post valve adjustment comments

[schnell944]

Well, some of you could tell I was doing my first valve adjustment today, what with all the valve related questions. I read so much about the procedure that I had felt I had done the job several times already.

Anywho, with all of the valves adjusted to spec. and checked several times, I buttoned her up and took her for a drive. My first impression was that the engine was much quieter in terms of valve ticking...which I though was odd because most of the valves were too tight before adjustment. I definately noticed more power, and the fuel economy was better to boot.

Upon bringing the car back into the garage and listening to the engine, the distinct ticking was back to the normal noise level. What could account for this? I made doubly sure that the eccentric pinch bolts were tight enough. Could it have something to do with it being a very cold day and the gap expanding once the engine was warmed up? In any event, I'm impressed with the difference. Allbeit this was in conjunction with a new fuel filter, plugs and O2 sensor in the same week, and the valves had not been adjusted in at least 50k mi.

[Alexlind123]

I think i noticed the same thing with the noise.

[632 Regal]

adjust them as it says at about 70 degrees temp stabilized for 24 hrs. but put them to 011, double check them when done and repost. when the engine is hot and its cold out your guessing at clearances.

[Kalevera]

Given that the cam and rocker pads aren't worn, and that there isn't any other excessive top end wear, the ticking is completely normal (and in my opinion, you don't want it to go away).

I set my valves to a tight 13 thou HOT, service work always got 13 thou cold because it's spec. I'm interested in giving the valves as much clearance as possible, for the obvious reasons. 13 thou hot is a little noisy when things are cold, even with the car's fresh head, cam, rockers and everything. Once it's warm, it's sweet.

[schnell944]

Regal,
The engine was cold and sat overnight when I adjusted them. I set them all to the .012 spec. I was just wondering what would cause the valve noise to be impressively quiet at first start-up, then progressively level out to the normal level after a good drive.

If this seems to be normal, I'll try not to worry about it....internal engine work always gets me paranoid.

[Robin-535im]

Given that the cam and rocker pads aren't worn, and that there isn't any other excessive top end wear, the ticking is completely normal (and in my opinion, you don't want it to go away).

I set my valves to a tight 13 thou HOT, service work always got 13 thou cold because it's spec. I'm interested in giving the valves as much clearance as possible, for the obvious reasons. 13 thou hot is a little noisy when things are cold, even with the car's fresh head, cam, rockers and everything. Once it's warm, it's sweet.
Yo - mysterious 3-grand master... What's with the name changing? Throws me off...

Re: valves.. I get similar behavior with the noise. Adjust, start up, quieter. Next day, start up, bit noisier, but quiets as engine warms. Some days just seem noisier.

[Jeff in MN]

535is with them m30 engine with 240k miles. The top of the valve can actually become dished with wear from the adjusting lobe. So when you are measuring the gap your guage is acutally spanning across the peaks on the outer edge of the valve, so the real gap that the adjusting lobe dips into is actually larger. So in order to compensate, I began setting my gaps on between the rocker and the cam lobe. Since the rocker is a bit longer on the cam side, I think I set them at 0.010 Go and 0.011 No Go.

Good luck
Jeff

[schnell944]

535is with them m30 engine with 240k miles. The top of the valve can actually become dished with wear from the adjusting lobe. So when you are measuring the gap your guage is acutally spanning across the peaks on the outer edge of the valve, so the real gap that the adjusting lobe dips into is actually larger. So in order to compensate, I began setting my gaps on between the rocker and the cam lobe. Since the rocker is a bit longer on the cam side, I think I set them at 0.010 Go and 0.011 No Go.

Good luck
Jeff

Interesting, didn't think of that. If I can find time to open 'er up again soon, I'll try to adjust using that method and see how that goes.

[bsell]

535is with them m30 engine with 240k miles. The top of the valve can actually become dished with wear from the adjusting lobe. So when you are measuring the gap your guage is acutally spanning across the peaks on the outer edge of the valve, so the real gap that the adjusting lobe dips into is actually larger. So in order to compensate, I began setting my gaps on between the rocker and the cam lobe. Since the rocker is a bit longer on the cam side, I think I set them at 0.010 Go and 0.011 No Go.

Good luck
Jeff

A good valve grind, both at the seat and the stem, will ensure the valves spin as they go up and down to even the wear at the top of the stem (where the rocker arm contacts the valve) and seat. The spin action is also designed to help the valve clear garbage off the seat before the valve gets 'burnt' by compression gases leaking by the obstruction.

I broke a rocker arm before due to incorrect adjustment of the valve clearance (the exact procedure you described). Granted this was a Nissan engine (that required checking clearances between the stem and rocker arm), but I would only use the proscribed procedures...

[Jeff in MN]

A good valve grind, both at the seat and the stem, will ensure the valves spin as they go up and down to even the wear at the top of the stem (where the rocker arm contacts the valve) and seat. The spin action is also designed to help the valve clear garbage off the seat before the valve gets 'burnt' by compression gases leaking by the obstruction.

I broke a rocker arm before due to incorrect adjustment of the valve clearance (the exact procedure you described). Granted this was a Nissan engine (that required checking clearances between the stem and rocker arm), but I would only use the proscribed procedures...

Rather than a valve grind, one of the guys on the other e28 board purchased "stem caps" which obviously go right over the top of the valve stem and provide a new machined surface to measure from. Saves the hassle of pulling the head etc....

[schnell944]

that seems like a less involved option...

[schnell944]

so, I haven't opened it up again, but consistantly, the car is very quiet for the first few minutes after I start it up cold. The valve noise then returns to normal after warmed up. what could be the mechanical workings behind this?