993inNC

Aren't the valves self adjusting hydralic as apposed to needing manual adjusting? I am begining to hear what seems to be a louder than reasonable "clack" from the motor, one side more than the other. Could it be valves in need of some kind of attention? I seem to remember when I did my V. cover gaskets that they were capable of being adjusted like the old 911 motors without the need for major surgery.....? Help anyone?

Steve Weiner-Rennsport Systems

Hi Chris:

You didn't mention how many miles are on your engine but if you are hearing a clacking sound from the motor at idle, its possible you are hearing a failed hydraulic valve adjuster.

Its not uncommon on engines that run hotter than average and you have a warm climate in NC,.... Hopefully, your engine undertray has been removed.

One can isolate this noise by using a long screwdriver as a stethoscope and placing the tip against the valve covers while the engine is idling. Put your ear against the base of the handle and you'll hear the "clacking" right in your ear,.... By moving the tip of the screwdriver around, you can isolate the offending cylinder(s).

FYI, when this happens, I usually replace all of them since it a seal failure issue on the adjuster and when one fails, the others usually follow suit. I deplore doing things twice so I do all of them to prevent this from recurring.

MrRoboto

What is this clacking that you speak of? I think my motor "clacks" more so than my other cars, but i thought it was just the natural sound of the flat 6. Can someone distinguish these engine sounds?

Steve Weiner-Rennsport Systems

Jimmy:

If you have a hydraulic lifter problem, the "clacking" sound will rise in frequency with engine RPM, but it doesn't get louder. It comes from under the valve covers.

Use the "stethoscope" method outlined above to determine whether you are hearing the same thing. FWIW,...one can buy a specific stethoscope made for this type of work.

993inNC

Steve, thanks for the response. To start, just shy of 100K on the clock. The clacking is throughout the throttle range.....don't recall it getting louder, just in time with the revs and I believe probably only on one cylinder (because of its frequency relative to the revs). Engine tray has been gone since I bought the car (came from the Boston area) with 93K on it. It has never run hot (this will be its first summer here) up to this point. Based on what I have seen you and other recommend when it comes to temps, this car is right on the money. Seems to have a high amount of milage go by without a top off of oil (3000+/-). I just picked my oil and filters yesterday and had planned on the old screwdriver trick to try and isolate the location.
I'm with you on the not having to touch things more than once. Would you be so kind as to advice whether or not this requires major surgery or not (motor out) or can it be done motor in and degree of difficulty?
Thanks again.

Steve Weiner-Rennsport Systems

Hi Chris:

IMHO, your mileage places you in a area of maximum exposure for this kind of thing. From what I've seen thus far, its not uncommon for the seals on the hydraulic lifters to fail and then the unit will not hold pressure.

The engine doesn't have to be removed from the car; just pull the valve covers although thats somewhat time consuming.

Each rocker arm must be removed to gain access to the lifter at the end of it but its pretty simple. There are 3 versions of valve tappets and you'll need to get the numbers off the ones you have to order the correct ones for your engine.

Its not hard to do; its simply not easy to gain access to the rockers and I'd replace all of them, based on past experiences. I cannot tell you how many times I only replaced the offending few, only to do the rest of them very soon after. Its a PITA.

Do it once and do it right, so you'll not have to do this all again later. Lifters run about $ 50/each.

JasonAndreas

From the DIY archives, Lifter repair 101 but follow Steve's advice and skip step 1.

993inNC

Steve, thanks, great news....as I guess repairs go on these cars! Guess I'll need to dive in a little further before asking any more questions. I'm just not yet up to speed on the construction sequence of the parts and pieces. My hydraulic VW heads require removing the cam to get at the lifter tappets. I know these are different, just don't have the clear picture in my head. Hope you wouldn't mind if I contact you once I get into it if I become unsure of what I see?

Chris

993inNC

Jason, thanks man. Now I get it.....thats easy. I haven't decided whether or not to skip step 1. Thinking about the LWF since it'll be clutch time soon.....we'll have to see how frisky I feel for that part!

deltawedge

What effect does having the wrong tappets (same as lifter?) for the engine? The ones I installed are 993 105 141 05. The ones I took off had a black sealing ring material (which split circumferentially when I removed them) and the new ones had a white sealing ring. Both exhaust sides were done (driver side at 65k and passenger side at 69k). The driver side is now noisier (not a single lifter, all 3 of them) than the passenger side. Do the lifters have a break in period?

Thanks, Steve. P.S. the chip is working great!

Steve Weiner-Rennsport Systems

Call me, anytime,....

Steve Weiner-Rennsport Systems

Hi Ken:

I think the lifters vary slightly in length to accomodate the production tolerances in the cam housings and still maintain lifter travel.

There are .05, .51, and .61 versions of lifters for these N/A engines. (there are 3 different versions too, for TT's). There is no break-in so if yours are noisy, I'd venture that the replacements are too long and they are operating in an almost collapsed position. I'd check to see what you have in the noisy side!

Glad you are pleased with the chip,...

Keep me posted.

Atgani

Hi Steve, your post makes interesting reading for me, my '95 993 RS started making what sounded like a noisy tappet noise a few weeks ago. I isoated the noise to one of the exhaust lifters on the n/s bank. On stripping all 3 out I found the seal had broken up on one of them. Like yourself, I thought no point in doing the job twice, so duly fitted 3 new lifters, (I soaked them overnight in a container of clean oil and primed the rockers as best I could) Built everything up and started the motor............................ you guessed, the noise is still there! As the motor was suffering fgrom cylinder head and base gasket leaks I decided to have the top end overhauled, (58,000 miles most with the engine undertray on) Once the motor was stripped we found all the exhaust guides badly worn and two very slightly bent exhaust valves. (The valve seats looked to have some leakage past them) Two points of concern a. I was n't aware there were 3 sizes of lifter available, my OPC said there were the std ones (approx $20) or some which they thought were for reprofiled cams $100 !!
Have you ever used the different sized lifters you mentioned in your post ?
b When my motor was torn down one of the rocker arms was different to the others on the same bank (different part no and a lot more heavy and chunky in design) sorry I don't have a picture. Are there different rocker arms available too ? Sorry this is such a long post but Porsche UK can't give me an explanation for the different parts available.

Atgani

Sorry Steve, do you have the part numbers for the three different sizes of lifter ?

deltawedge

Steve,
Not the answer I was hoping for. When I say one side is noisy, it is only in relation to the other side which is whisper quiet. After the first set of three was replaced, they were whisper quiet as well, but after 5k miles, they are louder than the other side, but still much quieter than the single offending lifter that prompted the change. Since all exhaust lifters have been replaced (and I didn't save the old ones, not smart) would pulling an intake lifter give me the part needed to replace them? What are the possible effects of running the wrong ones?
Thanks.