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> what do stock 1.7l pistons on 1972 engine look like?
jdlmodelt
post Mar 22 2013, 08:20 PM
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James D. Lane
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I pulled the head off of one side of my 1972 1.7l engine tonight and found dome top pistons/cylinders. They looked to have maybe 50% of life left. It also had the head "gasket" rings. The passenger side retainer wire was broke and the push rods had some wear on them, a scoring about 1/2 in long on all of them about 3/4 up the push rod on the head end. There was almost no noticable cylinder ridge wear. I haven't removed the valves yet but I can tell by looking at the edges of them that the wear is minimal. This may have been rebuilt 20k to 50k miles ago?

Question. Were the stock 1.7l engines dome top pistons? I guess I need to measure bore and stroke to determine what size pistons/cylinders are in this engine?
thanks,
James
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jdlmodelt
post Mar 22 2013, 08:29 PM
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Another question. If I elect not to use the head gasket rings. What do I need to do to accomodate?
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dlee6204
post Mar 22 2013, 08:32 PM
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(IMG:style_emoticons/default/popcorn[1].gif)

I have the same question. I have a couple sets of domed and one dished. I'm assuming the dome are stock 914.
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Dave_Darling
post Mar 22 2013, 09:21 PM
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The W-code engines had domed pistons. Not sure about the EA-code ones.

--DD
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jdlmodelt
post Mar 22 2013, 09:34 PM
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QUOTE(Dave_Darling @ Mar 22 2013, 09:21 PM) *

The W-code engines had domed pistons. Not sure about the EA-code ones.

--DD


Mine is a EA engine with domed pistons. Do you think it is factory or aftermarket?
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bradtho
post Mar 22 2013, 11:26 PM
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I've taken 2 of these apart, both from 72's and both most likely original. I swear I found one dished and one domed. euro-spec was flat and it's likely that anyone going to the trouble to rebuild would either reuse what they had or go to the euro spec.

I can't find any good pictures of the pistons from EA0033579 (claimed to come from a 72, I bought the entire engine from the owner who had just crushed the car, I didn't get the serial number from the body) which I recall being dished. here's a shot of the pistons that came out of EA02497. It had ~80k confirmed miles on it when I got it and had been garaged for 15'ish years, so most likely original.

Attached Image
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euro911
post Mar 23 2013, 02:21 AM
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I'm currently in the process of tearing my wife's early '71 1.7L apart (albeit slower than anticipated).

It's a 'W' case and I believe it to be the original 'unmolested' engine. The ODO stopped at 108k miles, don't know what happened after that (IMG:style_emoticons/default/confused24.gif)

I'm anxious to see what's been rolling around inside all these years and I'll share what I find (hopefully soon) (IMG:style_emoticons/default/shades.gif)

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nathansnathan
post Mar 23 2013, 07:50 AM
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The EA engines did have domed pistons as did the W as both are supposed to have 8.2:1 CR. The dished pistons that were in the EB California engines brought it down to 7.3:1, same as a bus. Looking at the compression ratios at the tunacan site, it seems there are only 2 builds for 914's (dished and domed), but there is a 3rd CR for 69-70 411's, a Z engine that had CR in between at 7.8:1 - could be that was the flat pistons.

http://www.tunacan.net/t4/reference/case.htm

About the head gaskets, I believe the bulletin that said to take them out was referencing 2.0 engines only, so it is debatable whether it is advisable on a 1.7 or 1.8. If you do it by the factory instructions, you put a shim at the base of the cylinder that ends up thicker than the original cylinder base shim and the head gasket and the paper gasket combined, effectively raising deck height by .023" and reducing compression/performance.

I have run no head gasket without adding the base shims, as long as you are comfortable with your deck height.

http://www.ratwell.com/mirror/www.dolphins...m/techbull.html

Here's bus guru, Richard Atwell's page discussing it, down under "head gasket"
http://www.ratwell.com/technical/Heads.html
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nathansnathan
post Mar 23 2013, 09:15 AM
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I should add, there is definitely info missing there, as I have an AE Type 4 engine in my bus (IMG:style_emoticons/default/wink.gif) and I think there was a carb'ed euro 914 with a 1.7 that I don't see there.
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Dave_Darling
post Mar 23 2013, 02:44 PM
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The European 1.7s had D-jet, just like the US-spec cars. The only 914-4s that had carbs were the 1.8 European versions.

--DD
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