 Piston orientation, Indent postition |
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| jeffdon |
 Oct 1 2013, 01:55 PM
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#1
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Senior Member  Group: Members Posts: 1,094 Joined: 24-October 06 From: oakland, ca Member No.: 7,087 Region Association: None  |
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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| type47 |
Oct 1 2013, 02:08 PM
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#2
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
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.
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| SLITS |
Oct 1 2013, 03:57 PM
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#3
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None  |
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 ......, |
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| euro911 |
Oct 1 2013, 04:56 PM
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#4
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Retired & living the dream. God help me if I wake up! Group: Members Posts: 8,849 Joined: 2-December 06 From: So.Cal. & No.AZ (USA) Member No.: 7,300 Region Association: Southern California 
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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 (IMG:style_emoticons/default/shades.gif) |
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| 0396 |
Oct 1 2013, 05:14 PM
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#5
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Advanced Member Group: Members Posts: 2,046 Joined: 13-October 03 From: L.A. Calif Member No.: 1,245 Region Association: Southern California |
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.
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| reharvey |
Oct 1 2013, 05:30 PM
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#6
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Senior Member Group: Members Posts: 573 Joined: 16-July 08 From: N. E. Ohio Member No.: 9,308 Region Association: North East States |
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. (IMG:style_emoticons/default/agree.gif) Yes---down. These look like 96mm AA pistons so there will be no arrows or other marks on these. Ray |
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| jeffdon |
Oct 1 2013, 08:22 PM
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#7
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Senior Member Group: Members Posts: 1,094 Joined: 24-October 06 From: oakland, ca Member No.: 7,087 Region Association: None |
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. (IMG:style_emoticons/default/agree.gif) Yes---down. These look like 96mm AA pistons so there will be no arrows or other marks on these. Ray Thanks 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. |
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| jeffdon |
Oct 19 2013, 01:07 PM
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#8
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Senior Member Group: Members Posts: 1,094 Joined: 24-October 06 From: oakland, ca Member No.: 7,087 Region Association: None |
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. |
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| yeahmag |
Oct 19 2013, 02:41 PM
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#9
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
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Valve pocket down.
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