white exhaust vales wtf

[loner]

I took the headers off today and noticed that inside the pipes of cylinders 2 and 4 are white, as are the valve stems.

Cylinders 1 and 3 are the usual black. Searching the web tells me that

1) white is good, and black is rich.

2) white is lean and black is good.

3) the cylinder head is leaking.

4) the timing is out.

Before I replaced the valve stem seals I only ever saw black soot inside the headers... and oil from leaking seals obviously.

The engine runs better cold now, but I think the vacuum is lower then before especially at idle... even when warm.

I get a miss when the engine is hot and I try and wind it out in 4th or 5th.

What's going on?

[Guest]

Plugs allgood and gapped correctly?

What have you touched or changed?

[Leufkax]

white is lean.

[loner]

plugs looked okay... though I have just put some new ones in to be sure.

When the motor was out it got new valve stem seals, valve grind and clearances set... new head gaskets and cam belt.

[Guest]

Did you check plug gap?

[loner]

I left the gaps of the new plugs stock... the old plugs had the same gap pretty much, just .002 inches bigger.

I think I may have bent the valves in the left head when putting the cambelt on actually.

There was a valve to valve collision... I was hoping to get away with it but that could

explain all the symptoms I think.

[loner]

Or maybe it's just the timing belt is off slightly... the exhaust cam sprocket on the left has the locator tab hole drilled out to allow

some adjustment. Maybe it needs to be retarded slightly with the much fatter than stock head gaskets.

[Optical]

I dont have anything particularly constructive to add other than I stripped a v7 engine once that had white and partially melted exhaust valves from running very lean due to a valve seat leak. Best to do a leakdown test or similar if you suspect they could have been bent

[boon]

Pull the plugs on the same side, have a look at the tips.

I had always understood that white = lean, or coolant getting involved.

[loner]

The plugs aren't white, just the valves, headers (on the left) and the turbo exhaust housing. There was no white before I took the motor out, and no missing on high load or weak vacuum at idle.

I will do a compression test and check the belt is on correctly. Because the head gaskets are 1.4mm up from 0.4mm on the stock motor, it was hard to line the cambelt up... so it's possible I

have screwed something up. Also the left exhaust cam sprocket has had the locator hole ground out, so maybe I was supposed to rotated it slightly in one direction, though I don't know which.

[loner]

Compression is good on all 4 cylinders... I will check the timing belt in the weekend.

Edited January 12, 2016 by loner

[loner]

I retested the compression this morning as I wasn't looking at the exact numbers, just that they were close.

Right side is 119 and 120, left is 114 and 115. So both slightly lower... still mostly likely the timing belt

is off a bit.