on it. Go figure.

 

[JDSfastGN]

Ok I'm not a cam expert at all, but why are all the aftermarket cams a completely different lobe separation, and duration compared to the stocker. Everybody talks about how good the stocker is but when we upgrade cams , it is nowhere even close to the original specs(the stocker has more exhaust than intake but most after markets are the opposite or are split duration). My personal observation is that I was running an ATR 313B 208/201 cam and wiped it. I rebuilt the motor and am now running a 204/214 speedpro which other than being a little more duration, is still the same basic set up that the stocker is just a couple steps up. I have not had a problem what so ever so far, knock on wood but it only has 10,000 miles on it. Has anybody ever lost a Speedpro cam due to no good reason before? I'm intersested to see because one reason i picked it was because I had never heard of a failure with one. Is my logic flawed in thinking that the way the cams are designed with a completely different ramp height, and duration and lobe separation compared to stock that it just doesn't work for the LC2s? Most stockers make it for the life of the car, so why are all the aftermarket options completely different?

 

[turbofrank]

My 2ctns, I bought a Lunati 200-200 two years ago along with a friend. About 3months ago his cam wiped #3 cyl mine is still
going strong and looks good. Was it they way they were
installed who knows?

 

[Chris McDade]

This is really a sore subject in the turbo Buick world. Im thinking it has to be the manufactors of these cams. Who knows?

I've been running a comp 218/218 flat tappet for about two year and 6000 miles. I took the motor apart and the cam looked good. A little worn, but reusable. This is after about 40-50 10 sec. passes. Im reinstalling the cam back into the motor. Hopefully mid to low tens.

 

[Louie L.]

Lets not forget the lifter bore issue.Many of theses blocks suffered from misaligned lifter bores which certainly adds to the failure rate.

 

[MSDGN]

As for those that believe the stock cam lasts forever all I can say is when I tore down a friends stock unopened 60K motor...stock cam...2 of the lobes were almost gone...in looking down the lifter bores of the wiped lobes with the cam in you could see that the lobes were more centered in those bores...plus the lifters for those were worn more than the others...I'm still stuck on the lifter bore out of alignment for some blocks theory...

 

[87GN_70GS]

That lifter-bore-out-of-alignment theory (actually, according to Jim Ruggles, GM released cam blank drawings with an error that put the cam core lobe smack in the center of the bore) is easy enough to prove and is what I felt led to the demise of a few of my favorite cams. Put the cam in with the lifter (no pushrods) and turn it by hand. The 5th lobe back, 3# exh, will turn opposite of the lifters on that bank, and usually much more slowly. No turn = fail. You can also pull the valve cover on a running engine and watch that 'shrod. It will spin opposite and usually more slowly. If you even imagine that you're hearing valvetrain noise and that pusrod is barely turning with the v/c off, it's already failed - might as well pull it and start over.

 

[turbowrenchhead]

So what do you all have to do to go to a roller cam? Springs? Do you have to put something behind the cam by the freeze plug? I know that lifter dude sells rollers but where can you get a affordable cam?

 

[750H.P.V6]

Guy's,

This is a good topic and there are a large # of problems that contribute to the Buick V6 cam saga.

The first of which is the misalignment of the lifter bore on the #3 exhaust lobe which causes accelerated lobe wear. If you measure the distance between adjacent lifter bores in the V6 block they are all the same except the pair of lifter bores on the #3 cylinder.

What happens is that the #3 exhaust lifter is not offcenter from the lobe and in turn the lifter doesn't spin correctly if at all. The severity of this problem varies from block to block and some are better or worse than others. This produces accelerated wear on this one particular lobe.

Another issue is that most people upgrade to a high performance cam. Any cam that is advertised as "High intensity, or with Fast Action etc." has more ramp rate ground into the cam profile itself. As the ramp rate increases so does valve train noise and wear also. Usually we install stiffer springs also which makes the problem even worse.

One theory I have about some of the failures that I cannot substantiate because I don't have the tools to check it is that some of the cam vendors less familiar with Buick V6 cams grind them incorrectly.

In a Small Block Checy (face it it's a Chevy world) the taper on the lobes all goes the same way so the cam thrusts aft. On a Buick cam the taper goes opposing directions on each bank . I guess this was Buick's way to try to minimize thrust either forward or aft. If the taper is incorrect the cam will eat itself.

Another piece of the puzzle which affects the whole marketplace is that the lifters available are really poor in the machining of the contact surface that rides on the cam lobe. This stems from the fact that Johnson lifter that was the largest aftermarket Mfg. went out of business and other smaller companies have had to step in to make up the difference. Many large camshaft companies have taken to re-machining the lifter contact faces to insure that they are ground properly.


Finally, Camshaft break in is absolutely critical and the first 30 seconds of the process will determine the longevity of any camshaft.

Sorry for being a bit long winded. I hope this makes sense.

Neal

 

[Two Lane]

THANKS FOR A VERY WELL-THOUGHT-OUT POST!

Terrific post, Neal!

Thanks for taking the time to cover some of the history and causes of the ongoing plague/epidemic of Buick V-6 "cam suicides"!

Other than super-attention to detail on install & break-in, are there any other things we can do of a preventative nature?

 

[750H.P.V6]

Two Lane,

Unfortunately a lot of the variables are out of our hands and in the hands of the manufactures themselves. All I can recommend is that you get a cam from a a company well versed in Buicks that has good quality control practices. I would purchase a kit so that if you have any kind of problem you bought all the stuff from them.

Personally I use Reed cam just for this reason. I figure Reed was good enough for Ruggles and I 'm comfortable with their level of expertise regarding Buicks. This is not to say they are the only good cam company out there just the one I like.

Neal

 

[turbowrenchhead]

So what is the proper way to break it in?

 

[turbowrenchhead]

So what is the proper way to break it in?

 

[1320n10]

I was told by a local racer that there was someone here in wisconsin that was building cams that were on a splined shaft of some sort. I guess each lobe is stacked on the shaft and shimmed.If a lobe were to go you just replace that lobe.I will look more into this and see if they are planning on any other cams than chevys.

 

[turbowrenchhead]

I have some really nice lifters from esp with the grove down the side for more oiling to the lifter surface. Is it possible to have the machine shop resurface the lifter faces?
A set of speed pro lifters from summit are $35 and from the dealer they are $144. Are the dealers worth it?

 

[chevyII]

lifter bore alignment

just read a reply from 750hpv6,he talked about lifter bore alignment. has anyone machined the bores bigger and put in bushings.in pro stock racing 1 hp is alot and in the last few years lifter alignment/bushing the bores has brought BIG gains. I would imagine the cost would be high?