Displacement?

[Timothy Keith-Lucas]

Could someone both confirm the displacement of my engine and explain how they confirmed it? I have it as 1098cc, but John Watson says more likely 948cc: "Austin Healey Sprite (Mk.1 'frog-eye') engine" which was a 948cc. It's an America model (despite RHD) The engine number is AEA 17 RS 19576, which I don't know how to decode. The frame is 1962 S2 #1160. The car raced in SCCA FP in 1962-66. 

 

Thanks a bunch.

 

 

 

 

 

[MV8]

The block will have 950 cast into it below the carbs to the right of the fuel pump. A 1098 will not. A 1275 will also not have side covers under the exhaust to access lifters. There are tags that provide indications but they are all removable.

Edited December 19, 2025 by MV8

[Timothy Keith-Lucas]

Thank you so much, MV8.  You are a wonderful source of wisdom. I will grab a mirror and go looking.  I do have access plates on the left side. 

 

Best wishes,

--Tim.

[7Westfield]

    Found this on a google search       They say 9J for 948

   

[Timothy Keith-Lucas]

Good morning, 7Westfield, and thank you.

So a 1098cc will not have "9J" but may have another casting ID like this "16J"?

Could you help me with the location of this mark? Is it "below the carbs to the right of the fuel pump" as MV8 says for "950"?

Thank you.

 

[7Westfield]

First off, I've not worked on an A series since the 70's, in my bugeye

I thought it looked like front, left corner above the pan    ahead of the pump?

 

there was also mention of racers back in the day putting 1098 heads on 948 blocks

I'll see if I can relocate the article

 

edit   try this page

https://www.mgexp.com/article/bmc-a-series-engine-codes.313

not the one I saw earlier, but looks helpful

Minimania might have something, but I can't get on their site today

 

It seems that for the early engines, they used a system where the number was the size group and letters were sub groups

so 8xx was anything in the 800-900cc range, and 9xx was the 900-1000 group

Edited December 20, 2025 by 7Westfield

[Timothy Keith-Lucas]

Casting marks:

On the engine in the car at present, left side rear of block, 2A 799

On the original engine, same location, sitting in my shop, 12A 497

 

How does that decode?

[MV8]

[7Westfield]

reach out to HealeyRacer 

 

from a couple of his posts, he seems to be a long time A-series addict

[Timothy Keith-Lucas]

BINGO! Behind the carb heat shield, behind the exhaust manifold, "950" along with the previously found "2A 799," exactly as in your photograph, MV8. I can rest merry (being sort of a gentleman) this Christmas, because I finally know that I have a 948cc engine. Thank you all and Merry Christmas/Happy Holidays to you all. 

[theDreamer]

4 hours ago, Timothy Keith-Lucas said:

BINGO! Behind the carb heat shield, behind the exhaust manifold, "950" along with the previously found "2A 799," exactly as in your photograph, MV8. I can rest merry (being sort of a gentleman) this Christmas, because I finally know that I have a 948cc engine. Thank you all and Merry Christmas/Happy Holidays to you all. 

Not to rain on your parade but, It was a 948. It may have been bored over or stroked or both seeing it was race car.

[Timothy Keith-Lucas]

Grinch! You would do that to an 80 year-old kid's dreams a few days before Christmas? Shame on you!

 

That is a very reasonable concern, and thank you for bringing it up. I'll check with Hayes Harris of Wire Wheels in Vero Beach about any history of serious engine work. He knew the car while it was racing (1962-66) and before it went into storage for 56 years.  Thanks. 

 

--Tim.

[wdb]

803, 848, 947, 948, 970, 997, 998, 1070, 1097, 1098, 1275, but who's counting...

[11Budlite]

I still have the 948 from my first car, a 1961 Bugeye, sitting in my basement. The bottom end has never been rebuilt, with around 70k original miles. 

[Timothy Keith-Lucas]

Quote "803, 848, 947, 948, 970, 997, 998, 1070, 1097, 1098, 1275, but who's counting..."

Pretty soon you rev it up and a piston breaks through to the water jacket.....spoils your whole day.

[IamScotticus]

Tim, what it your information that you "have it as"?

[Timothy Keith-Lucas]

Not quite sure that I understand the question, Scott, but my casting marks are identical to those posted by MV8 above, ergo it at least started life as a 948cc engine.  I have an email into Hayes Harris, who knew the car in the early 1960s when it was racing - he was a kid hanging out at the owner's garage.  He's now the owner of Wire Wheels, a sports/racing car dealer in Vero Beach, Florida and sold the car to me.  His ad for the car did say that the engine was "a race prepared BMC "A" series..."

[IamScotticus]

10 hours ago, Timothy Keith-Lucas said:

Not quite sure that I understand the question, Scott, but my casting marks are identical to those posted by MV8 above, ergo it at least started life as a 948cc engine.  I have an email into Hayes Harris, who knew the car in the early 1960s when it was racing - he was a kid hanging out at the owner's garage.  He's now the owner of Wire Wheels, a sports/racing car dealer in Vero Beach, Florida and sold the car to me.  His ad for the car did say that the engine was "a race prepared BMC "A" series..."

I'm wondering if you have a spec from a build sheet or you have made a physical measurement?  

I will side with @theDreamer  on this one@theDreamer

Edited December 22, 2025 by IamScotticus

[Timothy Keith-Lucas]

I was hoping to resolve the issue without taking the head off to measure the bore and stroke. The car was factory assembled, and I think we've established that it started life with a 948cc engine, but the term "race prepared BMC "A"" could hide all sorts of mischief. 

[MV8]

On 12/20/2025 at 6:40 PM, theDreamer said:

Not to rain on your parade but, It was a 948. It may have been bored over or stroked or both seeing it was race car.

Fear not. "950" cast into the block means it is started as a 948. No umbrella needed.