MOT & ZF gearboxes

[mole42]

Reading the latest SOC bulletin about new MOT rules makes me wonder whether a ZF gearbox constitutes a change to the original spec which means we’ll need an MOT?

[flying farmer]

The way I read it, transmissions were not even mentioned therefore don't constitute a major change.

[DJT]

From the current gov.uk guidance: https://assets.publishing.service.go...e-guidance.pdf

The following are considered acceptable (not substantial) changes if they fall into these specific categories:
• changes that are made to preserve a vehicle, which in all cases must be when original type parts are no longer reasonably available;
• changes of a type, that can be demonstrated to have been made when vehicles of the type were in production or in general use (within ten years of the end of production);
• in respect of axles and running gear changes made to improve efficiency, safety or environmental performance;
• in respect of vehicles that have been commercial vehicles, changes which can be demonstrated were being made when they were used commercially.

Whether the ZF conversion was being done before 1987, i.e. within 10 years of the end of production is something Clive Tait and Russell Lewis could answer. But certainly it could be argued that the conversion improves efficiency and environmental performance.

Mine has its MOT on Tuesday, so there will be 12 months for these arguments to be settled before its next one. I intend to keep having mine tested anyway.

[DJT]

I’ve just got around to looking at this month’s SOC magazine. On page 36, section 28 covers this.

[mole42]

Thanks Dave.

I wonder if I can get away with tubular headers on the “improvement of efficiency “ clause? :-)

[Klaus Schlueter]

Production years for ZF 4HP22

https://en.wikipedia.org/wiki/ZF_4HP22_transmission

Klaus

[Lingen]

I understand that gearbox alterations are not being questioned. However, for those with the RV8 and other horses under their bonnets, I looks like they may have to forget about H.V.status.
Mike

[Carboy0]

I think both the ZF gearbox and the Rover V8 conversion should be OK.

I receive the FBHVC bulletins and they were very heavily involved in the DfT consultation process. They commented on gearboxes particularly, there was a DfT expectation that a gearbox change would only ever take place to improve efficiency

”• in respect of axles and running gear changes made to improve efficiency, safety or environmental performance;”

I also think that Rover, Ford, Triumph straight 6 conversions should all be OK, another section of the DfT guidance talks about types of conversion that occurred within 10 years of the end of production, so as long as there is period documentation (maybe through the SOC?) then these will be OK.

“• changes of a type, that can be demonstrated to have been made when vehicles of the type were in production or in general use (within ten years of the end of production);”

the full DfT guidance can be found here,

https://assets.publishing.service.go...e-guidance.pdf

[KOY 23]

Yes but the Rover, Ford etc engines were aftermarket fitments and class as substantial modifications, had they been an optional original fit, they would not be a modification.

[Carboy0]

I think the key words that I have quoted above are “”changes”.....”in general use (within ten years of the end of production)”” this must mean modifications as Triumph were no longer making Stags after the end of production.

[KOY 23]

Maybe, I have read many different statements all leading to different interpretations. I was more interested in the ZF which is not an issue and EFI, which has not been mentioned in any of the documents I’ve seen. I can’t see it being a problem as it decreases emissions and improves efficiency. As many of us want an annual ckeck it makes little difference if our cars are MOT exempt, providing we maintain the historic status and no future discrimination against non VHI cars.

My view is that a Triumph with a Rover or Ford engine is substantially modified.

[Carboy0]

Yes, I understand your thinking, and it does appear that the ‘original engine’ rule should exclude some Stags from exemption. But then the guidance says that it will allow modifications if they are of a type that was current more than 30 years ago.

[Phil S]

This is a discussion that will go on for ever. it will be down to individual interpretations of the rules and some like myself will continue to MOT so that if an insurance claim is ever made l will at least be able to say as well as regular servicing the car has had an independent check. if you decide against an MOT or garage service to prove the car has been maintained because you have some modifications that you feel could affect the cars status then be it on your head.
we all will do our own thing and continues to agree and disagree.
most of us are grumpy old men at the end so enjoy a good moan!

[DJT]

Follow up from post #3 above: MOT passed today with no advisories. At least changing the brake drums has resolved the problem of "slight fluctuation in rear brake readings" on the advisories sheet for the past 3 years.........