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> 1.7 L piston compression ratio/tops W-series 1970engine, Dome vs flat-top ?
pgollender
post Apr 6 2017, 08:10 AM
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I have taken apart two 1970 W series motors and both had dome-top style pistons. Is the dome top still available as "new" or are all that are left are flat ones ?
I think the domes were rated at 8.2:1 compression ratio. The flat ones that I've seen are rated slightly less.
If the original pistons themselves are in good shape what would you do ? Re-ring them or buy new flat stock with less compression ? Where are members gone for new cylinders ? Surely those old oxidized ones can't dissipate heat that effectively.
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914Sixer
post Apr 7 2017, 02:24 PM
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All 1.7 Porsche had domed pistons and were 8:2:1. Flat top pistons where in the VW bus and VW 411. Do not know what is offered now. Every now and then a set of the OEM domed pistons show up for sale on Ebay or theSamba.com.
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PancakePorsche
post Apr 9 2017, 01:22 AM
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If they are within wear limit and no scuffing, do a light hone and re-ring. I did that to a GB code 2.0 with 8.5's and put on another 100K miles.
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