This is really getting old...

[Chattzx]

So ever since I have had my Z it has had a "knock." I know it's not a spun bearing or anything really bad because it doesn't sound THAT bad. I have tried anything from a synthetic 5W-30 to a 15W-50 and nothing makes a difference. I am starting to think it may be a collapsed lifter(s) just from the sound it makes and it tends to go away as the rpm's rise. I am replacing a bunch of stuff next week including:
-6 new 2011 Deatschwerks injectors with updated fuel adapter
-new plenum gasket
-new fuel filter
-EGR elimination kit
-new injector connectors

and I'm hoping maybe getting every cylinder firing with the proper spec injectors will smooth things out and cure the problem. And if it helps any it does sound like its coming from the top of the motor, not the bottom. If anyone has any ideas lemme know.

[tmeyer29]

Throwing random parts at it is not really the way to go about fixing it. Lifters don't really knock, its more of a tick. Piston slap is more of a knock. Need a better description of this noise. Make a vid if you think it will help.

[Nick (ASH-SPEC)]

Video would be helpful. If it is the lifters, I just posted up a "Lifter Reconditioning" writeup that Ash had posted on TT.net. Might help save you some $$$$ if that ends up being the case.

[Chattzx]

I'm not throwing random parts at it, It's needed all new injectors for sometime now and I've finally got around to ordering new ones. All 6 of the current injectors are WAY out of spec and cause the engine to misfire, so I'm pulling the plenum next week and seeing what happens. Doesn't a collapsed lifter sound pretty nasty though? And like I was saying the noise only comes after the car is fully warmed up after about 10 minutes or more of running, when its cold it sounds perfectly fine.

[Chattzx]

Throwing random parts at it is not really the way to go about fixing it. Lifters don't really knock, its more of a tick. Piston slap is more of a knock. Need a better description of this noise. Make a vid if you think it will help.

I will post a video in a bit and see if it helps identify the noise.

[Chattzx]

You guys aren't gonna believe this, but after driving around for about 50 miles today with the Shell T6 there isn't even the slightest sound of knocking coming from my engine. I am simply amazed on what this oil has done in 50 miles to this engine and it was knocking pretty damn loud with every other oil Mobil 1 has offered in my car.

[NolimitZ32]

I run Rotella 15-40 in the subie but have never heard of anyone running such heavy oil in a Z32. the subarus love the heavy diesel oils though.

[GerryO]

Adding about half a quart of Castrol 20/50 synthetic blend quickly quieted a noisy lifter in my VG30DE. It had been sitting for a couple of months, waiting for a WP/timing belt/oil seals/etc change and needed to be moved a couple of times. Each time I started the engine, the noisy lifter sounded louder. Since then I've converted to full 20/50 synthetic blend.

Another on this forum had a problem with a clogged intake screen in the oil pan, that was causing top-end oil starvation. It sounded like some sort of fancy oil filter had come apart or someone had added a stop-leak additive.

[Chattzx]

Yeah this Rotella T6 has made a night and day difference.

[sdhsbaseball]

Throwing random parts at it is not really the way to go about fixing it. Lifters don't really knock, its more of a tick. Piston slap is more of a knock. Need a better description of this noise. Make a vid if you think it will help.

He doesnt have knock at all it was just the lifters being load and ticking. I know what knock so he is fine there. I know in my TT i siwtched from royal purple to mobil 1 and had somewhat the same affect in everything being quieter.

Plus he needed new injectors big time all his were way out of spec and when i ohm them tommorrow i know thats what i will find.

[Chattzx]

Lol damn straight Justin

[BigTDogg (MA)]

So Chat is Chattanooga, gotcha. You don't have a location listed. You affraid someone is going to find out where you live? lol.

In the past I've run M1 20w-50 and the Z definitely felt like a slug. If you have noisy lifters, try adding a little less than 1 quart of ATF about 100 miles before your next oil change. Don't drive it crazy hard, but drive it through all gears at decent load levels. It'll clean the lifters. I just did this before my dyno day, and I was honestly amazed. No need to spend $40 on engine flush from Z1 when a $8 bottle of ATF does the same thing. No more tick on start up for me. Now I run Royal Purple 10W-40 and the car feels great.

[FknBuZZard]

I also had a intermitten knock as well, came to find out it was my timing belt pully falling apart.........

[Chattzx]

So Chat is Chattanooga, gotcha. You don't have a location listed. You affraid someone is going to find out where you live? lol.

In the past I've run M1 20w-50 and the Z definitely felt like a slug. If you have noisy lifters, try adding a little less than 1 quart of ATF about 100 miles before your next oil change. Don't drive it crazy hard, but drive it through all gears at decent load levels. It'll clean the lifters. I just did this before my dyno day, and I was honestly amazed. No need to spend $40 on engine flush from Z1 when a $8 bottle of ATF does the same thing. No more tick on start up for me. Now I run Royal Purple 10W-40 and the car feels great.

Haha I forgot to put a location, I shall change that and yeah Chatt is for Chattanooga. I agree I ran 15W-50 Mobil 1 in the Z and it ran like a total slug! It also made my motor sound like it had a nasty rod knock and I changed over to Retella T6 and now it doesn't make any nasty noises at all. My best guess is with the cooler weather that we were having while I was running that 15W-50 the oil was not getting to the lifters all that efficiently and was making them gum up making a noise as if they had collapsed.