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Chris

Cam Color

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I've just pulled the valve cover off my Z, and noticed that the lobes on my Engine are slightly different colors. Some are very shiny, while others are dull. Below are a couple of picture? And I to guess that the valves are out of adjustment. Some always touching the lobes, while some do not?

-- Chris

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Please notice the difference in color between lobes 5 & 6 from the right. The picture doesn't show it very clearly, but there is a difference. Also the orange strip.. I think it is paint, need to look closer, but does that identify what type of cam it is?

-- Chris

post-853-14150792062809_thumb.jpg

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Anyone notice in the other pictures the Socket extension in the end of the hose attached to the anti-backfire valve?

ROFL

-- Chris

post-853-1415079206396_thumb.jpg

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Impossible to identify a cam by just looking at it. You would have to either have some sort of markings on it if it is an aftermarket cam or you would have to measure the cam lobes.

As far as the difference in the wear patterns on the cam lobes, it looks to me like you have valves that are too loose. The wear patterns look pretty good on a few, but you definately need a good valve adjustment done on the ones that show little wear. If the valve adjustments were within spec they should all look nearly the same. Either that or the cam followers are shot on a couple valves, leaving you with too much valve lash.

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I do notice a slapping sound coming from the head when I start the engine. Would that be a sign of valves out of spec?

-- Chris

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Well, it would probably be more of a "ticking" noise if the valves are to loose, which I suspect they are by the looks of the cam. It might be a good idea to take the lash pads out for a "look-see" too. It may be the main problem is worn out lash pads, and this is what is causing the worst of the problem, the wear pattern on the cam isn't what it should be. You might be looking at more than just a valve adjustment, you might need lash pads replaced before you can get the adjustment right.

If you notice the one cam lobe seems to be showing most of its wear on the very tip of the lobe, which indicates to me that the valve adjustment is so far off it is barely touching the lash pad and the valve therefore is not opening as soon or as much as it should.

I think it might be in your best interest to remove the head and take it to a competant machine shop for a thorough check over. It might be a good idea to replace the valve stem seals, and perhaps the valve seats (if you don't already have hardened seats) and have them check the lash pads to see if they need to be ground or replaced. If it has run like this for a long period of time, the cam has probably worn the lash pad in such a way that it will be impossible to get a correct valve adjustment without replacing or at least grinding the lash pad.

Sorry, but the more I look at the pics, the more I suspect there may be some damage done that needs to be addressed soon. :ermm: Wait a day and see what other opinions you get here, mine aren't always right.

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Chris,

You could use a good valve adjustment. Good thing about a valve adjustment on a Z is that they are EASY.

I used to adjust my valves once a month because I liked to do it... no ****. Yep. :) I used to love to hear that thing puuuurrr..

Anyway, do your first adjustment when the engine is dead cold. Then, take 'er out and warm up the engine (be sure to put the cover back on :P ). Come back and adjust them again.

Not sure about the damage. 2mZ's used to race Zcars, so, he has had a lot of engine experience.

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I'm not an "engine guru" in any way, shape or form.

If you do a good valve adjustment, run it a couple weeks and take the valve cover off again and check the wear again on the cam lobes. If it still looks odd and not even across the cam lobes, that will be a good indication that the lash pads are bad. They can be ground at a good machine shop to give them a nice flat contact surface, unless there is too much wear. If they are worn beyond a certain point they will need to be replaced as they won't be thick enough, and will be in danger of failure.

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I'll agree with 2Many on the adjust and see method here.

If the valves have been out of adjustment a long time, you may have started to burn the valves or have caused detination problems with the pistons or seats (this would most likely take a long time to do). As long as you aren't seeing any - or much - blue smoke you should be okay here. Do a compression check. That may help determine where, or if, there is any damage to your valves - a leak down test may also be helpful.

But, the first step would be to simply adjust the valves and get a feel for how things are running. Probably a good idea to adjust your carbs while you're at it - misadjusted valves will breath differently.

BTW - nice clean looking engine!

Rick

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Chris,

One other thing to do before you pull the head. first set valves. Then have someone familiar with dial indicators and engines check the amount of valve lift at each lobe. This will show how much wear has taken place, and you'll know if the cam needs to be replaced befor taking the head off.

Phred

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