I found my problem the reason why chain tensioners are failing.... so, I'm going to swap back to my 06 tsx cams just to prove a point what's causing the tensioners to fail junk2's stage 1 cams. heres the link : Got timing chain slap? Skunk2 does. - K20A.org .:. The K Series Source . Honda / Acura K20a k24a Engine Forum
Do you have a skunk exhaust cam gear that you've retarded the timing? Their's a lot of read there, but basically the retarded exhaust gear is what he's attributing the chain slap to thus leading to tensioner failure. Although everything is relative to one another, that seems to be his general conclusion. It isn't just one part that's contributing to chain slap.
The video from the link.
Analyzing #1, we can determine that at this point, the valve springs are pushing up on the lobes of both cams. That is, resisting the clockwise rotation of the intake cam and pushing the exhaust cam clockwise. Because there is a fixed chain guide on the intake cam side of the chain, there is no net movement of the intake cam. However, on the exhaust side, there is the moving chain guide that is supported by the tensioner. The valve springs exert enough force on the cam to overpower the spring in the tensioner. The tensioner compresses, the exhaust cam rotates forward, but because the intake cam is also meeting valve spring resistance, it does not take up the slack. Thus you have the loose chain between the cam gears. It's a combination of the valve spring rates, cam ramp rates, and the relative timing of the cams that causes all this to happen.
Keep in mind, this is on the primary lobes at zero deg advance. I immediately realized that this lends further creedence to my theory that the tensioners were dying because of the loading/unloading of the timing chain. You could hear the tensioner unloading each time the chain popped. My previous theory on how to deal with this was to add more damping to the system (heavier exhaust cam gear). After making the video, I thought maybe I could change the phase of the cams such that the intake cam opens later, and thus change the point at which it begins to engage the valvespring. Only one problem, the video was taken at zero advance. I looked on my calibration and noticed that in the part throttle area I had 20deg of intake advance. The part throttle cells are where I was experiencing the tensioner noise. I changed it all to zero. I went for a drive, and no noise. None at all. I left the last 3 columns with the normal advance. At full throttle, I never experienced any noise from the tensioner to begin with.
Coincidentally, before I retarded the exhaust cam gear, I never had any problems at part throttle. The exhaust cam retard that Skunk2 recommends is -20 crank degrees. Funny that after I retarded my exhaust 20degrees, I had to retard my intake 20 degrees to get rid of tensioner noises. I'm confident that now, I will be able to regain the reliability I had with the skunk2 cams + stock exhaust cam gear while having the skunk2 exhaust gear retarded -20 crank degrees. Even with the stock cam gear, I had a tensioner fail at about 5000miles, but it was during startup under low oil pressure. My dual spring modded tensioner should keep that from ever happening again.
So the solution I have found is two fold.
1) less cam advance in the part throttle maps for the primary lobes
2) a dual spring modded failsafe tensioner
I think that more or less we are looking at it the same way. There is a particular phase between the intake & exhaust cam that will minimize tensioner wear at lower RPM when the vibrations are more pronounced. I'm sure if I re-tested and advanced the exhaust gear, the chain slap would be less. I could also retard the intake further (via bored keyway). There's all sorts of band-aid solutions I can think of, but the fact that the problem exists at 20deg advance but is imperceptible at 0deg advance lets me know that there is a harmonic interaction between the intake & exhaust cam that governs how bad your tensioner problems will be with these cams. It's a very simple way to look at it. I've always thought that this was the case, but now I have some empirical evidence to support my original hypothesis. And that evidence led me to a temporary fix to help myself and others that are running the same cams and having the same problems. Yeah, it's not ideal to have a low cam map that looks like this:
But it helped the situation with the noise from the tensioner. This may or may not work for everyone else's setup. Every setup is different, but at least now there is more info out on what needs to be done to deal with this problem.