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Heads 9 Bolts vs 11 Bolts
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Author:  grub [ Fri Mar 25, 2005 9:05 am ]
Post subject:  Heads 9 Bolts vs 11 Bolts
This is a bit of a curiosity quesiton. :?

Often it is mentioned if a head is 11 or 9 bolts. But it is never mentioned if a block has support for the extra holes. Do the big blocks already have the extra holes but aren't used? Or are there also 11 and 9 bolt blocks?

If so, if you have a 9 bolt block, can you have the extra holes put in?

Can you bolt a 9 bolt head to a 11 bolt block? And a 11 bolt head onto a 9 hole block?

Is there any designation on the blocks that state if it is 11 or 9 bolt other than ripping the head off and having a look (i.e. engine number range)?

Cheers!!!

G
Author:  poeee [ Fri Mar 25, 2005 9:23 am ]
Post subject: 
They drill and tap the holes and stuff for the extra bolts. I'm pretty sure it's both head and block, but maybe the block already has the 2 extra holes?

My 1275 LS engine has had the 2 extra bolts put in, as they never had them when standard. I think it's common practice in some companies (Link for eg) to put the extra bolts in when recoing 1275 engines.
Author:  miniron [ Fri Mar 25, 2005 9:47 am ]
Post subject: 
8)
All Cooper 'S' blocks have the extra holes in the block. Most non 'S' 1275 blocks don't. Non 'S' 1275 blocks can be drilled and tapped to take the extra studs. No difference in non 'S' 1275 blocks (apart from A+). You don't need the fancy 'S' front bolt. Just use 2 short head studs. Front bolt on 'S' is used because front hole is drilled through into water jacket and a stud will leak water around the threads. Non 'S' block is cast slightly different in area around water pump. Non 'S' stud holes are NOT drilled into water jacket. I don't think there is any way to tell if block is allready drilled and tapped if head is on. Not sure but only non 'S' 1275 blocks with extra studs were UK cars such as MG 1300 GT? and 1275 GT?

Hope this helps
RonR
Author:  drmini in aust [ Fri Mar 25, 2005 1:53 pm ]
Post subject: 
What Ron said is 100%.
I did 2 here last week- my 1300 auto block and 1310/71's 1100S one.
But I do use the S front bolt- it makes it look kosher.. :lol:
Author:  kazjim [ Fri Mar 25, 2005 6:53 pm ]
Post subject: 
But, is the small block also cast with the ability to add 2 extra studs ?
Not that i need it yet, but maybe the next donk.....

J
Author:  drmini in aust [ Fri Mar 25, 2005 6:58 pm ]
Post subject: 
kazjim wrote:
But, is the small block also cast with the ability to add 2 extra studs ?
Not that i need it yet, but maybe the next donk.....

J

Only can do if you fit a 940 or 1316 head.. small heads won't take it. No metal there. :cry:
998/1098 block? Not sure- but probably yes. Have a peek in front & back, with the rear welch plug out.. :P
Author:  supercharged 850 [ Sat Mar 26, 2005 12:41 am ]
Post subject: 
miniron wrote:
8) Front bolt on 'S' is used because front hole is drilled through into water jacket and a stud will leak water around the threads. Non 'S' block is cast slightly different in area around water pump. Non 'S' stud holes are NOT drilled into water jacket.


Oh..... this makes me wonder where my block and head originates. The 11th stud on my thermostat end appears to go into the water jacket in the block. It is drilled closer to the spark pug face of the head, than it is to the centre of the head.

I might need to get my engine number verified / decoded :?
Author:  drmini in aust [ Sat Mar 26, 2005 5:32 am ]
Post subject: 
The holes at each end are the same distance from front of head.
:idea: Sit a 1275 gasket over the head to check- all 1275 gaskets have these 2 holes in. :wink:
Author:  Stuartminidlx [ Sat Mar 26, 2005 4:32 pm ]
Post subject: 
do u need a drill press because i have a 1300 9 bolt block and 11 head. what are the advantages of the 2 extra studs. does it reduce the chance of blowing a head gasket.
Author:  benjamin [ Sat Mar 26, 2005 5:07 pm ]
Post subject: 
Quote:
what are the advantages of the 2 extra studs. does it reduce the chance of blowing a head gasket.



id say so because of the extra studs holding it. also there would be lesss strain on the head studs which means you could tighten the head down more with less chance of streching the studs
Author:  drmini in aust [ Sat Mar 26, 2005 6:20 pm ]
Post subject: 
benjamin wrote:
Quote:
what are the advantages of the 2 extra studs. does it reduce the chance of blowing a head gasket.



id say so because of the extra studs holding it. also there would be lesss strain on the head studs which means you could tighten the head down more with less chance of streching the studs

Yes it does, so they say. :wink:
But... you need to drill and tap the holes square, or the studs will be crooked and the head won't go on.
Best to do it under a drill press or milling machine, otherwise (if in car) hire a magnetic drill stand to keep it square.
Personally, I wouldn't bother, unless the block is stripped bare, you have the gear and know what you are doing. 8)
Author:  supercharged 850 [ Sun Mar 27, 2005 11:54 pm ]
Post subject: 
Definately something that is beter done when the engine is fully stripped - think of all the metal shavings that come off the drill bit.... then drop onto your engine :shock: dont want THAT stuff dropping into a complete engine - no way
Author:  grub [ Mon Mar 28, 2005 6:55 pm ]
Post subject: 
I am going for some head work soon so I was wondering about having the extra holes done on the head for strength. The head is a 12G940 and the block is a 9F/Sa/Y which is meant to be a Mk1 Cooper S. Despite this I can't assume it has the extra holes on the block? Did other models use this block?

I am also after the "Kosher" look as mentioned by Doc.
Author:  drmini in aust [ Mon Mar 28, 2005 7:03 pm ]
Post subject: 
A 9F/Sa/Y block `should' be a Cooper S. Does the block have 2 side `tappet' covers? If so it's an S, and will have these 2 stud/bolt holes. If no side covers it's a common 1275.
I've seen all sorts of numbers on blocks.. :lol:
Author:  grub [ Mon Mar 28, 2005 7:42 pm ]
Post subject: 
Where abouts should I look for the 2 side 'tappet' covers :?:
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