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Registered
Join Date: Feb 1999
Location: WV, USA
Posts: 59
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Where To Buy High Compression Pistons?
Anyone know where I can get 94mm pistons ranging from around 9:1 to 10:1 compression. I can't use anything other than 94mm in my racing class. European pistons aren't quite enough.
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01-28-2003, 01:54 PM
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Administrator
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The usual thing if you want more compression than the European pistons give you is to deck the heads. Bring it down to .040" deck height, or even a bit less, and re-figure compression.
If you really need more after that, then you might wind up needing to get custom ones from JE... --DD
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Pelican Parts 914 Tech Support A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling |
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01-28-2003, 02:13 PM
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Join Date: Feb 1999
Location: WV, USA
Posts: 59
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Dave,
What is the procedure for decking heads? I would have this done by a machine shop but still would like to know what would be going on with the heads. Do the cylinders also need machined? Thanks |
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02-09-2003, 06:36 PM
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Unless the cylinders are not true, they don't need to be messed with.
Decking the heads is a straightforward procedure. They set it up in a mill or lathe or other large implement of metal destruction, and shave off the area that the cylinder mates to. Usually you will have to tell them how much to take off, unless the shop is doing the assembly and such for you. To figure that, you will have to measure all of the volumes that go into figuring compression, then do the math. Re-figure with the smaller volume from having the cylinders stick into the heads further. Then go from there. The best bet is to talk to a machine shop who is good with Type IV motors. --DD
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Pelican Parts 914 Tech Support A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling |
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02-09-2003, 07:36 PM
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Join Date: Mar 2002
Location: Salt Lake City, UT
Posts: 21
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we are designing some of our squishy pistons for the T-4 engine right now. They are not cheap ($700/4 includes rings but not cylinders), but our type 1 sets have worked so well we can run over 13:1 compression on PUMP GAS, and the engine runs cooler then 9:1 with flat tops. I know many will think this is BS, but guys are doing it now, just ask around. We are running over 15:1 with them on pump, but no customers have gone that far yet.
John Aircooled.Net Inc. |
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02-10-2003, 01:38 PM
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Join Date: Jan 2002
Location: Long Beach CA, the sewer by the sea.
Posts: 37,792
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Re: Where To Buy High Compression Pistons?
Quote:
The ideal piston would be a 95mm. This would give you a 2013. One rule book I have allows you 50 cc over stock, another says you can replace your pistons with 1 mm over. Last edited by Zeke; 02-10-2003 at 04:50 PM.. |
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02-10-2003, 04:47 PM
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Join Date: Feb 1999
Location: WV, USA
Posts: 59
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That's correct. I am allowed a 1mm overbore but I have to run 1.8 displacement which has 93mm. 94 is my max and tech has a zero tolerance for bore size.
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02-10-2003, 06:23 PM
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Join Date: Feb 2001
Location: Aircooled Heaven
Posts: 1,054
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I have a set of domed JE forged 2.0 pistons I scored from a race engine overhaul..
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Jake Raby Owner, Raby's Aircooled Technology www.aircooledtechnology.com www.massivetype4.com |
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02-10-2003, 07:00 PM
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Join Date: Sep 2002
Location: dfw tx
Posts: 3,957
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Jake, If he can't use em i could.
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72 914 2056: 74 9146 2.2: 76 914 2.0 |
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02-10-2003, 10:10 PM
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74 Porsche 914 2.0 
