Hi Joe and Friends,
I think the listing you have of chamber volumn vs. geometric compression is
pretty close. Here are a couple more datum points that I've measured.
Chamber Ratio
59cc 9.19
43.5cc 11.09
The flow sheet from Comptune for my head:
Chamber cc= 47.6
Head thickness= 3.175"
stock valves
at 28" of water
valve lift cfm
.100 57.32
.150 77.44
.200 99.44
.250 123.22
.300 146.19
.350 165.63
.400 176.69
.450 179.90
.500 183.45
.550 185.50
I think there may be a factor to convert from 28" to 10" but don't have a
clue what it would be.
Btw, check your head gasket thickness again! :>}
Hope this helps.
Happy Racing!
Chip
----------
From: Alexander Joseph H[SMTP:AlexanderJosephH@Waterloo.deere.com]
Sent: Wednesday, March 26, 1997 4:28 PM
To: 'Friends of Triumph'
Subject: WHO & Tech advice
Friends of Triumph,
>
>I am getting ready to plane head and want to know what to tell the machine
>shop. I've done ok in the past, but I want to be more precise this time.
>
>Assumptions:
>
>87mm bore
>92mm stroke
>.635 gasket thickness
>Flat top pistons
>etc.
>
>I am starting with a stock head which I measured at 3.325 from the bottom
to
>the top of the milled surface for the valve cover.
>
>My objective is 11.7:1
>
>I am thinking about taking .140 off of the head and then sizing the
chamber
>to the compression I want. Since it is being flow benched and the flow
bench
>guy is removing more material than I did in the past, I might have to take
>another cut at the head.
>
>I have a table one of the fot folks made up translating the size of the
>chamber to the Compression Ratio based on the same numbers assumed above.
>
>He got 10.5:1 by taking .125 off of the head and then added Venolia
Pistons
>to get to 11.8:1
>
>According to his table which I abbreviated:
>
>54cc = 9.73cr
>49cc =10.49cr (.125 off head)
>42cc = 11.80cr (near my target)
>39cc =12.48cr
>
>Does this look ok to you?
>Do you have another method that would save me a step?
>
>Chip/HP/John....the flow bench guy has achieved somewhere around 104 CFM
>@10". One of his manuals indicated a benchmark of about 102 CFM @ 10"
given
>the size of the valve. (mine are .050 o.s.) He is at about 96 CFM @ 10" on
my
>head and still working. Does this sound ball park. I am just curious. I
dont
>want to invade any competition secrets.
>
>One guy called Comptune and the said they didnt have a baseline on a stock
>head. I think mine was in the mid 80s on CFM s. I dont know if the flow
data
>was asked for on a fully developed head but if it is something you have
and
>can share.....
>
>Oh ya, my Cam is an Isky TR-666 with .435 lift.
>
>Thanks guys....regards, Joe
>
>
>
>
>
>----------
>From: R John Lye
>Sent: Wednesday, March 26, 1997 2:49 PM
>To: Alexander Joseph H
>Subject: RE: Nomination: Henry Morrison - RMVR
>
>On Mar 26, 11:32am, Alexander Joseph H wrote:
>> I just sent the command as you suggested...failed
>>
>> >>>> who fot@autox.team.net
>> **** who: no such list 'fot@autox.team.net'
>> >>>> end
>> END OF COMMANDS
>
>OK, I went and double checked the syntax (sent "help" to
>majordomo@...) and that was fine. I also checked a couple
>alternate versions of the fot name and got "no such list".
>So, I suspect that mjb has disabled the "who" command for
>the list to avoid allowing spammers access to our e-mail
>addresses.
>
>John Lye
>
>rjl6n@virginia.EDU
>http://avery.med.virginia.edu/~rjl6n/homepage.htm
>
>
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