[Fot] GT6 Burnt plugs

[Bud R]

“but what about the main jets."



ZS jets actually are adjustable, just not easily. The depth (from the bridge to the top of the jet) of the jets on my 175 ZS carbs can range from 0.085 to 0.187 inches. I have mine set at 0.125” deep. Don’t know if 150’s are the same but I suspect it’s close to the same.

To adjust take a 3/8 inch bolt and grind it flat on the bottom. Put two nuts on to lock your “depth setter” bolt and then tap the jet down to a measured depth (with your dial indicator). To move it up tap from the bottom with a Honda valve guide (or similar protection) to protect the jet. I’ve set the jets with the carbs still on the carb.

0.085 is lean and 0.187 is rich so adjust accordingly. Be precise this is not a big range but it can make a difference.


Bud Rolofson

Extreme Parts Racing (more than just a haircut)

71TR6 CC57365 (Good 6)
71 Spitfire MK IV Race Car #3
69 Spitfire MK III (back up FE engine/dinghy car)
93 Minnie Winnie Race Support Vehicle 
77 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)












On Oct 15, 2015, at 2:12 PM, Kas Kastner <kaskastner at gmail.com> wrote:

> Did you check the plugs after the overheating so that you know it was from fuel problems not the overheating??
> 
> What needles are you running? How far open is the adjusting nut for the mixture?
> 
> Never be beaten by equipment.
> 
> 
> On Thu, Oct 15, 2015 at 6:42 AM, <damys at charter.net> wrote:
> Finally got the GT6 back together and had it at Brainerd for two track days.  First day still had overheating issues even with the oil cooler, external octopus oiling and scirocco rad.  Also had a vibration in the rear. 
> 
> Then we fabricated a full rad shroud and re-did one of the 240Z rear axles.  Lost all but a very minor vibration that show up at around 100 MPH which might just be from driving an 1800 lb car that fast. 
> 
> Cured the overheating and actually had to tape the rad and oil cooler.  After many laps the water was at 200 and the oil at 220.  Outside temp 65-70 degrees.
> 
> Our new problem is we burned the electrodes off of number 1 and 4 plugs. The other four looked a little lean, but not bad.  We are running 1.50 Strombergs.
> 
> It seems to me that the stock intake is starving 1 and 4. 
> 
> I've read that Kas drilled the float jets to cure starvation at high RPM's, but what about the main jets.  Will this cause serious bog at mid-RPM's.  Also would reworking the number 1 and 4 intake runners help the problem.  We are maxing out at 6000 RPM's.
> 
> As for the minor vibration, we have a rebuilt, fully welded 3:89. 
> 
> Planning on Elkhart in the Spring. Any ideas?
> 
> Thanks
> 
> Dave and Alex Amys
> 
> 
> 
>  
> 
> _______________________________________________
> fot at autox.team.net
> 
> http://www.fot-racing.com
> 
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/kaskastner@gmail.com
> 
> 
> 
> 
> _______________________________________________
> fot at autox.team.net
> 
> http://www.fot-racing.com
> 
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/levilevi@comcast.net
> 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/fot/attachments/20151016/f25f60bc/attachment-0001.htm>