Pictures and information by Karl Schluter. Copyright.
This article is NOT a “How to” in complete detail.
It is to steer you in the right direction to chose a system for your budget and
end use, whether you want a stock looking,, better performing system or a top
grade high powered ignition.
This is not a article on trouble shooting your non running car or how a stock system works. For that I STRONGLY recommend a factory workshop manual on how a system works and a detailed list of how to trouble shoot and get running a dead ignition fast, as the manuals pages are set out in a step by step proven method.
Remember regardless of the hype around advertisements from
ignition companies, little mpg or HP will be gained often over a freshly tuned
stock system in good condition. A high-powered ignition box can cover for other
problems like a rich mixture or worn plugs plus a optical system will mask worn
bushes in the distributor.
Note: I recommend you read the adjoining articles too as
they offer tips, books, websites, company contacts and other helpful
information!
Improving a stock system:
Spark plugs: I stay away from the multi tip or surface gap plugs
and go with proven name brands and heat ranges as specified in our manuals. I
gap them standard for stock systems but open them up .004” at a time for a
performance ignition until performance drops off then I close it back up one
step. (I favour NGK as they cover with one plugs heat range a wider set of
conditions but that just my personal opinion).
Leads: I have a Dyno test I can scan for people where a
tuned V8 of around 400hp was tested with diffence leads from budget priced to
the top grade performance leads. A difference of 4hp or 1% was found, enough to
be within the margin of error. Proving that there’s little to gain in leads if
yours are working fine.
However to look after your leads, remove them by grabbing
the boot (do this when they are cold and they are less prone to separate) and
test them with a multi meter to see if they are within manufacturer’s specs.
I would today steer away from solid core (copper wire)
leads as they are too “noisy” with radio inference. They can also interfere
with multi spark and computer ignition systems enough for these products companies
to especially ask they not be used.
The best type of leads for performance and noise
suppression is the “spiral wire” type. These have a fine wire wound around the
inside core. Standard carbon wires are fine but they will break down faster
with a hotter ignition box. Try to have no two leads running side by side for
any distance as arcing can result leading to a crossfire. Leads crossing at 90
degrees are less likely to do this. An air gap of 25mm or an inch between
different leads and metal or conducting objects (heater hoses etc) is a good
measurement to aim for.
Stock system tips,
Start with a sound distributor that’s tight in the bushes
and clean with a good free moving points plate (the plate the vacuum canister
moves), complete with its sound earth wire. Suck on the Vacuum advance line and
see if the points plate moves, keep the vacuum advance canister even in hot
street performance engines to keep the plugs clean (plus it’s worth mpg).
With the timing light pointing on the timing pointer,
slowly bring the engine up in rpm to check for a smooth advancing timing curve.
Sticky weights, broken, worn or missing springs plus worn weight pivots all
bear in this. Repair or replace any worn parts. A fresh rotor and good cap free
of tracking or cracks etc are needed too. If you have a choice use a cap with
brass terminals as these will last longer and conduct better than alloy. On
some Zephyr models a distributor cap from a Triumph can be used that allows you
to use push in leads.
Some auto electricians can run your distributor on a bench
mounted machine and check the curve of the advancing rate of timing and they
will adjust the springs and weights etc to better suit today’s fuel.
Point tips:
I set the points gap with a clean grease free feeler gauge.
Look for a set of points with a hole through one contact, these are vented and
will last longer. Never file points as they are mostly tungsten coated and
filing removes the coating. New points are often covered in light oil to stop
them rusting on the contacts in the packet so do remove that! An old trick was
to unhook and further bend the steel point spring to preload it more to make
the points arm follow the cam lobes on the distributor for better high rpm
performance. I have never had the need to do that for point bounce free high
rpm, plus the points rubbing block will in turn wear faster.
Polish the points cam and using a light amount of Vaseline
(go small and allow a small amount to gather on the points rubbing block so the
Vaseline smears on as the block wears over time) on the distributor cam. I set
the points on the larger side of the factory spec’s as this allows for the
points to bed in.
Initial Timing:
Always set the scale on the vernier adjustment dial on the
Lucas distributor body on the 4th line (this aligns into phase the
spark timing from the points action with the timing of the rotor tip aligning
with the right distributor cap terminal). For a stock engine, standard timing
settings are fine, however you can add 2 degrees at a time until you get slight
pinking under load, then go back 2 degrees. My engines liked more timing
than stock, see Hot engine rebuild .
I found a degree was about equal on a Mk lll lower pulley to
1mm however it would be best to divide the crank pulley into 360 degrees and
mark it carefully with the edge of a file. This is a good time to check the
condition of the lower pulley as they can split (but you know that I bet!).
Don’t over tighten that fan belt!
Rev limiters.
Why bother with a rev limiter on your car? Well do you
trust the guy who road tests your pride and joy? Or the panel and paint guy
etc? I know twice my car was “ race tested “ by people who thought I wouldn’t
know.
The cheapest Rev limiter on the Internet I have found is
made right here in New Zealand by Rite-Tec. They have models for 4, 6 and V8’s
and the adjustable rev limiter is the size of a matchbox so it can be hidden!
Rental companies use these as well. They also sell other models. Great people
to deal with: http://www.autopia.co.nz/rite_tec_js.htm
Jaycar (below in sites) sell a model made up from 2 kit
sets KC-5265 and KC-5255, that’s a nice unit for those of you who can solder as
well!
Continued in Ignition
Upgrade Part 2
Do visit the Ignition Upgrade Part 5 for links, companies etc.
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article