Irish Mini Owners Club

Well,

Had the NCT today in Ballymun, Passed most things, apart from the poxy emissions, HC to be precise.
Fair play to the mechanics up there, they really tried their best to get it through, and when It didnt were pretty cool about it. Its a bit of a story, as it went on the emissions machine 3 times.

Its a 91 Mini Cooper so, the Limits are 3.5% CO and 1200PPM HC.


1st round:
The C0 reading was 1.26% and HC 1124 ,Oil temp 84degrees(taken from thermostat from what I saw) Great I thought, until I saw that the machine wasnt set to the 1200PPM but the standard 750PPM. I point this out and the Mini is put back on the machine, albeit a different one.

2nd Round:

The inevitable happens, It fails....by miles. co was still like 1.26% but the HC were all over the place, the readings wouldnt stay still. Highest I saw was 3,000 lowest was 1500. Feckin Typical. I point out that How could It pass the 1st time, then fail by miles the 2nd time on a different machine(I dont think It was the same calibration as the 1st machine)

3rd Round.

NCT guys were sound and told me to bring it for a spin and bring it back. I took the opertunity to lean off the carbs as far as I could, and then brought the Idle up to 1400rpm. Still failed although the highest HC was 2,500PPM lowest was 1100. CO was like 0.13



I arranged to bring it back next week. So I need to get somebody with a machine, or some advice. Ive tried Dipthane, new plugs, leads, timing set as per Dizzy reccomendations for 1380, New filters, rotor. Mixture set up Bunsen Blue.

Its a 1380 with a 286 cam and twin carbs(AAA Needles). TMG advised to retard the timing by a few degrees, Its currentley running 30 degrees TOTAL advance.
Also Ive heard of opening up the tappets to a rediculous gap, would this work? Really I need a machine that will measure HC and accurate too. NO gunsons accurate to 5%.

Any advice, I feel kinda shafted as Ive a NCT sheet here with the magical sub 1200PPM on it.

kona wrote:TMG advised to retard the timing by 30degrees

The Marcos Graveyard wrote:

http://www.miniresource.com/forums/inde ... =emissions

My apologies Mr. TMG. You said 6-8 degrees, not30, dunno where I got that from, seemed a pretty crazy setting!

That is what I had to do with my 1380 engine, SPVP3 cam , 1.5 roller rockers, HIF44, luminition ignition.

I used a gas analyser to get the whole thing set up before driving the 20 miles to the test centre.

I can get a CO analyzer, but its abit pointless as there doesnt seem to be a relationship between CO and HC, so I couldnt even guess it right.

Suppose its time to let somebody with the correct tools and knowledge loose on it.

i guess setting the rocker gaps to a large number would help overcome the effect of a big overlap cam.

i *think* that the CO reading is a measure of the combustion part of the cycle, whereas the HC could relate to the unburnt mixture, either by cam overlap or incomplete combustion.
some bigger engine analyser devices measure 4 gasses:

As far as I know HC will be high if your burning any oil. What milage is on the engine?

There is about 20k on the engine, maybe a bit less. There is not evidence on the plugs of oil being burnt either, neither blue smoke out the exhaust, even at high RPM, but it could be a factor. I think the main problem is the over lap on the cam. Also I did have the carbs leaned off, so this could have caused a misfire, although it didnt sound like it was missing. Maybe a change of oil might help the situation.

keith wrote:i guess setting the rocker gaps to a large number would help overcome the effect of a big overlap cam.

i *think* that the CO reading is a measure of the combustion part of the cycle, whereas the HC could relate to the unburnt mixture, either by cam overlap or incomplete combustion.
some bigger engine analyser devices measure 4 gasses:

AFAIK Co is incomplete combustion, and HC is unburnt fuel. DO you know anybody with one of those sun machines? and willing to let me use one to try different things to reduce the emissions.

So far from reading around The high HC can be caused by:
Poor Cam timing.
Blocked PCV.
Burning oil.
High ratio Rockers.
Poor spark.
Overlap caused by cam.

Sine CO and HC aint really related, then I suppose leaning off wont make much of a difference.

Woiuld fitting a cat help? EVen though the HC will destroy the substrate?

Borrow a standard engine from somewhere and fit it for the nct, heard of it done before.

briain wrote:Borrow a standard engine from somewhere and fit it for the nct, heard of it done before.

I did think of it, but I just dont have the time to flute around with that at the min. Ive no garage either. Its last resort stuff. I think Ill try to get the current engine through as It *can* go under 1200ppm, how he did it I dont know but he couldnt get it the 2nd time.

I reckon opening the tappets may be my best bet.

I would say the cam has you screwed I had the same problem with a 266 in my 998 had to whip it out in the end I found out that the 266 is a copy of an old special tuneing profile I dont know about the 286 but it would be worth looking into
may save at lot of time and money in the long run if that is the case a swift tune sw5 would sort you out

CLUBMANGT wrote:I would say the cam has you screwed I had the same problem with a 266 in my 998 had to whip it out in the end I found out that the 266 is a copy of an old special tuneing profile I dont know about the 286 but it would be worth looking into
may save at lot of time and money in the long run if that is the case a swift tune sw5 would sort you out

Well It did get a reading of under 1200ppm on their machine so It is possible. they were very vague of how they managed to get a reading of 1124 and over 3,000 within 15 mins of each other. Thats around 2,000PPM in the difference between two machines, with no change to the minis settings. Mad stuff. Exactley what Im scared of, could have it set up one one machine then fail on theirs.

I really dont want to go pulling put the engine to change cams etc. alot easier to either tune it or stick a cat on it.

kona wrote: AFAIK Co is incomplete combustion, and HC is unburnt fuel. DO you know anybody with one of those sun machines? and willing to let me use one to try different things to reduce the emissions.

give paul a shout (merlin on here and other places) he's got a machine, not sure if its that one or not.

I'm thinking that i'm the long term you may want to go to a more modern cam. like the sw5? although i've not used it, i heard good things etc.

keith wrote:

kona wrote: AFAIK Co is incomplete combustion, and HC is unburnt fuel. DO you know anybody with one of those sun machines? and willing to let me use one to try different things to reduce the emissions.

give paul a shout (merlin on here and other places) he's got a machine, not sure if its that one or not.

I'm thinking that i'm the long term you may want to go to a more modern cam. like the sw5? although i've not used it, i heard good things etc.

Ive heard the opposite

You are right, I need more torque low down and the 286 is very, agricultural. I dont think Id go the sw5 route, I think its a overrated cam. I think a scatter profile would be the best, or a 16V head. Id lean towards the latter and eliminate the A-series head.

If anyone can sort it, Im sure Paul is the man.

You might be right about a scatter pattern on a tuned 1380 but the more you talk to people the more you will learn
so talk to as many people in the know about this i am sure the answer is out there good luck

CLUBMANGT wrote:You might be right about a scatter pattern on a tuned 1380 but the more you talk to people the more you will learn
so talk to as many people in the know about this i am sure the answer is out there good luck

I know the amount you learn on here from just reading threads. Im reading Vizards book too,but not much about MOT and HC
Hopefully Ill figure it out, I cant be the first person with this problem with a long duration cam

The problem being these cam profiles were designed with power in mind at a time when things like HC and CO were
of lesser importance so making the margins very tight now for an NCT pass on all counts

CLUBMANGT wrote:The problem being these cam profiles were designed with power in mind at a time when things like HC and CO were
of lesser importance so making the margins very tight now for an NCT pass on all counts

But its still being tested at a very generous limit 1200PPM is a crazy figure TBH. It should be achievable to get it to at least in and around 1,000PPM, which is still very generous.
CO isnt so much of a problem, its easily adjusted Via the carb. How to eliminate overlap is a bit trickier. I think that Ill have to open the tappets up, although, I need a Machine to see just how much I need to go.

A big part of the problem is the test tbh, they test at a rev range that probably equates to 40 mph for a standard family car, because thats the typical urban speed around town.
When you translate that to Mini terms you are only testing at 20mph or it's equivalent in revs.

This is too low down the rev range for many of the popular cam choices used in modified Mini engines today where the engine doesn't come on cam till about 1500 rpm.

So ideally you need to double the rev that the test is done at for a Mini.

The testers were very helpful as regards the test. they even let me into where they carry the test out on the machine. The car was idleing at 1300 RPM as I was trying to take into account the overlap. They did say by right they shouldnt even test the car at that RPM, The HC did fall when it was brought up the rev range the second time, but I was told that they couldnt accept the figures at 3,500 RPM.
Although the second time the supervisor was overseeing it. I have to say the guy the first time really did do his best to get it through, I reckon the 1124 PPM was taken at mid range RPM although Ive no idea how they take the figures. Oil temp was quite low too, just 4 degrees above the min temp for testing(84).

I must say, they were extremely helpful and are giving it every chance to go through, he even gave me the times hes in at and to get him to do the retest, He just told me to show up.

If I can get it on a machine and find out the rpm range that it is within limits at, I think hed run the car at those figures for the test.

i think yoresgarage in virginia have that sun tester... he did the emission on my 1275 carb, about a year and a half ago when he failed the emissions... it was only like 30 quid... hes just about 2 mile the dublin side of virginia..

mustard wrote:i think yoresgarage in virginia have that sun tester... he did the emission on my 1275 carb, about a year and a half ago when he failed the emissions... it was only like 30 quid... hes just about 2 mile the dublin side of virginia..

Ill keep them in mind although I'd like to find a place nearer to dublin , Im scared of Driving on a motorway with the mini set up not to run right.

I had problems getting mine trew before due to the cam,id say the 286 is wild enough,wouldnt go for the sw5 tho ,there wearing out and arent been changed under warranty either,piper do a similar cam that seems to be great and they will stand over them

BERT wrote:I had problems getting mine trew before due to the cam,id say the 286 is wild enough,wouldnt go for the sw5 tho ,there wearing out and arent been changed under warranty either,piper do a similar cam that seems to be great and they will stand over them

I heard that too about the sw5. Although I wouldnt get one as a 286 is already wilder than a sw5 and even then I think the 286 could do with a bit more. If you could get a inverse 286 and have the fun low down the rev range then that would be the cam I'd get!

Yours was a 93 too so the emissions limits would have been even tighter? Did you just swap the engines?