Intake valves diagnosis

ICEDVOVO

Took off the intake manifold to do some general maintainence and while at it took some pics of the valves visible on the inlet side. Cylinder 5 exhaust valve looking black and caked while all other valves very clean and shiny. Is it plugs, injectors or adjustment causing this condition? Car has done 210000Km.

ICEDVOVO

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ICEDVOVO

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ramrod

The stem seal for that valve is leaking

ICEDVOVO

Thanks. What's involved in fixing that and what impact could it be making on engine performance, etc?
New stuff for my old brain to learn and offset my dementia.

ramrod

The cam carrier needs to be removed to gain access to the seals.

That alone requires special tools as you cannot just remove it without having the holding fixture clamping down on the cam carrier as there’s valve spring tension beneath it.

The tool kit should also contain the cam locking holder tool.

You’ll need to either remove the complete lower cylinder head to service the valves and seats or the other way is via compressed air into the spark plug holes so to keep the valve from falling down once you have removed the collet keepers to then remove and replace the stem seals

Big job and most would recommend replacing that engine though I disagree with this as I am a repairer not a parts changer and I like to repair things that are repairable

ICEDVOVO

ramrod Thanks for the reply. It does sound like a big job and while beyond my skill level I'm willing to give it a crack when I get the time and courage. Robert DIY solves the valve drop by stuffing rope down the piston and rotating the crankshaft. He shows the in car method on one of his videos but by no means recommends it, suggesting removing the head is a a better way to go. There are symptoms of a failed stem seal by way of rough idle and poorer performance than I can remember when the car was new.

The other comments here are appreciated however cleaning the valves and throat does not solve the cause of the problem, ie replacing the valve stem seals and reseating the valves

Massey165

There is some great fixes for this problem on Swedespeed. Mainly involved using crushed wallnut shells as a abrasive agent under air pressure to clean the valves and the throat.

adrianw

Some gas turbine engines use crushed walnut shells applied whilst the engine is on start cycle without ignition, the walnut shells sprinkled into the intake to clean the first few stages of the compressor blades, not used on them so much anymore as it tends to block the narrow bleed air channels and caustic chemicals are used more now days. Walnut shells or ground peach pits as an abrasive agent work well and don't remove as much parent metal like sandblasting can.

An engine cleaning agent would probably give that a good clean, like an upper engine cleaner maybe, or good old oven cleaner, or a scouring pad and brake cleaner. As an ex gas turbine mechanic I would certainly give it a crack in cleaning it up myself.