Jump to content


Photo
- - - - -

Mini mystery cylinder head. (Leyland/BMC)


  • Please log in to reply
88 replies to this topic

#51 Kelpiecross

Kelpiecross
  • Member

  • 877 posts
  • Joined: October 10

Posted 19 August 2014 - 05:00

Sounds ridiculous but I think that photo is the MkII Cooper S head. The MkI head actually had slightly larger exhaust valves an the same pitch ie valves even closer together!!

Didn't the Mkll actually have slightly smaller valves compared to the Mkl? - I seem to recall that the Mkll was slightly looked down upon by Mini people.

Some of the really seriously modified racing Mkls had slightly bigger inlet valves and slightly smaller exhaust valves.

Advertisement

#52 gruntguru

gruntguru
  • Member

  • 5,304 posts
  • Joined: January 09

Posted 19 August 2014 - 07:49

As I said, MkII came out with a slightly smaller exhaust, inlet unchanged. MkI heads were slightly prone to cracking between valves.

 

Mk II heads were sometimes modified with a slighly bigger inlet for racing. To go beyond that, some folks re-pitched the valves, canted the valves etc to explore the limits of the stock casting.

 

OTOH I built a 28 psi turbocharged engine in the 70's using a 1100S (1275) head to utilise the smaller inlet (1.4") and allow a 1.4" exhaust. This equal valve head worked far better than a highly modified Cooper S head we tried on the same engine.



#53 Greg Locock

Greg Locock
  • Member

  • 4,521 posts
  • Joined: March 03

Posted 19 August 2014 - 22:49

A-M was a division of BL, I think in that timeframe, our division was JRT. They were still making the Morris Ital when the A+ was being developed, I remember one cow orker buying a new one, it had Starsky and Hutch type stripes on it!.



#54 Kelpiecross

Kelpiecross
  • Member

  • 877 posts
  • Joined: October 10

Posted 20 August 2014 - 04:16

As I said, MkII came out with a slightly smaller exhaust, inlet unchanged. MkI heads were slightly prone to cracking between valves.
 
Mk II heads were sometimes modified with a slighly bigger inlet for racing. To go beyond that, some folks re-pitched the valves, canted the valves etc to explore the limits of the stock casting.
 
OTOH I built a 28 psi turbocharged engine in the 70's using a 1100S (1275) head to utilise the smaller inlet (1.4") and allow a 1.4" exhaust. This equal valve head worked far better than a highly modified Cooper S head we tried on the same engine.


I misunderstood what you said about the exhaust valves.

#55 gruntguru

gruntguru
  • Member

  • 5,304 posts
  • Joined: January 09

Posted 20 August 2014 - 09:27

I remember one cow orker buying a new one, it had Starsky and Hutch type stripes on it!.

 

Them what orks cows 'll buy anythin.



#56 Kelpiecross

Kelpiecross
  • Member

  • 877 posts
  • Joined: October 10

Posted 20 August 2014 - 11:26


Took me all day to work out what a "cow orker" is.

#57 Greg Locock

Greg Locock
  • Member

  • 4,521 posts
  • Joined: March 03

Posted 20 August 2014 - 22:21

It's an old Usenet joke. 



#58 275 GTB-4

275 GTB-4
  • Member

  • 6,954 posts
  • Joined: February 03

Posted 21 August 2014 - 06:39

its slang for a female killer whale...

#59 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 21 August 2014 - 09:05

Something BMC themselves did on the Cooper S engines, along with much larger valves and shallower chamber.

That actually looks very nice. The only problem with grinding that wall away is you are losing compression, probably about 5cc. Though it should breathe a good deal better and no detonation grief at all. Am I right in saying those big valves are only usefull in short stroke big bore engines?



Advertisement

#60 gruntguru

gruntguru
  • Member

  • 5,304 posts
  • Joined: January 09

Posted 22 August 2014 - 00:18

Yes and that's what the Cooper S engines were, shorter stroke, bigger bore. The S head had lots of meat on the face so getting the CR up was easy - even with stock pistons.



#61 Kelpiecross

Kelpiecross
  • Member

  • 877 posts
  • Joined: October 10

Posted 22 August 2014 - 04:13


I have seen an S head with 3mm off it - but I think it needed some modification to an oilway.

#62 275 GTB-4

275 GTB-4
  • Member

  • 6,954 posts
  • Joined: February 03

Posted 22 August 2014 - 05:13

That actually looks very nice. The only problem with grinding that wall away is you are losing compression, probably about 5cc. Though it should breathe a good deal better and no detonation grief at all. Am I right in saying those big valves are only usefull in short stroke big bore engines?


When you clean up the head, of course you cc the chambers then skim the head or deck the block to adjust CR to your needs.

Big Valves, no its a physical limitation of the head design, if you stroke or offset bore (up to 1510cc?) it is in the knowledge that the head is going to be the limiting factor. Of course, smaller capacity engines work quite well with lesser valves.

Edited by 275 GTB-4, 22 August 2014 - 05:14.


#63 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 23 August 2014 - 00:38

When you clean up the head, of course you cc the chambers then skim the head or deck the block to adjust CR to your needs.

Big Valves, no its a physical limitation of the head design, if you stroke or offset bore (up to 1510cc?) it is in the knowledge that the head is going to be the limiting factor. Of course, smaller capacity engines work quite well with lesser valves.

I never like cutting the head. Makes it more flexi which is the last thing you need.And  eg 25 thou off the deck is the same as 50 thou+ off the head, That chamber is quite small still. Though I am no great fan of lumpy top pistons either. Though a small dome piston along with  a zero deck height usually gives decent comp.

 BTW some HQs in the past had over a 100 thou off the head though usually had head gasket problems. As well as chronic valve train geometry problems too. I pinged someone for shorter pushrods once, they were not happy!  In those days [on Avgas] I kept hearing about 13-1 comp engines,,, never happened. The most was about 12-1. I have done the math. And have seen dozens of those engines.

The poor sealers have to CC chambers now. And all those milled heads are on the shelf. That is why there is a shortage of red 202 heads!



#64 275 GTB-4

275 GTB-4
  • Member

  • 6,954 posts
  • Joined: February 03

Posted 23 August 2014 - 02:17

I never like cutting the head. Makes it more flexi which is the last thing you need.And  eg 25 thou off the deck is the same as 50 thou+ off the head, That chamber is quite small still. Though I am no great fan of lumpy top pistons either. Though a small dome piston along with  a zero deck height usually gives decent comp.
 BTW some HQs in the past had over a 100 thou off the head though usually had head gasket problems. As well as chronic valve train geometry problems too. I pinged someone for shorter pushrods once, they were not happy!  In those days [on Avgas] I kept hearing about 13-1 comp engines,,, never happened. The most was about 12-1. I have done the math. And have seen dozens of those engines.
The poor sealers have to CC chambers now. And all those milled heads are on the shelf. That is why there is a shortage of red 202 heads!


Lee, plenty of meat on an A Series head...

RED - had a new 1976 van, engine tuned so lean they would overheat at the end of the driveway...very high value thermostat didn't help (think I whacked a 160? 180 deg in it). Absolute lemon!

BLUE - VH Vacationer family tourer, so choked down with pollution gubbinry that they were asthmatic at the top end and wouldn't pull the skin off a rice custard in standard form.

 

Morris 1100's (I believe and stand to be corrected) initially suffered from a "heavy" piston flapping around on a "long" conrod...maybe they still do?



#65 gruntguru

gruntguru
  • Member

  • 5,304 posts
  • Joined: January 09

Posted 23 August 2014 - 08:45

Morris 1100's (I believe and stand to be corrected) initially suffered from a "heavy" piston flapping around on a "long" conrod...maybe they still do?

I think the suffering is over for most Morris 1100s. RIP.  :cry:



#66 Bloggsworth

Bloggsworth
  • Member

  • 7,470 posts
  • Joined: April 07

Posted 23 August 2014 - 15:38

Well there you go, my memory is failing me. I really did not recall them      being so tiny.

 

You or the engines?



#67 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 24 August 2014 - 00:58

Lee, plenty of meat on an A Series head...

RED - had a new 1976 van, engine tuned so lean they would overheat at the end of the driveway...very high value thermostat didn't help (think I whacked a 160? 180 deg in it). Absolute lemon!

BLUE - VH Vacationer family tourer, so choked down with pollution gubbinry that they were asthmatic at the top end and wouldn't pull the skin off a rice custard in standard form.

 

Morris 1100's (I believe and stand to be corrected) initially suffered from a "heavy" piston flapping around on a "long" conrod...maybe they still do?

Mick, 1100S is reputedly 1275? Which bore and stroke combo is it? 

 

As for the Holdens the HX engines were generally pretty bad. Poor answers to ADRs as well as some bloody awful head castings too. 

Blue VH was a bit better and generally went pretty well for the day. Though the casting flash around the guides was too very bad. Yella Terra maketed [still do I think] a very clean casting that usually made better power in speedway street stocks. Though an hour with a die grinder cleans up all the crap, if the head has not cracked before you do.

The casting and machine quality from GMH in the 70s and 80s was dreadfull. Ford was about 95% better.

My experience with BMC is simply servicing, replacing a head gasket, fixing minor leaks and sending for the auto elec to resolve a myriad of bad wiring and electrics! Pre XC Fords were near as bad!



#68 gruntguru

gruntguru
  • Member

  • 5,304 posts
  • Joined: January 09

Posted 24 August 2014 - 04:12

1100S is same bore and stroke as Cooper S 1275. Later block with no side plates, 9 stud head (10 stud + 1 bolt on Cooper S), smaller valves, milder cam, single 1.5" carb vs twin x 1.25", 63 hp vs 75. Of course a lot of the Cooper S goodies like Nimonic 80 valves, Nitrided EN40b crankshaft etc were also missing on the 1100S.



#69 275 GTB-4

275 GTB-4
  • Member

  • 6,954 posts
  • Joined: February 03

Posted 24 August 2014 - 05:56

Mick, 1100S is reputedly 1275? Which bore and stroke combo is it? 
 
As for the Holdens the HX engines were generally pretty bad. Poor answers to ADRs as well as some bloody awful head castings too. 
Blue VH was a bit better and generally went pretty well for the day. Though the casting flash around the guides was too very bad. Yella Terra maketed [still do I think] a very clean casting that usually made better power in speedway street stocks. Though an hour with a die grinder cleans up all the crap, if the head has not cracked before you do.
The casting and machine quality from GMH in the 70s and 80s was dreadfull. Ford was about 95% better.
My experience with BMC is simply servicing, replacing a head gasket, fixing minor leaks and sending for the auto elec to resolve a myriad of bad wiring and electrics! Pre XC Fords were near as bad!


1098cc (64.588 x 83.72mm) is the one I was referring to, not the 1100S that everyone found and scrapped once they had removed the 1275 (did I do that? twice? never! Oops! :-)

#70 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 26 August 2014 - 09:54

1098cc (64.588 x 83.72mm) is the one I was referring to, not the 1100S that everyone found and scrapped once they had removed the 1275 (did I do that? twice? never! Oops! :-)

20 years ago that is what happened to all 1100S. And evidently the blocks were no good for rear drive cars.



#71 Catalina Park

Catalina Park
  • Member

  • 5,713 posts
  • Joined: July 01

Posted 27 August 2014 - 03:01

Lots of them have been converted to rwd. Some even convert the long tail crank.

#72 275 GTB-4

275 GTB-4
  • Member

  • 6,954 posts
  • Joined: February 03

Posted 27 August 2014 - 07:28

Lots of them have been converted to rwd. Some even convert the long tail crank.


How do they address or machine out the East-West tendencies when you re-orient the engine North-South? I suppose they use different counterweights on the crank...instead of wedging, they might use duck bills like a platypus?

#73 Catalina Park

Catalina Park
  • Member

  • 5,713 posts
  • Joined: July 01

Posted 27 August 2014 - 09:39

How do they address or machine out the East-West tendencies when you re-orient the engine North-South? I suppose they use different counterweights on the crank...instead of wedging, they might use duck bills like a platypus?

If you hinge the bonnet sideways it will confuse the crankshaft and everything will be fine. 
With the Austin Montego they fitted the motor West-East instead of East-West so they fitted the carby backwards to compensate.
 



#74 gruntguru

gruntguru
  • Member

  • 5,304 posts
  • Joined: January 09

Posted 27 August 2014 - 10:53

Now I get it.   :drunk:  



#75 Kelpiecross

Kelpiecross
  • Member

  • 877 posts
  • Joined: October 10

Posted 27 August 2014 - 12:43


Not sure I do.

#76 Magoo

Magoo
  • Member

  • 2,487 posts
  • Joined: October 10

Posted 27 August 2014 - 21:28

Among my favorite events at the SCCA Runoffs each year were the epic battles in the GT-5 category between Doug Petersen in his front-drive Mini vs. Joe Huffaker in his rear-drive Mini. Ah, the SCCA rulebook. 



#77 JacnGille

JacnGille
  • Member

  • 1,600 posts
  • Joined: July 02

Posted 28 August 2014 - 01:23

Among my favorite events at the SCCA Runoffs each year were the epic battles in the GT-5 category between Doug Petersen in his front-drive Mini vs. Joe Huffaker in his rear-drive Mini. Ah, the SCCA rulebook. 

:up:



#78 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 29 August 2014 - 03:41

Lots of them have been converted to rwd. Some even convert the long tail crank.

Only going on what I am told. They wont bolt to a Morris Minor or A40 gearbox. 



#79 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 29 August 2014 - 03:48

Among my favorite events at the SCCA Runoffs each year were the epic battles in the GT-5 category between Doug Petersen in his front-drive Mini vs. Joe Huffaker in his rear-drive Mini. Ah, the SCCA rulebook. 

BMC made lots of rear drive Minis! Made a few twin engined ones too. With East West engines.



Advertisement

#80 Catalina Park

Catalina Park
  • Member

  • 5,713 posts
  • Joined: July 01

Posted 29 August 2014 - 07:30

BMC made lots of rear drive Minis! Made a few twin engined ones too. With East West engines.

How many rear drive Minis did BMC make? 
How many twin engined Minis did BMC make? 

Lee, you are seriously full of crap.



#81 Dipster

Dipster
  • Member

  • 216 posts
  • Joined: April 10

Posted 29 August 2014 - 07:50

And to think this all started from a mystery (still?) cylinder head!



#82 Joe Bosworth

Joe Bosworth
  • Member

  • 522 posts
  • Joined: May 05

Posted 29 August 2014 - 12:38

For sure there was at least one recorded four wheel drive Mini built; the one that John Cooper nearly killed himself in during the springtime of 1963,  In fairness to accuracy it is highly likely that BMC had precious little to do with this car's existence.  It was almost certainly the work of the Cooper Garage.  However the close working relationship of Charles and John Cooper with the management of BMC makes it quite possible that BMC knew of and was following this car's development.

 

It is also reasonably well recorded that there were several, (in the order of 10 or so), 4WD Mokes built in the UK and Oz as factory prototypes built to encourage military interest in the Moke, (without much succees of raising interest).

 

As far as rear wheel drive Mini's go it is very unlikely that even one was ever developed even for prototype purposes by the BMC factory or at least as my fading memory allows to be remembered. ;-(

 

As many low volume constructors demonstrated it is/was an easy job to place the entire front wheel drive assembly in the back of very functional sports/racing cars.  Australian builders Lolita and Nota as well as UK's Marcos come prominently to mind.  The Nota  Fang with 117 recorded as being built with BMC power is likley the most prolific.

 

Regards


Edited by Joe Bosworth, 29 August 2014 - 12:39.


#83 h4887

h4887
  • Member

  • 879 posts
  • Joined: July 04

Posted 29 August 2014 - 19:28

A rear engined Marcos?



#84 BRG

BRG
  • Member

  • 11,601 posts
  • Joined: September 99

Posted 29 August 2014 - 21:19

No such beast AFAIK.  But there are plenty of Cox GTMs which are definitely rear-Mini-engined.


Edited by BRG, 29 August 2014 - 21:19.


#85 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 29 August 2014 - 23:07

How many rear drive Minis did BMC make? 
How many twin engined Minis did BMC make? 

Lee, you are seriously full of crap.

I was being facetious. BMC did build a twin engined brick. for Rallycross? 

There has been a few rear engines ones built, and ofcourse mid engined too with all sorts of power plants for various motorsport deals. And a few as road cars too.  Which have been on various threads here and TNF



#86 Magoo

Magoo
  • Member

  • 2,487 posts
  • Joined: October 10

Posted 30 August 2014 - 00:03



BMC made lots of rear drive Minis! Made a few twin engined ones too. With East West engines.

 

Well, they didn't build this one. This is the fruit of the loins of the SCCA rulebook. Look where Joe is sitting. He's around six feet five. I don't know what that is in hands or stone or whatever you people use but he's a big fellow. 

 

 

HRce34.jpg



#87 Joe Bosworth

Joe Bosworth
  • Member

  • 522 posts
  • Joined: May 05

Posted 30 August 2014 - 04:46

h4887 responded in post #83, "A rear engined Marcos?"

 

That was in response to my post #82 Nominating Marcos as having built a rear engine Mini device. 

 

I was slightly correct in that the Marcos prototype XP62 was assuredly rear engined; the problem being that it was Corvair powered.  My apologies as my memory allowed me to mix that with the Mini Marcos for which some 1000 were built with the frant engine.  Adding to my confusion was believeiving that that one or more of the bread van Marcos' were rear engined, which none were.  All that was in an era 50 yeaqrs apst so furt5her apologies for my memory. :clap:  At least I got XP62 correct.

 

Regards



#88 Kelpiecross

Kelpiecross
  • Member

  • 877 posts
  • Joined: October 10

Posted 30 August 2014 - 05:49


I saw a rear-engined Mini in a magazine that used a Hayabusa engine/gearbox.

I am inclined to think that all the "specials" that used a Mini engine/gearbox would be incurably bum-heavy.
Another I just thought of was the "Deep Sanderson" which I think actually ran at Le mans.

#89 Lee Nicolle

Lee Nicolle
  • Member

  • 5,883 posts
  • Joined: July 08

Posted 31 August 2014 - 09:41

I saw a rear-engined Mini in a magazine that used a Hayabusa engine/gearbox.

I am inclined to think that all the "specials" that used a Mini engine/gearbox would be incurably bum-heavy.
Another I just thought of was the "Deep Sanderson" which I think actually ran at Le mans.

The problem with all front drivers, for weight distribution probably less of a problem in the back.

The ideal for a sedan is front engine [back as far as possible and a transaxle. Ahla Alfa GTV. Still practical as a car, though it still has a pile of problems. The engine speed drive shaft the biggest. Great car to drive but I never want to own one! Besides the rust!