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Caked on deposits in combustion chambers
Posted by Weston [Email] (more from Weston) on Sat, 23 Mar 2019 18:23:50
In Reply to: Re: Problem Found-NOT the head gasket......EXhaust Valve gone, 02 Viggen, Thu, 21 Mar 2019 12:46:36
After removing head gasket and finding it in perfect shape, and seeing hand written paint pen marks identifying the camshafts, cam bearing caps, I know the gasket was renewed at some point. Without measuring yet, but eyeing the half-moon recesses on bottom of cylinder head, it appears the head has been machined.
What is interesting is the black oily deposits in combustion chamber. Similar to the gunked-up spark plugs, they all had dark coked-on caked on deposits on flat side of valves, domed roof, and tops of pistons. The one difference was that top of cylinder # 2 was actually free of the hard deposits, but yet was wet/oily.
Carb cleaner was not very effective in removing the deposits. Mechanical scraping first, followed by Diesel fuel to loosen up the fibal layer of burnished, coke-like deposits.
The intake manifold ports were quite oily, but not to the thickness or hardness found on cylinder head dome. I found the top of cylinder head cam area, and rest of head and cylinder walls were pristine.
My guess is all the valve guide seals are bad, due to age?
Then, when enough heat and boost was present as I drove up a big long hill after engine had already warmed to operating temp for 20 minutes, the extra oil was burned and took out #2 exhaust valve.
I will take it to machine shop, and have guides checked, seals replaced, and burned valve replaced, but not have head resurfaced, since engine was not overheated.
I’m looking at a bunch of things ‘while I’m in there’-
Turbo steel water and oil lines pulled to remove rust scale and repaint
-alternator brushes (worn to nubs)
-heater core ( slight evidence of seepage, and a recent sweet smell in cabin, to boot)
-blower fan motor, been screaming for a few months
-loose power steering return hose clamp on pump trimmed/reattached
Also considering putting back a stock air filter and box-someone had removed it and put an Abbot ‘open’ type air filter.
posted by 24.161.9...
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