How to identify unleaded head

Side valve, 803, 948, 1098., 1275 and Vizard mods

How to identify unleaded head

Postby DonSoutar » Thu Apr 05, 2018 8:12 pm

20180405_195328.jpg
I am rebuilding a 1965 2 door and have just removed cylinder head which has casting number 12G202 SM - is this original or a modification. Also the exhaust valves have an easily seen insert so does this mean it has been converted to unleaded at some point. I have attached a pic. It also has an aluminium plate with 1100 on the block.
DonSoutar
New Poster
 
Posts: 4
Joined: Wed Jun 21, 2017 10:11 pm

UK Scotland (.j)

Re: How to identify unleaded head

Postby woodywoodchipper » Fri Apr 06, 2018 5:53 pm

looks like an unleaded conversion, can't help with no's thou,

A,
Image

When its done its done (for now)
Derv Turbo Power (Joosed)
User avatar
woodywoodchipper
.
 
Posts: 3792
Joined: Sun Nov 07, 2010 5:11 pm
Location: up to my neck in dudu
Awards: 7
Contributions 2011 (1) Contributions 2012 (1) Contributions 2013 (1) Contributions 2015 (1) Contributions 2016 (1)
Contributions 2017 (1) Contributions 2018 (1)

United Kingdom (uk) UK Lancashire (lk)

Re: How to identify unleaded head

Postby Panky » Fri Apr 06, 2018 6:37 pm

12G202 head is off either a 997 Cooper or Austin 1100, according to Calver, and the valve sizes should be 1.156"/29.36mm inlet and 1.00"/25.4mm exhaust
and wouldn't have had inserts originally so it looks like it could have been converted. I've got to say though that exhaust valve looks weird, it doesn't seem to fit right and that's a big recess in the face.

https://www.calverst.com/technical-info ... ng-number/
Image
User avatar
Panky
.
 
Posts: 1117
Joined: Sun Mar 22, 2015 6:00 pm
Location: Cheshire

United Kingdom (uk) UK England (.g)

Re: How to identify unleaded head

Postby MM » Sat Apr 07, 2018 9:04 am

Inlet valve seat/insert also appears to have a crack at about the 7 o'clock position. :?
Maurice, Kent.
1970 Trafalgar Blue Traveller

http://retrorides.proboards.com/index.c ... read=37056
User avatar
MM
.
 
Posts: 3693
Joined: Tue Jan 25, 2011 11:15 pm


Re: How to identify unleaded head

Postby DonSoutar » Sat Apr 07, 2018 2:57 pm

Hi, thanks for all your replies. The bit that looks like a crack at inlet valve was just a lump of carbon and the exhaust valve was loose and does actually fit snugly its just my rubbish photography.

I have been told since posting that the 12G202 head is standard on the 1098cc.

Thanks again, I am sure I will have more queries at the work progresses.
DonSoutar
New Poster
 
Posts: 4
Joined: Wed Jun 21, 2017 10:11 pm

UK Scotland (.j)

Re: How to identify unleaded head

Postby Custard » Sun Apr 08, 2018 7:49 am

Yes my 1098 had the 12G202 head and the David Vizard book does say 997Cooper Mini, Austin/Morris 1098 Mk1 Midget, Mk2 Sprite.

The Austin/Morris 1098 probably covering Transverse engine cars as well as the Minor.

I think the aluminium 1100 is standard on the 1098 Blocks.

Sean.
User avatar
Custard
.
 
Posts: 2378
Joined: Fri Jan 06, 2012 11:17 pm
Location: Blackpool
Awards: 5
Contributions 2012 (1) Contributions 2013 (1) Contributions 2016 (1) Contributions 2017 (1) Contributions 2018 (1)

Ireland (ie)

Re: How to identify unleaded head

Postby DonSoutar » Sun Apr 08, 2018 3:54 pm

Hi I have a further question. On checking the top of the pistons in my block they are stamped .508 which I believe is equivalent of 20 thou which means it has been rebored sometime in its life. Should I replace the piston rings as a matter of course given that I have come this far with it. If so are +20 thou rings exact same size - sorry if it that is a daft question.
DonSoutar
New Poster
 
Posts: 4
Joined: Wed Jun 21, 2017 10:11 pm

UK Scotland (.j)

Re: How to identify unleaded head

Postby woodywoodchipper » Sun Apr 08, 2018 5:56 pm

if its not smoking or using excess oil leave it alone,

and I think from your size's its had later mini pistons fitted, check out minispares and see what there piston size's are, I would not use 20 thou as a guide as a few thou difference can mean big trouble,
Image

When its done its done (for now)
Derv Turbo Power (Joosed)
User avatar
woodywoodchipper
.
 
Posts: 3792
Joined: Sun Nov 07, 2010 5:11 pm
Location: up to my neck in dudu
Awards: 7
Contributions 2011 (1) Contributions 2012 (1) Contributions 2013 (1) Contributions 2015 (1) Contributions 2016 (1)
Contributions 2017 (1) Contributions 2018 (1)

United Kingdom (uk) UK Lancashire (lk)

Re: How to identify unleaded head

Postby DonSoutar » Sun Apr 08, 2018 7:40 pm

I think you might be right Woodywoodchipper it wasn't smoking or appearing to use oil other than lots of leaks so think I will leave pistons alone and concentrate on cleaning it all up and fitting new gaskets.
Its great to have experienced people on hand to ask.
Many thanks again.
DonSoutar
New Poster
 
Posts: 4
Joined: Wed Jun 21, 2017 10:11 pm

UK Scotland (.j)


Return to Engine



Who is online

Users browsing this forum: No registered users and 2 guests

cron