[engine_work] Xu9j4 Mi-16 Rebuild

[Sandy 191]

You can't really relate the corrections between different ECUs, they all end up working best on different values due to the way the various compensations are calculated and combined. More than that, different engines, injector, tract designs etc will also hugely vary the best settings. Rest assured that I've got enough experience to make a pretty sound educated guess on extrapolated settings for a TB'd medium spec 16v on DTA!

 

There is an issue with the settings on this car because the bodies and TPS have been altered since I set it up, so the all important baseline has been lost. But a common mapping issue at low temps is that the compensations only go down 0 degrees and below that the ECU defaults due to being outside the table range. The Water and Air temp compensation I always program down to around -20, which checking the map I have here; but the lowest value on the starting enrichment table is at 1 degree, so that's possibly a problem. Simply changing the lowest temp value, from 1 to -20 (Essential Map settings>Engine Start Fuelling>Start Map Temps), will cure the problem, if that is the problem. The base settings at that end of the table are sufficiently rich not to need sloping further.

Edited January 26, 2013 by Sandy

[kyepan 291]

thanks for the reply sandy, i've amended the start map temp to include the -20 value, will report back in an hour or so.

[petert 588]

I always set the -34 value to zero. If the coolant sensor falls off for what ever reason, it defaults to the bottom value. We'll never seen less than -8 so it's a very handy safety net. Sorry, I forgot yours are TB's, the values above are for a standard Mi16 inlet etc.

[kyepan 291]

New set of plugs sorted it temporarily.

 

Need to fix the air leak, got some new manifold bolts to help that along, then need to take it apart and buy the correct o rings.

Also bought a couple of sets of plugs so i can just change them until i get the chance to do the bodies.

In the mean time i'm going to have to drive it a bit hard to keep it from sooting up.

[kyepan 291]

Checked the new set of plugs and they are sooted up too.. looking down the bores after a week sitting unused and they are dry as a bone which is encouraging! at least i'm not looking at some kind of watery head gasket grave...

 

more good news, my new improved large bore anti kink breather setup is working well, very little mayo in the breathers, still need to get some jubile clips from dads and secure it properly. Nothing appears to have come out of the overflow, so it's definitely catching in the catch tank

 

Mayo decanting from the breather looks reasonable for the 300 miles since the last look, perhaps 150ml of mayo, and a smidge of oil. (1l bottle) ideally some kind of separator and return would be nice.

 

New theory on the plugs - it's running too cold

reason - massive radiator, and we removed the blanking plate in the front valance.

Temp rarely gets above the second line, except when sitting in uber london jams.. and even then as soon as we're running again it drops like a stone. Despite the family sized can of heavy right foot that was opened on it the other week, oil temp is a think i rarely see much more than a hint of.

 

Plan for the weekend

Drive home with the laptop on, so i can monitor the temp in centigrade on a normal run

Re-seal the bodies with some industrial o-rings provided by a very kind local farmer I know.

Change the heater matrix to make sure that's not draining the header tank, it's definitely leaking because i can see it on the unions.

bleed when cold, bleed when hot, go for a drive and bleed again (gti-6 style - thanks paul)

Fit the new 2.0bar expansion cap, as mine has been leaking, i can see that too.

Set the tps stop back to sandy's original setting.

Load the original map

change the plugs / or clean them.

stick some gaffer over a portion of the rad, or if it's still in dad's garage, refit the banking plate.

[welshpug 1,657]

check the thermostat?

[kyepan 291]

mei, I can't remember if we put a new one in, can't hurt though can it

[kyepan 291]

right so... we're all good it would seem, read on if you want to know more.

 

Despite the o-rings being in with loads of sealant, they weren't sealing, so i had air links, which was throwing the idle out, and me fannying around with the throttle stops didn't help either.

 

Lets begin. Here's the heater matrix as it came out.. looks like 3 leaks. one from the union, then at either end.

 

one end

 

other end

 

 

holding the screws in with tape helped make fitting the unions easy.

 

The old O rings were intact, but still leaking, so they can't have enough interference to seal on their own. I think the route to go would be to use slightly thicker O rings then find a way of forcing the bodies and the manifold together. As they won't go by pushing alone.

 

 

So off came the bodies

 

 

They took an hour to clean up, masses of sealant everywhere, thinking how am i going to not rely on sealant to get the seal, deffo thicker rings and more interference.

 

Checked the od of the ring groove.

 

and the id of the manifold

 

so if this fails i can buy exactly the right size.

 

Paul had secured me some O-rings, that "should last 25 years with hot and cold going through them" so i was going to try and make one of the two sizes provided fit, 32mm, and 42mm. the 42 looked a bit thick, but the 32 stretched over the bodies fine. However there was no way they were going to go in by hand, assistance was required.

 

 

I figured, wind a bit of rope through both objects, then twist it with a bolt, like a pulley, we used it at scouts, i can't remember what for, this worked up to a point, but then i couldn't get enough force. They would not go in square.

 

In the end, the lower bracket was in place so I bolted that up, then used a pair of mole grips helped gently seat the tops of the o rings, then did the securing bolts. done.

 

and no sealant needed.. or so i thought

 

 

All back together,

 

Oh yes, before i forget, i also took the tin snips to the back of the air guide, as it was impossible to undo the airfilter without taking the valance off, now you can easily.

 

So fired her up --- running --very---rough---pop---gurgle-misfire... DOH... should have used sealant, leaks were bad enough to feel with my fingers across two of the bodies ... it was 5pm getting dark and i wanted to give up.. Then it occured that perhaps i could just undo the top nuts and check the o rings had seated. Two of course, had not and were pushed back. So a quick spray of silicone grease and more gentle use of mole grips later, they were seated. It fired on the button and ran fine.

 

Next, map, i loaded the original map.. (before i changed the tps pot recalibration) and i only changed the tps because..... it had an air leak messing with the idle, so now the leak was gone, the original pot setting worked, and the idle was what sandy set it to. Datum.

 

Next balance the bodies, done. TPS set, we have idle, and it sounded malevolent at idle, and crisp on the blip.. bwa-bwa-bwarp.

 

Went for the shake down and got some fuel, realised i may had a leak, water pissing tino the footwell, traced it back to one of the heater matrix hard pipes, it's a bit corroded where it pokes through into the engine bay. (new pipes don't fit). The slightly rubbish old jubilee clip didn't want to go any tighter, a new one nearly stopped the leak, but a second jubille today sorted it out. The glycol over the footwell meant the pedals were damn slippy, and the car smelt slightly sweet.

 

Next, cold running, monitoring the temps it was barely getting above 76... and still enricing slightly. Bit of tape over the rad.. didn't help. And i'd not changed the stat, but the cold side of the rad was cold. I went to silverstone and back with one eye on the gauge, and it was way cold. But i was seeing a good level of oil temp, especially when keeping up with a chimera off a few roundabouts on the a43, he couldn't pull away, i laughed, he looked miffed. Ant suggested I just get on and change the stat.. sound advice per usual.

 

Then changed the stat when i got back, immediately it ran hotter, even before the stat opened, then stablised, and the fan kicked in after a few minutes once it reached 85, then cut out at 83. Basically totally normal. So perhaps the stat was stuck open.. not sure. but the new stat cured the weirdness.

 

 

So it's back, and I took an old work colleague with a chipped fabia VRS out for a spin, pooteled about a bit, then some nice clear national speed limit open up and i turned on the Bwarp and played him some sonnet #4 pot in throttle major. His reaction was a mixture of childish giggling, seal gufforing and clapping. "Viceral" he said, amongst other compliments about it pulling from nothing and being as quick as his mates scooby.

 

We went for a spin in his fabia grunt box, it's deceptively quick, no noise, or fuss.. but you're doing rather cheeky speeds in no time. His favorite play things on the commute are other big range rovers, and cayennes..

 

Done. except for the knocking suspension and cams to install.

[Batfink 201]

yay! Its about time. If you need a set of ramps to get a better look at the suspension you know where I am!

[kyepan 291]

have you got a body shop yet! inner arches and boot speed holes need looking at!

 

Cheers

J

[Batfink 201]

not yet. Building a spray booth once my 205 chassis work has been finished. We've plenty of people who can do the welding work. A guy in the unit opposite does spraying. Not the best but he's good enough for what you need

[kyepan 291]

http://www.pistonheads.com/gassing/topic.asp?h=0&f=65&t=1242856&mid=0&i=380&nmt=RE%3A+PistonHeads+Sunday+Service%3A+17%2F02%2F13&mid=0

The rot box even made it onto the official photos from the PH meet i went to yesterday...ha ha ha

[kyepan 291]

oh, forgot, funny story.

 

Driving through Wycombe on the way to Silverstone, quite late, laptop open monitoring all the temps, prior to changing the stat.

 

Navigate a few roundabouts, and off up a hill, go down a pot hole, suddenly car dies with shift light on, then nothing, pull in..

try to start it, turns over.... ignition off, arm/disarm, turn the key, nothing... not a sausage, just the gentle whine of a starter motor turning in a futile attempt to start nothing.

 

"Swearing.. what on earth is going swearing on, gimme a swearing match and some swearing petrol, i've spent load of time on you this weekend you swearing swear box"

 

 

Look at the laptop, everything seems ok,

Is the cable in, no, looks like it have come out, plug in, ignition on, can it see the ecu, yes,

check all the ecu settings, all ok, "WTF WTFF..." check connectors on back of ecu, check relays, check fuses, pop bonnet check all the connectors are on... ?!?!?

 

Parked half on half off the road, bit precarious, roll back into a driveway when it was clear, and do a no power 3 point turn, give it a little push and roll back down the hill to a suitable spot slightly off the road..

 

Consider calling the AA, more swearing.. decide "i can fix this"

 

Luckily i had my small tool set, check for fuel, spark.. in that order

So off comes the inboard fuel rail, point it over the bonnet, and turn it over, nothing, no fuel.. Hopefully the injector driver isn't fried, because the cable came loose. "swearing swearity swear swear"

 

Close the dta app, open it, look at the ecu.. throttle pot ok, AH HA!! but no main engine settings, no rev limit, crank and trigger settigns, nothing.

 

Open map, flash ecu, turn key.. "thank swearing for that"

 

I think the laptop may have hit a key with the cable or something as i went down the pot hole, overwritten itself.. and .. silly, made me laugh.

[kyepan 291]

Right - so a quick update.

This weekend i'm going to install a peter t stage 2 inlet cam, and stage 1 inlet cam as an exhaust cam. I've got a set of piper vernier pulleys waiting to go on, and the DTI gauge, just hoping for some slightly more favourable weather.

 

Stage 2 inlet

 

 

Advertised Duration

271

 

Duration @ 0.050”

236

 

Maximum Lift

0.350"

 

Lift @ TDC

0.105"

 

Lobe Centre Angle

106

 

Stage 1 exhaust

 

 

Advertised Duration

260

 

Duration @ 0.050”

226

 

Maximum Lift

0.350"

 

Lift @ TDC

0.065"

 

Lobe Centre Angle

109

 

Part Number

16H426B

 

 

I'll be timing them via the TDC method mentioned here

http://www.taylor-eng.com/xu9j4/finding_tdc.html

 

So my lift at TDC in mm should be

Inlet - 2.66700

Exhaust - 1.65100 mm

 

 

The inlet actually has the same lobe center angle so i'll try by starting the vernier set up the same as my DW4 pulley (currently being used on the stage 1 inlet) and advance from there. The exhaust will be on a number 2 pulley and so i'll set that vernier up the same as the DW4 to begin with and then decide what to do from there.

 

Fingers frossed for the weather... it's currently snowing.

 

Then - once we're good to go, off to see sandy for a little remap, and if necessary play with the timing.

 

 

[kyepan 291]

Another quick update, i put the inlet cam in wrong, bent some valves turning it over by hand. the head is off and will be going to Paul Gardias shortly to check how many, we know 5 for sure. This is good because it explains why one cylinder was 80psi down on the others.

 

Once timed properly it ran, but was a tapper, so i knew it wasn't right, it was also flat as a pancake on the road, granted it needed mapping, but still, it was gutless, and i was slightly gutted.

 

On the plus side, it had mega compression on 3 cylinders, and the slightly suspect head gasket related type issues i'd been having were nothing to do with the head gasket, as that showed good seal on all cylinders.

 

Multiple small wins out of otherwise greater fail, watch this space, it will bark again.

 

In the mean time here is a video of it with just the manifold on after being properly timed. Thanks to Batfink, Anthony, Paul, and Tom cheesegrater for their continued support!

 

http://smg.photobucket.com/user/kyepan/media/VIDEO0193_zps15e1812d.mp4.html

Edited April 22, 2013 by kyepan

[petert 588]

Whoops! I bet that hurt. Never mind, glad to hear you're back on the horse and riding. Others have given up from far less.

[kyepan 291]

anything else I should do whilst it's off? larger valves (ducks) solid lifters? valve springs?

[kyepan 291]

cometic do these

http://www.pipercams.co.uk/pipercams/www/product.php?pid=C4225-051

 

Wind the compression up a bit, it's not like i'm using high lift cams and going to run into valve clearance issues.. right?

[welshpug 1,657]

thought you were at 11 odd already?

 

personally I'd just get it built with a standard gasket, they're 1.4mm aren't they? you wont gain much from 0.1mm, drop from 7.7 to 7.2 cc if my maths are correct.

[kyepan 291]

10.6 ish.

 

0.7mm MLS would give 7.7 down to 3.2 no?

[welshpug 1,657]

I couldn't see a 0.7mm MLS there? only 1.295mm?

[kyepan 291]

it is available on the cometic site, I just wanted a UK price. going to do a compression calculation, hoe many cc is the piston cutouts?

[kyepan 291]

bore = 83mm

stroke = 88mm

gasket bore = 84mm

compressed gasket thickness = 0.7mm

combustion chamber volume = 39cc

piston dome + dish - volume = - 2cc

piston deck clearance = 0.4mm

 

compression ratio - 11.1:1

[petert 588]

Sounds good. That will make it crisp. However, don't forget to measure to piston-valve clearance!

[kyepan 291]

serious question - how exactly do we do that, as currently we'd be estimating based on number of skims and head gasket thickness, i'd rather not solve some bent valves only to bend some valves.

 

Is there some trigonometry involved?

 

Your website states you can take 1.4mm off the xu9j4z engine, and i believe you can deck the xu9j4 by 0.4mm to bring the compression up.