grazy

I have a c4s and after a DE, my cats were rattling...actually it sounded like valves were tapping, but only at idle...I was worried after replacing them and all is well. Did another DE since then, and so far it's okay.

Not 100% sure about this. I was told that to test my lifters I should compress them and there should be some movement. On several I had 1.5mm-2mm or so of movement, but several were "locked down," which I was told indicated the were faulty.

Based on this I decided to replace all my lifters, and bought 24 brand new INA lifters. When they arrived I checked them and none had any movement, all apperared to be "locked down." I was surprised to say the least. But the lifters use oil pressure to expand, and these were brand new and have never been pressurized, so I am now assuming that they are good. I put them into my engine and will have it running tomorrow. If the tappet noice is gone I guess I will be happy, but not really sure of how to "test" lifters anymore.

Were you able to get these installed...and did it solve your problem?

Thank you...great picture. I doubt it is too...but hoping it's not tensioners (most likely I think)...

I just used a rubber mallet on the exhaust...tapped the cats and muffler and headers...got a sound like a marble dropping when I tapped the exhaust and muffler...cat's didnt seem to be making the noise %$? what could this be?

Make sure your 02 sensors are still screwed in tightly.

Thank you...I will check these, but can someone (Lorne?) show me where these are? Thanks again

Thank you for all the feedback folks. I will have the car checked out...all I know is that given the same oil brand and viscosity, operating temps, and ambient conditions...there is now a tapping noise when there was none before....something has changed. If it turns out that putting higher viscosity oil solves the problem..that may be a lot cheaper than other alternatives. The engine still runs great..very strong, smooth...just taps at idle now! Thanks again.

I just used a rubber mallet on the exhaust...tapped the cats and muffler and headers...got a sound like a marble dropping when I tapped the exhaust and muffler...cat's didnt seem to be making the noise %$? what could this be?

Thanks...I have done a lot of searching on several forums, but haven't found a good way to make a judgement about how to check. I have seen many posts about the oil type. I did check oil pressure and will need to go back to get numbers, but yes, once pressure steps up abit...rpms around 1000..the noise seems to go away. All I can say is that the noise is there now, wasn't before, all things being about same. Havent ruled out the coil or evap system though...appreciate everyone's thoughts about what to check...thanks

I have an '02 C4S with 31K miles. I am dealing with a significant metallic tapping problem...no issues when the car is just started and is not up to operating temp, but once it's warmed up, the tapping is there. When I rev the engine above 1000 rpm's, the tapping appears to go away. The sound is there with the clutch in or out; the oil is Mobil1 0-40 and is fresh. Any way to find out if it's lifters going bad or the chain tensioners..or ? The sound appears to be coming from both sides of the engine...maybe a little louder on the passenger side...please help!

Loren,

After tracking my '02 C4S, I noticed a ticking sound also...almost sounded like something like a muffler bracket was loose. As I rev the engine, the noise goes away. It sounds like the engine, not a bracket. Oil was just changed; 0w40 Mobil 1.

Thanks

Two reasons for the PSS9 or PSS10's: 1) I do like the lowered look much better...the US versions are all higher than the RoW specs and I think it makes a big difference. 2) I have only tracked this car once, and while it is altogether a much easier, much faster car than my '83 SC, there was more roll an floating than I was hoping for. The adjustability is a great feature.

My big issue right now is whether to go with a C4 fitment or a turbo fitment. Loren says turbo, Bilstein and a dealer said C4...and there a long thread on this as well...same issue. It appears most people side with the turbo fitment.

Anybody have any experience with the PSS10's vs. PSS9's??

Thanks

Grazy, why would you put PSS9's on a C4S when that car is supposed to be already lowered and has a beefed up suspension?

Im asking because I have a 996 Cab-4 and have been considering PSS9's + GT3 sways + performance exhaust but kind of decided that it would be smarter to just get a 997 C4S instead.

If you are looking at PSS9s because they are height-adjustable remember that anytime you adjust the height you will have to get your front-end realigned (and corner-balanced in the case of having adjustable shocks). But again, I thought the C4S was already lowered.

If you are looking at PSS9's because they are stiffness-adjustable then Im disappointed because I thought the C4S, with its suspension just like the turbo, did not have a problem with body-roll. I see a different post here asking about upgrading sway bars on their C4S... again making me wonder if the C4S/Turbo suspension allows too much body-roll.

It would be great to hear from other 997 C4S drivers about these questions!

Loren,

Is the PSS9 for the C4 the same as what you would spec for the C4S? or would the proper one be the turbo?

Thanks very much