Burnt Cam lobes??
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From: Alberta
Okay, now you have me going here looking at your pictures. The thing that jumps out to me is the fact both cam shafts are completely coated with shellac and the rest of the engine is relatively spotless. How can this be unless those shafts were lifted from another engine and placed in the “clean” one?
My only questions would be— Given that the original cams in the s2000 are not known to be a common fail point (unlike the retainers), why change cams? Also, If the original cams were somehow damaged then wouldn’t it be safe to assume that the previous owner would also need to change out the rocker arms as well? If the owner upgraded to a aftermarket cam then likely things like springs, retainers, etc would also be changed out. However, I can still see the original markings Honda on the springs (intake and exhaust)...
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From: Alberta
Are they OEM cam shafts?
To me the engine looks good generally and only the cam shafts look a little different - darker - than I remember mine looking. But, I'm going on memory and they could well look 100% normal. Of course there is that discoloration on the Cyl. #1 intake lobe. Does the discoloration on the lobe feel rough to the touch? Could we see a pic of the pointy side of the intake lobe on #1 where it makes contact with the valve stem top?
Did you measure the existing valve gaps? How were they?
Is there any sign of scorching to any of the other bits around those intakes?
I tend to agree with the others that it looks like a bit of corrosion - and minor at that.
Its not hard to do a compression test to set your mind at ease a bit. If it were me, I would do a compression test for peace of mind.
To me the engine looks good generally and only the cam shafts look a little different - darker - than I remember mine looking. But, I'm going on memory and they could well look 100% normal. Of course there is that discoloration on the Cyl. #1 intake lobe. Does the discoloration on the lobe feel rough to the touch? Could we see a pic of the pointy side of the intake lobe on #1 where it makes contact with the valve stem top?
Did you measure the existing valve gaps? How were they?
Is there any sign of scorching to any of the other bits around those intakes?
I tend to agree with the others that it looks like a bit of corrosion - and minor at that.
Its not hard to do a compression test to set your mind at ease a bit. If it were me, I would do a compression test for peace of mind.
The valve clearances were correct and acceptable on all the intake valve lashes. However, the exhaust valves were a different story as literally every single one was completely off spec (could not even fit the smallest spec feeler gauge between the lashes) —too tight.
One I get a chance, I’ll post more specific photos of the lobes in a few days.
Joined: Sep 2014
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Okay, now you have me going here looking at your pictures. The thing that jumps out to me is the fact both cam shafts are completely coated with shellac and the rest of the engine is relatively spotless. How can this be unless those shafts were lifted from another engine and placed in the “clean” one?
Joined: Jun 2016
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From: Vermont
Its seem really odd to me that all the exhaust valves are way out of spec like that, and all the intakes are perfect. Its almost as if perhaps someone screwed up a valve adjustment. Doesn't make a lot of sense. But, since the exhaust valves were extremely tight for who knows how long I would definitely do a compression test for peace of mind. I suppose the other way to look at it is whats done is done and if its running fine so be it. Just put it back together and drive it. But, as I say, I would want to see if I've got good compression.
Joined: Aug 2012
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From: Foothills East of Sacramento
I went into my archive and found this picture of my engine with the cover off when I performed my first valve job. This is a 2009 with 40K miles on it (at that time) and I have always used Mobil 1 0W-30. I performed another valve adjustment last year with 60K miles and there was no change in appearance and one minor adjustment needed.
I wanted to see what my cam shafts looked like. It does appear that the rough unfinished parts are darker in color.
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From: Alberta
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From: Eastern Ontario
I believe noodles is from across the pond and had the answer right away. Your car should be fine, just enjoy it now. 
Joey also cleared up any possible long term issue, all good.