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12G940 Head - Does It Have Unleaded Seats Already?

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#1 ajperry

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Posted 05 March 2019 - 02:02 PM

Hi all, undertaking my first engine re-build and I have a 12G940 head. it came on a metro 1275 A+ block so was originally thinking it was leaded fueling and needed to be modified for unleaded fuel but looking at my valve seats I think it's already been converted?

Could I get some second opinions?

Thanks

Perry

 

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#2 nicklouse

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Posted 05 March 2019 - 02:33 PM

my thoughts are no it has not got any insets.



#3 KTS

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Posted 05 March 2019 - 02:35 PM

hard to tell from the photos.  the hardened seats are essentially steel sleeves pressed into the head, so if you run your finger around the underside of the valve seat it you should be able to feel a uniform flat surface all the way round.  compare to what the underside of the inlet valve seat feels like - should be noticeably different if inserts fitted



#4 Moke Spider

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Posted 05 March 2019 - 03:47 PM

It doesn't look like it has Inserts.



#5 absx2

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Posted 05 March 2019 - 07:10 PM

Just use a scriber or something sharp to attempt to scratch the seat, on a hardened insert it will just glide over the top whereas with cast it will dig in.



#6 wile e coyote

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Posted 05 March 2019 - 07:30 PM

Agree - although would concede its hard to tell from a photo - factory inserts trickier to spot than retrofitted ones which are only totally necessary on the exhaust valves....give it a very good clean up and we may all be surprised

 

The only guaranteed factory identification "giveaway" UL heads were the 12G940B from the Spi or the MPI head that has a machined section between thermostat and plug no 1.....



#7 JonnyAlpha

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Posted 05 March 2019 - 08:46 PM

I have been researching refurbishing my salvaged MG Metro Engine and came across a post that suggested that unleaded inserts were fitted to all A+ post 1986. My engine is from a 1988/89 car and on showing the machine shop (a wise old fella) my head he reckoned that it was still leaded.

 

He also said that as there was so little metal available he would not be prepared to fit inserts due to the possibility of cracking the point between the inlet and exhaust valve.

 

Here is a pic of mine and the valves are pretty tight (almost overlapping :-) )

 

zcSqfq6.jpg



#8 ajperry

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Posted 05 March 2019 - 10:04 PM

Thanks all for your answers. I’ll give it a good clean and have a feel... ooer.

It’s defintely not a 940B as it’s flat all the way across the top by the thermostat and it’s not an MG metro head as the valves are standard 33 and 29 so I’ve got a bit more room to play with if I need the inserts. I’ll report back.
Also recommendations and contact details for anyone doing good head machining appreciated. I live in Berkshire but happy to travel a bit for the right person.
Thanks!

Edited by ajperry, 05 March 2019 - 10:11 PM.


#9 cal844

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Posted 05 March 2019 - 10:36 PM

Turbo Phil is in Cumbria and does very high quality work, as does AC Dodd

Both on this forum and I'd expect either to reply soon

#10 wile e coyote

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Posted 05 March 2019 - 11:11 PM

or Rob Walker Engineering in Witney isn't too far from you....



#11 DeadSquare

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Posted 07 March 2019 - 09:44 AM

I'm sorry Mr. Perry, there are no exhaust inserts in cider your cylinder head.



#12 ajperry

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Posted 07 March 2019 - 01:50 PM

Thanks all for the recommendations. Agree with all previous and DeadSquare that it's not got any inserts.

Now shopping around for head work. Case closed!  :D







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