engine and drivetrain Problems with valve adjustment

[scestes]

I've put a mark on the rocker and eccentric to note where it should be when the valve is properly adjusted. I adjusted them this morning, put this mark on, and then bumped the engine. I noticed while I was adjusting other valves, this valve managed to get bumped by the cam lobe and so I checked it again. It was already out of whack. It went from .008 to .011 just from me bumping the starter.

I'm going to admit that I'm pretty stumped right now. My options are to remove the head, take it back to the machine shop and see if he can figure it out (not my favorite option of course) or order some new eccentrics, nuts, washers, and bolts, and HOPE that the eccentrics are just a little to thin to for the rocker arm to keep a firm grasp on them.

Anyone else have anything to suggest? Please feel free to throw in the kitchen sink as it may be easier to test/verify than the alternative of removing the head again.

[ryanOC]

uhhhhhhhhh i'm not an expert (yet), but it looks like the rocker is cracked dude

i'm going to guess that the flexing that caused the crack is also what makes the lobe vulnerable to going out

looks like your head is going to have to come off

you may want to invest in the rockers sold from ireland engineering (i think)

[scestes]

Nope. that's just a shadow from the sun. I should have used a fill flash to get rid of the shadows, but I didn't want to look for new batteries. Here is the rocker from the angle of that casting seam out of the shadow.

[scestes]

I'm going to throw this out there and see what people think. What are the possibilities that the wrong springs were installed on the head and that the springs currently on the head provide too much recoil strength and are pushing my eccentrics out of their settings? At this point, aside from the possibility that the eccentrics are a little thinner than they should be, I can't think of anything else it could be.

I'm stumped.

[02jake]

I just had a look at the factory manual and it looks like the eccentric is on backwards. Have a look in the manual and see if you can see a difference. when adj valves are you pulling to the outside of the head to reduce clearance. and you are setting the feeler between the eccentric and the valve? I know it is an obvious question but it has to be asked. One thing that came to me, are the retainer clip sleeves in correctly. Are the rockers sitting on the cam properly? I would not pull the head until speaking with the machine shop.

[scestes]

I just had a look at the factory manual and it looks like the eccentric is on backwards. Have a look in the manual and see if you can see a difference. when adj valves are you pulling to the outside of the head to reduce clearance. and you are setting the feeler between the eccentric and the valve? I know it is an obvious question but it has to be asked. One thing that came to me, are the retainer clip sleeves in correctly. Are the rockers sitting on the cam properly? I would not pull the head until speaking with the machine shop.

All very good questions actually. When I adjust the eccentrics I am pulling them towards the outside of the head to apply more pressure (close the gap). That's correct isn't it? The rocker arms all appear to be sitting nice and firmly on top of each of their respective valves. I am indeed making my gap measurements between the eccentric and the valve tip, not where the cam and rocker arm come into contact.

I'm going to talk to the machine shop first thing in the morning actually and see if he can give me any additional ideas. My biggest fear is that I'm going to pull the head, get it to the shop, he's going to look it over and have the same head scratching experience I am.

[trangieboy]

Could the valve springs be going coil bound ? Or the valves hitting the pistons ?

Mal.

[scestes]

Could the valve springs be going coil bound ? Or the valves hitting the pistons ?

Mal.

Good question. It would explain as to why no matter how tight I snug down the nuts, they still get pushed out of whack. When the head was put on, we look for the TDC mark on the front pulley. From there we honed in on TDC on the block by looking in the viewing window at the back of the block where the engine mounts to the transmission. We looked for and found the little hole drilled in the top of the flywheel in that window. We then made sure the chain was aligned so that the cam also read TDC. Here is a pic of what the cam looks like presently when the engine block is at TDC. Am I off by a tooth? It looks right to me at least. Given the choice of where I'm at and one tooth either direction, i think I'm sitting in the correct tooth.

[dapbmw]

if your 292 cam is a regrind you might need the oversize eccentrics. btw valve adjustment specs is same as stock cam .006-.008 with the engine cold as in never been run at least 12 hours

[scestes]

if your 292 cam is a regrind you might need the oversize eccentrics. btw valve adjustment specs is same as stock cam .006-.008 with the engine cold as in never been run at least 12 hours

Hrmm. Aren't the oversized eccentrics to compensate for less material being on the cam? Meaning, I wouldn't be able to actually do a real valve adjustment because the amount of lobe available on the stock eccentric is too small? Or does the increase size of the eccentric give it more grip in the rocker when you tighten it down?

[scestes]

I just talked to my machine shop and the owner reminded me when I got the car that the valve adjustment was quite a bit off from where it should have been. I've shared much of the info about the car since I got it with him, so he knows quite a bit regarding the issues I've found. It looks like this is quite probably an issue that the PO was having (a problem amongst many other problems) as well. I'm headed to the dealership to buy some new Bolts, nuts, eccentrics and washers to see if the ones I have a too thin and are slipping.

[JohnN]

is at TDC. You should see the letters "OT" through the hole in the tranny bell housing, NOT the little ball.

Regards,

John N

[scestes]

is at TDC. You should see the letters "OT" through the hole in the tranny bell housing, NOT the little ball.

I've looked and I see no T near the O. At least not that I'm able to see. I look at the front pulley and I can see it's at TDC, I've gone back to the little window and I see what looks like an O or a drilled out portion of the flywheel, but I see no T.

[scestes]

FYI. I also see a Z that shows up before the O if I spin the crank around.

[ryanOC]

when we got a 292 cam for a customer car, we also got lash caps as well

pop those on the stems and we won't be needed to buy any bigger lobes