12 replies to this topic

[miniaddict92]

I currently have a 998cc 1990 mini mayfair which i want to engine swap and put a 1275cc engine maybe new but probs second hand, this summer.
I guess it isnt as simple as lift one out and put a bigger engine in. what other parts of the car will i need to change/replace/upgrade ??
Also some things to check when buying a second hand engine would be appreciated.


cheers

[rids]

top rad mount is different and make sure you have the correct final drive ratio in new engine. thats about it

[cal844]

when buying a second hand engine, make sure it is still in the car when you go to buy it so it can be heard running, if possible take the car a road test to ensure the gearbox is working normally.

[holmesy]

the swap is very simple my first time took 3 days to get my 998 out and a metro 1275 in and back onto the road but I was doing other jobs at the same time.

always get a engine you can see running or test is even better. once you get it you might as well change things like crank seals and clutch as these are hard to do in the car. things that need doing for the swap is
top rad mount.
shorten the link pipe

[tiger99]

As your car already has disc brakes, from its year, there is nothing major to change. (Drums would not be adequate for a 1275!) If you have the radiator that belongs with the replacement engine, you will also have the correct brackets. Obviously you need the carburettor, manifolds and distributor too, but swapping the complete power plant is straightforward. Much earlier models may have different clutch hydraulics and various other detail differences.

I would suggest changing everything in sight that wears while the engine is out, i.e. both mounts, top and bottom steady bar bushes, various hoses, etc, and give everything a good clean and rust prevention as needed. With the engine out, it is a convenient time to fit things like solid subframe mounts (all, or none, never half solid and half rubber, and poly are no good at all here), and while doing that, swap the steering rack, only if it will be needed soon, plus any other maintenance needed around the front subframe area.

As already suggested, before you start treat the new engine to such consumable bits as might be needed soon, i.e. all accessible oil seals, gearchange rod seal upgrade kit, possibly new clutch, and new fan belt.

Be prepared to deal sensibly with the driveshafts, and under no circumstances ever mix parts from different pot joints, even if they look the same. The preferred way is to keer your existing shafts intact, as you will know that they are good, and extract the pots from the diff. Undo the hubs from top and/or bottom arms to do that, not the bodger's way of just relying on something seperating as the engine is lifted. It means thet they will go back in to the new diff without any fuss and bother. The need not be taken out of the subframe.

Apart from any maintenance activities, which can take advantage of the accessibility while the engine is out, it really is a case of undoing the old and lifting it out, lowering the new in and doing everything up.

I recommend getting an insurance quote before starting the work just in case it will turn out to be more than you were hoping.

[garrymacmini]

Drums may not be adequate on a 1275 but Hell they are a load of fun! get out of my way!

[tiger99]

I did not find drums very useful even on a 998! Just about ok on an 850 van. But I really don't like hitting things.....

[bmcecosse]

It's a straight swop - lift out the old engine and drop the new one down on the box. Make sure you have the correct angle primary gear on the 1275 crank to match with the drop gears on the 998. Use a Cooper S ' ? ' shape top rad hose - and either the 1275 top rad mount, or make a very simple one from strips of 1/8" steel.

[AGoaty]

I would say that the best plan would get a running Mini engine, gearbox and clutch, which you can see and hear and buy that. You'll pay about £300 for this but could save a lot of time in the long run. You have a Mini already so know what it sounds like. Noisey engines stand out a mile and oil burning engines need work so walk away.

Parts you will need to swap complete the conversion are, carburettor with airbox, inlet and exhaust manifolds, full exhaust pipe, radiator top bracket and hose, breathers and piping are different, flywheel housing, the clutch may be different but any complete set will work,

Parts you could use from your 998 are wiring, the engine/gearbox mounts, alternator, fuel pump, water pump, radiator, driveshafts and brake setup.

I also recommend asking insurance company for a quote before doing this as anyone under 25 will pay a hefty price for this modification.

[miniaddict92]

many thanks for everyone comments and now have to do some searching and add everything up. insurance wise i know the figure it will jump up to its only £200 more being 20 years old maybe less when i check again . only problem is most engines arent in the car running ,90% are already out of the car for sale. also what could you do to a 998 to put it close to the power of the 1275 and cost of this? compared to that of buying and fitting an new engine. i have the space to strip and clean the engine but not to get it out and put the new one in so would most likely need to go to a garage and what type of labour charge would i expect to come with it.

[rids]

any engine bought without hearing it run or unknown history is worth stripping and checking before fitting. I bought a 1293 2 years ago as recently rebuilt, when i checked it, the cam had next to no lobes left and a knacked clutch. bearings, pistons and rings had been re-newed tho. why do people do 1/2 a job?

[998kid]

im also thinking of doing a swap like this only with a 1330cc engine, i presume the process for the swap is the same, but how do i ensure the final drive ratio is the same?

[tiger99]

To check the final drive ratio, which you can do in or out of the car, lock one driveshaft (e.g. wheel on ground, or put some kind of clamp round the pot joint). Put a mark on the other wheel, or pot joint. Now engage top gear. With spark plugs out to make it easier, turn the engine via the crankshaft pulley nut, counting the turns, until the wheel or driveshaft has made exactly ten turns. You can use the timing marks to count crankshaft turns. Divide the number of turns you made by 5, and that is the diff ratio, provided that normal drop gears are fitted.

You divide by 5, not 10, because the diff is causing one output to move twice as far as normal while the other is locked. You only need 10 turns to get decent accuracy, it can be done with less if you can measure fractional turns of the crankshaft somehow.