Yesterday, I was reassembling the head for my daughters mini and the first thing I noticed was the colletts were different - 2 different shapes.

So, on closer inspection, 4 of the valves had a slight dome and the others were straight on the bottom. Umm, which ones are the exhaust valves and which are the inlet?

Then, with the different colletts, 4 of the valves finished above the valve springs while the other 4 were flush with the top. It all fits of course, it's just that I may have installed the exhaust valves where the inlet valves should be.

Cheers for the help guys

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Rod
http://smg.photobucket.com/albums/v607/Rodney/

as far as I know all the collets should be identical whether they are exhaust or inlet?? someone has done a dodgy on your head previously?

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Lillee - 1969 Morris Mini K

The inlet valves are the larger valves. Exhaust (even on hot racing motors) are smaller to stop heat build up and retention.

Is this a standard head and has it been machined ???? There is several different types of heads out there that do use different collet types but normally not on the same head. Different length valves on the same head is going to give some valve lift (rocker setting) problems.

Can you take a digital photo or two and show us

I will pm you my email if you need that for the photos

Sounds like maybe somebody has put 1275 inlets in (they are ~2mm longer and have the different collets with a narrow U shaped groove).
Very common mod. But better to machine down some 1275 exhausts to 27mm , and fit them too.
If I do this, I pack the springs up with 12mm dia flat washers and put 2mm ground steel packing plates under the rocker posts.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

In a totally coincidental and random course of events, Graham Russel pulled me over to have a look at my old 202 head that I gave him (as he needed a spare) and he mentioned to me that in the later heads, mainly clubman ones, Leyland used combination of valves. Single small/regular collet valves were used in the intake and cooper style "slot" collet valves were used on the exhaust. This was a factory thing apparently.

Sorry didn't ask him why it was so as I was not interested until I realised that cooincidently Rodney was talking about the exact same thing (well at least I think he is) on Ausmini. Thanks for your attention

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Lillee - 1969 Morris Mini K

Yes there was a changeover to the small (1275 type) collets- most late heads with the flat (not sculpted) manifold face used `em.
But, these smallbore valves were all the same length- if any are longer, they came out of a 12G940 or 12G1316 head.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hmm.... very interesting, me thinks.

Ok, I took out two of the valves and measured them and yep...had them back to front (inlets in the exhaust and so on). There is a combination of valves and the set up is exactly as Lillee says in his post - so 4 of the valves are longer than the others, with different colletts and a spring clip around the top to keep things together.

So cheers once again - I think every mini engine is different as well as the actual body of our cars......no two are the same!!

I'll post one or two pics in a few days time.

Hooroo

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Rod
http://smg.photobucket.com/albums/v607/Rodney/

The old spring clips are a waste of time really- give it a good rev and they'll finish up lying on the head...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

So, do I get rid of 'em Kev????

Cheers

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Rod
http://smg.photobucket.com/albums/v607/Rodney/

I do.
But if you really do want to keep them (eg. you're an originality tragic) squeeze them in before refitting.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Are they really necessary????

Cheers

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Rod
http://smg.photobucket.com/albums/v607/Rodney/

IMO, NO.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Then into the rubbish bin they shall go!!

Thanks Kev

Hooroo

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Rod
http://smg.photobucket.com/albums/v607/Rodney/

Hi Rod, any chance of a look-see before you put the beast together
Have you got the head on the block yet ?

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'98 Mpi Sportspack + 7 port alloy head

Hi Bob,

I'm not too far from having it finished. Of course you are welcome to come and have a gander - am doing the work at Peter's garage in Moolap.

Here's a pic of the head with the valves I was talking about



See the different colletts??? Kev, I took the pic before taking off those springs we have discussed. (Hmm...good close up picture)

Hooroo

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Rod
http://smg.photobucket.com/albums/v607/Rodney/