A contribution

[Ben Wight]

Just thought I would make a contribution. The first thing that pops into mind is cheap power increases.

Its been many years since I played with a standard carby 1600, but I do remember that there are a few points of factory power restriction.

The first I can think of is the factory air cleaner with its snorkel and heat riser. The rist thing that should be done is the snorkel cut shorter about 100mm so you comletely cut off the 'summer - winter' switch for the heat riser. The snorker is restrictive (just my opinion) and the heat riser allows heat to enter the inlet air making it less dense and therefore inhibiting engine power (fact).

If you make a bell mouth in the snorkel after you cut it (bash it somehow) and then try and duct cold air to it, you will be on the right track, increasing flow with the bell mouth and air density with the cooler air. Cool air can be ducted from the front of the car, near where the battery sits, or a good spot I have used is cut a hole is the fresh air inlet cover (the black panel covering the heater fan unit). This pressurises with air as the vehicle travels forward at speed (its what supplies the interior's fresh air vents), so you will get a minute amount of forced induction, as you might also get from a duct at the front grill.

Another trick is to buy an air filer of the same diameter as the standard one, but taller by about 15mm, and then turn the lid of the air cleaner upside down and screw it back into place. This will leave a gap around the top of the air cleaner under the lid, and will potentially increase air flow through to you carburetor, as you have a filter with more surface area, and more air being able to reach it, instead of having to travel through the snorkel. This mod however will negate any effect of a pressurised cold air intake.

The next thing I can think of is the factory exhaust system. My favourite exhaust for a mild or hot 1600 is a set of extractors, 2.25" system with a stright through in factory location, and hot dog in tailpipe. This however will probably cost about $500 fitted for new bits.

The first thing I can remember doing is removing the factory resonator in the tailpipe, and I put on a 2.5" tailpipe from the factory muffler. It definitely sounded louder, but I guess it didn't make much more power at all due to the dramatic pipe diameter increase from stock muffler to tailpipe, and the fact that the factory muffler is restrictive as buggery. If you can scrounge together $150 or so, get a straight through muffler put in the standard muffler location, with standard pipe size, and go no bigger than 2" for the tailpipe, ditching the factory resonator in the process. I haven't tried this, but the exhaust will be much less restrictive, and relatively quiet due to the small pipe diameter. If still too loud, $55 will get you a hot dog fitted to the tailpipe. I also bought a set of genie extractors SH for $50, this is also highly recommended as the factory exhaust manifold is pretty piss poor.

The next thing I can think of is the distributor, assuming you can set your point gap properly, I think the factory ignition timing is 6 degrees BTDC. This means that you will get 30 degrees total, as the distributor offers 24 degrees mechanical advance on its factory internal setting. I would guess that the engine will make most torque at around 36 degrees total timing on optimax, due to its low compression. Therefore, I used to runy10-12 degrees static ignition timing. If it audiable detonates, and you dont want to adjust your distributor internally, then back it off 1 or 2 degrees and give it another run.

You should really find that the engine will perform best with a static timing of about 16 degrees, and a mechanical advance of only 20, but this will require internal mods to the mechanical advance mechanism. Its very easy, but you have to pull apart the dizzy and become familiar with how it works, best to do that with a dizzy other than the one making your car run.

Another mod I did early on was to swap the nikki for a 32/36 DGV weber carb, a good investment for both power and economy, but will cost you about $200 to buy the bits and then dyno for right mixtures.

A 10" thermo fan can be bought new for around $80, and a temp switch for $40. Removing the factory engine fan will save several hp.

The only other thing I can think of before pulling the head off would be to port match the manifolds/extractors to the head, which will require new gaskets, but should be less than $30 for both intake and exhaust.

More mods next time I get the itch to do some typing.

Ben Wight

[TXcoupe]

i good investment while doing these mods would be a decent set of spanners, some axle stands, and a very very understandable parents.

another way of getting good cheap Hp is to get a hole saw and cut circles in the rear of the air cleaner if u have problems with the police

[rob_w]

another way is to buy a chrome air cleaner for $40, and wire the nikki secondaries together, as mentioned earlier.

if you have a heap of spare parts available to you, you may want to try fitting a g200 camshaft to the g161. you will need the rockers from the 2ltr though, as my rockers were just too short.

[good power from 2000-6200 rpm,on a stock g161 with a 32/36 extractors+2"pipes.]

didnt cos me anything to do, got more response down low, too.

[TXcoupe]

i havent heard that one about changing rockers. The rockers on the g200 look the same size as the other g series motor.
another good investment is a big valve head