Thanks for all suggestions. The car is well prepped -
the head is torqued properly (local legend says 55 ft
lb) using ARP studs and assy lube, torque wrench is
calibrated by our cal shop at work, but it has been
almost two years. Block holes are chamfered. Head
was skimmed and magnafluxed in April, block was
checked with a true straight edge (my aerospace
company happens to be attached to a 40,000 sq ft
machine shop). Leakdown test was OK, but with a
homemade gage. Compression is checked once or twice
at the track during the weekend, as usually there
isn't much more to do between sessions, knock wood.
Valves adjusted after each weekend also.
Compression went from 190 190 170 170 to 190 across
the board with a composite gasket from Peter C. Frank
threatened to shatter my kneecaps if I used a copper.
This car has missed one 25 minute session over the
last two seasons dating back to 2003 out of 70 or so,
the problem always seems to come up every 2 or 3
weekends after I'm done with the weekend, obviously
after the most flogging has occurred in feature race.
There are other scientific and non-scientific factors
I don't want to get into (chuck gave some of the best
logic; my witch doctor thinks it may be "The Curse of
Waxing Porasik's Ass", as everytime I beat him this
happens).
For now, we're good.
--- dmeadow@juno.com wrote:
> I'd suggest the copper. Moss sells the "right" one.
> Mini Mania sells
> the right one and a cheap imitation. I don't know
> the part number
> offhand.
>
> Probably more important, though, is your head
> torquing procedure.
>
> First, you need flat surfaces. Both the head and
> block need to be
> smooth. If you've run through three headgaskets
> without truing the head
> and block, you probably need to have it done.
>
> Then you need to install ARP studs, if you haven't
> already.
>
> I use a copper headgasket spray, as well, although
> opinions differ.
>
> Torque initially to 60lbs, in sequence, 10-15lbs at
> a time, lubricating
> the studs/nuts with a little motor oil or moly lube.
> Ignore the ARP
> instructions and just do it. Remember the rocker
> studs don't need this
> torque, 35lbs is plenty.
>
> Adjust the valves.
>
> Run the engine up to temperature at lower rpms, let
> it cool down
> overnight, then retorque. Readjust the valves.
>
> The next time you run the car, retorque the head
> again once you've let it
> sit overnight. Readjust the valves.
>
> Probably a good idea to retorque the head and
> readjust the valves after
> every race weekend.
>
> David Littlefield
>
>
>
Ron Soave
"You shouldn't let other people get your kicks for you." - B. Dylan
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