GT big block experiance : New GT crank info added

[1469leach]

Are we talking degrees Celsius or Fahrenheit Eden? I'm assuming its Celsius,my rapido 225 runs at around 220-230 deg f CHT on a dual carriageway,wondering if that's seems ok?


Cheers Jeff

[eden]

Where is your sensor mounted and have you tested that the sensor reads correctly by dropping it in to boiling water?
Anything over 200 degrees C is getting dangerous

[1469leach]

Sensor is under the spark plug,it's running at 220-230 Fahrenheit not Celsius.havent tried it in boiling water but seems a good idea.Got no reason to think it's not working correctly though.

[eden]

that's around 107 which is very cool.
how long have you been running down a duel carriageway to get that temp? My engines take a good 4 to 7 miles to get the head up to temp!

[1469leach]

Dual carriageway is about 4-5 miles long where I give my bikes a test run,surely being cool is a good thing on a lambretta within reason isn't it?Travelling around 55-65 mph when registering that temp.still get a bit of pinking when I push it a bit harder which goes when I give the remote choke a squeeze so need to look at the jetting and richen up a bit at that point on the throttle,temperature don't shoot up when I get it tho which I thought it might.Having said that I never let it happen to long before I get on the choke to sort it.


cheers Jeff

[Minority]

Dual carriageway is about 4-5 miles long where I give my bikes a test run,surely being cool is a good thing on a lambretta within reason isn't it?Travelling around 55-65 mph when registering that temp.still get a bit of pinking when I push it a bit harder which goes when I give the remote choke a squeeze so need to look at the jetting and richen up a bit at that point on the throttle,temperature don't shoot up when I get it tho which I thought it might.Having said that I never let it happen to long before I get on the choke to sort it.


cheers Jeff

CHT takes much longer than EGT to respond as far as I understand (only used a CHT myself), which probably explains why you don' t see a rise in temp before you use your choke to fix the problem.

[eden]

The GT kit since Davos has successfully done Shipston and today did a 333 mile round trip to the Darlington LCGB members rally and back.

Today it averaged 42mpg over the 333 miles, took 4 hours to get there including 3 fuel stops and 3 1/2 hours to get back including 2 fuel stops.
Also today was the first proper run out using the ignition curve I created for the Kheper ignition coil. its set at static 24 degrees, starts retarding at 4400 rpm to 22 degrees at 4800 rpm, then retards to 17 degrees at 5900 rpm then retards to 15.5 degrees at 9500 rpm

Temp readings were all good today with that curve, its one thing to set a curve and dyno the engine to see if its making improved power with the curve but there is nothing like actually going out and doing a few hundred miles in varying conditions to see how the engine performs in the real world with a given ignition curve!

Its running great at the moment

[1469leach]

Thats a nice average speed over that distance Eden,what do the manufactures of the GT kit recommend to set static timing at?

cheers Jeff

[eden]

16 or 17

[Muppet]

rich told me 17 deg static