Project Daily Sigma (16V TU)

[darrenjlobb]

As anyone who knows me in person will know, ever since taking the Derv Bus off the road, I've been driving either the Audi, or for the last 12 months, my daily driver, in the form of, yes, you've guessed it, a 306... Ph2 Sigma blue 1.6 8v which looks like this:



The idea being it just works, no issues with it really, just service it / drive it....

However...having now covered 160k, and still being on its original gearbox and engine, it was seriously starting to show its issues, mainly the gearbox, which has recently got the point of having to hold it in gear / the radio simply not being enough to overcome the whine on the motorway, and also engine using oil / failing MOT on emissions etc (head gasket is starting).
Obviously the sensible thing to do here would be find another low mileage 8v motor / box and drop it in, or rebuild the current one / find another box, etcetc...

However the child inside of me (most likely missing the DT) decided this was not going to happen, and that I would replace it with something a bit different, and more complicated. One thing I do love about this car, its got to be said, is the way it handles, clearly down to the lightweight TU up front, the front end of this thing really does handle so well, better than any 306 ive driven id almost go as far as saying...

Anyway I decided i wanted to leave a TU in it, thought about converting it to derv but then thought this would be the biggest mistake in history, given it would result in having 3 turbos and a p pump on it in the first month, and that would be the end of all things "reliable" about my "reliable daily driver"!! So decided to put a TU5J4 16V in it out of a saxo vts / 106 GTI...haven't really seen anyone else on here do it so thought why not, bit more power, responsive little TU, shouldn't loose its back road fun, but have a bit more power etc on the motorway / B road hooning

Anyway, decided to buy a motor while the 8v was still running (the gearbox really is THAT bad!!) and rebuilt it while its out the car ready to drop in, so collected some parts together and stripped the motor down:







Really just a good overhaul with new seals / gaskets / oil / filters / cambelt / waterpump / tensioners / some nice newmans camshafts, etcetc

Started putting the motor together:







Trying to keep things looking fairly OEM, so no painted up block or anything really, its just the daily...

Then things went quiet for a while due to being extremely busy on the farm etc, however prompted by the gearbox getting to the point where holding it in gear with your knee was simply driving me insane, I decided it was time to swap it over, I had pre planned most of the issues I thought I would encounter, although did hit several other "issues" along the way, as with everything!

So started by tearing the allmighty 1.6 8v out....








Proceeded to spend a bit of time cleaning the bay, sorting a few small rust spots, and tidying up a few bits and pieces...

Then started tearing down the 8v for ancilieres for the new motor, Wanted to try and retain the oem setup so that i didnt have to bother switching the E-Pas and loose the aircon.

Tearing the old girl down:



Bolting it up, this was the final setup I came up with, ran into several issues here due to the 16v running a normal width cambelt not a narrow one, causing the crank pulley to stick out to far, and nothing to line up, so had to modify the pulleys / use different belts here, but as you can see got it looking pretty much OEM in the end, and still easy to change belts / work on etc, new idler fitted also for piece of mind.



Then started the task of wiring, this was quite a lengthy process, mainly due to the old 8v being on bosch management and the new one being on magneti marelli.

Started with both stock 306 8v and saxo vts looms:



Proceeded to tear off all the tape / plastic:



Went about it by basically separating the "management" side of the loom and the "car sensors etc" side of the loom, on both looms cutting the management parts out, and splicing them into the stock 306 loom, so the oem bulkhead connector plugs in etc, so really just a case of belling out all the wires that join in "half" of the stock looms, to find out what ecu pins they go to, and then looking at ecu pin outs to figure what they are, and then hook them into the other loom, takes a minute or two, but fairly easy once you get going.

Some "lobb" technical notes :

[darrenjlobb]

Then the "management" loom on the engine, with all the "tails" hanging off the table ready to splice into oem loom:



Tidied:



Then dropped the motor in the car, had to modify the engine mount somewhat, and use bits from each motor, but fairly painless being the same block down below. main issues with mount was literally just cambelt clearance / cylinder head clearance. Looks happy in there:






Next issue to resolve was fuel lines, for some funky reason (anyone know why other than to save running two lines??) the 8v on the 306 only has a single fuel line to the engine bay, and runs the pressure regulator under the rear seat, which was an issue as the vts motor has a more conventional setup with the pressure reg on the back of the fuel rail, so i just sacked off the rear regulator, ran a new fuel host front to rear (clips right into oem clips) and that sorted that out:





Few modifications needed to throttle cable, but again, nothing serious.

Then started on the exhaust, using a stock saxo downpipe, in this case an aftermarket 4-2-1, it bolts right on, but terminates about 2-3mm away from the subframe, leaving no options on pipe routing, so decided to shorten it up to give me some space to work, and then weld a flange on the end so that I could bolt on a "up and over" pipe to go around the subframe thats in the way on the 306.

Bits of pipe i started with:




Chopped collector up to shorted it up:



The rough idea:




Might be worth noting at this point, please ignore the HORRIFIC attempt at welding that the PREVIOUS owner of this manifold has done!!!


Welded up:



Welding flange onto "up and over " pipe:



OEM lambda sensor fouls the sump, so bunged it, and drilled a new one:





In situ:



Support bracket under engine (to stop weight of exhaust flexing manifold):



Up and over in place:



Then started on the exhaust itself, basically used a stock downpipe, (aftermarket one with bigger bore) then bits and pieces to make up a full system of 2 1/4" bore.

Welded a D turbo flange on the end to mate with the new "up and over" pipe i just made:



Changed rear bumper for one with cutout (sadly not exact colour match as its from a phase 1 sigma, and this is a rather rare ph2 sigma), anyway all i had so mounted it / welded some exhaust mounts on and got that fitted up:



And all in, after quick test drive:




Had to modify the gear linkages (cut a section out the selector arm, and shorten the "long" rod. Having a missfire issue under load, but 99% sure its the coilpack, typical coil over plug, seems fine when cold, but gets worse and worse as it heats up, so have ordered a Ford coilpack and some HT leads to relocate that , so hopefully then it should be up and running.

Also worth noting, air filter is a temporary bodge Will locate it in the wing in front the battery asap, but need to find some OEM looking black hose first!

I know its likely to attract the old typical "why bother and not just mount a gti6 motor", well mainly just because I like to try things that are different, and tbh, I can genuinely say i preferred driving the stock 8v over a gti6, and this even with a bad coil pack has shown me that it still retains the super lively TU feel, with more power, the love is with Derv, but it has to be said, this car is yet to let me down, so credit to it (cough petrol cough) for that, hopefully this will keep it going for some time yet!

Videos of the conversion,

Part 1:



Part 2:



Thanks for reading/watching

[ozonehostile]

fairplay man, its about time one of these cracking little motors ended up in a 306

[puglove]

YES darren, iv always wanted to see this happen, i imagine its pretty dam good due to the revy nature of the engine and the minimal weight, got to be better than a 1.8/2.0 16vs offered in the 306??

[Ruan]

I love the conversion Those little motors are great!

Still not as light as a 1.8, though! The TU5s are still a cast block.

[puglove]

True that ruan

[Piggy]

Awesome Darren

Good effort.

Can see a boosted or TB'd version though...Im sure you will want more umph!!!

[darrenjlobb]

Haha meh I was happy with the 8v so this is just great Its just the mile muncher !

[bashbarnard]

Love the little 16v engines nice and revvy

[Niall]

They are a fantastic little engine and always wondered why more people don't put then in 306s. Plenty of power to haul them about and good on fuel when your careful

[welshpug]

Tis a nice but hefty lump, weighs more than the 1.8 and 1.9 16v engines! Though the iron ones are a good 20+kg more.

trouble is you still have an ma box

[darrenjlobb]

Tis a nice but hefty lump, weighs more than the 1.8 and 1.9 16v engines! Though the iron ones are a good 20+kg more.

trouble is you still have an ma box

Yeah i guess 1.8 is lighter...but thats a stock engine, was trying to do something a bit different, I know im far from a petrol head, but I just think the way the little TU 1.6/1.4 revs / drives is so much more "fun" than the bigger XU counterparts...

Yeah the box is always a let down, considering trying to retro fit a gti6 box, its always the boxs that die, and the ratios really let the whole car down, but its a rebuiult MA on there atm, so should at least last for a while.

The aim is just to try something a bit different here, not be better.

[welshpug]

a 5 speed BE will fit easy, just get everything from a later berlingo/partner

as for a 6 speed, it can be done, needs the TU-BE bellhousing modifying in a few places for the selector shaft and reverse detent then fitting to the 6 speed main casing, but nothing major, there's a few pics of that floating about on the interwebs

[Eeyore]

Good to see someone else doing something different. I'm amazed that this is heavier than the 1.8!

[welshpug]

I'm not, its cast steel!

[darrenjlobb]

Yeah I see the BE4 from picasso comes fitted factory to a JP4, so was hoping to retrofit a 6 box to that bell housing, something for the future when i get bord.

Heh, I have bad experiences with all ally blocks to be honest, do like a cast block

[Mattcheese31]

my first 306 was a 1.6 and i had helluva lot of fun with her before the engine got tired, 60mph in 2nd gear just before the limiter was good fun . . .

[darrenjlobb]

Bit of an update,

Have had a missfire since putting the motor in (fine on idle / part throttle without much load) but as soon as you load it with much throttle go past 1/2 throttle at certains rpms, you get a missfire...which seemed to get worse as it got hot...

So I made the assumption that the coilpack was likely bad (stupid coil on plug getting hot crap that i detest) and ordered up a ford coilpack and some HT leads and converted it..

However the problem seems to be made worse! I now have a really bad missfire upon even the most slight throttle use....and its a constant missfire on load....

Now im kind of thinking we seem to have an ignition feed issue? Would the newer coils likely require a stronger pulse in the first place, hence upgrading the coils has made the "issue" worse if i have a bad pulse?

Will go over grounds / power feeds tomorrow, but wondered if anyone had any ideas? Was going well otherwise, but this made it alot worse!

[ozonehostile]

Possibly a faulty map sensor? Seem to be pretty temperamental on these engines

[darrenjlobb]

Could a map sensor cause a missfire though? Id have thought that would just effect the mixture?

[Piggy]

What I perhaps missed, and am wondering if its the reason, what management are you using?
Is there a loom difference missed also with the ignition?

Are the plugs ok? - basics, but can be missed, and new leads/coil would be stronger and may show it up more

[darrenjlobb]

What I perhaps missed, and am wondering if its the reason, what management are you using?
Is there a loom difference missed also with the ignition?

Are the plugs ok? - basics, but can be missed, and new leads/coil would be stronger and may show it up more

Standard management (discuss in video)...

Ignition wires left OEM other than obviously now re soldered to the new coil plug, but all done proper etc...

Had new plugs as i rebuilt the engine...

[Piggy]

Worth checking plugs? May highlight which are misfiring.

So management of the 8v or 16v?

[darrenjlobb]

16v management.....

Had plugs out already, appear to be clean and "normal" from what i could see...Just trying to figure out of its possibly an ECU drive issue, ground issue, or power issue?

Im a diesel head really, so "common" issues arnt so common to me!

[Piggy]

MAP sensor be worth checking then.

Odd that the plugs are clean...but if its MAP sensor, that makes more sense

And usual earths...but be surprised if it was an earth

[welshpug]

Does it do it from cold? Lambda if when it warms up, map if its from cold.

[Niall]

Wait isn't the 16v GTi fully sequential? And you have fitted a semi sequential coil pack? May be a slight cause of the issue.

[Dum-Dum]

Plug gaps correct?

[Ruan]

Wait isn't the 16v GTi fully sequential? And you have fitted a semi sequential coil pack? May be a slight cause of the issue.

Nope, wasted spark

[Matt-Rallye]

Are you running the dual 16v lamdas or just one? Sometimes causes missfire issues in modified tu lumps.