IVA cats and engine dates

[PeteC]

If I built a '1.8 1994 pre cat' engined car and got it all road legal and registered and wanted to change the engine to a '2.0 1999' engine, what changes would i have to make to the paperwork/V5?
Would I have to retro fit a catalytic converter?
Would I have to retest because of change of engine size?
Anybody been here before?
Pete.

[kevp]

Pete

You would have to fit a cat.
Just fill in the engine details on V5
Thats it.

[MattD]

If it's on a Q plate it's still visible smoke test only.
No proper missions test, so no CAT required.

[kevp]

Matt, thats not my experience.

On a Q plate car the engine has to be older than 1992 to avoid having a cat fitted. When you go for an MOT it is up to the owner to prove the age of the engine so the relevant test for age can be undertaken. If the car was registered before 1992, then a cat is not expected. If the car is newer then evidence of engine age is required.

All my MOTs have been far more stringent than just a smoke test. And twice I have had to prove engine age, to avoid the cat issue.

[MattD]

Hmmm, interesting.
As far as i am aware a Q plate is age or origin indeterminate, hence a visual inspection only..
My MOT tester is a personal friend, I will have a look at a current MOT testers handbook !

It's possible IVA tested cars are flagged differently on the DVLA computer.
In 10 years the engine age in my SVA tested car has never been mentioned, it just falls into the flat rate road tax bracket, rather than one based on CO2 value.

Quite likely it's down to how the tester interprets the rules.

[PeteC]

Oh thats opened a can of worms!!
My car is not finished yet, but I plan to have the silencer in the sill. If I do then there is not a lot of room and so avoiding a cat would be easier to fit, cheaper and leave the engine breathing better (without the resulting power loss!).
I wondered if I could go thru IVA with an old engine (without cat) and change it later to the newer one (still without cat).
Now I know you all going to say "why not just keep the older engine?", and the only answer is I've got a nice low milage 2.0 from an 1996 reg mondeo and I don't think I'll get a decent pre cat engine that I would be prepared to keep.
I really hope Matt is right, but I doubt it. My money is on Kev.

[stylussprinter]

My original 2lt zetec was 1992 and was sva'd in 1999(completed in 1998) . Only the smoke test was done although I did have to quote the relevant section in the mot rule book for that to be established . Once on the road I over heated it due to a jubilee coming off . Matt had it from me and I started again with a 1998 2lt zetec . That also only got a smoke test and no one asked to check the engine number ----- which , as it came from Dunnell , didn't have one anyway . The place next to the flywheel sensor where it's stamped has now't on it . It was on the road till 2004 , well legally but usually on the trailer. A cat was never demanded and their words were '' oh it's on a Q plate , no cat '' . I think the answer is to get it mot'd at your best local guy and keep to him then sort what you'd really like later

[Sook]

This is what the book says (according to http://www.motuk.co.uk)

Vehicles Fitted with a different engine

Test according to which is older, engine or vehicle. e.g. A 1995 car fitted with a 1991 engine (of whatever make), test to 1991 standards for emission purposes.

Note: The onus is on the vehicle presenter to prove engine age.

It also says :

Vehicles having a Q plate registration when presented for MOT are to be treated as being first used on 1 January 1971.

The water is muddied further by the following flowchart which suggests the CAT test requirement would be based on the first used date rather than the engine age! http://www.motuk.co.uk/images/cat1.pdf.

Good luck deciphering the bureaucratic gobbldigook!

[PeteC]

This is all related to an earlier post of mine asking about TIG welders, I was planning on having a go at making my own exhaust manifold. Has anybody out there made their own? Used a cat with the silencer in the sill? If so how much space did you need? Any photos?
Pete C.

[stylussprinter]

Depends on what power you intend shoving up the pipe . Personally I wouldn't put it down an enclosed cill anyway , way too big a fire risk . With small power you canuse a 4 inch silencer but most other bigger grunt engines won't be quiet enough without a 6 to 7 in . That willbe dangerous down the cill even with reflective glued on . If you expose it fully underneath and the side the risk is low . A cat could be put in the front cill behind the front wheel with some clever pipe work -- a Motorsport one is very small .

[PeteC]

Well I'll eventualy run a 2.0 silvertop zetec on individual throttle bodies and would be happy to get up around 185bhp with some decent cams. The silencer will be fully exposed and I was considering a quadrant shape seen from the end, I hope this will give me the maximum internal volume and follow the Stylus body shape on the outside. I thought about joining the cat and silencer almost in one part, but the lambda sensor would not be very accessable. The point was could I get away with out the cat on a later engine?
Pete..

[MattD]

Well I'll eventualy run a 2.0 silvertop zetec on individual throttle bodies and would be happy to get up around 185bhp with some decent cams. The silencer will be fully exposed and I was considering a quadrant shape seen from the end, I hope this will give me the maximum internal volume and follow the Stylus body shape on the outside. I thought about joining the cat and silencer almost in one part, but the lambda sensor would not be very accessable. The point was could I get away with out the cat on a later engine?
Pete..

Silvertop is early & pre-94 isn't it ?
A '99 Zetec would be a blacktop I think.
Correct me someone

[PeteC]

"Early, ‘Silver Top’ engines (with an aluminium cam cover) were fitted to Escorts from 1991 onwards, late Fiesta Mk3s and then the Mondeo. These early units were known as Zeta (only becoming Zetec in 1993). The unit evolved into the Black Top unit (with a plastic cam cover) with the Escort phased out and Focus introduction. These later engines have longer rods and lower piston crowns, mechanical rather than hydraulic lifters plus the distinctive black cam cover." (BURTON POWER)
Not sure what year the change over from silver to black was but I think my silvertop came from a 1996 mondeo.
Pete..

[stylussprinter]

My first 2lt zetec was a 1992 but it's replacement is a 1998 2lt zetec and looks identical so I'm guessing anything 1999 and onwards will be a Blacktop solid lifters . Didn't know the rods and crowns were different though.