Here is some info that applies to all Weber carbs. If you have a good fuel
curve and the weather changes on you, simply go up or down on the main jet
only. The air corrector jet only effects the very to end of the RPM range. The
main jet effects the whole fuel curve.
Hope this helps,
On Sunday, November 30, 2014 11:07 PM, Allen Washatko <firstname.lastname@example.org>
I think you hit on it. I was going to bump up the primary jets on the Weber's
and/or drop the air correction jets but never got the opportunity. The cold
weather just accelerated the problem. The experience of others losing motors I
assume due to similar issues would support this theory. Won't be able to verify
this until next season but will let you know the results.
On Nov 30, 2014, at 8:40 PM, Rick Parent wrote:
It's not stretched head studs. Your engine is most likely on the edge
concerning your jetting. I believe your deduction on the Fall event having
better air because of the cooler weather is correct. We had a crazy year
concerning weather changes. I always jet a little fat and we had trouble at 2
events this year, we didn't lose any motors but quite a few others did. I have
an air density gauge and a weather station, they both do the same thing and are
mandatory for keeping our engines safe.
>On Sunday, November 30, 2014 6:38 PM, Allen Washatko <email@example.com>
>Does anyone have experience with head studs stretching? My ARP head
>studs were installed in 2002 and run in race events for seven years. I
>didn't race from 2009 - 2014. During that time, I did a frame-off
>restoration on the TR6. My first event out was the Hawk at Road
>America this year. After the first few practice runs, I blew a head
>gasket. We replaced it and went on to place in class. We did find that
>we were running too much timing and dialed it back.
>The next outing was the VSCDA fall event at Road America. It was
>extremely cold (high of 50). We quickly blew another head gasket! This
>gasket was an upgrade to the stock head gasket I had been running for
>years. We replaced it at the track and the same thing happened again.
>The car is running 12.8:1 compression, triple Weber's and full race
>cam. Studs always torqued using ARP assembly lubricant to ARP
>recommended torque rating using their three step approach. Torque
>wrench has been calibrated. The failed gasket has been deteriorating
>at the bridge between cylinders. Location varies. We checked the
>flatness of the head and it is perfectly flat.
>Because it was so much colder at the VSCDA fall event, were we
>producing more power due to temperatures which caused the multiple
>failures unlike the Hawk where we were able to finish with much warmer
>temperatures? Could stretched studs be the cause of this somewhat
>Allen & Jody Washatko
>1971 TR6 - Number 6
Jody & Allen Washatko
W51 N664 Highland Drive
Cedarburg, WI. 53012
tel. (262) 617-6801