Banjo bolt backed itself out, front end ticks now... how bad is that??
So I've been hearing some noise from the engine lately, so I decided to do a valve adjustment, hoping it was just a noisy valve... Pull the cover off, and I see a banjo bolt just lying there... dammit! The frontmost bolt had worked its way out and off the rail, and was just lying there in a valley. Luckily, I had Don's new bolts in hand, so I replaced them and adjusted the valves to .013, replaced the cap and rotor (Bosch), new igntion wires (Bremi), and a set of new plugs (NGK V-power, .30 gap). Put everything back together, and fire it up... still hear the damn metallic tapping from the front of the engine. So... how bad is it? Does this just mean I'm going to have a noisy engine (I can live with that), or is something damaged and going to fail in the future? I also snapped the stupid bolt that bolts the valve cover down (the front one, only bolt on there as opposed to nuts everywhere else), half of it's hanging out in the head somewhere... whatever!
Anyhow... anybody know what that noise means, and is it going to get worse or will something break?
-Tim
total casualties: 1 snapped valve cover bolt, one banjo bolt (AWOL), 1 twisted allen key (from trying to loosen the rotor), and 4 skinned knuckles (gotta love spark plug #6!!)
Don, valve lash caps could be used to repair a damaged
stem provided you can back the eccentric off far enough for them to fit.
And keep in mind as your tightening the valve clearance that the cams aren't pressure fed.. that you're depending on drip and it needs clearance between the cam and rocker in order for oil to get in there for lubrication for the 2 surfaces... a couple of other things to mention are valve stem rotation for cleaning the valve seating surfaces and heat transfer..
You don't hear about too many burnt valves but you do hear about dropped exhaust valves, I don't know if reduced heat transfer is related to the fatigue issue that occurs on the valve tulip and stem area resulting in dropped valves or not but just thought it might be a good idea to bring up these points. I personally would rather err on the side of looseness rather than tight...BYMMV
Quote:
Originally Posted by gale
If you can isolate which cylinder(s) it is with a stick held up to your ear, take the cover off again, take a close look at the tip of the valve stem & maybe take the eccentric off & make sure the stem isn't cupped or the eccentric has any flat spots. Next time I adjust mine, I'm going to replace all the eccentrics and pinch bolts. It might be a bit of overkill but they've been adjusted so many times I'm afraid one of these days I'm going to snap off one of the pinch bolts when tightening it & I did remove a couple eccentrics last time & examined them under magnification & could see that there was a slight sharp corner at the end of the worn patch & the virgin portion just beyond where it rubs, & could be responsible for some ticking when swivelled to a new position when adjusting them. Not much you can do for a cupped or pitted valve stem short of a valve job. Also could be a noisy injector, try the stick trick with them too.
Also, even tho .013" is better for smoother idle, right now I have mine set at a tight .012 & next time I'm going to set them at .011, it seems to have a bit more power & smoother at upper rpm's with a tighter setting & I'm willing to sacrifice idle for that. Rarely do we hear of an m30 with a burned valve so I'm not worried about running them tight.