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Re: [turbobike] Re: SOHC Honda headgasket problem

John C Williamson (john.williamson5@virgin.net)
Thu, 20 May 1999 23:29:26 +0100

After thinking about this for a bit I think that the main reason that coper
gaskets 'go' as such (apart from the oil seep / cappiliary problem) is that
the head may 'lift'. The PEAK cylinder pressure goes up enormously with
ignition advance but power output may only increase marginally. So if you
have clamping / barrel stud strength problems causing you to blow gaskets it
makes much sense to reduce full advance to a lower figure, and up boost
instead, producing less peak pressure but more where it counts ie, later!
when the crank is in a better or more advantagous position to take advantage
of the increased cylinder pressure to produce more torque from less
pressure. I suspect most detonation / pre-ignition / head gasket probs are
caused by too much advance.
This is one of the reasons that Nitrous does not seem to cause detonation
and head gasket probs as often, because it is inert (and can put out fires!,
like C02 does!) and only breaks down into Oxygen & Nitrogen (most of the
atmosphere - and does not support combustion) LATER in the chamber as it
takes time for this to occur. Just the same as less advance really.

So basically if you want to go fast safely, go rich - less advance - and
loadsa boost and Nitrous and you will not break the engine.. look for black
smoke (a little!) and anything that sounds harsh or 'pings' (you cannot hear
it on a bike...) nedds less advance... This will still blow gearboxes /
clutches etc,  even more so in fact but the motor should be OK without
expensive parts.

I welcome your coments (Rick?) , anybody!

JOHN WILLIAMSON
----- Original Message -----
From: Bob Shammas <b.shammas@worldnet.att.net>
To: Rick <gsxr1100@ptw.com>; Turbo list <turbobike@natvideo.com>
Sent: 20 May 1999 22:16
Subject: Re: [turbobike] Re: SOHC Honda headgasket problem


> I like the multi-layer steel head gaskets.  They probably don't make one
for
> that application but I've found they seal compression very well without
> o-ringing (I either use Yamabond-4 or Gasgacinch as a sealer) and tend to
> leak much less oil than solid copper.  I still use solid copper for my
KZ/Z1
> dragbikes (and put up with the oil seepage), but go for MLS anytime it is
> availbable for one of my newer projects.
>
> Bob
> -----Original Message-----
> From: Rick <gsxr1100@ptw.com>
> To: Turbo list <turbobike@natvideo.com>
> Date: Thursday, May 20, 1999 10:33 AM
> Subject: Fw: [turbobike] Re: SOHC Honda headgasket problem
>
>
> >
> >----- Original Message -----
> >From: Rick <gsxr1100@ptw.com>
> >To: John C Williamson <john.williamson5@virgin.net>
> >Sent: Thursday, May 20, 1999 6:25 AM
> >Subject: Re: [turbobike] Re: SOHC Honda headgasket problem
> >
> >
> >> I would try like john said but I use Yamabond on the head gasket.
> >> Silicone gasket sealer made things worse than nothing at all for me.
> >> If that doesn't work then try oringing the cylinder.
> >>
> >> Turbo Rick
> >> 350HP Turbo GSXR1100 Street bike
> >> Web Site  http://www.ptw.com/~gsxr1100/
> >> Southern California Timing Association 1998 Fastest Bike of the year
> >> EL Mirage Land speed Record holder 204.626 MPH
> >> E-mail gsxr1100@ptw.com
> >>
> >>
> >> > Slightly more seriously, make sure that the gasget is well annealed,
> and
> >> > that the surface of the head / block is FLAT and not polished. A
> >flycutter
> >> > usually used to machine the surfaces leaves a 'machining' pattern on
> the
> >> > surfaces. This 'bites' into the gasket and holds it into position.
Make
> >> sure
> >> > that the surfaces are fully degreased, and then use a SMALL (I mean
> very
> >> > small smear!) smear of silicone gasket sealer (very thinly!) around
all
> >> the
> >> > bore edges, and oilways. This stops the capilliary effect that
actually
> >> > makes the oil penetrate under the gasket, which allows the gasket to
> >blow
> >> > out of position. Try to get stronger studs as they probably lift /
> >stretch
> >> > under boost.
> >> >
> >> > John Williamson
> >> >
> >> > ----- Original Message -----
> >> > From: Joe Allan <beak@seaside.net>
> >> > To: <turbobike@natvideo.com>
> >> > Sent: 20 May 1999 06:13
> >> > Subject: [turbobike] Re: SOHC Honda headgasket problem
> >> >
> >> >
> >> > > Hello All;
> >> > >   Just came back from trying out my supercharged 750 Hondamatic
dirt
> >> > > dragger, goes good but after the 10th run down the track the copper
> >head
> >> > > gasket blew :-(  Pulling it apart tomorrow....any hints??
> >> > >   Stock studs only allow 16 pounds torque.
> >> > >  Joe Allan
> >> > >  Vancouver Island
> >> > >  Canada
> >> > >
> >> > >
> >> >
> >>
> >
> >
>