Sunday, April 26, 2009

Off with its head!

After a Parts Department sort out at my father's place in NZ, there's a pallet of parts due to arrive in Brisbane late next month. I uncovered a lot of bits opportunistically grabbed over the years, many cleaned, repainted and wrapped in newspaper before being put away and mostly forgotten. The pallet includes a Type 9 gearbox, new 23-spline clutch, Subaru diff, Triumph Tune 330lb/in springs (I 'd go for 450lb now but hey), NOS Monroe Herald rear shocks (which may fit the GT6, I'll wait and see), and shiny front wishbones and turrets.

One box contained 6 cylinder engine parts, as I originally planned to put a PI engine in my Herald coupe. I uncovered VP2 010" main and big end bearings, new valve guides, gaskets and a timing chain tensioner. I also dug up an 'F16' camshaft from Kelford Camtech in Christchurch. It's the same grind as in my 13/60, and certainly made a difference to a friend's 2000 Mk2:

Valve lift: intake 0.426, exhaust 0.422
Duration at 050: intake and exhaust 220

The TR5, by comparison, has 0.372 valve lift and 226 duration (http://www.hottr6.com/triumph/tr6cams.html), so less lift but slightly more duration. A longer duration cam may be worth trying at a later date, but for now I'll build it with what I've got.

I took the head off the GT6 motor today to see what lurked beneath. It's a low compression US-spec engine, and turns out to have flat pistons in a recessed block, and the head casting - 312388 - and machining numbers - 218255 - are the same as Mk2 PIs, 2500TCs, as well as the GT6 Mk2, which had domed pistons to raise the compression. The head numbers indicate a height of 3.400" compared with 3.300" for the flat-pistoned Vitesse Mk2, so it'll need at least 100 thou shaved to get the compression up.

The pistons can be moved around in the bores, so a rebore is on the cards. 60 thou forged maybe? Interestingly, the outer 4 are stamped 'A' and the inner two 'B'. The photo shows the recessed bores - it looks like the head gasket's still in place, but that's the step in the block!

Sunday, April 19, 2009

April fooling

Before the New Zealand winter clamped down, I flew back to Christchurch. The official reasons were to visit my father for his birthday, to see friends and see the autumn landscape - Queensland doesn't have an autumn, the trees stay a dull grey-green all year round. I went up to North Canterbury with a friend, and to the Botanic Gardens (cliched but beautiful nevertheless).

The unofficial reasons for the visit were to send my V8 Herald to the body shop (Brands Hatch) and bring back a pile of restored but never used parts for the GT6 in Australia. Having two restoration projects on the go simultaneously in two countries makes life interesting. Because it's in my garage in Moranbah I can do 90% of the work on the GT6 myself, whereas I have to farm out 90% of the work on the Herald coupe because I'm away 50 weeks of the year.

Andrew Stanton completed the chassis modifications with this backbone connecting the front and rear suspension. The idea is that this will provide additional rigidity to counter the torque of the V8. He also built a 'wide-track' front end and fitted a Holden diff. No way this baby will blow up!

Seeing if the carpets still fit. The front floorwells are the only unaltered parts of the floorpan!
Once again Ashley's Tow Taxi swung into action

The Herald at Brands Hatch

Saturday, April 04, 2009

Megajolt assembled

The latest version of Megajolt Light Jr (version 4) is a tricky little bugger to assemble if, like me, your soldering skills are infrequently tested. Most of the components are surface-mounted, which makes assembly far less of a D-I-Y proposition than previous incarnations. I tried, realised it's harder than it looks and gave up before damaging anything. Luckily, my brother Tim is an electronics genius (I knew this before I ordered the kit, of course) so I gave it to him. Here's what he emailed me today:

"Hi Nick,
"Almost had it complete on Thursday evening, and had it all done yesterday afternoon, done the basic tests, voltages all correct and on correct points. Reworked your solder joints, you really need a very fine tipped iron for SMD stuff, needle tipped less than 1mm diameter at point, and I use 0.6mm diameter solder, to ensure I get an appropriate amount, and even then I often still suck and reflow the joint. I've secured the Map sensor with two M3 stainless bolts cut to appropriate length, and I used a compound to prevent the nut from coming undone, rather than use a plastic cable tie, as the diagrams seemed to suggest, which may give way or not prevent vibration, and failure of the 6 brass legs or solder joints.

'I have also replaced the leaded filter cap (electrolytic) with an SMD tantalum, like the one on the output of the 5V regulator, I did this because the electrolytic caps, especially 85 deg rated devices do dry out, or leak, and thus are more prone to failure down the track, especially in a vehicle, where the temperature can become very high during summer, and in winter drop very low. Where possible, and we have them in stock, when replacing caps in radios, we fit the SMD tantalum types for improved reliability in the longer term. Standard electrolytic caps would be rated for say a 5 year life at 50 deg C, this will decrease with increasing temperature."

I'd say I owe the lad a curry and lager for that one!


Oh, my chassis is back from the sandblaster and half painted. When it's finished I'll post a few pictures. And start trying to remove POR-15 from my hands ;-)