Engine swaps and the DVLA: Resolved

[cliftyhanger]

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

I am 100% certain that fitting EFI is NOT a substantial change. Neither is swapping from a 4.11 to a sprint axle. Or even fitting sprint running gear to a dolly 1300. (as it all comes from the same family of cars)
Fitting an MX5 engine IS a substantial change. As would be changing to a different rear axle etup.

[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

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

My mistake, really bad typo in that. It should be:
For example, replacing carbs with electronic injection or changing the final drive ratio would NOT be a “substantial change”.


Or at least a substantial change that can be argued is for efficiency/environmental reasons

[Carledo]

I spent a bit of time wading through the quagmire of wooly and imprecise definitions but my take is that:- a car is "substantially altered" if the number of cylinders is changed (ie from 4 to 6 or or the capacity is increased by more than around 50%. Though it's not explicit, the implication is that, if you use an engine from a different maker, that is enough to make it out of bounds, regardless of size or capacity or number of cylinders.

Personally I don't see anything to be gained from debating (or leaving open to debate) whether or not your car is immune from MOT for one reason or another. Surely it's worth £50 or less a year to cover one's behind!

The only GOOD thing I take from these different sets of rules is that neither DVLA OR DVSA have anything at all to say about brake upgrades which are "free" in both cases.

Steve

[Boost All The Dollys]

I spent a bit of time wading through the quagmire of wooly and imprecise definitions but my take is that:- a car is "substantially altered" if the number of cylinders is changed (ie from 4 to 6 or or the capacity is increased by more than around 50%. Though it's not explicit, the implication is that, if you use an engine from a different maker, that is enough to make it out of bounds, regardless of size or capacity or number of cylinders.

Personally I don't see anything to be gained from debating (or leaving open to debate) whether or not your car is immune from MOT for one reason or another. Surely it's worth £50 or less a year to cover one's behind!

The only GOOD thing I take from these different sets of rules is that neither DVLA OR DVSA have anything at all to say about brake upgrades which are "free" in both cases.

Steve

Even if my car was MOT exempt, I’d still take it once a year, but at least I wouldn’t have to worry about missing a deadline.

Yeah, I always thought it was a bit odd that the DVLA kind of skip over brake changes, even for the “radically altered” regulations. Maybe they assume that people will take their braking system seriously through common sense.

[Carledo]

I spent a bit of time wading through the quagmire of wooly and imprecise definitions but my take is that:- a car is "substantially altered" if the number of cylinders is changed (ie from 4 to 6 or or the capacity is increased by more than around 50%. Though it's not explicit, the implication is that, if you use an engine from a different maker, that is enough to make it out of bounds, regardless of size or capacity or number of cylinders.

Personally I don't see anything to be gained from debating (or leaving open to debate) whether or not your car is immune from MOT for one reason or another. Surely it's worth £50 or less a year to cover one's behind!

The only GOOD thing I take from these different sets of rules is that neither DVLA OR DVSA have anything at all to say about brake upgrades which are "free" in both cases.

Steve

Even if my car was MOT exempt, I’d still take it once a year, but at least I wouldn’t have to worry about missing a deadline.

Yeah, I always thought it was a bit odd that the DVLA kind of skip over brake changes, even for the “radically altered” regulations. Maybe they assume that people will take their braking system seriously through common sense.

I doubt any assumption of common sense enters the equation! Nanny state rules!

DVLA rules is more a list of what you CAN'T do, or at least you can only do so much to retain the 8 points needed. if there were a couple of points for brakes, that'd be a couple of points you could spend somewhere else and keep stock brakes on your fire breathing monster! Not perhaps the best idea! Even THAT theory is giving DVLA more credit than it normally deserves, but I can't think of another feasible explanation.

Steve