Duratec in detail

[TrackScotland]

Congratulations again David

You also missed off the MOST important award for the year! You won the Team Trophy too

Class A winner
Team Trophy winner
2nd place overall


We def need to be in the same class next year. I'm not sure whats what with class regs for 2015 just now but from what Rory reported they will prob use a similar class structure to the one we discussed (increasing gaps as the class increases - so same style just slight tweaks). If I end up in B I think I'll opt to run in the same class as you (i.e up a class if you are in A if needs be). I'll never be able to attend a full years events so best to make the most of those that I can.

I should have my car out in a couple of weeks Getting the winter testing started early.

[Dominic]

[Ferg]

Great results. I've enjoyed the track reports and mod blogs from this year a lot. Top job!

[robin]

Great result!

[David]

With the season over I'm enjoying a caffeine overdose in the workshop and have started planning the next upgrade campaign.

I removed the roller barrels and started to look at what will be required for the switch the taper bodies. I've chosen to make significant changes to the fuel supply by adding a return and fuel rail regulator. Maybe that's normal in turbo charged cars but Caterham use a single line.

Here's them side by side - the taper bodies slightly longer but the main difference is the injectors being further out and underneath.

l


This means that I need to block the old injector hole in the head. Rather than just fit a blanking plug, I decided to make some dummy injector blanks to fill the injector cavity. I'm not sure if the cavity would have any detrimental effect but it was a good excuse to play with the lathe



To make these:



That fit here:



They are a tight fit and are locked in with loctite and a punch.

[robin]

Hi David,

Loving the plug work Did you consider putting some injectors in there and not wiring them up .... reason I ask is that I know some ECUs support 8 injector configurations - the advantage is in resolution and response; by using two injectors you get more control over fuelling; by having injectors near the port, you get better throttle response (I believe), but for power you want them further away from the port, so 8 injectors allows you the best of both worlds (at the expense of yet another parameter to control in the ECU map).

Cheers,
Robin

[David]

Hi David,

Loving the plug work Did you consider putting some injectors in there and not wiring them up .... reason I ask is that I know some ECUs support 8 injector configurations - the advantage is in resolution and response; by using two injectors you get more control over fuelling; by having injectors near the port, you get better throttle response (I believe), but for power you want them further away from the port, so 8 injectors allows you the best of both worlds (at the expense of yet another parameter to control in the ECU map).

Cheers,
Robin

Yes, the thought did cross my mind. The taper bodies do have a position cast for the second injector (at the bottom of the photo) but I understand it was dropped after results proved to be insignificant. That's not to say it wasn't an improvement, just not enough to make it a marketable option. I have heard of some Duratec engines running 8 injectors but it's all a bit bespoke and experimental and just a little beyond my comfort zone, so I'll stick with the four for the time being. But maybe one day . . .

[David]

After a frustrating few months where domestic commitment stopped progress on Sadev upgrade, I've finally managed to start and took the engine out this week.



Dimensionally the two boxes are the same (this is a Caterham spec box as fitted by the factory) so it should fit but there are differences - namely the fixing bolts are M12 and screw into the gearbox, whereas the caterham six used M10 that screw into the bell housing. The gear position is also said to be poor, so some mods are needed there, but I might test fit it to make my own mind up about that first.



This means drilling out the bell housing M10 threads to a M12 clearance hole.




As the clutch is accessible, I thought it worth stripping it down to check it out. Having done 7 sprint events and several track days, it was surprisingly clean with little or no wear.




The only noticeable difference from new was a where the release bearing hand worn a groove in the spring - but no signs of distress anywhere.

[Stu160]

I wish I had more spare time, the 211 has sat in the garage since Cadwell/Oulton, and i havent even had time to think about going out to work on it .

Perhaps in the new year.

Liking the mods for next year

Stu

[robin]

Hi David,

Looking at the groove worn into the springs I was quite surprised. If the spring metal is uniform then will the bearing keep wearing through them at the same rate? i.e. if you do 10 track days - which is probably the equivalent of 500 events - will you have a really deep groove there?.

Or is there some sacrificial layer like paint or similar?

Cheers,
Robin

[David]

Hi David,

Looking at the groove worn into the springs I was quite surprised. If the spring metal is uniform then will the bearing keep wearing through them at the same rate? i.e. if you do 10 track days - which is probably the equivalent of 500 events - will you have a really deep groove there?.

Or is there some sacrificial layer like paint or similar?

Cheers,
Robin

I was surprised too! There's quite a lot in the Super Clutch instructions about release bearings and they require a 'round' as opposed to a 'flat' profile . The bearing supplied by SBD is round - I'm guessing that the small point of contact is causing rapid wear but will reduce at the surface area gets larger as they mate together.

[robin]

Ah yes - wear will be a function of pressure - fingers crossed that all works out then!

[David]

Yesterday I started to look at what's involved with the prop-shaft upgrade. With the diff and prop out it gave me a change to compare them side by side.




The standard yoke is 70mm and the upgraded one is 82mm (2 3/4 and 3 1/4 inches) so half an inch bigger.



There is a standard modification required to fit the upgraded shaft and I originally thought that it was to allow for increased running clearance, but it looks like it is simply needed to physically slide the shaft into place - the clearance between the chassis members being 75 mm. Maybe there's a possibility to dismantle the joint to get it past rather than bend the chassis.



I'm off for my Christmas lunch now so I ponder it between the small talk with a few beers.

[David]

I'd been putting off the over-size prop problem for too long - idea of bending the chassis was terrifying but it did seem to be the only option.




So with a plan in place, today was the day.

I started by fabricating a jack. It was designed with arms that curve just a little more than was required and was placed in the appropriate position. It was then screwed out until the arms were in contact their whole length.



After removing it the rails sprung back a little but where bent enough to let the prop pass.



No damage or kinks - it just looked as though it had always been like that

Feeling rather chuffed

[robin]

Top effort - you should now sell your jack design to Caterham Motorsport (or just the jack - for the number of these that get fitted, it could just get shipped around the country).

Cheers,
Robin