Re: Compression ratio testing

[Rob P]

Never been run on regular fuel SFAIK. Was previously in a circuit racing Datsun 1200 for testing and carby setup only.   Volume @ BTC unknown. Head U67, Block L20B   Carbies untested by me, but were set up for this motor.   I'll keep you all posted when it's all together and dynoed.   Cheers, Rob P ----- Original Message ----- From: Chris Simpson To: [EMAIL PROTECTED] Sent: Friday, November 29, 2002 5:28 PM Subject: Re: Compression ratio testing 13:1 means a diet of Avgas or similiar. I'd be checking your figures if you think that it was run on regular pump fuel before.   What was the volumn of the cylinder when it was at BTC What head is on it?   Twin 45's should be fine so long as it is tuned properly. Dont expect the carbies to run well if they are not tuned and jetted to the motor.   Chris s ----- Original Message ----- From: Rob P To: [EMAIL PROTECTED] Sent: Friday, November 29, 2002 4:45 PM Subject: Compression ratio testing While we're on the subject, here's an update on my L20B rally motor (as yet still not tested since purchased complete). I put number one piston to TDC and tilted the engine on a stand so that the sparkplug hole was facing directly up. Filling a 60cc syringe with oil, I then squirted it into the chamber and filled it to the top of the spark plug hole, fully covering the threads (accidently). It came to 45cc exactly, less if you remove the sparkplug volume. My mechanic buddy calculated a compression ratio "of 12.84 to one, let's call it 13:1" We all stood around grasping our beers, shaking our heads and looking suitably impressed. ;-P Does this sound right? (Flat top alloy pistons, head still within 3 mm of maximum shave) If so, do I need to run 101 racing fuel or will BP Ultimate 98 do to avoid pinging? Will a Bluebird series II/III fuel pump adequately feed the twin 45 Webers? I have a Holley Blue fuel regulator but am told a Malpassi rising rate regulator may be the go?   Any advice always greatly appreciated --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ --------------------------------------------------------------------- --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ --------------------------------------------------------------------- --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ ---------------------------------------------------------------------