Engine swaps and the DVLA: Resolved

[Carledo]

I’m not arguing here at all, enjoying a lively discussion….

As Steve says, it’s very vague !!

The guidance also states….
Acceptable changes
It does not count as a ‘substantial change’ if….axles and running gear have been changed to improve efficiency, safety or environmental performance

Does a more modern fuel injected engine give better environmental performance or is it more efficient than a Sprint engine ? I suspect yes, so the engine swap isn’t substantial.

The first thing I’m going to do when my car is ready is to get an MOT, even if I categorically don’t need one…

That would be a mighty difficult one to prove. And is so grey as to be worthless.
To cover ones posterior (very important) an MoT is essential.

I don't think there have been any recent prosecutions, but if the brown stuff ever hits the fan, I want to be able to produce a document to cover me.

In my own cases, i'm pretty sure I COULD prove a better environmental performance, simply chuck the car on an MOT CAT test and get a printout!

Both my Vauxhall powered cars have near factory spec nineties/noughties EFi systems and are wired for lambda sensors (a single one on the 2.0 8v and two on the 2.2 16v) I have, on several occasions, had both the cars on the MOT cat tester, though neither actually HAS a catalytic converter fitted, both will pass the most stringent emission test available on the machine for both CO and hydrocarbons and only miss the Lambda reading by a few thousandths of whatever it is it measures (residual O2 maybe?) so i'm fairly confident their environmental performance is WAY better than a standard Sprint which struggles often to meet much milder requirements.

As Clive says though, all this is moot as I wouldn't dream of running without an MOT. Even on a standard car, let alone a modified one! The MOT doesn't ONLY cover emissions and I like to get a second opinion, even if it isn't really worth the paper its printed on. The printouts I have of the CAT tests is also fun to have when discussing environmental factors of running a classic with tree huggers!

Steve

[ian.stewart]

I had my Toledo 16v tested last year, I was told by the tester it only needed to be a visual test, mind he did notice the front wheel bearing was a touch loose, despite being tightened just prior to the test, I think they are Chineseium specials, and generally last about a year,

[cliftyhanger]

I had my Toledo 16v tested last year, I was told by the tester it only needed to be a visual test, mind he did notice the front wheel bearing was a touch loose, despite being tightened just prior to the test, I think they are Chineseium specials, and generally last about a year,

I don't think testers really understand the rules, they think anything over 40 years old is exempt. Sadly, many owners do too. The number of VERY modified (ie just the logbook is original) hotrods and stuff out there which are simply incapable of passing an MoT.

As to wheel bearings, Timkin available, try Witor for a good price on them.

[Carledo]

I had my Toledo 16v tested last year, I was told by the tester it only needed to be a visual test, mind he did notice the front wheel bearing was a touch loose, despite being tightened just prior to the test, I think they are Chineseium specials, and generally last about a year,

I don't think testers really understand the rules, they think anything over 40 years old is exempt. Sadly, many owners do too. The number of VERY modified (ie just the logbook is original) hotrods and stuff out there which are simply incapable of passing an MoT.

As to wheel bearings, Timkin available, try Witor for a good price on them.

I'm not sure the rules themselves have remained static! When I first built the Carledo (2011 first test after build) and for several years afterwards I was offered the choice, test as the age of the CAR , 74, so visual smoke check only, OR test as the age of the ENGINE, in my case, 1988, so pre-cat, no lambda, not much different from the test for a stock post-75 Sprint, up to 4.5% CO and less than 1200ppm hydrocarbons.

But since about 2020, he's wanted to test at the age of the engine, this was fine for the Carledo which flew through as noted above, a little more problematic for the Dolomega which has a 2000 model year engine, which, by rights, should probably have a catalytic converter fitted (it certainly had one on the donor car) However i'd built to the earlier standard and not fitted the cat. Since it didn't HAVE a cat fitted, he tested to the intermediate standard, 86-92, IIRC 2.5% CO and 300ppm hydrocarbons which it passed with plenty of room to spare.

There is also a sort of loophole available, if you don't KNOW the age of the engine (or don't want to say) the tester is obliged to test the car as presented, ie the age of the CAR. So the best advice is, if he ASKS, shrug your shoulders and say "Dunno mate!" If he DOESN'T ask, don't volunteer anything!

A lot depends on the tester, if he's a sensible sort, as most ARE, he'll just cut to the chase and test it as is and without a fuss. It's perfectly reasonable to buy an engine off ebay or ANYWHERE without a clue as to EXACTLY how old it is. Most testers don't care enough to debate the grey areas. But you do come across the rare "jobsworth" variety from time to time, my advice here is simple, find another testing station more sympathetic to your cause!

Steve

[SprintV8]

Emissions from the MOT testers Manual.

Vehicles fitted with a different engine
If a vehicle first used before 1 September 2002 is fitted with an engine that’s older than the vehicle, you must test it to the standards applicable for the engine. The vehicle presenter must have proof of the age of the engine.

If a vehicle first used on or after 1 September 2002 is fitted with a different engine, you must test it to the emissions standards for the age of the vehicle.

So my interpretation is.
My 1980 Sprint would be tested as a 1980 Sprint as the engine (2007) is younger than the car so
4.5% and up to 1200 HC.

Bonus the 13b rotary came out in around 1975.
So could argue it’s a 1980 engine updated with fuel injection.

[Carledo]

Emissions from the MOT testers Manual.

Vehicles fitted with a different engine
If a vehicle first used before 1 September 2002 is fitted with an engine that’s older than the vehicle, you must test it to the standards applicable for the engine. The vehicle presenter must have proof of the age of the engine.

If a vehicle first used on or after 1 September 2002 is fitted with a different engine, you must test it to the emissions standards for the age of the vehicle.

So my interpretation is.
My 1980 Sprint would be tested as a 1980 Sprint as the engine (2007) is younger than the car so
4.5% and up to 1200 HC.

Bonus the 13b rotary came out in around 1975.
So could argue it’s a 1980 engine updated with fuel injection.

This section of the rules seems concerned with a car where the engine is OLDER than the car (good news for me as I was considering a SBC in my latest Omega, didn't think it was do-able but turns out it is!)

But it doesn't say anything about the engine being YOUNGER than the car, is there another bit dealing with that? Or don't they care?

I really MUST get a copy of the latest rules, I miss being a tester!

My Omega engine has a much narrower availability band, the 2.2 variety was introduced in 1999 as an upgrade of the 2.0 and died with the Omega, ending production in 2004. Later 2.2s, superficially similar and still going into Zafiras and Insignias today are chain driven and not even the same maker ancestry!

Steve

[Boost All The Dollys]

Emissions from the MOT testers Manual.

Vehicles fitted with a different engine
If a vehicle first used before 1 September 2002 is fitted with an engine that’s older than the vehicle, you must test it to the standards applicable for the engine. The vehicle presenter must have proof of the age of the engine.

If a vehicle first used on or after 1 September 2002 is fitted with a different engine, you must test it to the emissions standards for the age of the vehicle.

So my interpretation is.
My 1980 Sprint would be tested as a 1980 Sprint as the engine (2007) is younger than the car so
4.5% and up to 1200 HC.
…

THIS is useful information! As I haven’t had it tuned properly yet, it’s likely running very rich so if I can get it tested at the 1975 Dolomite engine rather than the 1999 Jag engine, it’ll give me a bit more room.

Also, I looked up the cut off for testing and for petrol cars used before 1st of August 1975, it’s just a visual emissions test. Any petrol car used after this has a proper emissions test. Which is annoying as mine was first registered on 15th of august 1975!

[Carledo]

Emissions from the MOT testers Manual.

Vehicles fitted with a different engine
If a vehicle first used before 1 September 2002 is fitted with an engine that’s older than the vehicle, you must test it to the standards applicable for the engine. The vehicle presenter must have proof of the age of the engine.

If a vehicle first used on or after 1 September 2002 is fitted with a different engine, you must test it to the emissions standards for the age of the vehicle.

So my interpretation is.
My 1980 Sprint would be tested as a 1980 Sprint as the engine (2007) is younger than the car so
4.5% and up to 1200 HC.

…

THIS is useful information! As I haven’t had it tuned properly yet, it’s likely running very rich so if I can get it tested at the 1975 Dolomite engine rather than the 1999 Jag engine, it’ll give me a bit more room.

Also, I looked up the cut off for testing and for petrol cars used before 1st of August 1975, it’s just a visual emissions test. Any petrol car used after this has a proper emissions test. Which is annoying as mine was first registered on 15th of august 1975!

I think you'll find that "very rich" by 1999 standards is almost impossibly lean by 1975 standards!

Having been involved in squeezing recalcitrant older vehicles (not just my own by many hundreds) through MOT emission tests since such things began, I can assure you that the 1/8/75> test of 4.5% CO and 1200ppm hydrocarbons, (no lambda) which is a struggle to achieve, even on a well tuned standard Sprint, is an absolute breeze for an engine designed to comply with even a 20 year old cat test!

On the Carledo, I have an adjustable fuel pressure reg to boost fuel supply and add a few extra horses for track and strip work, but which I normally run close to the standard spec of 2.7 bar. But even if I winch it up to 4.5 bar, at which point the idle gets very lumpy, it'll still pass a 75> emission test, just by only about half the massive margin of the standard value setting.

My opinion, FWIW, is if you Jag motor will idle without lumping up and stopping, it will pass the 75> limits fine!

Steve

[Boost All The Dollys]

I think you'll find that "very rich" by 1999 standards is almost impossibly lean by 1975 standards!

Having been involved in squeezing recalcitrant older vehicles (not just my own by many hundreds) through MOT emission tests since such things began, I can assure you that the 1/8/75> test of 4.5% CO and 1200ppm hydrocarbons, (no lambda) which is a struggle to achieve, even on a well tuned standard Sprint, is an absolute breeze for an engine designed to comply with even a 20 year old cat test!
…
My opinion, FWIW, is if you Jag motor will idle without lumping up and stopping, it will pass the 75> limits fine!

Steve

That’s a bit of relief. When I first got the car MOT 9-10 years ago, it failed on emissions and I put it down to bad air filter and some untuned carbs after the engine reconditioning. The problem I’m currently having with the Jag motor is just getting it to idle lower. With the ITBs, I think the adjustment is a tad coarse so the lowest I’ve got it to idle comfortably is 1.1-1.3k RPM running a tad lean based on the AFR readings. Prior to tuning the idle, it would be best described as running hilariously rich, like smell raw fuel in the air rich and backfiring every so often.

That’s all I’ve managed to tune to any extent at the moment as the garage it’s in is a tad small and echo-y so trying to hold it at MOT fast idle of 3k RPM has been somewhat challenging on the ears and lungs. I have a base tune that I think is a bit rich for now but hopefully some driving to get data logs will help.

Steve, Clive, and all of you, thank you for all your help. You’ve been very helpful with all this. If I ever see you at a meet or show, I owe you a drink

[cliftyhanger]

The problem I’m currently having with the Jag motor is just getting it to idle lower. With the ITBs, I think the adjustment is a tad coarse so the lowest I’ve got it to idle comfortably is 1.1-1.3k RPM running a tad lean based on the AFR readings. Prior to tuning the idle, it would be best described as running hilariously rich, like smell raw fuel in the air rich and backfiring every so often.

That’s all I’ve managed to tune to any extent at the moment as the garage it’s in is a tad small and echo-y so trying to hold it at MOT fast idle of 3k RPM has been somewhat challenging on the ears and lungs. I have a base tune that I think is a bit rich for now but hopefully some driving to get data logs will help.

Steve, Clive, and all of you, thank you for all your help. You’ve been very helpful with all this. If I ever see you at a meet or show, I owe you a drink

How well are the ITBs balanced? If you have 6 it won't be easy, the 4 on my spit are a challenge (Though a Morgan Carbtune has made the task MUCH simpler)
However, I still find idle a mystery, the AFR is not at all steady. But I have a suspicion the ECU does not interpolate between cells as well as it could.

[new to this]

I think you'll find that "very rich" by 1999 standards is almost impossibly lean by 1975 standards!

Having been involved in squeezing recalcitrant older vehicles (not just my own by many hundreds) through MOT emission tests since such things began, I can assure you that the 1/8/75> test of 4.5% CO and 1200ppm hydrocarbons, (no lambda) which is a struggle to achieve, even on a well tuned standard Sprint, is an absolute breeze for an engine designed to comply with even a 20 year old cat test!
…
My opinion, FWIW, is if you Jag motor will idle without lumping up and stopping, it will pass the 75> limits fine!

Steve

That’s a bit of relief. When I first got the car MOT 9-10 years ago, it failed on emissions and I put it down to bad air filter and some untuned carbs after the engine reconditioning. The problem I’m currently having with the Jag motor is just getting it to idle lower. With the ITBs, I think the adjustment is a tad coarse so the lowest I’ve got it to idle comfortably is 1.1-1.3k RPM running a tad lean based on the AFR readings. Prior to tuning the idle, it would be best described as running hilariously rich, like smell raw fuel in the air rich and backfiring every so often.

That’s all I’ve managed to tune to any extent at the moment as the garage it’s in is a tad small and echo-y so trying to hold it at MOT fast idle of 3k RPM has been somewhat challenging on the ears and lungs. I have a base tune that I think is a bit rich for now but hopefully some driving to get data logs will help.

Steve, Clive, and all of you, thank you for all your help. You’ve been very helpful with all this. If I ever see you at a meet or show, I owe you a drink

What ECU are you using ?

Dave

[Boost All The Dollys]

How well are the ITBs balanced? If you have 6 it won't be easy, the 4 on my spit are a challenge (Though a Morgan Carbtune has made the task MUCH simpler)
However, I still find idle a mystery, the AFR is not at all steady. But I have a suspicion the ECU does not interpolate between cells as well as it could.

They’re definitely difficult to balance, mainly as I had to trim the tops off them to clear the bonnet so getting a seal around them is hard but I did manage to balance them fairly evenly.

What ECU are you using ?

Dave

I’m using a Speeduino ECU, it’s an arduino based ecu that’s a good bit less expensive but still has a lot of features that I need, like VVT etc. only downside is lack of injector/ignition outputs so I’m running wasted spark and paired injectors, which from what I’ve heard isn’t bad compared to sequential injector/ignition.

At some point, I’m going to be redesigning my intake manifold to add a balancing tube so I can connect an idle valve to it so I can properly control the idle

[Carledo]

That’s all I’ve managed to tune to any extent at the moment as the garage it’s in is a tad small and echo-y so trying to hold it at MOT fast idle of 3k RPM has been somewhat challenging on the ears and lungs.

That 3k RPM fast idle test only applies to CAT tested vehicles, the 75> values are tested at normal idle speed, ie circa 8-1200 rpm.

Steve

[Boost All The Dollys]

I’m not arguing here at all, enjoying a lively discussion….

As Steve says, it’s very vague !!

The guidance also states….
Acceptable changes
It does not count as a ‘substantial change’ if….axles and running gear have been changed to improve efficiency, safety or environmental performance

Does a more modern fuel injected engine give better environmental performance or is it more efficient than a Sprint engine ? I suspect yes, so the engine swap isn’t substantial.

The first thing I’m going to do when my car is ready is to get an MOT, even if I categorically don’t need one…

Just to come back to this, I think when they say “substantial change” that they mean “replaced with different to stock”. I think they mean more along the lines of modification to the stock running gear/axles that deviates from how it left the factory (i.e. like-for-like replacement of parts for maintenance or repairs)

For example, replacing carbs with electronic injection or changing the final drive ratio would be a “substantial change”. Replacing a bad sprint engine with a better sprint engine wouldn’t be that substantial but replacing a bad sprint engine with a modern engine would be too substantial to argue the benefits. It likely could be argued for some other historic cars like pre-war cars/pre-war replicas where the engine isnt easy to come by and therefore it’s more cost effective/ efficient to fit an alternative engine

[new to this]

I’m not arguing here at all, enjoying a lively discussion….

As Steve says, it’s very vague !!

The guidance also states….
Acceptable changes
It does not count as a ‘substantial change’ if….axles and running gear have been changed to improve efficiency, safety or environmental performance

Does a more modern fuel injected engine give better environmental performance or is it more efficient than a Sprint engine ? I suspect yes, so the engine swap isn’t substantial.

The first thing I’m going to do when my car is ready is to get an MOT, even if I categorically don’t need one…

Just to come back to this, I think when they say “substantial change” that they mean “replaced with different to stock”. I think they mean more along the lines of modification to the stock running gear/axles that deviates from how it left the factory (i.e. like-for-like replacement of parts for maintenance or repairs)

For example, replacing carbs with electronic injection or changing the final drive ratio would be a “substantial change”. Replacing a bad sprint engine with a better sprint engine wouldn’t be that substantial but replacing a bad sprint engine with a modern engine would be too substantial to argue the benefits. It likely could be argued for some other historic cars like pre-war cars/pre-war replicas where the engine isnt easy to come by and therefore it’s more cost effective/ efficient to fit an alternative engine

I hope your wrong as on my car i am changing from carbs to EFI, i thought as its still the same engine it wouldn't applied to me ? I've already got historic status on mine, didn't think i needed to tell DVLA my changes only the insurance company ?

Dave