What's the deal with EVO cam bearings ?
#21
08-20-2010, 01:27 PM
Just look at it as an opportunity to upgrade your EPA cam. If you're not a drag racer, I recommend the Andrews EV13. Much better cam without hurting your fuel mileage.
By the way, the lifters are a sore point in Evos, too. Crane, Jim's, VelvaTouch- anything's better than OEM.
#22
08-20-2010, 05:46 PM
Greetings,
As you said, the INA bearing is a good design in a limited load environment. Open construction for good oiling and the cage has less drag than roller against roller so it runs slightly cooler at or below the design load.
In a twinkie, which I think has the same bearing(don't know for sure - don't mess with twinkies), the cam has HALF the load from the valve springs and better load angle so there is no comparison to an EVO.
Over the last 20 years, I see approximately a 28 percent failure rate of this bearing in EVOs at various random mileages - the rest were changed and lived happily ever after.....
Of the motors with the failure, most had no damage to the cases, but a couple had no choice. Some were early cases with cracks and leaks not related to the bearing but the bearing was the case killer - they said they could live with a small leak as that's what Harleys did. One wanted more than the stock cases could handle anyway and used this as an excuse to get an S&S stroker.
Pay a little now or a lot later.
In an EVO, I would just change it and have peace of mind in an otherwise trouble free motor.
As you said, the INA bearing is a good design in a limited load environment. Open construction for good oiling and the cage has less drag than roller against roller so it runs slightly cooler at or below the design load.
In a twinkie, which I think has the same bearing(don't know for sure - don't mess with twinkies), the cam has HALF the load from the valve springs and better load angle so there is no comparison to an EVO.
Over the last 20 years, I see approximately a 28 percent failure rate of this bearing in EVOs at various random mileages - the rest were changed and lived happily ever after.....
Of the motors with the failure, most had no damage to the cases, but a couple had no choice. Some were early cases with cracks and leaks not related to the bearing but the bearing was the case killer - they said they could live with a small leak as that's what Harleys did. One wanted more than the stock cases could handle anyway and used this as an excuse to get an S&S stroker.
Pay a little now or a lot later.
In an EVO, I would just change it and have peace of mind in an otherwise trouble free motor.
Hmmmmmmm.... well, kinda wrong again.
If all the valves were open at the same time, then half load would apply. But they are not. The overlap is far from fully open load. So that theory is shot to bits. There is however more total load OVER TIME. Now that can be said to be true.
And you have assumed the same spring seat pressure, which is quite wrong.(lift being a major factor here)
Approximately 28 percent? Are you sure that is not actually approximately 29 percent?
Evo run a B138. Early twinkie B 148(2), then late B168(2). Same brand and series of bearing, but a different size.
Evo motor trouble free apart from the cam bearing.
Base gasket leaks.
Blown head gaskets.
Cracked cases.
Loose case inserts.
Studs pulling out.
They are certainly an ok motor. No reason not to have one.
But trouble free apart from cam bearing issues?
That simply is not true.
#23
08-20-2010, 05:53 PM
No, they are all bad, from '92 to the new Evos the MoCo sells. They cheaped out by using a caged bearing without a full complement of needles. The bearing is cheaper and makes assembly go faster. And the hell with whether it's the appropriate bearing or not. The replacement Torrington bearing has a full complement of needles and is virtually bulletproof.
Just look at it as an opportunity to upgrade your EPA cam. If you're not a drag racer, I recommend the Andrews EV13. Much better cam without hurting your fuel mileage.
By the way, the lifters are a sore point in Evos, too. Crane, Jim's, VelvaTouch- anything's better than OEM.
Just look at it as an opportunity to upgrade your EPA cam. If you're not a drag racer, I recommend the Andrews EV13. Much better cam without hurting your fuel mileage.
By the way, the lifters are a sore point in Evos, too. Crane, Jim's, VelvaTouch- anything's better than OEM.
Makes assembly go faster??????????????
Have you actually seen one. Assembly is COMPLETELY UNCHANGED!!!!!!!
OEM lifters for evo (the new B type), are the best thing going.
They are to be recommended.
NO ONE can make a cam recommendation without a full knowledge of the rider, model, and engine spec. That is why there is more than one cam grind available. Otherwise, they would only make the one. You could say, "I recommend the EV 13 for this effect with a stock motor, and particular riding style", as that would make sense.
#24
08-22-2010, 12:45 PM
Gee, I guess I could have been more technical. Since the original poster didn't say anything about being dissatisfied with the OEM cam, I just thought I'd throw in the suggestion that a mild cam upgrade could be done as long as everything was apart, which would improve the characteristics of his engine that he liked, while not creating any negatives, like excessive valvetrain noise, or the need to rev the engine a lot higher to make power, thus killing the fuel mileage, etc. Satisfied?
And I stand by my statement about the INA speeding assembly, namely the alignment of the camshaft during assembly. I didn't say any change in asembly, did I?
Nor did I say every INA inner cam bearing fails. But since there is a well-known chance of failure, even in stock engines, that does mean the INA in question is inappropriate for this particular use.
And I stand by my statement about the INA speeding assembly, namely the alignment of the camshaft during assembly. I didn't say any change in asembly, did I?
Nor did I say every INA inner cam bearing fails. But since there is a well-known chance of failure, even in stock engines, that does mean the INA in question is inappropriate for this particular use.
#25
08-22-2010, 10:11 PM
#29
02-12-2021, 08:05 PM
Seasoned HDF Member
