Quadcammer

Ok gents,

96 turbo, 89k miles

So for a while I've noticed that while driving next to a jersey barrier or wall, i get a ticking sound from the engine. Now, when I'm not next to said walls, the engine sounds fine. Bit noisy at idle, but no real noticeable tapping. Car runs fine, power hasn't fallen off, just a bit noisy with the reverb.

Now, I have no engine undertray and no mufflers, so the engine is basically exposed to the world through the wheel well and there is nothing to insulate the sound. As you guys know, without water jackets, the engines are noisy as is.

As far as I know, the hydraulic lash adjusters are original. I'm guessing the seals on the exhaust lifters are probably worn.

So, I ask the following:

1. Does anyone have similar noises despite lifters being ok?
2. Anyone done this without pulling the turbos?
3. Besides exhaust rings, vc gaskets and bolts, turbo studs and nuts, are there any other parts I'll need?
4. Any other tricks on doing this job?

Its an awful lot of work to get to these things on the turbos, so I'd like to make sure its necessary.

Thanks all,
Oliver

ca993twin

Here's one more question to ask before you tear into it:
Is there any harm done to this engine if the lifters are noisy but the car runs fine?

I'd like to know this as well (mine are NOT noisy... I just want to know this answer).

kevin5889

I just washed my car and I haven't started it for over a month... I noticed a loud ticking noise too. I am concerned too, is it sticky valves guides? Car has 32K on it and was told it may have worn valve guides but the car drives fine. I warmed the engine up and went for a 5 min drive. After I let it idle a little more I noticed the ticking noise was almost gone.

Mike J

Really hearing the valves when driving next to walls or barriers that reflect the sounds is normal - not a reason to replace the lifters. If they fail, you will know it, it gets REALLY noisy - it can be quite scary. Mine makes the same noise, and I cannot remember a 993, Turbo or not, that did not have increased lifter noise when driving next to a barrier or wall. Some are noisier than others, it does seem to vary a bit with oil temperature as well (thinner oil == noisier?). Also, if the O rings are gone, it may take a bit of time to pressurize - I know I have one weak lifter right now that takes a few seconds more to stop ticking after the car has sat for a day or two.

What you will find when pulling them is the lifter O rings will either be in tatters or completely gone. Those O rings seal the lifter into the rocker arm, so if the O ring is gone, the pressurization of the lifter is not very good. I have seen that on cars with 50K miles or less, so on a car with your miles its virtually certain to be that case.

You cannot do the lifters without pulling the valve covers, so the Turbos and the surrounding stuff have to come off. Its the same job as changing the valve cover gaskets, which you should do if they are not fresh. I would remove both turbos, and the sheet metal so you can get to the top and bottom valve covers from the underside and work from there. I work with a lift, so my approach might be a bit different than jackstands.

Other parts are valve cover gaskets. once the cover is off, you rotate the engine to take the pressure off each rocker, remove it, pull and replace the lifter, and put the rocker back in, torquing the retainer bolts. You can pre-soak the lifters with oil, and also put a bit of ZDDP break-in grease on the swivel foot of the new lifter. Some people may replace the valve covers gasket retaining bolts, just to have that nice clean look, and to have a fresh bolt so they do not strip the next time around. The valve covers are only 7 ft-lbs, and the key part is to make sure the pressure is even around the cover so it does not leak. Use no sealants, but I do coat the gaskets with Dow Corning 101 Silicon grease to keep the rubber supple.

Cheers,

Mike

Mike J

If the lifter fails, it a very loud and repetitive metal-on-metal noise - you will know it.

you can run the car, but the noise is caused by the impact of the cam's to the lifters etc - > so lots of shock gets transmitted into the rockers, on the cam surfaces, etc. The car's power may be down given the valves are not opening as much as with the lifter is active. I would not run it too much on very loud lifters, but you can run it a bit. Typically, the engine will run fine, pull fine, but be noisy as hell. You would be hammering the valve train quite a bit.

Cheers,

Mike

ACEparts_com

Being air cooled we get to hear all sorts of mechanical symphonies from back there! You will know when a lifter fails as you'll assume you've lost a bearing or something!

Quadcammer

hmm, thanks for the info guys. From what I'm hearing, I'm guessing the lifter seals are probably worn, but it may not be time for replacement. I'm planning an engine out at 100k, so maybe that will be the time to take care of it.

Thanks all.

BLT4SPD

Your timing is impeccable! I just did 99% of this job last week! I didn't do lifters, but I had the valve covers off for gaskets and I lowered the engine while I was at it for spark bolts. Looking back on it, I would say the following:

1. Strongly consider the rubber connectors from the intake pipe(s) to the turbo(s). Between living directly behind the rear tire and getting oil on them from the valve covers leaking, they just needed to be refreshed. I bought high temp (nomex reinforced) silicone hose and cut to length. I spent all of $15/shipped and they should last a lifetime now.

2. Same as above for the boots that connect the intake tubes to the y-pipe. Mine weren't in "bad" shape, but since I was buying/shipping silicone hose anyway, I replaced them. Another $10 well spent IMHO.

3. If you haven't already, it's a great time to upgrade the turbo oil feed lines and check valves.

4. You'll need/want the drain plug crush washers for the turbo sumps. 18x24mm and $0.26/ea from AutoHausAZ. I actually stripped out the allen head insert on one of mine and ended up buying both plugs from Sunset. They were cheap, they had them in stock and I was having them ship an intercooler hose anyway.

5. *I* had a heck of time getting 2 of the valve cover bolts out on the driver's side. Even with the turbo removed, the flange on the exhaust manifold provides some challenges and I had to cut down a 5mm allen key so it would fit in-between the manifold flange and the valve cover bolt.

6. If you have upgraded to Alu. lower valve covers (like my car), they are juuuuust thick enough that it will get trapped between the rocker arm and the exhaust manifold flange. It took me a few minutes to figure out what was going on, but I figured out that you have to turn the motor over until the rear most rocker arm (#1?) is on the base of the cam lobe (and fully recessed into the cam tower) before the valve cover would come out.

7. If you have your original intercooler hoses, inspect them closely or just buy new one from Sunset and have them waiting. Also a good time for upgraded hose clamps.

That's all I can think of for now, but I'm sure more will come back to me.

Slate993tt

As Mike says you WILL know. On my rebuild we had 2 bad lifters that would come up and when the car started it sounded like a kid banging on a metal pot with a metal ladle. It was LOUD!

As everyone has said valve train noise next to reflective surfaces is normal. Mine makes some and its basically brand new.

With all that being said at 89k I'm sure your exhaust guides are out of spec but that doesn't mean it doesn't have lots and lots of healthy miles of running for you. I rebuilt my motor as I had the money in hand to do it and didn't know when that might be as handy so I jumped on the opportunity. IMO If it's not using a lot of oil and still passes state emissions tests then just keep driving it. that is unless you have $$$ burning a hole in your pocket like I did.

Quadcammer

good info.

Seems like I should be ok for a while. Can never be too careful when it comes to ticking from the engine.

My oil consumption is about 1 quart per 3k miles, so I'm in no rush to do guides. No problem with SAI or emissions testing at this point.

rlme36

So a comment on the crush washers. I got a lifetime supply at rm European as I recall they were a nickel for either the oil plug or the sump with the corresponding one being double the expense at a dime. ;-). Just saying if you are already ordering just pile them on best use of 4 bucks ever

Rob

AOW162435

Excellent write-up.



Andreas

Mike J

I strive to make my write-ups as good as how the bottom of your cars look - and I need more improvements to reach that astounding level...

Thanks for the kind words Andreas!

Cheers,

Mike

Quadcammer

thanks, very helpful.

what size silicone tubing did you get for those spots?

I have new IC tubes and stock valve covers.

I've done cat pipes, so I've gotten fairly close. it was a pain, but ultimately, doable.

BLT4SPD

Interesting....I was just perusing RM's website and they do indeed, have GREAT prices on the crush washers. I checked some of the other stuff (valve cover gaskets, lifters, etc) against my gold standard, which is AutoHausAZ and RM just can't compete, but the crush washer prices are simply amazing. It would also be hard to beat AutoHaus when you factor in the free shipping they offer.

FWIW, I have a huge assortment of crush washers in all sizes from 10mm to 24mm in a Winzer drawer and I just refill the empty slots as needed from a local metric supply warehouse. I was just throwing AutoHaus out there a supply for a DIY'er that may not have the assortment on hand like I do.