Difference between Single Port and Twin Port?
benny_acko - September 21st, 2011 at 09:26 PM
Hey
just wondering what the difference between a single port engine and a twin port is (apart from an extra port!!)
Also, what are the advantages/disadvantages between these?
Can you still have a twin carb with a single port engine?
Thanks
68AutoBug - September 22nd, 2011 at 01:18 AM
| Quote: |
Originally
posted by benny_acko
Hey
just wondering what the difference between a single port engine and a twin port is (apart from an extra port!!)
Also, what are the advantages/disadvantages between these?
Can you still have a twin carb with a single port engine?
Thanks
|
Hi
the early engines were all single port until the 1600 Dual ports came out [in Australia]
You can fit twin carburetors.. usually Kadrons..
single port engines have slightly more torque than dual port engines..
Dual port engines can rev more as they have better breathing
I have a single port 1600 engine and have never really thought about changing the heads etc to dual port..
even though I have replaced the heads..
cheers
LEE
Sides - September 22nd, 2011 at 09:22 AM
Extra to what Lee's said, here's some differences I know:
Twin port engines are usually all 1600's, though there were also some twin port 1300's.
Twin port engines used a different crank case - two oil pressure relief valves instead of just one and larger diameter oil galleries
internally
Twin port upright engines have better cooling as they use doghouse oil coolers, with the different fan shroud and tinwork to suit
Twin port engines the engine bolt nearest #3 cylinder threads into the crank case, while single port engines there's a nut that has to go on
Advantages/disadvantages...well as standard there's the obvious capacity advantage and better cooling, but also a twin port crank case is a better
base if you're going to build a big engine.
There's no reason at all you can't put twin carb's on a single port engine, just there are less options and kits around to do it. Think old school,
with two stock VW carb's mounted up rather than twin Weber's or Dell's.
Bottom line... unless you've got a good single port on hand already, go for twin port.
68AutoBug - September 22nd, 2011 at 01:20 PM
all the things I forgot... lol
You can of course fit a doghouse oil cooler and fan shroud and wider fan...
If the engine is OK
You can fit twin solex or Kadron carbies..
and an SVDA distributor for better acceleration...
plus an extractor exhaust system...
Lee
Joel - September 22nd, 2011 at 01:29 PM
