Unknown Deposits Around Valves

Unknown Deposits Around Valves

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Beanie D

Original Poster:

1 posts

Saturday 10th May
quotequote all
Hi all,

I’m currently rebuilding the engine (M16A) on my 2014 ZC32S Swift Sport.

My cylinder head has been rebuilt by my engine specialist with new valve stem guides, de-coked, pressure tested etc. Today I went to fit it to the block and as I was cleaning the mating surfaces, I noticed that there were some greyish looking deposits left around the valve seats/ports.

Now, I’m assuming that this is just left behind carbon deposits, but I would expect it to be a lot darker in colour. Can someone possibly please tell me what this might be? I don’t want to fit the head until I know what this is, because as far as I am concerned, these areas should be perfectly clean.

I can’t currently upload photos for some reason, possibly because I’ve only just signed up to the forum!

Edited by Beanie D on Saturday 10th May 14:43

GreenV8S

30,736 posts

297 months

Saturday 10th May
quotequote all
That's a question for your engine specialist.

finlo

3,878 posts

216 months

Saturday 10th May
quotequote all
Sounds like valve grinding paste.

stevieturbo

17,728 posts

260 months

finlo said:
Sounds like valve grinding paste.
It does, and it absolutely should not have been left there. It should have been thoroughly cleaned off