GT big block experiance : New GT crank info added

[eden]

Picked up the 1st new GT crank today. Quality looks very good.
With luck I'll be fitting it into my GT230 tomorrow so will post some pics and report on how the fit goes.

Once this crank has done a few miles to iron our any issues that may arise the cranks will become available.

The one I'm fitting is a 60 X 110 version using the new stepdown little end bearing.

[eden]

I installed the crank this morning, all went well.

Its a shame the prototype 60mm stroke crank came before the 62mm version as I would have like to have fitted the 62, however as my GT230 has always used a 60mm stroke maybe its a good thing.

I was a little concerned about the small chamfers on the oil seal races but the seals seem to have rode over them ok.






The conrods in the GT cranks all have an eye for an 18mm gudgeon pin and are all 110mm long. The rods can also be used with pistons that use a 16mm pin though because Richard has also made some step down little end bearings, the piston I use in my GT230 has a 16mm pin so I will be using one of the step down bearings.



the bearings come in two different widths, 20mm and 22mm. the one ill be using is the 20mm wide one as it works better with the wossner piston I use.

The bearings in this image are :
top left, standard 18mm for use with an 18mm pin
bottom left, standard 16mm for use with 16mm pin

top right, step down 18-16, 22mm wide
bottom right, step down 18-16, 20mm wide



in this image you can see how much thicker the little end bearings are, the two on the right are the GT step down bearings.



when fitting the sprocket and cush drive the spline was perfect as was the internal thread.



I then lapped the taper to find out if the taper was correct, as you can see in this image the grind paste marked the taper along the full length of the flywheel boss which shows the taper is bang on




the key sat in correctly allowing the flywheel to sit on the taper.




The heated mag race slid on and was tight



The crank pulled into the driveside bearing nicely and the mag housing went on nice too, the crank turned freely both while installing and after everything was tightened up.

Just waiting for the piston to come now before I try my hardest to twist and or brake this crank!




Maybe Richard can add some more info about the balancing, stuffers and the reason for the 18mm rod eye and when they are expected to become available along with the target price.

[Mr G in NYC]

Crank Looking good ....I put another 30+ miles on my GT200 kit this past weekend .
Running in nicely. G.

[Burnside]

Any updates on the crank Eden, how's the testing going?

[eden]

Still waiting for a new piston to arrive
Could put the old one back in but it's done over a lot of miles so while apart I may as well renew it.

[eden]

Still waiting for the fking piston


so I'm still riding the 250..

some footage from the weekend on the Derby 150

[eden]

Fired up my latest creation. It picks up really well and spits nothing from the carb. all good so far, cant wait to take it out!

its a bit special this engine is.





TV200 case




recessed head



Ive tuned it to pull but it should still rev on



modded 71mm H2 Wossner



62X115 crank



Set up for a specific set of timings



top spec Cyclone 5 speed



LTH 7 plate clutch



Electrex Ignition



All new parts!









more to come

[Dimitrios_231]

The engine sounds great
nice looking cranks.

[gerryjunior]

sounds nice, who sells the electrex ignitions.

[Grumpy225]

http://www.electrexworld.co.uk/acatalog/STK-720.html

That is a good looking electronic ignition. Flywheel sounds like it's the same or similar to the BGM type.