Date:         Tue, 15 Sep 2009 23:22:29 -0400
Reply-To:     Greg Potts <greg@POTTSFAMILY.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Greg Potts <greg@POTTSFAMILY.CA>
Subject:      Re: 2.1 heads
Comments: To: Ian Allan <ian.allan@BMTS.COM>
In-Reply-To:  <CBB1C252-FB50-4C82-8533-80C77A61E7AF@bmts.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi Ian,

Have the heads CC'd, then calculate the amount of material that would
need to be removed to get to the desired CR.

In this instance, the uncompressed volume is 600cc. So to get the
compression down to 10:1, you need a TDC chamber volume of 60cc. If it's
possible to remove enough material from the heads to accomplish this
then that would be the answer.

You might also be able to remove volume from the pistons, but that would
depend on the shape, etc. The heads would be a lot safer place to go
looking.

On my aircooled 1697cc type4 engine no machining was reqiured. In that
case I reduced the compression by adding shims at the base of the
cylinders. That won't work on a WBX unless you have a source of thicker
head gaskets to accomodate the increased distance between the head and
block created by the shim.

Another area you could explore is to shorten the connecting rods
slightly. That is another option to increase the volume of uncompressed
space, but I don't know if it's all that practical. I do Graphic Arts
tech support for a living, not auto mechanics.

I am still hoping to ship shirts later this week BTW.

Happy Trails,

Greg Potts
1973/74/79 Westfakia "Bob the Tomato"
1987 Wolfsburg Weekender Hardtop
www.busesofthecorn.com
www.pottsfamily.ca

Ian Allan wrote:
> I have a friend who purchased a van with a Go Westy 2.4 engine. The
> engine has suffered from detonation issues among other things. Any
> ideas as to practical machining processes to REDUCE the compression
> ratio?
>
> Ian
>