940 head

[Harryhotrod]

I've bought a 1275 engine it's been built before, When i looked up heads there are 2x 940 heads 1 with 33mm valve 1 with 35 mine is the 33. So I've measured the head and seems it's had 20thou off already I've cc the combustion chamber it's 23cc but when I've read normally it's 21cc does anyone have any more info. Fitted with +40 TRW pistons which are dished so I believe std which I worked out to 8.28 compression

[philthehill]

There are more than two 940 heads!
Photos of what you have would be beneficial to determining the origins of your 940 head.
Are there any additional stampings or markings on the head?
What valve collets are fitted i.e. single or triple groove?
The standard head has a depth of 2.75".
The standard ex factory combustion chamber size is 21.4cc. The 23cc combustion chamber may have been increased to compensate for the higher compression when 0.040" plus pistons are used. 25cc combustion chambers are widely used when engine capacity is increased.

[Harryhotrod]

I will take some pics tomorrow

[Harryhotrod]

Here is the head also made a mistake with compression calcs lol works out 8.91

[philthehill]

Thank you for posting the photographs.
If the valves do not have the triple groove collets (1275cc MG Metro Turbo) the head is from a MG 1275cc Metro.
The combustion chambers have been cleaned up but not seriously reformed.
I hope the above is of help.
Have a merry Christmas.
Phil

[Harryhotrod]

Single groove valves 29 & 33 maybe its a mix and match Thanks Phil have a good Xmas mate

[philthehill]

Duplicate post. Deleted

[philthehill]

duplicate post deleted.
Have a good Christmas and all the best for the new year.