Interesting concept to have multiple keyways on the crankshaft duplex gear to facilitate correct camshaft timing.
http://www.ebay.co.uk/itm/BMC-Morris-Mi ... 4198c3cdbc
Interesting timing gear adjustment
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philthehill
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Re: Interesting timing gear adjustment
Surely it will weaken the sprocket quite seriously? I had one of these snap in service on a Mini... Engine was running fine - refused to restart - rockers not moving - investigation found the duplex sprocket broken and no drive to the cam.....
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philthehill
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Re: Interesting timing gear adjustment
As both chain sprockets are made from billet steel (admittedly it does not say what billet steel is used) with the crankshaft sprocket induction hardened I would suggest that the crankshaft sprocket is more than capable of transmitting the drive to the camshaft without failure.
The lands between the keyways appear to be more than the thickness of the woodruff key so they should be more than capable.
I would rather use this method of cam timing than an offset woodruff key in which the thickness/cross section of the woodruff key is reduced as the offset is increased.
bmc
Was the crankshaft sprocket that you had fail from one of these kits or was it either a modified Cooper S crankshaft sprocket or AN OTHER type/make/style?
If the postage was not so prohibitive I would give the kit a try.
Perhaps some of our Australian message board contributor's would like to comment on this product or produce any reports either good or bad on this product.
See attached link for further information.
http://www.romac.com.au/TCS.html
It is a pity that they only do the RED series for the BMC 'A' series and not the GOLD series which is better quality steel and treated to the nitride process.
As a comparison I currently use a billet steel Kent Cams vernier adjustable duplex camshaft & crankshaft sprocket which has proven to be very good though it does take some time to set the camshaft timing properly as per Kent Cams specification.
Phil
The lands between the keyways appear to be more than the thickness of the woodruff key so they should be more than capable.
I would rather use this method of cam timing than an offset woodruff key in which the thickness/cross section of the woodruff key is reduced as the offset is increased.
bmc
Was the crankshaft sprocket that you had fail from one of these kits or was it either a modified Cooper S crankshaft sprocket or AN OTHER type/make/style?
If the postage was not so prohibitive I would give the kit a try.
Perhaps some of our Australian message board contributor's would like to comment on this product or produce any reports either good or bad on this product.
See attached link for further information.
http://www.romac.com.au/TCS.html
It is a pity that they only do the RED series for the BMC 'A' series and not the GOLD series which is better quality steel and treated to the nitride process.
As a comparison I currently use a billet steel Kent Cams vernier adjustable duplex camshaft & crankshaft sprocket which has proven to be very good though it does take some time to set the camshaft timing properly as per Kent Cams specification.
Phil
Last edited by philthehill on Fri Jul 31, 2015 9:00 pm, edited 1 time in total.
Re: Interesting timing gear adjustment
The car was actually no longer mine - I had sold it - and this happened on the buyer's way home. I sent him another sprocket and it also failed.... I suspect they had over-revved it and had actually broken the crank.... Can't think of any other explanation. Both sprockets were good leyland/Rover parts. I heard no more from him. As for 'timing in' the cam - how do know what's best for your engine/your use of the car? Only extensive rolling road testing will tell you! I've checked and never found any significant variation with dot to dot set up.
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philthehill
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Re: Interesting timing gear adjustment
bmc
Many thanks for the explanation.
The Kent Cam's setting are only the base settings (but given after extensive dyno testing) - you are right in that only with extensive rolling road or road testing can the true settings be determined.
With the cam/rocker gear/decked block and well skimmed head fitted to my engine and the resulting close tolerances of the piston to valve it does not leave much room for varying the cam timing or ouch.
The beauty of the vernier adjustable cam sprocket is that you can adjust the valve timing to suit the engine build specification.
Of course with a standard specification engine there is much more opportunity to alter the cam timing as the clearances are much more.
With a re-ground camshaft it is imperative that you time the camshaft to the base settings as the re-ground cam profile may not start at the same engine degrees though some re-grinds are better than others. I personally have never used reground camshafts and Kent Cams have stopped supplying them and now only supply new billet ground cams.
A standard 'A' series according to David Vizard can benefit from advancing the cam timing by a couple of degrees. Of course the standard cam setting is for all round performance and economy and so has to balance the two requirements.
If the cam is advanced the clearance between valve and pistons must be checked/determined.
Phil
Many thanks for the explanation.
The Kent Cam's setting are only the base settings (but given after extensive dyno testing) - you are right in that only with extensive rolling road or road testing can the true settings be determined.
With the cam/rocker gear/decked block and well skimmed head fitted to my engine and the resulting close tolerances of the piston to valve it does not leave much room for varying the cam timing or ouch.
The beauty of the vernier adjustable cam sprocket is that you can adjust the valve timing to suit the engine build specification.
Of course with a standard specification engine there is much more opportunity to alter the cam timing as the clearances are much more.
With a re-ground camshaft it is imperative that you time the camshaft to the base settings as the re-ground cam profile may not start at the same engine degrees though some re-grinds are better than others. I personally have never used reground camshafts and Kent Cams have stopped supplying them and now only supply new billet ground cams.
A standard 'A' series according to David Vizard can benefit from advancing the cam timing by a couple of degrees. Of course the standard cam setting is for all round performance and economy and so has to balance the two requirements.
If the cam is advanced the clearance between valve and pistons must be checked/determined.
Phil