They're Here......

Here's a grumpy Initial Citylink courier - he didn't like heavy things!

Never mind that though - what did he bring? Six lovely boxes of shiny new things!

In the boxes were: New vented front discs and solid rear discs:

Reconditioned Hand-brake calipers:

Reconditioned Rear Hubs:

Reconditioned front calipers:

Reconditioned Diff: Reconditioned rear calipers, New universal joints and new brake pads (EBC Greenstuff)

Plus lots of assorted bits and pieces - see the full list.
Everything checked off and accounted for and a new list of various odds & ends I'd forgotten has been complied!

Now I've got the replacement wishbone I need to crack on and prep and paint the last front corner and then I can start re-assembly - which reminds me I need to phone GD and check on the chassis delivery date and order some other bits (springs, shocks steering rack etc.)

At Last!

Phoned Wards today - everything is ready and the courier is booked. So day off booked for tomorrow - lets hope I don't have to sit around until 6pm - anyways the garage could do with a bit of tidying ready for the new arrivals.

In the meantime with not much to do I re-jigged the gearbox ratio / speed /rpm calculator spreadsheet (E-mail me if you would like a copy).

RIGHT CLICK ON IMAGE FOR LARGER COPY

30th and Counting........

Spoke to Wards again today. They did apologise as there had been some mix up with the handbrake callipers. As I'm away next week that gives them a few days to sort things out and I've been promised everything will be delivered on Tuesday the 30th!

So there will be nothing new to report until the 30th - then there should only be 4 to 5 weeks until my chassis is ready.

Then it'll get interesting!

Shiny Bits Imminent - NOT

Well a week has passed and again nothing from Wards - they gave me the impression that everything was finished?

So all I've done is clean the remaining parts - sprayed the front hub - waiting to paint the hub carrier, upper wishbones and pivot shaft when I get the replacement lower wishbone - whenever that might be?

So all a bit fed up really - however off on holiday on Saturday for a week so this will probalby be the last update for a while - unless by some miracle some shiny things arrive???

Shiny Bits Imminent

Spoke to Wards today, just waiting on the handbrake calipers... so should be here in the next few days - now I can really crack on! Not done much else other than pack the n/s front stuff away and put the offside stuff into degreaser to soak. I won't paint until I get the replacement lower wishbone so I can do it all in one go - that'll be the end of painting - thank god. Whilst I was on the phone I ordered replacment brake pipe brackets as my donor items were badly bent and I managed to break them trying to bend them back - yes, I was being a little optimistic. Funny how you never notice these things when you pick them up - still only a few quid.

Anyways.... just to maintain interest here's a short video about the Shelby Cobra Daytona Coupe - Gorgeous Car!

The end is nigh?...........

…… of painting that is! It has been a productive weekend. Saturday I stripped, cleaned and acid etched all the components for the nearside front suspension.

The only bit of bother was cleaning all the old grease out of the front hub. I had soaked it in POR marine clean (1:5 with boiling water) for a day or so but getting inside to clean it out wasn’t easy. Solution – take one nylon toilet brush and some scissors – cut down the bristles so the brush is about 10mm bigger than the inside of the hub. Cut off the end of the handle so it will fit into an electric drill. Next find somewhere dirty (Not the utility kitchen sink like me!) and in a couple of minutes it’ll be as clean as a whistle. (Must remember to buy a replacement toilet brush before the domestic authorities find out!)

Having a nice clean hub I thought I might as well paint it. So out with the acid, masked off the disc contact areas, wheel studs and then paint. I used VHT calliper/drum spray paint – 3 coats 10 minutes apart and 3 hours to cure – much quicker than using POR15! Result – nice new hub.

Sunday was back to laborious painting by brush – at least there’s not much left to do now and the end results are well worth the effort.

So that just leaves one final corner – front offside. Allthough at the minute I’m missing the lower wishbone. Despite being careful three of the four spring pan bolts and the two shock mounting bolts were seized solid and eventually broke. Despite attempts to drill them out it started to look like a bit of a write off. Now seeing as it was only 25 quid for one from Wards there seemed little point in aggravating myself any further. Which reminds me – I forget to ring them last week to see where my bits are.

Following on from my last post I spent some time following threads on the UK Cobra Club forum regarding differentials and gearboxes. I came to the conclusion that the open diff / LDS debate is far from over and will probably go on forever! There was a lot of good info / advice regarding gearboxes and diff ratios and I found that although there is no definitive answer there were plenty of do’s and don’ts. What I did find though was that the combination of top gear and diff ratio was perhaps more important for a predominantly road based car. In summary I’m happy with my intentions – the net result (I think) being a slight bias towards acceleration rather than economy – fine by me. With a 1:3.54 diff and a 0.64 overdrive 5th I should be cruising at around 2000 rpm. This also means that the engine mustn’t be too “camy” - anything with a lumpy idle or “muscle car chop” won’t be on cam until after 2000 rpm which means it will struggle to cruise at 70.

It's a Question of Ratios.............?

Haven’t achieved much over the last few days apart from getting some of the front suspension parts into degreaser to soak. I have however been considering gearboxes and have realised that much more thought was required than I envisaged. The gearbox of choice for Cobra replicas is currently the Tremec TKO as shown below:

However the TKO’s come in three flavours:
So which one to choose?.... there are a few things to consider:

The first is the Starting Line Ratio (SLR) also known as the Launch Ratio and is particularly important when selecting a gearbox and/or differential.

Starting Line Ratio = 1st gear ratio X differential ratio.

The optimum SLR range is 9-11 with 10 being the ideal. Less than 8 will result in excessive clutch slippage to get the car moving and greater than 12 will provide lots of noise but not much movement. These figures are based on an overall wheel height of 28” (This info comes from our friends across the pond) and therefore the SLR needs to be factored to take account of actual wheel size:

SLR = 1st gear ratio X diff ratio X ( 28 / Wheel Height in Inches )

So now I need two bits of info – diff ratio and wheel height. My Diff is 46/13 or 3.54:1 there were various ratios fitted to the XJ6 dependant upon engine size and intended market (2.88, 3.07, 3.31, 3.54, 3.57, 3.77, 4.09, 4.27, 4.55) the 3.54:1 is fairly common. A number of these diffs were available either as Limited Slip Diffs (LSD or Powr-Lok) as well as Standard (or Open) Diffs. There are many opinions regarding the relative merits of LSD’s and open diffs and it seems to be an eternal quandary. However, having read many arguments I am sticking with my open diff as:

1) In normal or spirited road use it should prove more than adequate and should also provide improved turn-in of the car as opposed to an LSD.

2) LSD’s can produce some unintended “end swapping action” especially when accelerating out of corners, as a result of wheelspin with the diff locked – both wheels spin = no lateral grip. With an open diff only one wheel should spin therefore the other should still provide some grip.

I reserve the right to change my mind after driving the thing!! - and should the open diff not be satisfactory then the Grand Plan would be to fit Quaife ATB internals !!!

Getting back on track – overall wheel height is needed next. Many people fit 18” wheels with low profile tyres. I will however be going for the “period look” with 16” wheels and taller tyres. Now I don’t know the tyre size for the 16” wheels but I know that the Mark IV GD can be fitted with 18” wheels and 285x40 tyres (to fill the larger rear arches). This gives an overall wheel height of 27” (26.97).

So – for my car the SLR will be 1st gear ratio X 3.54 X (28/27)

Or 1st gear ratio X 3.67.

The TKO 500 has a first gear of 3.27 giving an SLR of 12.00

The TKO 600 has a first gear of 2.87 giving an SLR of 10.53

So this appears to be a “no-brainer” – TKO 600 it is.



I suppose you should argue that with around 400 hp and 400 lb ft torque you should be looking at the 8-9 range as a more powerful engine will be able to cope with the taller gearing. Certainly if you look at the original specs for 427 Cobras (420hp & 480 lb ft) its SLR is closer to 8 than 10. The 289 Cobras (271 hp & 314 lb ft) SLR’s are around 9.3.

There are two TKO 600’s the 600 and the 600RR. The RR is the Road Race version without an overdrive 5th gear – this would result in higher rpm (and increased fuel consumption) at cruising speeds – so a standard TKO it is.

So – a TKO 600 will give me the following:

Obviously aerodynamics will restrict 5th gear maximum speed!! One last thing to calculate is the distance to 2nd gear. Using the Calculator provided by http://www.5speedtransmissions.com/ I have calculated the distance to second gear to be:

1) For a normal gear change at 2500 rpm and less than 50% torque = 19 Feet.

2) For a full throttle gear change at 6000 rpm and full torque = 55 Feet.

Now all the numbers seem fine to me, but I still have a nagging feeling that the overall gearing should be a little taller (i.e. numerically smaller diff ratio). I’ll have a rummage on some of the forums and see what comes up?

Seconds out...... Round Two

Well that’s the rear finished now – all I need is the reconditioned parts back from Wards and I can commence re-assembly. I suppose in theory this is a minor landmark – but it doesn’t feel like it – there still seems plenty to do before I have enough parts to start assembling onto a chassis. I suppose this is no big deal as my chassis won’t be ready until end of February / early March.



I’ve dug out all the parts for the front near-side ready for cleaning and painting – as you can see there doesn’t appear to be as many as for the rear. Some parts are not required such as the steering arm (this is replaced by a Gardner Douglas item as the steering rack is in front of the wheels as opposed to behind as on the Jaguar). The anti-roll bar mounting is not required either as the chassis is being constructed without. Advice from GD was that this is not really needed unless some serious use on track was planned. However it can be retro-fitted at a later date should I feel it’s necessary.


I am re-conditioning the front hubs myself as these are relatively straightforward compared to the fancy preloaded bearing efforts on the rear hubs. Stub axles, inner and outer wheel bearings are being replaced and new powerflex bushes will be fitted to the wishbones. Not sure if I’ll be able to fit these myself or if I’ll have to “borrow” a press?

Here we are at the end of one year and the beginning of another. I wonder how far on the build will be at this time next year? I have always had a rough programme of 2 years but without going into any detail. I have steered clear of having a strict build programme – mainly to avoid disappointment I think! I would hope that this time next year as a minimum I would have a complete rolling chassis with running engine and should be just starting work on fitting the body out. Now this may not seem like much – but I’m trying not to be overenthusiastic whilst remaining realistic with regard to budget.

On the subject of Colour......

Thinking about body colour (again) today. I have already decided to opt for a "gel coat" finish for two reasons:



1) Going to the expense of painting seems unnecessary given the quality of the finish that can be obtained with GD's gel coat - many mistake it for a conventional "paint job" apparently.


2) The "gel coat" has an appreciable thickness which means that stone chips do not tend to reveal primer (as would be the case with a conventional paint job). It's also a lot harder wearing - in fact Andy Burrows recommended "gel coat" if Track Days were to be on the agenda - which I think they may well be!


It has been said that using gel coats limits the number of available colours - obviously you can't have metallic or pearlescent etc - only solid colours. GD can supply a body shell in any RAL colour. Below is a picture of the full spectrum of RAL colours - in my book I wouldn't call it limited!









I have a copy of "COBRA The First 40 Years" by Trevor Legate (excellent book by the way) in it there are some excellent pictures of "39 PH" painted in the Team Willment Colours. I think this is what I'll go for - red gel coat and the stripes can be done with vinyl (but not by me if I want them straight!).

"39PH" is pictured here fitted with it's Le-Mans Hardtop - but you get the idea - haven't made my mind up about the white roundels on the sides yet though? Just need to identify the appropriate shade of red now.

More Painting

Painted all the remaining components for the rear-nearside today in one go. It gets a bit tricky over coating black on black to ensure complete coverage- especially when the existing coat has quite a high gloss. I had solved this problem with a cheapo LED head torch this shows up the fresh coat you are applying quite nicely.

So that's all the components for the rear refurbished and painted. I'll leave the paint to cure for a couple of days - remove the masking tape, fit new grease nipples and pack away with the parts for the offside. All I need now are the reconditioned and new parts back from Wards and I can start re-assembly. I must remember to ring them next week and find out how they are getting on - they did say at the time that no news would be good news - but no news at all?


I suppose now I need to prepare myself for tackling the front suspension and hubs - I don't think there will be as much prep and painting although there are more, but smaller, parts - probably end up being a bit fiddly. I also need to get all the old grease out of the hubs - nice.

No Man's Land -

You know the place - that time between Boxing Day and New Year. Thought it was time to crack on with the prep and painting for the other side of the rear. Had already painted the lower wishbone but decided I was gonna paint all the rest in one sitting to save time (and paintbrushes - don't seem able to get them clean so it's new ones each time) Just before Christmas I had stripped all the parts so today it was a matter of final cleaning and degreasing.

I use hot water all the time now - mainly it means that all the parts dry pretty quickly with being warm - it also means that the passivation process from the acid etching doesn't take so long either. But perhaps more importantly - as it's about zero degrees in my garage at the minute it's much more bearable on the hands! Which reminds me - I best leave the prepared parts in the house overnight to warm up ready for painting tomorrow - it's just a little too cold for the paint.

I've also been tinkering with the blog and added some more links (needed to set up my own website as a repository for all the info). I've also added a webcam! not bad for a net-virgin. At the moment it aimlessly stares out of the study window - It will be moved into the garage and the plan is to provide a time-lapse animation of the build. Perhaps a little ambitious? ...... we'll see. It's either going to be a looooong USB cable (which might not work) or a wireless webcam (which might not work either)!

Dreaming of Engines................

Today is the first day of the Christmas Break!! However half of today has been wasted by recovering from the "Christmas do" last night. Didn't feel up to much so I wasted some more time thinking about engines. I haven't even got a full collection of refurbished donor parts yet never mind a chassis so engines are a long way off - but then again - engines are the exciting bit!

From the outset I was always going to use a Chevy 350 (0r 383 as these are 350's with a stroker crank). After the unbelievable test drive in the GD demonstrator (a 400HP LS1) I had again made an instant decision that approx 400 HP was what I wanted. The general motors LS engines have a lot going for them - but at the end of the day they just do not compare to a 350 Chevy on looks - I've said before that this project isn't necessarily about sensible decisions!

So... spent some time on the 'net and came across pro-performance unlimited .... you would not believe what treasures lie await on this site!!. Just to whet your appetites and to give you a feel for why Chevy 350 (383) over GM LS - then have a look at these video clips courtesy of pro-performance unlimited:

PS. Don't forgrt to turn up the sound!

OPTION 1 CHEVY 350 - 420 HP



OPTION 2 CHEVY 350 440 HP



OPTION 3 - CHEVY 383 - 450 HP



Should have spent some time filling in the blanks to get the blog up to date - but I think you'll agree this was more worthwhile! - However this is a monumentous occaison as it represents my first REAL TIME POST!

Here we go again.

Now it's time to start all over again with the other side - not wishing to bore everyone with a repeat of the previous side ..... Here's some hot painting action instead!

One down.... loads to go.

That's all one side of the rear finished - all packed away ready for building up. Took the opportunity to fit new grease nipples to the lower wishbone. Didn't fit too well - looks to me like it needed a washer but none was present when I tripped it - more vanishing bits? Not to worry I took the old nipples off the universal joints I had junked and cleaned up the alloy domed washers of them - perfect.