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PostPosted: Fri Jul 27, 2018 10:04 pm 
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998cc
998cc

Joined: Wed Jul 02, 2014 11:38 am
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Learnt something today Bought a 1100s auto block and it has all 1/4 studs where it mates to the gearbox.
Studs beat bolts every time.This is a thick flange block Vizard saying drill and tap 5/16 I dont believe this is so good.
My present build is thin flange and I left it alone .Studs are the way to go I think when performance is what you want.
Its standard bore and has the dreaded hole above the centre main.I will polish that up if it ever was an issue


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PostPosted: Fri Jul 27, 2018 10:23 pm 
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Vizard was really talking about the thin flange S blocks, it became usual to fit 5/16 bolts on race motors. Block was pretty flimsy compared to common 1275 ones.
I have never had a thick or thin flange 1100S block leak at the flange with 1/4" bolts.

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PostPosted: Sat Jul 28, 2018 7:59 am 
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848cc
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Ian_B wrote:
............ and has the dreaded hole above the centre main.I will polish that up if it ever was an issue


Can you elaborate on this please?


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PostPosted: Sat Jul 28, 2018 10:16 am 
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998cc
998cc

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Hi Ben Some, not all 1100s blocks have a hole cast in the block above the centre main.
Vizard gives mixed ideas on it and said he has seen three breakages from it.
He then says he has seen them used in race motors and never broke.
His suggestion is to smooth it all out .
My new block is thick flange, has the hole and it is an imported block with the number riveted on


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PostPosted: Sat Jul 28, 2018 10:54 am 
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848cc
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Thank you.
I have read the DV book, but probably skimmed over it as I didn't realise I had an 1100S block at the time.
I'll look to see if it has the hole before I reinstall the gearbox :)


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PostPosted: Sat Jul 28, 2018 11:43 am 
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1360cc
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Ian_B wrote:
... has the dreaded hole above the centre main.

There was discussion about the lack of reinforcing around the centre main of early Cooper S blocks in this thread. Is that what you are referring to?

viewtopic.php?f=2&t=57996

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PostPosted: Sat Jul 28, 2018 2:54 pm 
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998cc
998cc

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No they are 1100 S blocks.Most thin flange seem to not have the hole.
Rob and I looked through his many thick flange and they all had the hole.
Lincoln recently did an auto block conversion and I observed it was thick flange and no hole
My auto block is pommy cast and is thick with hole.
I reckon studs are better than Vizard drilling thin flange to 5/16


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PostPosted: Sat Jul 28, 2018 10:29 pm 
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Even the blocks without the hole have hardly any metal thickness there and it's only grey cast iron. weak in tension.
Just deburr the hole, I bet half the group Nb race Minis here have an 1100S block with the hole in it.... and they rev them to 9000 rpm or so.

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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. :mrgreen:


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PostPosted: Sun Jul 29, 2018 12:40 pm 
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998cc
998cc

Joined: Mon Jul 07, 2014 12:36 pm
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Location: Bentleigh, Melbourne
Hi doc, I have an 1100S engine in my car. Should it be able to be taken to 7000 rpm quite safely? Not that I really do, just curious. Other than being balanced (i.e. no centre strap etc) the bottom end is standard with the 1100s crank. Top end it quite modified, extensive head work, big valves, GR cam, followers, heavy duty valve springs etc.
Thanks
Mikal

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RH tank cos I needed it crossing the Nullarbor etc..


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PostPosted: Sun Jul 29, 2018 10:19 pm 
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@Mikal,
Mine goes to 8000 but the electronic limiter is now set to 7500.
7000 will be fine.

I don't run a main strap, centre caps don't break unless you buzz it to 9000+ on overrun. So Graham said.
And milling the cap flat weakens it, it is only grey cast iron not steel.
My 1412 had a strap but I shaped it to fit he standard cap. Strap was EN25 not rubbish mild steel. But really wasn't needed. So I didn't bother with the current 1360.

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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. :mrgreen:


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