I haven't followed the thread closely, so sorry if i'm out of step here.
If you believe you know the current compression ratio and displacement,
you should be able to get a good estimate of the new compresison ratio,
since you can calculate what the total chamber volume is. Now, if the
gasket bore, etc, are different from when the CR was spec'd originally,
that will be a source of error.
eric
> FWIW, I have 5.2l magnum short block sitting on the floor of my garage. I
> have
> not measured but I would estimate the pistons are a good 0.040-0.050" down
> into
> the bore. Also, for accurate compression calculation besides the
> compressed
> thickness of the head gasket you need to know it's bore (and it's a lot
> larger
> than the bore of the cylinder). For example the 360 I just built using
> magnum
> heads for my Barracuda has a head gasket bore of 4.180" (Fel Pro brand
> gasket).
>
> Dave Clement
> 99 SLT+ CC 4x4
>
> In article <BAY19-F2A4FA00FA45825121239EC3F20@phx.gbl>,
> scsilverdakdml@hotmail.com ("Ronald Taylor") writes:
>>
>>
>> To get a accurate calculation, you need to know the Piston Deck Height
>> as
>> well, not just the chamber volume, and head gasket compression
>> thickness......
>>
>> Most factory shortblocks have the piston so far down the hole you need a
>> flashlight to find the piston top!.......not good for building cylinder
>> pressure.. ;)
>>
>> Ron
>> 01' Dakota Sport RC 3.9...
>> http://www.dodgetruckworld.tenmagazines.com/mygallery.asp?id=8143
>> http://www.dragtruck.com/ENTRIES/RUSCAS2XUMHU.html
>>
>>
>>
>>
>> From: "Bernd D. Ratsch" <fasstdak@hotmail.com>
>> Reply-To: dakota-truck@dakota-truck.net
>> To: <dakota-truck@dakota-truck.net>
>> Subject: RE: DML: Compression calculation?
>> Date: Tue, 14 Jun 2005 17:20:30 -0500
>>
>>
>> Hehehehe...seen the same calculator on many different sites. :)
>>
>> - Bernd
>>
>> -----Original Message-----
>> From: owner-dakota-truck@bent.twistedbits.net
>> [mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of
>> david.clement@verizon.net
>> Sent: Tuesday, June 14, 2005 4:40 PM
>> To: dakota-truck-moderator@bent.twistedbits.net
>> Subject: Re: DML: Compression calculation?
>>
>>
>> Here you go! http://www.csgnetwork.com/compcalc.html
>>
>> Dave Clement
>> 99 SLT+ CC 4x4
>>
>>
>> In article <MABBLNOKHJLBHKDDEKOJAEEKGMAA.joeman@gbonline.com>,
>> joeman@gbonline.com ("Joseph Orsini") writes:
>> >
>> >
>> > OK are there any compression calculators out there? If I am using
>> > stock parts and have a 10.5:1 CR with 64 cc heads and switch to 79cc
>> > heads how much will my CR drop? Are there any web tools out there
>> for
>> > figuring this out?
>> >
>> > Thanks,
>> >
>> > -Joe
>> >
>>
>> _________________________________________________________________
>> Don’t just search. Find. Check out the new MSN Search!
>> http://search.msn.click-url.com/go/onm00200636ave/direct/01/
>>
>
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