The engine feels strong and very responsive even on the stock tune. So that bodes well for later on. Found out what the classes mean. The class relates to the bearing diameter of the arm. Altering these will definitely have an effect on the valve geometry. Tigger 1.0 had class 4 rocker arms and class 2 intermediate arms. Going to pull the new ones out tomorrow, check the classes and mic them to see the difference. Oh how I wish to be locked in the same room with the engineers that invented this abortion. Ten minutes that's all I'd need....to explain my point of view that is.

 

They always gotta try to re-invent the wheel. SMH. why can't they just keep it simple for us.

 

Using Tigger's old head and a dial indicator I verified lash adjuster preload is 1.25mm +/- .01mm on the intake cam and 1.35mm +/- .01mm on the exhaust cam. Measured the new head and found it to be 1.54mm. Way too much preload. Also found evidence of premature wear on the rollers of the intermediate arm and drag lever arm on the intake take side. The exhaust side was fine.





The new head had class 4 drag levers and class 3 intermediate arms. The old head had class 4 drag levers and class 2 intermediate arms so I installed the class 2 arms on one cylinder and measured again. You would think that a smaller class number would lower the valve lash preload but it works in reverse. Installing the class 2 intermediate arms increased the preload to about 1.88mm. So we ordered two class 4 intermediate arms as well as two class 3 and class 5 drag lever arms. With that combination we should be able to mix and match as necessary to reach the correct preload. Once complete we will order the rest of the arms and give Tigger a spin.

 

Eyes wide open and blinking. Oh, and question marks over my head too.

 

Yeah tell me about it. Since BMW didn't publish a procedure for this I had to write one.

1. Disassemble valvetrain.
2. Bleed lash adjusters.
3. Re-assemble valvetrain.
4. Install dial indicator with .100" preload and zero indicator dial.
5. Remove valvetrain compressive force.
6. Measure lash adjuster extension to determine preload.
7. Repeat procedure two more times and average results.
8. Drinks a beer and give BMW the bird.

Step 8 is optional but highly recommended.

 

Exactly....first half of step 8 sounds great

 

Ok so I got bored waiting for parts to arrive and decided to take an old valve cover from Tigger1.0 apart. I believe it was Oldbrokenwind who was kind enough to do a cut away on an N14 valve cover so we could see how the system works. Hopefully, this will help answer some questions on the newer system.

Here is a general overview picture. The "I" is where PCV gases inter the valve cover. The "R" is where oil that has fallen out of the gas is allowed to return to the cam galley and the "X" indicates the four ports where the PCV gasses exit the valve cover. The center exit port in the back actually leads to the inlet path of cylinder 2 and 3. The one on the left and on the right lead to the inlets for cylinder 1 and 4 respectively. The final "X" in the upper right leads to the inlet hose upsteam of the turbo.



Here's a slightly different angle to help visualization. You can also see the oil baffles slightly better in this picture.



The following photo wherein my rather poor drawings skills are displayed illustrates the gas path as it works its way through the valve cover. Notice the orange valve on the left. This valve comes into play when the engine is first started cold. During a cold start the intake butterfly on the N18 is partially closed and intake vacuum is considerably higher than normal. This pneumatically operated valve partially closes thereby preventing over scavenging the crankcase.



A closer shot of the oil baffle.



Last but not least we have a picture of a small rubber check valve that has been the cause of more than a few difficult to find boost leaks. Under normal operation this valve allows the PCV gases to flow to the inlet ports in the head just upstream of the valves. Under boost however this valve is closed by the higher pressure in the inlet ports...or rather it is supposed to. As you can see from the photo my valve has torn. This allowed boost pressure to pass through the valve cover, exiting through the front port and reenter the inlet path between the turbo and MAF sensor.



Happy Motoring.

 

Thank you for bringing the inner details of the N18 valve cover to light - this is very interesting! Essentially an OCC built in.

I wonder if it would be possible to make a fitting that would insert through the front port (that leads to the turbo inlet) to block off the check valve that leads to the inlet ports, so all the PCV gas could be routed through an external OCC.

 

The only solution I came up with was tapping the passages to the inlet port and installing 1/4" SS threaded plugs. A tedious process as once the valve cover is removed, you must also remove the intake to prevent metal from the tapping process from entering the engine. In addition if you break the tap in the head you've bought yourself some heartache removing it.

 

Saw that in your other thread, looking for a simpler / easier way to accomplish the same thing.

Back to your engine build...

 

Parts came in today wahoo! Unfortunately, I'm in the middle of overseeing a regulatory audit where I work. Might be a few days before I can get back to it.

"Life" - It's what happens while your making other plans. ;-)

 

Tigger, are you modifying the pcv system like you as well ? If so, would you be willing to show that in great detail ? I've got the pcv delete system on mine.

 

I'll send you a PM.

 

I don't like it when the regulators show up. Generally it goes ok but I can think of better things to do.

 

There are times that I know what you mean. Aviation is a highly regulated industry but rightly so for the safety of the flying public. The company I work for specializes in corporate jet and turbine aircraft and maintains eleven domestic and foreign repair station certificates so it's rare when I go more than two months without being audited by someone. Each can take from a day to a week of my time in addition to my other duties overseeing quality control. So once every couple of months I go from marginally sane to absolute crackers. Still quality improvement is a continuous process and it's good to have an outside view of things from time to time.

 

I work in the nuclear industry and one of the things we do is perform non-destructive testing QA on aircraft parts (turbine blades).

Audits are a necessary process but can be stressful. Good luck.

I'm anxiously awaiting the completion of your project. I'm hoping that if I copy your build on a proactive basis that I will avoid the mission creep and headaches that you have experienced.

 

I can't take the credit for the N14 cutaway you describe. I believe it was the Czar who did that. I've also seen someone else do a similar process. All of it is great info, as is yours.

I'm still evaluating different solutions for my PCV problems. Hope to publish results soon --- no pics tho.

 

Oops. My apologies to Czar then. They say our memory is the second thing to go as we get older. The first is umm...oh wait it's ah...no, no that's not it either...hmm. Let me get back with you on that one. Maybe my wife knows ;-)

 

Played mix and match with the lever and intermediate arms today. Managed to get the lash to less than .001" of what it's supposed to be. Call it close enough for government work. Ordered six more 04 intermediate rockers and six more 03 lever arms. They should arrive on Thursday. Also took a rough estimate of the bill from the builder. If you know anybody that's looking for a kidney let me know lol.

 

Took the parts a bit to come it with the recent weather but the builder installed the rest of the intermediate and lever arms on the other three cylinders yesterday. Runs beautifully and the valvetrain noise is long gone. I'm pretty sure somebody else will end up doing an engine swap similar to this in the future. So in a perverse sort of way it's probably a good thing we ran into these issues and were able to solve them. Hopefully it will save somebody some heartache and head scratching down the road. Pretty stoked about picking Tigger up today.

 

awesome! so is your left kidney doing ok after removing the right :P lol J/K gj!

 

I hope the other kidney keeps working well. If it quits that's gonna suck Seriously though Redline is a great shop to work with. Very reasonable on price. Maybe not as pretty as some shops but their work has always been spot on.

 

Would your shop be open to doing out of area work? I would rather pay a bit more for someone experienced with the build than a local who typically only builds V8s.

 

No problem. I'll shoot you a PM.

Brought Tigger home today. Wahoo!!!! Man did I miss the sound of that exhaust and the way the car handles. I'd swear Tigger was making a happy growl the whole way home.

 

This is so awesome. Can't wait until it's broken in.