Yep GK is an early 1147. High Compression is a bit of a misnomer, it'll only
be 8:1 , and the camshaft is the early sort with very little lift. (You can
get an extra 4 or 5 HP with no downsides in these engines just by swapping
to a later cam).
First check tappets are 10 thou.
Point gap is 15 thou. Dwell depends if you have +ve or -ve earth, it'll
either show as 60 or 30.
Timing, I start at 10 degrees (marked with paint on front pulley or us a
timing gun with selectable advance) and work from there, check advance
changes as revs increase and vac works, max advance with vac and centrifugal
is over 50.
From that 10 degrees I advance until engine starts to pink under load and
turn it back slightly. It depends on the engine, fuel grade etc. Final
result will be between 6 and 12.
Best tip, pick up some old garage test equipment. This is really cheap now
as it's no use on moderns so is a bargain for us old car tinkerers.
Put Sun Analyzer into Ebay I have the UK equivalent to one of these made by
a firm called Crypton. The old 60s stuff looks coolest but the 'scopes from
that era don't work well and normally there is no gas analyser. I also
have a PC based system from 1991 that does just about everything, timing,
waveforms, printouts, gas, it even runs through a test sequence where it
starts and stops the engine automatically. It would have been thousands new
but cost me less than $100 as the seller needed the space.
Most modern bit of kit here is a late 90s US made Sun automotive
oscilloscope that shows spark graphs, strength etc for all cylinders across
the rev ranges, that'll even work off 12v, bet there is one on US Ebay...
yep, search Sun Oscilloscope that's the exact model I have but $600 seems
very expensive, I paid about half that for mine.
Sorry, the engine stuff on my website needs an update, will do that soon.
David C
From: Ed Price [mailto:]
Sent: 18 July 2010 10:56
To: david@manbus.com
Subject: RE: [General Amphicar Discussion-t-20831] engine timing and dwell
If I may quote Dave Chapman from quite a few years back; he described the GK
engine for us:
Type 1 - GK engines,
These are Amphicar 1147cc or Herald 13/60 (1296cc). Triumph made a mistake
and used the GK numbers for a second time in 1968 on the engine in the
Herald 13/60. Two engines might have the same number. Be careful ordering
parts from Triumph suppliers, they do not all know this. Amphicar GK engines
will have a 6 port cylinder head, flat core plugs, a spring clutch, a water
pump housing with temp sensor on top and an engine number less than
GK5000HE. Triumph GK engines will have 8 port cylinder head and diaphragm
clutch. If the engine is apart you can measure the cylinder bores. The
Herald GK engine is explained in Type 6 below. The Amphicar GK engine is
almost identical to the Herald GA engine, Type 2 below.
GK was assigned to the batch of 5000 engines that Triumph (in fact the
parent company - Standard Motor Co) sold to IWK in 1962, but, they forgot
and Triumph reused the same GK prefix on a 1300 engine in 1967 although I've
never seen one of those with a number less than 10000.
IWK bought all 5000 engines in one go because expected production was 30000
cars a year, the surplus engines were sold to Iran to power irrigation
pumps.
HE is High Efficiency, all it really means is the compression ratio is about
8.5:1, a lot of these engines were exported and the LE version had a much
lower ratio so less power but could run on just about any fuel.
OK, no timing info, but I thought you might like to see this.
Ed Price
IAOC Membership Registrar
El Cajon, CA USA
WB6WSN
1961 Amphicar 770
1987 MB 420SEL
_____
From: antique459 [mailto:]
Sent: Saturday, July 17, 2010 5:42 PM
To: edprice@cox.net
Subject: [General Amphicar Discussion-t-20831] engine timing and dwell
If I have an early car and the data tag lists the engine as Gk473HE what
should the timing and dwell be? Thanks in advance (no pun intended)
Keith
63 Red waiting to leave for Celina!