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twofifty AZU
Firing on two.
Joined: May 16th, 2010, 5:04 pm
Posts: 835
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 Re: 8.5:1 and 9:1 Russell wrote: Perhaps drilling a small hole in the 9:1 piston to let the extra compression out would equal it out? Only lapping in the valves on one barrel works equally well as the relief hole, and it saves the bother of taking off the head to drill a hole in the piston crown.
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| April 26th, 2011, 11:57 am |
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Sean
Firing on two.
Joined: April 22nd, 2009, 11:06 pm
Posts: 3684
Location: Ecosse
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Re: 8.5:1 and 9:1 alternativley for the high powered option.
add some ball bearings through the sparkplug hole to increase the compression on the 8.5 side ( should also help stop piston crown and plug from coking up)
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Kissing the Lash
"Any advice of a technical nature is given on the understanding that I've actually done this shit, not just read about it in D*lly club mag some time ago.
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| April 26th, 2011, 12:04 pm |
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twofifty AZU
Firing on two.
Joined: May 16th, 2010, 5:04 pm
Posts: 835
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Re: 8.5:1 and 9:1 Is there an optimal size for the bearings? I'm wondering whether to use a quantity of small ones or a few larger bearings? I'm guessing they need to have a diameter of at least 8mm to prevent escape through the exhaust valve opening? http://cgi.ebay.co.uk/BALL-BEARING-STAI ... 3367217846Will these do the job? I thought stainless would be better than chrome steel.
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| April 26th, 2011, 1:12 pm |
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Sean
Firing on two.
Joined: April 22nd, 2009, 11:06 pm
Posts: 3684
Location: Ecosse
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Re: 8.5:1 and 9:1 get 7.5 mm then you have spares when you take the lid off the gearbox
youll have to open the tappets to 1mm clearance so they don't escape till you need them
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Kissing the Lash
"Any advice of a technical nature is given on the understanding that I've actually done this shit, not just read about it in D*lly club mag some time ago.
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| April 26th, 2011, 1:56 pm |
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Rhythm Thief
Firing on two.
Joined: March 10th, 2010, 12:37 am
Posts: 1927
Location: Alone in my polytunnel with my pitiful competition onions
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Re: 8.5:1 and 9:1 Sean wrote: get 7.5 mm then you have spares when you take the lid off the gearbox
youll have to open the tappets to 1mm clearance so they don't escape till you need them 1mm? Surely you mean 1.05mm?
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The best things in life aren't things.
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| April 26th, 2011, 2:51 pm |
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knightley
Firing on two.
Joined: June 19th, 2010, 8:40 pm
Posts: 761
Location: Kingswood, S.Glos.
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Re: 8.5:1 and 9:1 Mornington Crescent!
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John Jordan
It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a d'olly.
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| April 26th, 2011, 2:56 pm |
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twofifty AZU
Firing on two.
Joined: May 16th, 2010, 5:04 pm
Posts: 835
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Re: 8.5:1 and 9:1 Rhythm Thief wrote: Sean wrote: get 7.5 mm then you have spares when you take the lid off the gearbox
youll have to open the tappets to 1mm clearance so they don't escape till you need them 1mm? Surely you mean 1.05mm? This is serious technical discussion, I don't think we should drag increased valve clearances into it and get sidetracked. I am however going to take an angle grinder to the base circle of my camshaft to increase its lift. I think that setup may require 9.3mm ball bearings. I just need to figure out whether to use a 40 grit or 80 grit disk on the angle grinder.
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| April 26th, 2011, 3:03 pm |
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Rhythm Thief
Firing on two.
Joined: March 10th, 2010, 12:37 am
Posts: 1927
Location: Alone in my polytunnel with my pitiful competition onions
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Re: 8.5:1 and 9:1 twofifty AZU wrote: I just need to figure out whether to use a 40 grit or 80 grit disk on the angle grinder. 80.05. ... sorry, I'll stop now. 
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The best things in life aren't things.
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| April 26th, 2011, 5:27 pm |
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Nelsthebass
Firing on two.
Joined: October 5th, 2009, 8:22 pm
Posts: 1415
Location: Stone, Staffs
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Re: 8.5:1 and 9:1 Now I am absolutely sure that people who run A series are totally mad....not me though, I'm a pink canary.....look at me flyyyyyyyyyyyyyyyyyyyy
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2014 Suzuki Swift Sport
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| April 26th, 2011, 6:39 pm |
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Neil
super slot
Joined: November 28th, 2008, 11:14 pm
Posts: 8797
Location: Cornwall, UK
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Re: 8.5:1 and 9:1
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| April 26th, 2011, 6:50 pm |
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