kiwican Posted December 9, 2021 Report Share Posted December 9, 2021 Does anyone know why the method for setting the timing changed between CP and CR models? I know the camshaft is different and the metering is as well, although I dont know what is changed in the metering unit between CP & CR (apart from the green top) The CR method would seem to delay the actuation of the injectors a little. Just curious. Thanks. Simon. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted December 10, 2021 Report Share Posted December 10, 2021 13 hours ago, kiwican said: Does anyone know why the method for setting the timing changed between CP and CR models? I know the camshaft is different and the metering is as well, although I dont know what is changed in the metering unit between CP & CR (apart from the green top) The CR method would seem to delay the actuation of the injectors a little. Just curious. Thanks. Simon. I was told it was an emissions thing. That was from an aging Triumph engineer. That does not make it correct. Quote Link to post Share on other sites
saffrontr Posted December 11, 2021 Report Share Posted December 11, 2021 The change was brought about in order for the 6 throttle PI arrangement to meet the 1972 ECE emission standards. Triumph in conjunction with Lucas had been developing a single throttle PI solution from 1969 onwards in an attempt to reduce production cost and improve the emission performance of the existing arrangement however it couldn't be made to work satisfactorily. Derek Quote Link to post Share on other sites
BlueTR3A-5EKT Posted December 11, 2021 Report Share Posted December 11, 2021 12 minutes ago, saffrontr said: The change was brought about in order for the 6 throttle PI arrangement to meet the 1972 ECE emission standards. Triumph in conjunction with Lucas had been developing a single throttle PI solution from 1969 onwards in an attempt to reduce production cost and improve the emission performance of the existing arrangement however it couldn't be made to work satisfactorily. Derek I've touched one of the single throttle PI inlet manifolds. It has TRIUMPH cast in the top. Quote Link to post Share on other sites
saffrontr Posted December 11, 2021 Report Share Posted December 11, 2021 Peter, It does seem a shame that they spent so long developing it for it to fail at the final hurdle, they even had hopes of it being used in the USA TR6 at one time. It would be good to see an image of it, someone, somewhere must have some photos. Derek Quote Link to post Share on other sites
kiwican Posted December 11, 2021 Author Report Share Posted December 11, 2021 Thank you Peter and Derek. I had only ever seen the instructions for the CP cars and was unaware of the change. A follow up question is did it work? Presumably improved emissions means improved efficiency and so better fuel economy? I know there were changes to the cam and metering unit so it might not be possible to answer this. Derek, my TR6 is also Saffron. I am not sure it is colour i would have chosen if I had bought it new but if I were to restore the car and had a choice of colors I would go back as saffron. Thanks again for the replies. Simon Quote Link to post Share on other sites
saffrontr Posted December 12, 2021 Report Share Posted December 12, 2021 Hi Simon, It was recorded in the General Managers Report for the Triumph Motor Company Board meetning of the 7th July 1972 that the 1973 PI vehicles had satisfactorily passed the compliance tests at the Dutch Testing Station and had received approval relative to Emission Standard E15 which was due to be adopted iin Europe for all cars built after 1st April 1973. From this it appears therefore that the changes made did indeed work. Good to hear that Saffron has grown on you. I've had mine since 1978 and whilst it wasn't my favourite colour at the time it is now. cheers Derek Quote Link to post Share on other sites
Waldi Posted December 12, 2021 Report Share Posted December 12, 2021 Wish mine was saffron, my first TR was. Cheers, Waldi Quote Link to post Share on other sites
Peter Cobbold Posted December 12, 2021 Report Share Posted December 12, 2021 On 12/9/2021 at 11:06 PM, kiwican said: Does anyone know why the method for setting the timing changed between CP and CR models? I know the camshaft is different and the metering is as well, although I dont know what is changed in the metering unit between CP & CR (apart from the green top) The CR method would seem to delay the actuation of the injectors a little. Just curious. Thanks. Simon. The extra delay may have been useful in minimising manifold "wall wetting" and hence the fuel octane fractionation that causes the brief pinking upon flooring the throttle. Peter Quote Link to post Share on other sites
roy53 Posted December 13, 2021 Report Share Posted December 13, 2021 What is the timming for a CR car then ? Quote Link to post Share on other sites
kiwican Posted December 13, 2021 Author Report Share Posted December 13, 2021 (edited) This is the method for setting the CR cars Edited December 13, 2021 by kiwican Quote Link to post Share on other sites
roy53 Posted December 13, 2021 Report Share Posted December 13, 2021 Thank you for that . I have only dealt with CP cars and thought they would be the same as CR Quote Link to post Share on other sites
kiwican Posted December 13, 2021 Author Report Share Posted December 13, 2021 1 hour ago, roy53 said: Thank you for that . I have only dealt with CP cars and thought they would be the same as CR I did not know there was a difference either so it made me wonder why so I thought I would ask. Thanks to all. Simon Quote Link to post Share on other sites
SeanF Posted April 25, 2023 Report Share Posted April 25, 2023 I know this is an old thread, but I have a CR car which has a CP engine block fitted, but using the CR throttle bodies. I suspect that the CR metering unit has been fitted to the CP engine but am not sure. How can I tell?, and if it is a CR MU with a CP block, which timing method should I have used....and indeed would it matter which was used? I'm pretty sure I used the CP method back when I did it but can't really remember. I'm having some running issues so want to go back to first principles. Many thanks in advance. Sean Quote Link to post Share on other sites
stuart Posted April 26, 2023 Report Share Posted April 26, 2023 17 hours ago, SeanF said: I know this is an old thread, but I have a CR car which has a CP engine block fitted, but using the CR throttle bodies. I suspect that the CR metering unit has been fitted to the CP engine but am not sure. How can I tell?, and if it is a CR MU with a CP block, which timing method should I have used....and indeed would it matter which was used? I'm pretty sure I used the CP method back when I did it but can't really remember. I'm having some running issues so want to go back to first principles. Many thanks in advance. Sean Depends on what cam you have fitted. Stuart. Quote Link to post Share on other sites
SeanF Posted April 26, 2023 Report Share Posted April 26, 2023 10 minutes ago, stuart said: Depends on what cam you have fitted. Stuart. Hi Stuart, thanks for this. I realise I should have included more info. I have a standard CP cam and had the dizzy converted to CP my Martin Jay. Also had the pump, MU and injectors refurbed by Neil F with him aware that it was a CP block using the CR throttle bodies so all should be good from that perspective. I just wanted to know whether I should have timed the MU for CP or CR and I think I am talking myself into concluding that it should be timed as a CP. Is this correct? Many thanks Sean Quote Link to post Share on other sites
stuart Posted April 26, 2023 Report Share Posted April 26, 2023 20 minutes ago, SeanF said: Hi Stuart, thanks for this. I realise I should have included more info. I have a standard CP cam and had the dizzy converted to CP my Martin Jay. Also had the pump, MU and injectors refurbed by Neil F with him aware that it was a CP block using the CR throttle bodies so all should be good from that perspective. I just wanted to know whether I should have timed the MU for CP or CR and I think I am talking myself into concluding that it should be timed as a CP. Is this correct? Many thanks Sean Yep CP timing to go with the cam. Stuart. Quote Link to post Share on other sites
michaelfinnis Posted April 26, 2023 Report Share Posted April 26, 2023 21 hours ago, SeanF said: I know this is an old thread, but I have a CR car which has a CP engine block fitted, but using the CR throttle bodies. I suspect that the CR metering unit has been fitted to the CP engine but am not sure. How can I tell?, and if it is a CR MU with a CP block, which timing method should I have used....and indeed would it matter which was used? I'm pretty sure I used the CP method back when I did it but can't really remember. I'm having some running issues so want to go back to first principles. Many thanks in advance. Sean I believe CR metering units originally had green plastic caps on the top cover rather black as for the CP. They can be altered from one to the other during overhaul though, so I don’t know how reliable a guide that is. Quote Link to post Share on other sites
john.r.davies Posted April 26, 2023 Report Share Posted April 26, 2023 The green cap was for the rare altitude tolerant M/u Quote Link to post Share on other sites
astontr6 Posted April 27, 2023 Report Share Posted April 27, 2023 On 12/11/2021 at 10:14 AM, saffrontr said: Peter, It does seem a shame that they spent so long developing it for it to fail at the final hurdle, they even had hopes of it being used in the USA TR6 at one time. It would be good to see an image of it, someone, somewhere must have some photos. Derek It would never have gone to the US purely on cost grounds as per original reason and Triumph garages did not have a clue about mechanical PI. PI was stopped dead in its tracts by the Marketing Manager of JRT. USA. Bruce. Quote Link to post Share on other sites
michaelfinnis Posted April 27, 2023 Report Share Posted April 27, 2023 16 hours ago, john.r.davies said: The green cap was for the rare altitude tolerant M/u According to information in Chris Wittor, Moss, Revington books and web pages the CR cars could have green caps, no mention of colour for high altitude units. Quote Link to post Share on other sites
john.r.davies Posted April 27, 2023 Report Share Posted April 27, 2023 Oh, OK! Quote Link to post Share on other sites
saffrontr Posted April 27, 2023 Report Share Posted April 27, 2023 A digression to Sean's question but I thought worth mentioning that when introduced back in the day the green caps were originally fitted to the export and high altitude units RKC0094 and RKC0095. Subsequently it was found that the RKC0094 met the requirements for high altitude and the high altitude unit RKC0095 was dropped after only one month. The UK unit was RKC0220 and was not suitable for high altitude use. Of course any colour cap can be fitted nowadays even a red one which was fitted to the 2.5PI high altitude metering unit. Derek Quote Link to post Share on other sites
john.r.davies Posted April 27, 2023 Report Share Posted April 27, 2023 So altitude units got both Red AND Green? How high were they? Quote Link to post Share on other sites
saffrontr Posted April 28, 2023 Report Share Posted April 28, 2023 John, Somewhere I have a copy of some altitude test data but I can't locate it at present. Meanwhile attached is a Lucas document about the green cap being fitted to the European export TR6. From the start of the 1974 model at CR5049 the export and home market metering units were one and the same so that is maybe when all metering units had the green cap? Derek Quote Link to post Share on other sites
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