Identification of cylinder heads

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sparesman
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Identification of cylinder heads

Post by sparesman »

Amongst the cylinder heads we have in the club stocks we have a new old stock head which appears to be a 1098 but has the part number 12G193. i cannot find this number in any A series parts list I have. Can anyone help identify it?
Bryan Gostling
1934 Morris 10/4 in Dark Green / Black - BGO517
1953 S11 Traveller in Birch Grey - oldest survivor ? Export model now reg PPO924
1953 S11 Traveller in Black - 3rd oldest in UK PPX344
RobThomas
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Re: Identification of cylinder heads

Post by RobThomas »

Any photos? Might help with identifying why it has different number.

I've a faint memory of a 12G192 being a 998 head.
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philthehill
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Re: Identification of cylinder heads

Post by philthehill »

12G193 not shown in any of the cylinder head lists I have.

Are you absolutely sure that the casting number is 12G193 as the casting numbers are sometimes very indistinct and can be misread.

As per Rob above - a photo of both the casting number and the head especially the ports and combustion chamber will help determine the head.

Some of the early big bore engines had cylinder heads with combustion chambers that looked like they originated from a small bore engine.

Large bore 12G940 head at the top and a large bore 12A185 head at the bottom.
12G185 head 4.JPG
12G185 head 4.JPG (586.14 KiB) Viewed 2615 times

sparesman
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Re: Identification of cylinder heads

Post by sparesman »

Its definitely 12G193 and it takes standard 1098 valves. Sometimes I have found numbers cast on BMC parts is one different to actual part number but not found this with cylinder heads as with the 12H295 head we also have in stock.
1934 Morris 10/4 in Dark Green / Black - BGO517
1953 S11 Traveller in Birch Grey - oldest survivor ? Export model now reg PPO924
1953 S11 Traveller in Black - 3rd oldest in UK PPX344
philthehill
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Re: Identification of cylinder heads

Post by philthehill »

Should that not be 12G295 ?

Below is the list of the common cylinder heads with Casting/Pt Numbers:

Heads not included are later versions of the heads listed and are the 940 head with air injection anti smog ports casting/Pt Nos: 12G1316 and the 998cc Mini again with air injection anti smog ports Pt No: CAM4004, 998cc Austin Metro Head Pt No: CAM4810, 1275cc head with Carb & single point injection Pt No: 12G9408 and NMQ-BMC (South Africa) 12G940.

There are slight variances to all of the actual castings but the same casting/Pt No: still applies.

I am still interested to see photos of the head in question.

Phil
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cyl head details.jpg
cyl head details.jpg (870.85 KiB) Viewed 2563 times

sparesman
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Re: Identification of cylinder heads

Post by sparesman »

Phil
Hit wrong key. My laptop has just run out of waranty and sudenly it is not typing double leters or numbers (as you can se from this uncorected sentence) and doing al sorts of weird things plus going very slow. Rather suspicious dont you think?
Cannot easily get at the head to take photos as it is right at back of my garage and there are now several large boxes stacked in front of it as have just started a massive stock take of the club spares.Once I've finished in about 4 weeks I'll try to get at it and photo it.
Bryan
1934 Morris 10/4 in Dark Green / Black - BGO517
1953 S11 Traveller in Birch Grey - oldest survivor ? Export model now reg PPO924
1953 S11 Traveller in Black - 3rd oldest in UK PPX344
philthehill
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Re: Identification of cylinder heads

Post by philthehill »

An update to my post above:-

A variant of anti-smog head casting number 12G1316 has BL part number 38G431.

ampwhu
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Re: Identification of cylinder heads

Post by ampwhu »

I know the head here is from a 803/948, but what are the negatives of it being fitted to a 1098 block?
head.JPG
head.JPG (121.43 KiB) Viewed 2368 times
engine id.JPG
engine id.JPG (36.87 KiB) Viewed 2368 times
its on my van which has a low compression engine. the van runs fine and will sit at 60mph all day.
philthehill
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Re: Identification of cylinder heads

Post by philthehill »

Poor breathing and resulting lack of performance.
I would say a total retrograde step.
The 12G202 head was not fitted to the 1098cc engine as a design whim - the 1098cc engine needs the 12G202 head even if the engine is low compression.

ampwhu
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Re: Identification of cylinder heads

Post by ampwhu »

Arrrggghhh not what I wanted to hear. It doesn't feel underpowered and doesn't really leak oil either. I guess I need a 1098 head at some point then
philthehill
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Re: Identification of cylinder heads

Post by philthehill »

Whilst the 2A629 head will work you are not getting the best out of the engine.

ampwhu
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Re: Identification of cylinder heads

Post by ampwhu »

philthehill wrote: Sun Jan 12, 2020 2:00 pm Whilst the 2A629 head will work you are not getting the best out of the engine.
having checked my spare heads, i have a 12G202. Also a 12G940 but i guess that won't fit the 1098.
philthehill
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Re: Identification of cylinder heads

Post by philthehill »

The 940 head will fit the 1098cc engine but you do need to make sure that the exhaust valves have enough clearance between the head of the valve and the top of the block.
One way of getting around the problem of the exhaust valve hitting the top of the block is to sink the valve into the head. Use the search facility to find the details as regards clearance.

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