I really admire and appreciate your attention to detail and meticulous preparation. We at BMC special tuning would never have drempt of doing this even on the works cars. The only time that BMC suggested machining the base of the rocker pedestals was to take 0•050" off of the bases if the longer competition tappet screws (C-AEA 692) weren't used on the race camshaft (C-AEA 648). BMC always recommend lightening the old style rockers, by the way those newer lightweight ones were introduced from engine number 9F-SA-Y 34540. Shan't comment anymore about the valve gear as I assume that you will be covering this and the tappets in later episodes. It's great to hear how our competition modifications became standard on later cars, don't forget that I left BMC in 1964!!
Thanks Tony, It is always great to have the complements of some one involved in the original production of this equipment. I am also delighted to be aforded the opertunity to work on this equipment we the level of detail they so richly deserve
Hi, just found your channel and find it extremely informative just as I'm about to rebuild and fit a 12G940 cylinder head to my 998. also I'm contemplating also fitting a pair of HS2 SU carburettors. I would be grateful on your thoughts about this modifications. Also like your description of a digital vernier caliper, as a retired toolmaker these were known as "guessing sticks" Thanks again, Keithd
Great vid paul😃, Just a quicky- if the posts are different heights, how can the shaft in the jig be perpendicular with the base? Would they not bend the shaft in the jig? 🚗🏁
@@tones61 He is skimming them to make them equal heights because he wants to machine the bases ..so when they were machined originally at the factory the important size is from the base to the centre of the spindle ..the top of the posts sits in fresh air they are just for clamping down.
Good point. He has assumed that the pedestal base to rocker shaft centre line is accurate and consistent. It isn’t and this is proved when he compares the finished overall heights after skimming. The jig should not use the pedestal base as the datum but the shaft centre. Similarly skimming the pillar faces to make them parallel does not mean they are accurately perpendicular to the shaft. Not sure what the point is for that exercise as they are just abutments for spacer springs. I think a revised jig/method is needed to get the base/centre height dimensions consistent.
I agree, the base of the post to the shaft centre is the critical dimension is it not? Other wise you will have a shaft that is not running true and therefore more likely to fail? I would correct that, not the top.
Loved this episode great to see your engineering solutions, did raise a question or two. Firstly have the beds for the rocker posts been leveled as well? And does the thin wall of the original Cooper rocker shaft allow for less heat retention, and greater oil flow at less pressure?
Yes we machined the cylinder head completely flat, regarding heat retention the oil flow through the rocker shaft seals with that. As far as the pressure and flow are concerned the oil feed passage in the head is 6mm I’d and the hole through our rocker shaft is 6.8mm there for o shaft has a higher flow capacity than the head can supply 👍 glad you enjoyed David thanks for the intrest
Hi Paul, just wondering what the dimension is for each rocker pedestal machined base to the top of a fitted rocker shaft, do you find that it varies much as when I have machined any of these pedestal's it has been one at a time inverted in a machine vice and using a rocker shaft located across the jaws to give a height datum.👍
if youre pulling the posts down with the shaft aagainst the plate are you not going to pull distortion into the bar ? SO that when youre done machining the holes for the shafts will be parallel but not in line ?
Mr. H!! JG here, as always your video is bitchun!! My train of thought was dragged to a brake question even though I now question the efficiency of the little levers bangin away under my valve cover. I was wondering ( for the fast road going mini ) what your best braking system would comprise of? OH, I run stock steel wheels with a 1293 stage 1 engine 7.5 discs and stock drums in back no booster in a 67' RHD. Sorry for the drift in thought hope all is well!
HI JG, Glad you enjoyed the video. My go to brake setup for that spec would be 7.9 twin piston Cooper S brake setup. ITs relatively in expensive and with a good set of discs and Carbon Metallic pads can be more than enough stopping power for any mini
The reason they moved the location screw, was because the unsupported END of the shaft would break off. If you were 75 years old like me, you would have had it happen to YOU.
I really admire and appreciate your attention to detail and meticulous preparation. We at BMC special tuning would never have drempt of doing this even on the works cars. The only time that BMC suggested machining the base of the rocker pedestals was to take 0•050" off of the bases if the longer competition tappet screws (C-AEA 692) weren't used on the race camshaft (C-AEA 648).
BMC always recommend lightening the old style rockers, by the way those newer lightweight ones were introduced from engine number 9F-SA-Y 34540.
Shan't comment anymore about the valve gear as I assume that you will be covering this and the tappets in later episodes.
It's great to hear how our competition modifications became standard on later cars, don't forget that I left BMC in 1964!!
Thanks Tony, It is always great to have the complements of some one involved in the original production of this equipment. I am also delighted to be aforded the opertunity to work on this equipment we the level of detail they so richly deserve
Great to watch. The attention to these details are brilliant. Role on part two (when you’re ready of course).
Thanks Mike, glad you enjoyed its on the way
Great work once again Gentlemen looking forward to part two. 👍
Thanks brother 👍
Great Video again, with usefull information. Paul.
👍👍
Thanks 👍
Hi, just found your channel and find it extremely informative just as I'm about to rebuild and fit a 12G940 cylinder head to my 998. also I'm contemplating also fitting a pair of HS2 SU carburettors. I would be grateful on your thoughts about this modifications. Also like your description of a digital vernier caliper, as a retired toolmaker these were known as "guessing sticks"
Thanks again, Keithd
Great vid paul😃,
Just a quicky- if the posts are different heights,
how can the shaft in the jig be perpendicular with the base?
Would they not bend the shaft in the jig? 🚗🏁
The centre of the holes would machined from the base of the posts the overall heights are not important .
@@jimbethpiggy why is he skimming them then?
Not sure why he's doing the posts bud?
@@tones61 He is skimming them to make them equal heights because he wants to machine the bases ..so when they were machined originally at the factory the important size is from the base to the centre of the spindle ..the top of the posts sits in fresh air they are just for clamping down.
Good point. He has assumed that the pedestal base to rocker shaft centre line is accurate and consistent. It isn’t and this is proved when he compares the finished overall heights after skimming. The jig should not use the pedestal base as the datum but the shaft centre.
Similarly skimming the pillar faces to make them parallel does not mean they are accurately perpendicular to the shaft. Not sure what the point is for that exercise as they are just abutments for spacer springs.
I think a revised jig/method is needed to get the base/centre height dimensions consistent.
I agree, the base of the post to the shaft centre is the critical dimension is it not? Other wise you will have a shaft that is not running true and therefore more likely to fail? I would correct that, not the top.
At 36.15 you are relying on a unknown surface. You should put in an axle and dial in 90 degree on that.
This content totally rocks!!! (Sorry Paul!)
Bad a bum thssssss 😂
Loved this episode great to see your engineering solutions, did raise a question or two. Firstly have the beds for the rocker posts been leveled as well? And does the thin wall of the original Cooper rocker shaft allow for less heat retention, and greater oil flow at less pressure?
Yes we machined the cylinder head completely flat, regarding heat retention the oil flow through the rocker shaft seals with that. As far as the pressure and flow are concerned the oil feed passage in the head is 6mm I’d and the hole through our rocker shaft is 6.8mm there for o shaft has a higher flow capacity than the head can supply 👍 glad you enjoyed David thanks for the intrest
Hi Paul, just wondering what the dimension is for each rocker pedestal machined base to the top of a fitted rocker shaft, do you find that it varies much as when I have machined any of these pedestal's it has been one at a time inverted in a machine vice and using a rocker shaft located across the jaws to give a height datum.👍
if youre pulling the posts down with the shaft aagainst the plate are you not going to pull distortion into the bar ? SO that when youre done machining the holes for the shafts will be parallel but not in line ?
Wondering why you chose en21 over say en24 or even en36. We call them very-nears btw
We went with EN21 in this case Jonny as it affords a better level of temper after heat treatment than the En36.
But, if the posts are different heights, is the shaft actually parallel to the fixture base, before refacing?
Yes sure is
nice vid as always now im off to my workshop lol
Thanks 👍
What was the name of the You Tube surface channel...? I'm Australai so my Irish not so good...🤣
Mr. H!! JG here, as always your video is bitchun!! My train of thought was dragged to a brake question even though I now question the efficiency of the little levers bangin away under my valve cover. I was wondering ( for the fast road going mini ) what your best braking system would comprise of? OH, I run stock steel wheels with a 1293 stage 1 engine 7.5 discs and stock drums in back no booster in a 67' RHD. Sorry for the drift in thought hope all is well!
HI JG, Glad you enjoyed the video. My go to brake setup for that spec would be 7.9 twin piston Cooper S brake setup. ITs relatively in expensive and with a good set of discs and Carbon Metallic pads can be more than enough stopping power for any mini
The reason they moved the location screw, was because the unsupported END of the shaft would break off. If you were 75 years old like me, you would have had it happen to YOU.
The engine only had 16,305 miles on it
Thanks Dude I in all fairness shows in the qulity of all the OE equipment
1st Paul 👍
Good to hear from you Paul