Compatability Issues - 850 to 1275 Engine Swap
Discussion
Hi all, first things first, Merry Christmas 
As you know I plan to perform an engine build and transplant. I have a few concerns/questions about compatability;
1. Are the drive shafts different or is it just a straight swap - 850 out 1275 in?
2. The 850 is an A series block. Changing from A to A+ engine, any issues there?
I've been offered an Metro 1275, with high lift cam also; apparently it has come out of a mini, so I'm guessing the engine mountings are Mini rather than Metro.
Thanks in advance, Tom
As you know I plan to perform an engine build and transplant. I have a few concerns/questions about compatability;
1. Are the drive shafts different or is it just a straight swap - 850 out 1275 in?
2. The 850 is an A series block. Changing from A to A+ engine, any issues there?
I've been offered an Metro 1275, with high lift cam also; apparently it has come out of a mini, so I'm guessing the engine mountings are Mini rather than Metro.
Thanks in advance, Tom
Tom,
The issue is not so much the engine as the gearbox.
All later Minis with disc brakes used the same drive shafts and hubs and gearbox output parts. However, drum braked cars may well be a different issue entirely, especially 850's. What is the date of manufacture of your car. Get that and come back and Richy will tell you what bits you need including the part numbers.
I don't think you'll have any issues with the engine fitting so long as the engine mountings are Mini, not Metro.
I'm assuming the car is currently a rod-change model.
In theory it's an easy job!
The issue is not so much the engine as the gearbox.
All later Minis with disc brakes used the same drive shafts and hubs and gearbox output parts. However, drum braked cars may well be a different issue entirely, especially 850's. What is the date of manufacture of your car. Get that and come back and Richy will tell you what bits you need including the part numbers.
I don't think you'll have any issues with the engine fitting so long as the engine mountings are Mini, not Metro.
I'm assuming the car is currently a rod-change model.
In theory it's an easy job!
Cooperman said:
Tom,
The issue is not so much the engine as the gearbox.
All later Minis with disc brakes used the same drive shafts and hubs and gearbox output parts. However, drum braked cars may well be a different issue entirely, especially 850's. What is the date of manufacture of your car. Get that and come back and Richy will tell you what bits you need including the part numbers.
I don't think you'll have any issues with the engine fitting so long as the engine mountings are Mini, not Metro.
I'm assuming the car is currently a rod-change model.
In theory it's an easy job!
Hi Cooperman, the date of manufacture is 1979. Im on drums all round. The issue is not so much the engine as the gearbox.
All later Minis with disc brakes used the same drive shafts and hubs and gearbox output parts. However, drum braked cars may well be a different issue entirely, especially 850's. What is the date of manufacture of your car. Get that and come back and Richy will tell you what bits you need including the part numbers.
I don't think you'll have any issues with the engine fitting so long as the engine mountings are Mini, not Metro.
I'm assuming the car is currently a rod-change model.
In theory it's an easy job!
Yes, the car is a rod change model. With a big engine you'll really need to go to disc brakes. I once had an MG1100 engined former 850 with drums. I soon fitted discs!
What you need is a complete set of 8.4" discs c/w calipers, hubs and drive shafts. The shafts will have the correct ends, but you'll need to check that the shaft inner ends will go straight into the gearbox, which they will if it's the box which comes with a A+ engine, maybe not if it's originally an 850 box.
You may need to change the brake master cylinder and fit a servo. The ideal would be to fit the later combined servo and master cylinder as the dual circuit non-servo master cylinder can be a b****r to make work if it's been reconditioned in any way.
Maybe someone on here will have the bits you need.
What you need is a complete set of 8.4" discs c/w calipers, hubs and drive shafts. The shafts will have the correct ends, but you'll need to check that the shaft inner ends will go straight into the gearbox, which they will if it's the box which comes with a A+ engine, maybe not if it's originally an 850 box.
You may need to change the brake master cylinder and fit a servo. The ideal would be to fit the later combined servo and master cylinder as the dual circuit non-servo master cylinder can be a b****r to make work if it's been reconditioned in any way.
Maybe someone on here will have the bits you need.
Cooperman said:
With a big engine you'll really need to go to disc brakes. I once had an MG1100 engined former 850 with drums. I soon fitted discs!
What you need is a complete set of 8.4" discs c/w calipers, hubs and drive shafts. The shafts will have the correct ends, but you'll need to check that the shaft inner ends will go straight into the gearbox, which they will if it's the box which comes with a A+ engine, maybe not if it's originally an 850 box.
You may need to change the brake master cylinder and fit a servo. The ideal would be to fit the later combined servo and master cylinder as the dual circuit non-servo master cylinder can be a b****r to make work if it's been reconditioned in any way.
Maybe someone on here will have the bits you need.
I see, so my A series driveshafts and hubs are no good for an A+ gearbox? Thats exactly what I didn't want to hear! I intend to change the brakes, however I need them to fit under 10's.What you need is a complete set of 8.4" discs c/w calipers, hubs and drive shafts. The shafts will have the correct ends, but you'll need to check that the shaft inner ends will go straight into the gearbox, which they will if it's the box which comes with a A+ engine, maybe not if it's originally an 850 box.
You may need to change the brake master cylinder and fit a servo. The ideal would be to fit the later combined servo and master cylinder as the dual circuit non-servo master cylinder can be a b****r to make work if it's been reconditioned in any way.
Maybe someone on here will have the bits you need.
Tom
From my (limited) experience I would suggest that if your 850 existing engine/box has a rod change gearbox with pot joint cvj's on the output shafts of the gearbox, then your existing driveshafts(the thin , spindly 850/1000 non disc type) will mate up to your new metro rod change box.
Not the ideal situation but I used these drive shafts (in ignorance) on a 1380 sprint car for several seasons with no problems. They were ,of course, mated to Cooper s discs brakes via the larger, outer CVJ.
As Cooperman suggests, you will need to upgrade your brakes eventually, perhaps sooner rather than later and his suggestion of finding a complete Mini disc brake set up will give you the larger(disc brake) CVJ and the thicker driveshaft, but not calipers/discs that will fit under 10" wheels.
Not the ideal situation but I used these drive shafts (in ignorance) on a 1380 sprint car for several seasons with no problems. They were ,of course, mated to Cooper s discs brakes via the larger, outer CVJ.
As Cooperman suggests, you will need to upgrade your brakes eventually, perhaps sooner rather than later and his suggestion of finding a complete Mini disc brake set up will give you the larger(disc brake) CVJ and the thicker driveshaft, but not calipers/discs that will fit under 10" wheels.
Mini_Lund said:
Cooperman said:
With a big engine you'll really need to go to disc brakes. I once had an MG1100 engined former 850 with drums. I soon fitted discs!
What you need is a complete set of 8.4" discs c/w calipers, hubs and drive shafts. The shafts will have the correct ends, but you'll need to check that the shaft inner ends will go straight into the gearbox, which they will if it's the box which comes with a A+ engine, maybe not if it's originally an 850 box.
You may need to change the brake master cylinder and fit a servo. The ideal would be to fit the later combined servo and master cylinder as the dual circuit non-servo master cylinder can be a b****r to make work if it's been reconditioned in any way.
Maybe someone on here will have the bits you need.
I see, so my A series driveshafts and hubs are no good for an A+ gearbox? Thats exactly what I didn't want to hear! I intend to change the brakes, however I need them to fit under 10's.What you need is a complete set of 8.4" discs c/w calipers, hubs and drive shafts. The shafts will have the correct ends, but you'll need to check that the shaft inner ends will go straight into the gearbox, which they will if it's the box which comes with a A+ engine, maybe not if it's originally an 850 box.
You may need to change the brake master cylinder and fit a servo. The ideal would be to fit the later combined servo and master cylinder as the dual circuit non-servo master cylinder can be a b****r to make work if it's been reconditioned in any way.
Maybe someone on here will have the bits you need.
Tom
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