Head Identification

[Tony Press]

I have a spare cast iron head with the following cast numbers,  single bolt water outlet.  What sort of engine was it from?  
Can anyone identify it please

Bob

3  11  8

1A 670

{  AF  }   ignore the curly brackets
{   2   }
{   T   }

3rd November 1928 ?

I thought a '28 had petrol tap primers in them??

My LC head with brass blanking plugs in what had been intended for priming cups is 1A38  J3 (and also AF2). I believe it to be early 1929 in keeping with the rest of the engine.

I always have trouble deciphering the Index Cards-

You are right- the earlier low compression head with tap primer plug holes was 1A 38 (Part No BC 28)

The primer holes were deleted, but other than the parts listings deleting the plugs there doesn't seem to be a change in the part number or casting number shown on the cards for this later low compression head up to 1933.

Apparently casting number 1A 670 was introduced under Part Number BC 82 in August 1933, the cards then showing this crossed out and a later casting number 1A 684 for BC 82 sometime before 1936. 

Confused of Malvern.

[bob46320]

Thanks for all the replies - I think I will be happy to fit it to a '32 engine with the solid mounts on the crankcase (Ie; no rubber between chassis and motor mounts). I will pose another question in a new thread.
thanks
Bob

[AustinWood]

The head on my 1929 car is 1A 38 but has no brass plugs in primer holes. Also no date code.

[Viteran]

I had a look at the head on my 37 Ruby and it is marked IA 684 and the no’s 29.4.6
I assumed that meant a date of 29th April ‘36 unless Austin writes dates back to front
When it would be 6 th April ‘29 which would fit with IA 684 being an early casting?

[Steve Bryant]

I dug out my spare head and looked at the production date? - 30.7.5 part number 1A 684

Would the compression ratio of this head be any higher than that of the earlier 1929 head with the brass plugs where the priming taps used to be?

Cheers,
Stephen

[Ruairidh Dunford]

Were priming cocks ever used on production cars?

They exist on our '26 12/4 (and I use them)....

[Steve Bryant]

Re posting this as I'm still wondering.....



I dug out my spare head and looked at the production date? - 30.7.5 part number 1A 684

Would the compression ratio of this head be any higher than that of the earlier 1929 head with the brass plugs where the priming taps used to be?

Cheers,
Stephen

[Bob Culver]

Heads were a nominal 1.5 inches deep. The depth to the plateau from surface seems to be about .2" for pre 1933 and .14" for the later. Capacity of the latter about 37cc. You can work out the capacities backwards from the recent article! The curious thing is that contemporay road test of the RN with lc head and restrictive carb got better performance than the RP! Unless the test example was specially prepped.

[Ian Williams]

Stephen, the answer to your question is yes, I have found there is also a difference in the chamber of the XL heads so it appears Austin had more than one rethink.

---

The transfer port on the RP head is inferior Bob

[Tony Press]

Re posting this as I'm still wondering.....



I dug out my spare head and looked at the production date? - 30.7.5 part number 1A 684

Would the compression ratio of this head be any higher than that of the earlier 1929 head with the brass plugs where the priming taps used to be?

Cheers,
Stephen

I think this is the progression-


The earlier low compression head with tap primer plug holes was 1A 38 (Part No BC 28)

The primer holes were deleted, but other than the parts listings deleting the plugs there wasn't a change in the part number or casting number shown on the cards for this later style of 'low compression' head up to 1933.

Casting number 1A 670 was introduced under Part Number BC 82 in August 1933 with a slightly raised compression (5.2?) .


Casting number 1A 684 for BC 82 appeared sometime before 1936 (not sure of the change here but it is listed for the three bearing engine ?). 

In 1936 head number is listed as 1A911 - the new 'high compression' with two bolt water outlet.

Out of interest the later head gasket is shown as 1A 912 Klingerite or 1A 915 C/A.