After running a 4AGE turbo setup for some time now, I decided it was time to try something different.
3TC's are not modified here in New Zealand it seems, even though awesome power outputs are common in places like
Peurto Rico, Phillipines, Malaysia and America.
As well as good horsepower, I am interested to see how much torque it puts out. Especially if bored out to 89mm from
85mm, creating a 1970cc block. I'm hoping this is really useful for 3rd and 4th gear corners.
Thank you to everyone who's helped or offered advice with this setup: Garage Dori Team, Lance, Brendan from Nite Parts, overseas advisors Ryso, club4ag members
Checking Standard 3TC Clearances:
Measured with standard 3TC motor, with a standard used (albeit compressed a fair wack) head gasket
Intake valve to piston clearance: 3mm.
Exhaust valve to piston clearance: 5mm.
So, if you want to plane the head, I would recommend 2mm at most to be safe. But this should result in a hefty
compression increase. I don't know how much lift the standard cams have, so how much lift and planed head you can
get away with you'd have to calculate out from above.
NB: These measures were done with a rather crude measuring tool, and if anything, errs on the safe side by a fair
bit. You could probably add 0.5mm to each of those clearances.
Fitting the 20V Silvertop Quads:
Carburettor Port Outlet: 28mm
3TC Intake Port Size: 32mm -> 35mm
20V Outlet: 40mm
20V Inlet: 46mm
The 3TC intake ports have a small step in them, and it looks like they could be ported out to 35mm very easily with
a dremel. But the question is:
I just open it up to 35mm following the same path as the existing ports?
Or should I take more out of the top or bottom?
Or, should I not do anything?
- UPDATE (early sep):
Thanks to a link from Flashman on club4ag, I've decided just to leave them standard for now:
Engine Porting
Myths
- UPDATE (late sep):
Seems others running really good 1/4 mile times are porting the head, so I'll see what happens with a cam and quads
before trying to port a head.
