[Fot] GT6 crankshaft prep for mild race use

[Jason Sukey]

Scott,
       Thanks for the info!  Sounds like the factory crank drillings are
not the limiting factor here.

Jason

On Tue, Sep 4, 2018 at 8:22 AM Scott Janzen <sjanzen at me.com> wrote:

> My GT6 has the full external oiling system- fed off the main (vertical)
> galley, to the remote filter, then the cooler, then a manifold from which
> four lines run - one to each main.
> I have never gone the extra step of drilling the crank.  I have a 30 psi
> pressure switch on the number one bearing oil feed line wired to a big red
> light on my dash, which has never come on. Hot oil pressure is 70+ at full
> rpm, 40+ at idle.
> I use a stock TR6 pump with the wire basket on suction end. Main bearings
> .002+ clearance, rods .0018-. Mains rarely show much wear, rods need
> replacement after 2- 3 seasons of 5-6 weekends.  Maybe the rods would last
> longer if the crank was drilled.
> The engine is typically at 4500-7200 rpm throughout a track session.  I
> hit 7000 on virtually every shift.
> No bearing failures yet!  This has worked through several different
> engines and numerous rebuilds over 12 years.
>
>
> Sent from my iPhone
>
> > On Sep 3, 2018, at 5:25 PM, Jason Sukey via Fot <fot at autox.team.net>
> wrote:
> >
> > I'm finally looking into my GT6 engine after parking it Friday of
> Kastner Cup weekend.
> >
> > Back story:
> > Car ran great and allowed me to complete the competition school Thursday
> (4 full sessions), but during my first practice session Friday, I pulled in
> early with low oil pressure and an audible rod knock.
> > The #1 rod bearing was the source of the problem (extruded out the side
> gap). That's the only bearing that shows failure.
> >
> > Best I can tell it's a classic case of not enough oil to the front of
> the engine on the 6 cyl block.
> > I was not running any auxiliary oil feeds- I plan on adding that, along
> with modifying the oil galleries in the block "per The book".
> >
> > My question is this:  For the GT6 crank on a very mild engine (shifting
> at 6200 or below), is there any need for the additional oil drilling in the
> crank throws as suggested for the 1500 engines?  What are you other GT6
> guys using?
> >
> > At this point, if the crank passes mag check, I'm planning to have it
> ground/balanced/nitrided and using it for the rebuild.
> >
> > Thanks for the advice,
> > Jason
> >
> >
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