andrew,
as far as i can tell the cam is timed correctly (advised by ivan tighe cams in brissy). it is a 76 works grind. i'm using standard ngk plugs. the combustion chambers have been relieved around the heel of the valves - however i think i'll take it to the local head shop and get some advice. i like the idea of increasing the head chambers. see what happens.
thanks,
dunc.
>From: andrew smith <[EMAIL PROTECTED]>
>Reply-To: [EMAIL PROTECTED]
>To: [EMAIL PROTECTED]
>Subject: Re: HELP - comp ratio
>Date: Wed, 30 Jan 2002 07:41:31 +0800
>
>Duncan,
>Has the combustion chambers been radiused and what heat range plugs are you using.Did
>they use a high speed timing light to determine the total advance.What cam is in it
>and do you know the close point on the inlet,sounds like the cam might be to small
>for the comp ratio or just closing to early on the inlet.Maybe your right and you do
>have to much comp but there's plenty of L series around with that much comp running
>34 or more ignition timing.What head are you using cause you maybe able to squeeze a
>few cc's out of it by deshrouding etc.
>Andrew Smith
>
>SHILLITO Duncan wrote:
>
> > Hey guys,
> >
> > I know this topic has been visited over and over again, however after
> > much fiddling and experimenting I need a little more help.
> >
> > I have approximately 10.9:1 compression ratio in my 2.3L L series (full
> > house). The engine is pinging severely from about 4000 rpm onwards. I'm
> > using 98 ron optimax fuel with a total of 28 degrees advance timing ?
> > retarded to stop pinging, but is very sluggish.
> >
> > I believe my goal is to reduce the comp ratio to about 10:1, so I can
> > get maximum power using more advance of 36 deg. My options are: ????
> > 1. Remove the head and add the appropriate steel
> > decompression plate to reduce the comp ratio. However these extra
> > gaskets hinder the swirling effects required for optimal burning and are
> > likely to leak oil and coolant.
> > 2. If possible remove more metal from the head to reduce
> > the comp ratio. This may be expensive and also hard to achieve since the
> > head has already been shaved 30 thou and has 44mm inlets valves.
> > 3. Add toluene (methyl benzene) from shell & optimax at the
> > cost of about $1 per litre. (with webers this equates to about 7km/$ =
> > V8 territory hehehehehe).
> >
> > I have to pull the head off now anyway due to a water leak - so I need
> > some quick fire assistance if possible. I've just had a tune diagnosis
> > completed (using optimax) and air : fuel ratios didn't change or reduce
> > the pinging.
> >
> > Also, what cost and where can I buy some 36mm chokes for my 45mm webers
> > ???? I'm on the Gold Coast. I believe that 38mm are too large for the
> > stroker - max hp at 5250 rpm and I'm sure 36s will help with higher
> > velocities into the head (see ? bernoulli's theorem can be put to good
> > use). hehehe
> >
> > Thanks for any help.........much appreciated
> >
> > dunc.
> >
> > Duncan Shillito
> > Technical Officer
> > Reticulation Services
> > Gold Coast Water
> > Mob: 0414 180 775
> > e-mail: [EMAIL PROTECTED]
> >
> >
> >
> >
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