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Original Message
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| RE: Help! Keep wiping cams! |
| By Gerry Proctor - 06/10/2004 6:59:26 AM; IP 207.133.188.254 |
Unless your dealing with a manufacturing anomaly, such as sub-standard Rockwell hardness on the cam or lifters, your wiping the cam out is likely something you’re doing. Despite the “Internet truth” floating around regarding a certain cam company, it’s highly unlikely that you’d get two bad cams. I believe the attribution of quality issues regarding this company is more a matter of the popularity of the brand increasing the likelihood of the finger being pointed in that direction. So, with that being said, you need to look at the causes from a non-manufacturing perspective.
Most cams get wiped by not explicitly following the directions of the manufacturer. Those are using high performance valve springs that don’t allow the lifters to rotate on the cam lobe, not applying sufficient break in moly lube to the cam and lifters, not maintaining a high enough rpm during the break in, and insufficient splash lubrication. Of course (and I’m sure you’re not doing this) using old lifter on a new cam is a big no-no.
If your springs are the recommended springs for the cam, they could be too stiff for break in. Usually, anything over 140lbs seat pressure is going to be a good path to wiping a lobe. It’s a crap shoot, though, but you have to observe the valve train when the engine fires to ensure that the pushrods are spinning. If the pushrod isn't spinning, then neither is the lifter. The cam manufacturer will usually specify if the recommended springs can be used for break in.
You want to slather as much of the break in lube on the cam lobes and lifter face as you can. Just a film coating is insufficient. Too much is just about right.
The reason all the manufacturer specify the 2,000 to 3,000 rpm for 20 minutes or so is that the cam is lubed only through oil splash from the spinning crank and rods. Lower rpms and shorter break in times may not sling enough oil onto the lobes during the period where the convex lifter face is becoming friendly with the cam lobe. There could be an issue with bearing clearances and rod side clearance restricting oil splash but this is such a technical long shot that I wouldn’t even seriously consider it. Seriously resist the temptation to allow the engine to return to idle during the break in. Impatience in wanting to hear the lope is an excellent way for the lobe to get wiped. Also, do not crank the engine over to establish oil pressure. Prolonged cranking can also be an issue in getting the engine to fire. This is why it’s critically important that the engine fire and run in as soon as you start cranking.
It’s possible to ignore all of the recommendations and warnings and still have a successful break in. It’s done all the time. But the bigger the cam, the more likely that something will go bad and you’re trying to stack the odds in your favor.
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