Discussion
revingtosh said:
..Which Minis came with the 11 stud head and which came with the 9??
Only Minis with 11 stud heads were the Cooper S models, but the 1300GT also had an 11 stud head.revingtosh said:
...Can a 9 stud bloke be converted to an 11 stud? Or is this a big no no?
Yes, no problem all 940 heads can be drilled for the extra 2 studs.guru_1071 said:
yes
if your planning to do this fancy engine you need to buy copy of the vizard engine book. that will answer all the questions you have asked here - and probably a lot you havent even thought of
+1. It's a very, very good book. And it will teach you not only about tuning the A series, but tuning engines in general, regardless of their age or type. It doesn't just "say X and Y will net you 10bhp", it goes into depth about what different things do and how they interact, so you can decide what you want the engine to do.if your planning to do this fancy engine you need to buy copy of the vizard engine book. that will answer all the questions you have asked here - and probably a lot you havent even thought of
Yes i already have the book thanks, ive had one for some time.
I dont normally take advice from just one person though. Some of the questions ive asked on this forum are not covered in the book, and in any event its nice to discuss such an interesting topic with likeminded people! PH is certainly one of the better forums for technical advice.
I dont normally take advice from just one person though. Some of the questions ive asked on this forum are not covered in the book, and in any event its nice to discuss such an interesting topic with likeminded people! PH is certainly one of the better forums for technical advice.
All you need to go from 9 to 11 stud is an 11-stud head as a pattern to establish bolt positions. Then just drill out the head and then copy the hole positions through to the block. The extra stud hole at the LH end is 3/8" UNC and the one adjacent to the thermostsat is 5/16" UNC. You will probably (make that almost inevitably!) go through into the water jacket with the 5/16" UNC hole, but don't worry, just put a bit of black RTV sealant on the bolt threads when fitting the head and all will be well.
At 1380 cc it is advisabe to go 11-stud.
At 1380 cc it is advisabe to go 11-stud.
Cooperman said:
All you need to go from 9 to 11 stud is an 11-stud head as a pattern to establish bolt positions. Then just drill out the head and then copy the hole positions through to the block. The extra stud hole at the LH end is 3/8" UNC and the one adjacent to the thermostsat is 5/16" UNC. You will probably (make that almost inevitably!) go through into the water jacket with the 5/16" UNC hole, but don't worry, just put a bit of black RTV sealant on the bolt threads when fitting the head and all will be well.
At 1380 cc it is advisabe to go 11-stud.
Impressive stuff! I drilled the block for mine, but I wouldn't have wanted to drill a head....only lack of knowledge I hasten to add.At 1380 cc it is advisabe to go 11-stud.
Mine was a 1380cc incidentally, back in 1979.
drilling the head or the block is not advised with a hand held drill - not that ive ever done anything as daft.....
best to use a decent piller drill!!! {ahem!}
i tend to drill the stud nearest the water pump to accept the larger stud - rather than the spindly bolt, it makes better sense and is a lot stronger.
the problem with water dribble is a pain, but again, if you use a stud its not so much of an issue as it doesnt need winding out as often.
its even worse on 1071's or 970's as there is 1/4" less meat on the top, so your forced to drop the threads right to the limit to get a good bond on the block. its even possible to screw the stud (or bolt) into the block the correct amount and discover that it jams the impellor on the water pump!, again, another mistake you only make once!
with 11 studs, correctly tailed to the right length and a decent gasket (the tam1521) ive never ever had water issues or blown gaskets on any of the 1071's ive owned.
best to use a decent piller drill!!! {ahem!}
i tend to drill the stud nearest the water pump to accept the larger stud - rather than the spindly bolt, it makes better sense and is a lot stronger.
the problem with water dribble is a pain, but again, if you use a stud its not so much of an issue as it doesnt need winding out as often.
its even worse on 1071's or 970's as there is 1/4" less meat on the top, so your forced to drop the threads right to the limit to get a good bond on the block. its even possible to screw the stud (or bolt) into the block the correct amount and discover that it jams the impellor on the water pump!, again, another mistake you only make once!
with 11 studs, correctly tailed to the right length and a decent gasket (the tam1521) ive never ever had water issues or blown gaskets on any of the 1071's ive owned.
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