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  #1 (permalink)  
Old 06-16-2021, 03:31 AM
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Default UK Based BackDraft 153 Revival.

Hello Everyone!

(Sorry this post is made up of a series of other posts on a different forum)

I was looking at all sorts, Caterham's, Atoms, Cayman GT4's, GT3's and even a Macca 570s in one of my weaker moments.

None of them though really got me going. The Caterhams were too samey when compared to what I had before and the Porkers were too much like 'normal' cars.

Then the Mrs chimed in with why don't you get something you've always though was cool, and literally the first thing that came to mind was a Cobra.

I've always loved them since been little. I've been around kit cars since I was 16 so know them inside out, whats good, what isn't, whats correct etc.

So I set about looking, with my criteria list:

As close to period correct visibly as possible
Flat dash
Offset shifter
Open inner doors
15's with bubble tyres
Correct riveted bonnet and hood scoop
Correct body shape at the rear and front
Side pipes
And most importantly a Ford derived 400ci + motor

Annoyingly wanting all of the above basically throws out all the UK made reps, bar the £125k ali bodied ones. Even AC's own repos all use LS motors now.

The likes of Dax, AK and Pilgrim all have a design at the rear where it falls away too quickly compared to the real car, and the Pilgrim especially has an difficult front end.

The UK ones also have really odd interiors with the dash and trans tunnel merging. They also generally have chevy 305ci's in them, as they are cheap and plentiful. As well as hateful 17" wheels! (Sorry owners with these!)

So I was only really left with the American made reps (well the shells are done in South Africa). The two companies making the majority of these been Superformance and Backdraft.

Now the search was a tough one, very few of these cars are in the UK, and when they get offered through a dealer, they end up being a huge price. Then you can add in the fact its impossible to see one atm and it made it stressful.

Then I randomly found on on car and classic, which was local but had no price. Spoke to the owner, he said all the right things (sadly he got clobbered by Covid), so I've bought it unseen. Hopefully collect it this week!

Short spec:
Backdraft Cobra 427 SC
Imported 2017
5000 miles since it was built
Period correct bright work
Extra passenger roll hoop
Painted stripes
Stainless side pipers
15" wheels
Smeding Performance 418 V8.
Built T500 gearbox

Collected it,......

8 Weeks Ago.....

The paperwork is mental. Even have the copies of the payments cheques for the body ex engine from the USA.

First job was getting all those stickers off:

CO2 aware in this household....

Well... Iíve still not driven it and Iíve broken it...

Was going through all the boring check stuff to make sure it wouldnít fall apart when I first take it out.

When checking the clutch range of movement the slave cylinder s**t itís self. Only a £30 part though so no biggie. Better then it happening when Iím out and about!

Also look at the harnessís, they are from a 1971 aircraft. I'm not using those!!

Week 2.............

TRS harnesses ordered.

As well as what I assume to be the correct slave cylinder too. The broken one is still on the car and I canít be bothered to take it off atm.

Hopefully have the first drive next weekend, weather dependant.

Engine shots.... its a bit bling for me. Wi'll be making it look more original in the future.

Photo of the car from when it lived in California!

Some parts have come!

New clutch slave cylinder
Bonnet gas strut
Steering wheel frameless button holder
Brass adapter for the vac gauge

Still awaiting:

High temp clutch fluid
Funk motorsport clutch and brake line heat protection
TRS Harness'

Also ordered:

Classic switch label set
1960 Lucas single push switches

Clutch slave cylinder done!

As you can see it was a right t**t to bleed.

Iím glad my guess at a 1991 Landrover Defender slave cylinder was right though!

Clutch all re set and it nice to use!

Rolled out of the garage for its maiden drive.


Bad points:
It runs lean on acceleration
The near side front break squeals all the time
The tyres had 16 psi in them
Itís too low on the front and the tyres rub
Steering is a proper effort at low speed

Good points:
LHD is fun!
Itís sounds biblical
Itís actually nice to drive
The Mrs loves it
Itís a f**king Cobra
It shakes like a badass at idle
All the little fixes Iíve done have make it better

All in all Iím calling it a great success!!

Neighbour update:

3rd noise complaint today...

So after much reading I set about re setting the carb....

Carb update:

Took the jets, metering rods and springs out.

Found it was set to:
12% Lean cruise
15%!!!!!! Lean throttle

No wonder I had issues.

Now set to:

4% Lean cruise
6% Rich throttle

So hopefully that helps.

If not, I can go to:
0% Cruise
15% Rich throttle

The current 21% swing in rich fuelling should sort me.

Some photo's of how it stands now.

Oh yeah, also fitted all the funk motorsport heat proofing to my clutch and brake lines that pass the manifold.

The lean saga continues.

Carb all set up, idles fine, drives on light throttle fine. Lean as hell with any proper throttle.

So popped round the parents in it, Dad wanted to see it running.

Had the bonnet open, started it, running happily but....

Fuel pressure was through the floor, knocked the engine off and its back up to where it should be. The bloody fuel pump is on its way out!

So to distract me from making this thing fuel injected.... I finished the interior.

When I got it, I didnít really show the interior. It had a Nismo wheel FFS....

So here are some before:

And now, with new wheel, switch gear, labels and the daft carbon fibre panel painted black:

Week 3............

I caved.....

Holley Sniper EFI unit

Just ordered an 044 pump which will 'just' about keep up with the fuel needs of 7000cc at full chat.

Sniper on and half the wiring done.

This is going to be an adventure....

This weekend

So today was eventful.

First off my new pump and filter sit very low! Low enough that I think they need a shield making.

Other than that, got it all plumbed up. Ran the pump and fuel every where. The one bit of hose I hadnít changed was leaking. Typical.

Sorted that.

Finished the wiring off for the sniper. Do all the settings, set the wizard off to make a map and..... all itíll do is crank, no rpm signal.

Test everything no issues, odd.

Have a route for a better tach signal under the dash and whatís that? A bloody MSD programmable ignition unit. Who knew. Took the tach signal off that.

Boom she starts, straight into a happy idle. Within 2 mins the guy from 6 doors down was on the drive, I told him to sod off and checked for any more leaks.

All been well, time for a test drive. Within a mile I nearly lost a wheel. The cap nuts had bottomed out on the studs, so they could wind them selves out. Mrs came to my aid and I swapped the cap nuts for some open ones, sorted.

By now the car was in warm and was idling at 2000 with the idle valve closed, checked for air leaks, none. Weird. Quick google and I hadnít adjusted the hot idle screw. Idiot. Quickly sorted that and off I went for it to self tune.

After 20 mins or random driving, for the first time ever I gave it all it had...

HOLY f**king s**t

This thing is fast.

Did a bit more driving, got cold, went home.

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  #2 (permalink)  
Old 06-16-2021, 03:32 AM
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Whoa looks like there's no auto resize going on here!
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Old 06-16-2021, 03:36 AM
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New surge tank mocked up. Hopefully fit it at the weekend and run new fuel lines through the car.

So on to mocking up where the pumps and filters can live.

For the test run, they were all just on where ever they'd fit, which isn't ideal for flow, seeing leaks or servicing.

So I'm looking at moving them all to be in one place, underslung off the diff mount.

I did a quick mock up with some ali hole board, hose in place of AN fittings and lots of cable ties.

Its hard to photo, but they look a lot lower than they are, in reality they are higher than both the sump and the gearbox bell housing. They are around 20cm from the ground.

I think though, I'll get them mounted to some ali plate then build in a stand off with a skid plate below them.

The other option is to go up into the boot with them, but then you are asking the pump to draw upwards all the time and I think I'd see starvation issues.

I could run a 1.5l swirl in the right hand side of the boot. Run the 044 straight off it. Use my weakened Gates pump as a lift pump under no pressure. The return line already goes near that side of the boot.


MaxpeedingRods surge tank is here. How they make them for £25 is beyond me. Its REALLY good quality.

Fuel system re done and I have 3 leaks.

Two of the outlets on the top of the tank.

The underside of the fuel filter.

Been at it 7 hours today. Trying to be tidy. So those leaks can wait till tomorrow.


Used copper hardline where I could up to the boot.

Took the leaking joints apart.

On the fuel filter the copper ring had a nick in it. The ones on the tank that leaked just needed the mating faces cleaning up.

On the lift pump the electric fittings were push on, not really liking those I tapped them to M5 thread and put a lock nut on.

Tidied all that up and sorted the wiring and it fired first time.

Also junked the stupid oil breather lines and fitting some Moroso oil recirc caps.

Happy days. Just need some sun now.

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Old 06-16-2021, 03:37 AM
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A big box came!



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Old 06-16-2021, 03:39 AM
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I think Iíve found the cause of my squeal.

Ordered some top mounts, started with the one from the noisy side.


Thereís no grease in the baring, only sand.... that California life! The baring doesnít even spin!!

New one on, will do the other side tomorrow too.

New above, old one below.

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Old 06-16-2021, 03:41 AM
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Go out for a little blast while the Mrs is on call annnnnnnd

Ping noise and now I have no speedo...

Cable is still fitted on both ends so it looks like I’ve snapped it. Check the big book of cobra bits to find out what cable I need and I find out that in 5800 miles it’s had 6 cables..

So, the issue is the routing at the gearbox end, which I can’t change, so I have a few options:

1) Import a $100 custom cable for it to break in 1000 miles ish.

2) Take the feed from a VSS sensor on the diff, like a E36 would, run it through a $300 converter and potentially still have an issue with the 90 degree gearbox behind the gauge

3) Buy a $360 GPS to mechanical converter (not strictly legal in the uk) and potentially still have an issue with the 90 degree gearbox behind the gauge

4) Spend £300 on a new electronic gauge and a gps feed unit

Leaning to option 4 atm.

Ordered a Smiths 100mm electronic Cobra style gauge today along with a Veethree gps sender.

New (to me) Smiths reverse sweep Cobra speedo is here.

I’ve rigged it up to work from a 12v plug supply as I have a little project I want to try with it.

As you can see it’s on 1547 miles. My Cobra is on 5900ish.

I want the mileage on the new speedo to match. Smiths in all sensibleness make them neigh on impossible to manipulate the mileage (for good reason).

So I need to think laterally. Each mile requires 16000 pulses to the speedo. If I set it to a feed at 761hz using an Adrino I’ve programmed it should set/run the speedo to 170mph... the stepper motor will have a fit if I set it to over 180mph, so 170 has a bit of safety built in.

I need to add 4350ish miles to it, so it’ll have to run for 25 and a bit hours.

In that time it’ll deliver 69,600,000 pulses and bobs your uncle the mileage will be correct on the new gauge.

Should be fun.

Its only bloody working!

Speedo also overreads by 1mph at 170!

Great success.

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Old 06-16-2021, 03:43 AM
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Shopping car!

New wheel bearing too.

In other newsÖ turns out I had a squeak and a chirp.

Top mounts fixed the squeak.

The chirp is still thereÖ new wheel bearing ordered.

Bearing seemed to pull off nicely, till I saw the inner race was still on the stub.

Had to take the grinder to my small pulley puller, to make it pointy-er. Then with some cable ties and mole grips the inner race came off.

New bearing on, went on lovely.

Brakes all back together.

Took the studs out of the old hub and they were copper greased in! Cleaned all that s**t off and re fitted them in the new hub with some loctite.

Hopefully give it a drive this week to see if itís all fixed.
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Old 06-16-2021, 03:44 AM
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Finally itís something like finished.

It doesnít even squeal when you are driving along anymore.

Went to get some milk in it. Good car.

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Old 06-16-2021, 03:46 AM
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After doing 200 miles in it over the weekend, I've decided it could be even better.

The steering is very direct but the column at the steering wheel moves about 1mm in all directions, which gives a horrible disconnected feeling. Most classics have this kind of float, due to rubber/plastic bushes and not overly tight tolerances.

So I've stripped the upper column out of the car. on measuring, I think I can get some proper needle bearings in there.

I've ordered some press on inner races and correctly sized needle bearings to try.

Sadly I've not got enough room to get some conical bearings in there, so I will have to just use tension to stop thrust movement in the shaft, but that shouldn't add any more weight to the unassisted steering.

Its also time for me to accept my temporary placement of the wideband 02 sensor in the cylinder 1 manifold branch, is no longer good enough for fine engine tuning. So I'll be adding a boss onto my 4-1 collector to hopefully give me that extra level of accuracy for part throttle tuning.

I've also noticed my belt run is being dragged off line by the alternator pulley, so I'll be shimming the alternator to get that perfect too. Good job its raining this weekend!
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Old 06-16-2021, 09:32 AM
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Cobra Make, Engine: Backdraft RT3 #1133, Ford Racing 306
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Good work. Beautiful car. BIG photos. Have fun.
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