How long do they last? Would it be a good idea to replace them since they're 15 yrs old and I spin my air pump to 6K?

 

Age alone doesn't wear them out. If there's nothing wrong with them, just leave them alone.

 

Hi,
My old 305 TPI has run for 20 years with the same rollers no problem with them.
But I think that will be more interesting the amount of miles on it.

Concern the components involved, roller bearing, a tiny ball and spring I can imagine that they will go for and other 10 years with out problems.

I will say that the most weakness part would be the ball (check ball), if these will get rusty or picked for some reason than you will have a problem.

Keep them under oil would be the most preventive solution.

Regards,
Cobra289

 

Just thought i'd question it since I tapped a couple of valves on the pistons. A couple of people said that it wasn't due to weak springs but due to weakening lifters.

 

You would not believe it but most of the problems at the lifters are related to a bad oil level.
To high and you get foam, to low and you get air. Now that is something that the lifters don't like to have and are the first items that start to complain. You know they start to get noisy at idle but disappear at higher revs, etc.

When we talk about weak lifters, I get the impression that that can't be true.
I never have hear about weak hydraulics!
If the lifters are functionally correct (no faulty parts) the hydraulics will never get weak.
I hope that you understand what I mean.

Regards,
Cobra289