I recently picked up a very nice 912E with a 2.0L type 4 running stock L-jet injection. Didn't run well at all, I didn't really care at the price I paid. Upon doing the initial survey, I found about 10 quarts in the crankcase. The owners manual for the 912E is a dual 911/912E version, so I thought someone did the unthinkable and filled the old girl up to the brim. When I drained the oil, it was obvious that the excess was in fact fuel.

The compression check revealed a suspect cylinder, and sure enough, when I popped the valve cover, there was the rocker assembly laying there for the world to see. A rocker shaft nut backed off, then the stress caused the other one to snap the stud. Thanks to some very careful welding, I extracted and replaced the stud and got it all back together. On a curious note, when the engine was rebuilt in 1999, they "upgraded" to hydraulic lifters. I have no experience with hydro. lifters in a type 4. As good practice I went ahead and adjusted the valves (warm engine up, and before the lifters leak down, adjust to 1/2 turn past 0 lash).

Engine runs great, and after a little clean up and a clutch adjustment, it drives very very well. The problem I'm having, and the point of this post, is that I can hear a faint knock. So faint that most people couldn't pick it out, you really have to isolate the sound in your mind, but it's there. It's a bit deeper than a lifter tick, which it shouldn't have with hydros anyway. But the sound is fairly faint. I tried pulling plug wires one at a time, but the sound is quiet enough to be masked by the dropping of a cylinder.

It does not get any louder at higher RPM's, if anything, it blends in as the engine is sped up. Obviously I can just throw caution to the wind and drive it, or I could go ahead and pull it for a reseal and inspection. I just hate not being able to know one way or another. Everyone I know is just an occasional builder, more or less like I am, so I probably need someone who lives and breathes them to hear it. The main problem I'm having is that I never heard the car run any other way, so I don't know if it's just part of the engines awkward symphony, or if there an actual issue. I tried to compare the sounds with the 1.8L in the Dijon bomb before Ferg picked it up, and as near as I can tell, the sound I'm hearing is unique to the new car. Thanks!

does the sound lessen as the car wrams up at idle? the clackity clack as the lifters pump up (sometimes, after sitting) is a bit startling.

k

sorry ....I thought the valves were to be adjusted on a dead cold engine?

Actually, even with solid lifters, in an ideal world, you would adjust them on a warm engine. That way you are adjusting based on real expansion, not on a fixed number (.006 for instance). In this case, it has hydraulic lifters, so you want to adjust them when the lifters are fully primed. If it was cold, the lifters have give to them, and you could never get an accurate adjustment.

Oh, and it is not just on cold start-up. I suppose there is the possibility of a collapsed lifter, but everything looks fine. I would think with all the fuel that ran through the engine, all the oil passages would be squeaky clean and free of gunk (although some bearing material may have been shed due to the lack of lubricosity).

Bump for the engine builders who actually work for a living

Alllll rightee now....

Efffin hydro adjusting made easy.....

Hydros are supposed to pump up to remove the rocker/valve gap. If the adjust screw is too far out (gap like regular solid lifters), the valves and rocker arm clatter. They are designed to run with a slight compression from the rocker arm. Too much compression and you run into other problems such as a collapsed lifter.

Step 1. Make sure you are running synthetic. The VW hydros lay horizontal and are notorious for getting gunk in them. Synthetic is the only oil that works in my Vanagon along with a clean filter.

Step 2 Get some new valve cover gaskets. You are going to be in there adjusting at least two different times.

Step 3 Crank the engine to pressurize the lifters. Remove the valve covers and set the valve gap to just touch. Some set it to a slight gap such as .006 and retighten the lock nuts. What you want to do is to allow the lifter to fully fill and move out as far as it can. Who knows what a DAPO did to set the valves. Maybe one is partially collapsed.

Step 4 Put the covers back on and run it to pump up the lifters. Some (like me) run it for a day or 2. This guarantees the lifters move out, the synthetic cleans the gunk, and all air is purged.

Step 5. Pull the valve covers again (when cold) and recheck the valve gap. Readjust so the adjust screw just touches and then turn in two 1/2 turns. No, not 2 1/2 turns but 2 turns of 1/2 of a turn. The manual calls for 2 full turns and is WRONG!

Step 6, retighten the lock nuts, replace the valve covers and enjoy.

Yes, I am an engine builder and engineer, but my daytime job is Patent Law. So, technically I work for a living. I have driven a VW hydro engine for the last 20 years......

Ken

Want to make sure it is not a rod knock, its easy, with the engine running at the rpm that makes the noise, pull a spark plug wire at a time, if the knock goes away, it is on that cylinder. if not its not a rod bearing problem, Look back at the lifters.

And yes, I did stay at a Holiday Inn Express last night.



Erik Madsen

Thanks for the replies guys. That's pretty much the technique I followed for adjusting the lifters and checking for the bad rod bearing. The main difference being that I went ahead and adjusted the lifters with the engine at operating temp, and only went in 1/2 turn. I did it in three stages(loose, just touching, and to 1/2 turn in) to ensure the lifters were fully primed.

I think I'll drive the car a bit and go through another session of lifter adjustment unless someone can come up with a better idea. Ok, back to your regularly scheduled Friday night activities.

I'm gonna ask one more time.

Are you running CLEAN synthetic oil? You can really clear up a lot of old hydro lifter issues with it.

No synthetic, you can chase your tail for awhile. No, I'm not gonna say how I know...

Ken

give the oil a couple of minutes to drain out of the valve covers. it will still be plenty hot.

k

I was trying to avoid synthetic due to leaking. Having a two and a half gallons in the crank case didn't do the seals any favors. I'll drive it around for a day or so, then switch to synthetic, and do a followup adjustment of the lifters to see if any freed up.

Oh, by working for a living, I meant that my initial post was during regular business hours, so the bump was for the guys that worked all day instead hanging around the computer.