9 replies to this topic

[PIIIOWW]

Hi,
I have an L-plate SPI Cooper but want to run it with a DCOE 45 carb arrangement. All the rest of the engine spec is pretty highly tuned so the carb should be well suited to the set up. I'd like to better understand if this is actually a viable route or if it will be an out-and-out failure based on the emissions.

I understand the age of vehicle needs a lambda sensor and cat fitted regardless of whether they're actually functioning. Today I spoke to my MOTer for my daily vehicle and he said many people remove the cat etc after the MOT cert has been issued. The exhaust I've specced for the car also doesn't have a lambda sensor port and even if it did, with no ecu for fueling present, it wouldn't be feeding any data/signal back to anything. The MOT guy said just make sure a lambda sensor is fitted even if not functional and make sure the wire is presented in such a way that it's not suspected for cheating - just take the car for its MOT and see if it passes...

I'm reluctant to do this in case it's going to be a dramatic failure and wondered if anyone had any knowledge/experience on the matter.

I do have a cat in the system.

The rest of the engine spec is: 1380, high end, big valve head (29-36mm), 286 cam, 1.5:1 rockers, large bore LCB and of course the DCOE 45 carb mounted on a 5" maniflow inlet. I'm also planning to use an ignition-only ecu which could help if programmed to meet an emissions spec??

Any thoughts or discussion is welcomed.

Thanks

Edited by PIIIOWW, 06 January 2020 - 10:14 PM.

[sonscar]

From my limited understanding L(92/93) will need a cat test possibly.The tester should input the vin and the system will point him to the correct test as some 92 cars were fitted with cats and carbs and there is a special exclusion for these.As yours was injected this should not apply.It is possible to get carb cars through a cat test as some Kitcar owners have done this but it will be difficult and the cat will probably die.More knowegeable people will reply but my advice is tread carefully and further explore EFI solutions.Just my 2p,Steve..

[imack]

Pretty easy to work out from the testers manual if you have the registration date and the chassis no.

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[PIIIOWW]

Thanks for the responses.

The 1990 RSP Cooper was a cat and carb combination so why would the presence of a carb foul/poison/kill the catalyst unless heavily over-fueled?

My question is more aimed to get a sense of 'will the car pass the mot on the emissions given the combination of engine and exhaust components?'

The mot guidance merely states to check a: cat, lambda sensor and egr valve are present as per the legislative requirements for the age of the vehicle. If the car will pass with the carb and cat alone that would be a perfect outcome and it would be worth fitting an exhaust system that can accommodate an O2 sensor even if the sensor is doing nothing to help the emissions.

[nicklouse]

If an injection car it will need to pass the injection emissions test. Not a hope in hell. Unless I believe you can prove the engine is much older. Or some such.

[imack]

If its a post August 92 car and the chassis code is listed in the emissions data book you won't get a carb'd car with a 286 cam to pass the required emissions standards.
If it's pre August 92 you may get it to scrape through.

[PIIIOWW]

If an injection car it will need to pass the injection emissions test. Not a hope in hell. Unless I believe you can prove the engine is much older. Or some such.

If it's a post August 92 car and the chassis code is listed in the emissions data book you won't get a carb'd car with a 286 cam to pass the required emissions standards. If it's pre August 92 you may get it to scrape through.

It's been a while but picking this back up (I'm blaming my tardiness on a certain contagious respiratory disease which impacted my interest in the build).

Anyway, in light of the information imack posted above I'm debating if there is an actual Issue. The guidance says on vehicles first used before 01/09/2002 (check) the MOT emissions should meet the standard of the engine fitted even if the engine was changed.

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Given my block is likely from the 80/90s (invoice says Nov 1992) I should be held to the standards of that engine regardless of the catalyst fitted to the car when it was manufactured with the SPi system.

Two routes follow from this. The engine has associated emissions values in the MOTer's book and the engine should adhere to those (orange path). The emissions should not exceed 0.3% CO, 200ppm HC.

If my engine isn't listed, it follows the more lenient blue path <3.5% CO, 1,200ppm HC.

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The other issue I forgot to mention when I started this thread was I used this exact engine and cam in my Mini 30 along an HIF44 carb. The key differences with this build are the change of head (change to better flowing head) and carb (DCOE 45 still 1-3/4 but twin barrel). The Mini 30 never failed an MOT on emissions, however that was tested as a 998 at the MOT station and 998s aren't listed on the emissions standard.

Am I being naïeve or does it seem the engine will pass with this carb and cam or is it the 998 aspect that allowed the 286/HIF44 combo to pass in the past?

Edited by PIIIOWW, 25 September 2024 - 09:35 PM.

[nicklouse]

Back in the 80s I really struggled to get a very similar spec engine through an MOT. It had been rolling road set up and the HCs were just too high (cam overlap) I ended up putting some wynnes product in the tank ran it around and even though the testers eyes (and mine) it reduced the HCs to a passable level. The other gases were fine and way under. It would have passed easier with an HIF44 on.

[PIIIOWW]

Yeah, I get the cam duration would result in excessive HCs. I would expect the CO to be higher too if combustion (complete oxidation of the carbon) isn't adequate which you may expect with less time exposed to the heat within the cylinder.

I don't understand why changing from a single barrel 1-3/4 carb to a twin one would make any difference though. Any foresight on that? Surely the cylinder will only draw what charge it needs regardless of what's supplying the fuel.

I'm wondering if mine passed as it was declared as a 998 on the logbook.

I suspect if you ran it on a different fuel (something like methanol) you'd get better emissions during an MOT. The carbon is already partially oxidised so there's less work on the molecule to get CO2 instead of CO. I suspect that's what Wynnes was doing(?)

[PIIIOWW]

I spoke to my MOT tester today about how they'd run through the process if I were to present my Mini with an engine change. They essentially said don't advise the MOTer of the change as you should provide a letter from the manufacturer (Rover - yeah right) or an engineer that the engine has been swapped. Other than to show it's been done safely it seems a little onerous to have to do this. There also appears to be not mention of having to provide a letter on the gov.uk inspection manual, just that you must be able to prove the age of the engine (I can show the age from the receipt from Mini Sport).

They indicated it would only have to meet the 3.5% CO 1,200ppm HC limit though. The DVSA In Service Exhaust Emission Standards for Road Vehicles (19th Ed.) only lists four classic Minis, three of which are TBi (SPi) type like mini was built to be. The other is the MPi. Given the car is pre-2002, you can engine-swap to an older engine and not have to meet the TBi/SPi limits. If the car is not listed on the emissions test instrument or DVSA document, you can default to 3.5% & 1,200ppm. I have a lot more confidence in this now given I had no issues with the 286 cam in this 1380 engine when fitted to my '998' Mini 30.

I also queried about the need for the catalyst. They said it should be present. I debated the exhaust and cat belong to the engine not the car but they advised a cat should be present on any spark ignition car from 1992.

Links showing the same info in these rather embarrassing videos:

https://youtu.be/JWs...7RDc5HxVanH7qoB

https://youtu.be/BPT...leCPCAund0V76rT