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> Head cc's
Dave Bell
post Nov 14 2005, 01:21 AM
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Anybody know where you can find the head volume, cc's, for the different 914 stock heads?

1.7L
1.8L
2.0L

- Dave
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MattR
post Nov 14 2005, 03:36 AM
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Its going to vary from engine to engine. If you're calculating compression ratio, CC your heads after all the valvework is done. To do that, place a piece of clear flat plexiglass on top of your combustion chamber with a small hole in it. Fill the chamber with a fluid (automatic transmission fluid works). Then transfer it all out with a syrenge into a beaker with measurements in cubic centimeters. That will give you head CCs.
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SpecialK
post Nov 14 2005, 04:50 AM
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....or just use a graduated syringe (bigger the better), and keep track of how much it takes to fill it. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)
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Jake Raby
post Nov 14 2005, 09:38 AM
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Measure the heads!!! You never know if they have been flycut or not, and you can't guess..

BUT here are the default numbers-
1.7= 50cc
1.8= 55cc
2.0= 57cc

These are 100% stock numbers- But don't trust them- MEASURE!
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davep
post Nov 14 2005, 09:46 AM
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Are the heads all the same for all the various VW designs; that is, are all 1.7 heads the same? For the different compression ratios, say on the 1.7 engine, were the variations accomplished with different dishes in the pistons? I'm referring to all variations regarding the VW type 4 engine, not just the 914 variants.
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Bleyseng
post Nov 14 2005, 10:20 AM
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The heads have different combustion chamber shapes with the 1.7l being the smallest in size. VW then used different pistons to adjust the compression ratios- ie domed or dished pistons.
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Dave Bell
post Nov 14 2005, 01:16 PM
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O.K. ... measure them

I have two sets of 1.8 heads, couple of questions

Let's assume I am building a 2270 with a 78.4 stroke.

I open up the heads to 42 x 36... is this enough for this engine starting with the 1.8 head geometry?

______


I run the CR calcs for a flat top piston, 0.060" deck height on stock 94's cylinders bored out to 96 and stock 55 cc combustion chamber... I get a CR of 9.6... a bit high. Need to go up to 60 cc just to get down to 9:1 CR..... dremel out the heads to get the xtra volume?.... do the main metal removal before or after putting in the new valves?

.... haven't even gotten to chosening cam... this head/cam stuff is black magic to me.
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nebreitling
post Nov 14 2005, 02:20 PM
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i wouldn't dremel out the heads unless i really knew what i was doing (i don't)... figure out the c/r after you've chosen your cam -- your cam will 'want' a certain range of c/r. talk to the cam builder/distributor to find out what that 'magic zone' is.
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MattR
post Nov 14 2005, 02:24 PM
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Do NOT dremel the heads. They are shaped that way for a reason.




If you're running 96s, Im guessing you have KB flat top pistons, in which case trim the piston top if you're trying to lower your compression ratio. If the engine is put together you can also use cylinder spacers, but I trimmed my piston top...
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Dave Bell
post Nov 14 2005, 04:03 PM
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I don't have the pistons yet, but you guessed right, I am looking at the KB's off of aircooled.net with 1.11" pin height and running the deck height and compression numbers based on that and some 5.394" SCAT rods.

If I need to pick up 5cc that would be a 0.0068" trim

If I need to pick up 10 cc that would be 0.0136" trim

How much room is there on the KB to trim given material and ring considerations?
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Mark Henry
post Nov 14 2005, 04:27 PM
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Unless you know someone with the proper boring jig for your cylinders get the jugs and slugs from Jake. If you try to hone them size they will be out of spec and the "made in china" 96mm cylinders are junk.

The Scat rods for the 78mm T1 rod are crap.

It would cost you maybe $100 extra but get your rods and crank off of Jake. Well worth it.

If you buy a bunch of parts off of Jake he'll help you out with th cam.

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Mark Henry
post Nov 14 2005, 04:36 PM
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BTW....are you going to chance the cheap lifters... or go with ceramic's?

They have a group buy going on ceramic lifters right now.

http://www.shoptalkforums.com/viewtopic.php?t=94549

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Jake Raby
post Nov 14 2005, 05:02 PM
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Oh no...
I see someone heading down the wrong road- But I'm tired of supporting parts that other people sale!

I could have taken all the guesswork away from the project. Guesswork is expensive and time consuming!

I can make all those parts drop right in-

With the right cam and matching CR the heads may not need any chamber work, but port work is a necessity if you want a correct powerband..
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Dave Bell
post Nov 14 2005, 06:30 PM
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O.K. Jake... I pm'ed you.
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