- Local time
- 2:39 PM
- Joined
- Apr 13, 2012
- Messages
- 39,112
- Reaction score
- 142,956
- Location
- Granite Bay CA
My feeling is basically that, if a new cam/lifter fails within 1000 miles, it started that process(of failing) during the break in.
Watching the Powell machine videos I saw enough evidence of poorly machined lifters to know that there are going to be cases where they are the culprit responsible for the failure.
I’ve measured the taper on cams that failed and know sometimes the taper is insufficient, and that the cam was surely a contributor to the failure.
The point being……… I don’t paint the picture of the current FT breakin process as being all “roses and unicorns”.
If you want to stack the deck in your favor, take all the precautions………and then hope for the best.
See, this does help.
The manufacturers want to blame the installer or the oil. The installer wants to blame the manufacturer. I have not heard any major oil company blame themselves. In fact, specialty oil companies have blamed the No zinc oils as a valid selling point to market their oils.
Dwayne’s (as well as others here) input leads me to think that due to some inconsistencies in manufacturing, the fault can be placed in several areas.
People drive with no seat belts and never have a collision that could kill them. Some people smoke and never get cancer while others might take every precaution and live healthy yet still die young.
I appreciate all the input and guidance on this matter. I hope that it benefits others as well.
My engine turned 550 HP and 675 Lb Ft of torque when I ran it on a chassis dyno at the Hot Rod Power Tour (as driven on the tour: full mufflers, air cleaner on, etc.). This was a "fun run" event, so I had no opportunity to tune anything. The horsepower dropped off after about 4900 RPM. Something was going on, and it likely is a fuel delivery problem. With 675 torque, Horsepower should be up over 600. But I haven't had time to diagnose the issue and find that lost HP.
EVERY TIME. Also, my father-in-law's shop won't even build a flat tappet engine without lifters that direct oil the cam (they do this through a small hole drilled in the bottom or a small groove in the lifter that allows oil to seep through on to the cam).
The No flat tappet builds practice seems to be popular for many engine builders. The hassle of replacing a dead cam and cleaning out all the debris really sucks.
I’ve seen in videos where the cam lobes have a different degree of taper compared to the lifters even when they are the same brand. It seems that you’d expect them to match for equal load bearing at the lobe/lifter interface. Maybe since the lifters are actually rebranded instead of made and machined in house is the main reason?
This has me curious about the process of refacing original, used lifters. It seems that if the new cam is measured for taper and then the lifters are refaced to match, you drastically reduce the risk of those leading to a failure? This still makes me wonder that at what point can you push it… if you have properly matched lifters and lobes, would there be a known point of spring pressure or valve lift where reliability drops off dramatically?
Looking at how a lifter rotates and slides on a cam lobe, I wonder how the heck they don’t fail sooner. Think about all other metal to metal interfaces there are in an engine. The crank spins in the block while supported by bearings made of a softer metal while relying on a wedge of oil. The piston rings slide along the bores millions of times. The timing gear has a chain that rubs the sprockets when turning. The rocker arms pivot on a shaft. Most of these only last because of pressurized oil but the lifters just get splash oil that squirts from the rod caps? The lifters are under greater risk of failure as the spring pressures go up, right?
For the guys that have never had a cam or lifter failure, did they just have tame combinations or were they just incredibly lucky?
My first three cams in Mopars were the 280/474 in my first 440, an MP 284/484 in my second 440 and the 292/509 in the stroked 440. None of those went bad despite conditions for break in were not optimal and this was when I knew even less than I do now.
Last edited: