I lost a lot of low end here lately and decided to go back and double check my valve clearance. Sure enough the intake valves won't even fit a .0015" feeler gauge between the cam and shim. Im sure they were hanging open. Im already down to a .089" and .087" shim on the intake valves which the BMW service manager told me was small already. Has anyone had to go lower than this??

 

I thought the valve clearances were between .004 and .006. Anybody know what the manual says they should be?

 

.10 to .15 mm 0r .004-.006 in.

 

<< I thought the valve clearances were between .004 and .006. Anybody know what the manual says they should be? >>



Exactly. Since my valve clearance is less than .000&quot; then the valve is always open and never seats, hence no compression and loss of power.

 

rocky- who ported ur head and intake for u? Did u notice a differance?. Was it worth it? I am looking to do some engine work on mine, but not really sure on what to do,or who to have do the work.thanx

 

Rockey - I had to decrease from my stock shim size too when I adjusted my valves a few months ago. My stock shims were .0895 (if I remember correctly), all four of them, and my intake clearance got down to .002 on both valves so I went down to the next size smaller shim to open the clearance back up. Seems like the shim increment is .0025 if I'm not mistaken. There are many sizes smaller than those that I bought available, so I don't know why the tech told you it seemed small. My dealer didn't have what I needed, so I ordered them from RWR - $5 each.

I'm at work now, but I have all this documented at home, including a complete list of all available shim sizes and BMW part numbers. If you need it, I can mail it to you. Let me know, and I'll do it tonight when I get home.

 

Okay, here's the site with all the shim info. I was mistaken - the valve shim increment is .002, not .0025, and I also must not have remembered correctly on my shim size either - all four of my stock shims were .0886, not .0895. I called and had the ol' lady look it up for me in my DS folder! I dropped down to the .0866 on both intakes, to get them up to .0045&quot; on clearance.
Valve shims

 

<< rocky- who ported ur head and intake for u? Did u notice a differance?. Was it worth it? I am looking to do some engine work on mine, but not really sure on what to do,or who to have do the work.thanx >>



I ported the head and intake myself. As soon as I get this problem fixed here I will be back at the track to see what kind of gains it made. Watch for a post later on in the week. If you want more details on the head then feel free to PM me.

 

<< Okay, here's the site with all the shim info. I was mistaken - the valve shim increment is .002, not .0025, and I also must not have remembered correctly on my shim size either - all four of my stock shims were .0886, not .0895. I called and had the ol' lady look it up for me in my DS folder! I dropped down to the .0866 on both intakes, to get them up to .0045&quot; on clearance.
Valve shims >>



Thanks Chris! I got one valve in spec now and it looks like I will have to drop down lower than .0826&quot; on the other to get it in spec.

 

i had the same trouble with my shims. i lost lowend power and was lucky to get the bike started most of the time. both intakes had no clearance. ended up going down 12 thousanths to get them right