Hi all - For the life of me, I cannot recall which way the indent for the valves goes on the pistons. Is the piston in the picture oriented the correct way, or is it upside down?
Also, this piston only has 8000 miles on it. Is the carbon build up troublesome?
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Full Version: Piston orientation
not too familiar with a 1.7 (it's a 1.7, right?) but you should be able to match the indents with the valves in the heads. (Assuming I'm right in thinking the indents are for valve clearance). All the pistons I've done have marks to locate them toward/relative to the flywheel. Maybe yours do too under the carbon.
The indents are for valves.
The valve is angled in the head. I am not looking at a head now so you look at a head and you will figure it out.
Those deposits are pretty heavy and look like oil or you are running really rich as it has a wet look. Your rings should have seated by now, but ......,
The valve is angled in the head. I am not looking at a head now so you look at a head and you will figure it out.
Those deposits are pretty heavy and look like oil or you are running really rich as it has a wet look. Your rings should have seated by now, but ......,
The pistons typically have a small arrow stamped at the edge of the crown, in line with the wrist pin.
If you can't determine orientation by the valve reliefs, scrape the carbon off the outer edge and you should be able to see it.
I'd de-carbonize the pistons anyway - look for any cracks or defects, etc., not to mention that a clean motor is a happy motor
If you can't determine orientation by the valve reliefs, scrape the carbon off the outer edge and you should be able to see it.
I'd de-carbonize the pistons anyway - look for any cracks or defects, etc., not to mention that a clean motor is a happy motor
From what little that I know, the valve cut outs should be pointed down as posted in your picture. If one of our resident engine masters chime in to confirm that would be fantastic.
QUOTE(396 @ Oct 1 2013, 07:14 PM) 
From what little that I know, the valve cut outs should be pointed down as posted in your picture. If one of our resident engine masters chime in to confirm that would be fantastic.
Yes---down. These look like 96mm AA pistons so there will be no arrows or other marks on these. Ray
QUOTE(reharvey @ Oct 1 2013, 04:30 PM)
QUOTE(396 @ Oct 1 2013, 07:14 PM)
From what little that I know, the valve cut outs should be pointed down as posted in your picture. If one of our resident engine masters chime in to confirm that would be fantastic.
Yes---down. These look like 96mm AA pistons so there will be no arrows or other marks on these. RayThanks for all the help. Yeah, the carbon is wierd. Brand new 2056 build, the good oil, my plugs look really good when i read them (webers, by the way). Car was running great, no flat spots. Seems like a ton of build up. Maybe I drive like a little old lady and need to do the "italian tune up". Half Italian, I can say that.
Someone yesterday told me the indent should be on the upside? This is someone that has built a number of 914 motors. Now I am confused.
They consensus here was to run them with the indent down, like my picture. Looking for a few more opinions.
They consensus here was to run them with the indent down, like my picture. Looking for a few more opinions.
Valve pocket down.
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