12 replies to this topic

[BaronVonchesto]

Hello everyone. I'm looking for a 1098 crank for my next engine project. There are a few scrappers here who think they might have a 1098 crank. I was wondering if anyone knew casting numbers to look out for, or measurements I could take to validate if it is indeed a 1098 crank.

 

Additionally, I have a micrometer. Does anyone know where I can find the measurements for the big end and crank faces to know if oversized bearings would be needed?

 

I have pictures of 2 cranks I have shortlisted if that helps.

 

 crank1.jpg   37.5K   2 downloads

 crank1a.jpg   61.27K   3 downloads

 

And for this second crank, its way cheaper since it looks very rusted. but im concerned about the notch and apparent cut in the crank. Could it indicate it was previously balanced? What else should I be looking out for in a crank, besides checking for Cracks?

 crank2.jpg   26.09K   3 downloads

 

Thanks in advance

[nicklouse]

Ok first things. The cut in the Rusty non Mini crank are standard from the factory cuts.

 

now are you looking for a small bore 1098 or a big bore (South African build engine) 1098 crank? 

[BaronVonchesto]

Ok first things. The cut in the Rusty non Mini crank are standard from the factory cuts.

 

now are you looking for a small bore 1098 or a big bore (South African build engine) 1098 crank? 

 

Hey nick. I wasn't aware of the big bores at all! So I guess I'm looking for a small bore crank - the kind that went into an ADO16 or MG Midget.

My plan is to take the 1098 crank and conrods and put it into a 998 A+ block I'm thinking to overbore to +40 with new pistons.

[timmy850]

The casting number is 12G82 for 1098cc small bore

[timmy850]

In your pictures:
12A670 is for an 850
12G179 is an 1100 crank, but for an inline engine (rwd) like Morris Minor

Assuming you’re building a mini engine you’ll need a mini or ADO16 crankshaft with the long tapered tail for the flywheel and primary gear.

RWD crankshafts have a boss to bolt on a flywheel and aren’t compatible with a mini

Edited by timmy850, 28 December 2025 - 08:44 PM.

[BaronVonchesto]

In your pictures:
12A670 is for an 850
12G179 is an 1100 crank, but for an inline engine (rwd) like Morris Minor

Assuming you’re building a mini engine you’ll need a mini or ADO16 crankshaft with the long tapered tail for the flywheel and primary gear.

RWD crankshafts have a boss to bolt on a flywheel and aren’t compatible with a mini

 

Much appreciated! Yes Im building a mini engine. I need to look for a 12G82 crank then.

[BaronVonchesto]

For future reference, if anyone is looking for part numbers, I found this excellent list on Someford Mini's website

https://www.somerfor...-998-and-1098cc

[Spider]

There are at least 3 different 1098 Inline Transverse Cranks. Sorry, I don't have the numbers to hand.

The earliest had a 1-3/8" tail
The next had 1-1/2" tail

Somewhere in there too is a cross-drilled type.

 

<EDIT to correct dumb error !! >

[gazza82]

There are at least 3 different 1098 Inline Cranks. Sorry, I don't have the numbers to hand.

The earliest had a 1-3/8" tail
The next had 1-1/2" tail
Somewhere in there too is a cross-drilled type.

Some had 2" mains too. (Spridget 10CC block).

Pretty obvious though if inline as flywheel bolts on .. not the taper fit of the transverse engines.

[BaronVonchesto]

There are at least 3 different 1098 Inline Cranks. Sorry, I don't have the numbers to hand.

The earliest had a 1-3/8" tail
The next had 1-1/2" tail

Somewhere in there too is a cross-drilled type.

 

So I found a 12G82 crank that the guy says is "cross drilled" (I think thats what he said anyway, it sounded more like "cross bit" which makes no sense to me)

I gather a cross drilled crank is technically better since the oil outputs in the journal are 90 degrees offset, which is good at high revs (though a 1098 shouldnt be revd too high). Are any modifications in the end caps or the block needed for a cross drilled crank?

[BaronVonchesto]

There are at least 3 different 1098 Inline Cranks. Sorry, I don't have the numbers to hand.

The earliest had a 1-3/8" tail
The next had 1-1/2" tail

Somewhere in there too is a cross-drilled type.

 

Hey Moke, did BMC or Leyland ever make their own cross drilled cranks in the factory? I found a good post of yours here explaining that cross drilled cranks arent actually good for a road car. Since I would use this as a fast road car (city drive, motorway, hill climbs), but no motorsport - i'm guessing a cross drilled crank would actually be bad?

[Spider]

 

There are at least 3 different 1098 Inline Cranks. Sorry, I don't have the numbers to hand.

The earliest had a 1-3/8" tail
The next had 1-1/2" tail
Somewhere in there too is a cross-drilled type.

Some had 2" mains too. (Spridget 10CC block).

Pretty obvious though if inline as flywheel bolts on .. not the taper fit of the transverse engines.

 

 

For the Inline cranks yes, there were a few - however I made an error in my post, which I've now corrected - I was actually referring to transverse cranks !

[Spider]

 

There are at least 3 different 1098 Inline Cranks. Sorry, I don't have the numbers to hand.

The earliest had a 1-3/8" tail
The next had 1-1/2" tail

Somewhere in there too is a cross-drilled type.

 

Hey Moke, did BMC or Leyland ever make their own cross drilled cranks in the factory? I found a good post of yours here explaining that cross drilled cranks arent actually good for a road car. Since I would use this as a fast road car (city drive, motorway, hill climbs), but no motorsport - i'm guessing a cross drilled crank would actually be bad?

 

 

Yes, they did do cross drilled cranks, at least for the (small bore) 1100 and also on some of the Cooper S Cranks. It's the latter I have seen crack through the X drilling, but that's not to say the 1100 cranks didn't do the same. In that brief list I put up here, I think it was the early 1100 cranks that were cross drilled, which they went away from, I think that's telling in itself.