KiwiTR6 Posted September 5, 2016 Report Share Posted September 5, 2016 Hi All. A new member here who has been fortunate enough to purchase in the last few days a beautiful body-off restored car that has undergone a comprehensive refurbishment to a very high standard. However, one of the issues that the previous owner has encountered is poor running at low revs and similarly poor starting. The motor has been fitted with a CP camshaft and I'm aware that because this cam has more overlap than the later CR, it produces less vacuum thus requiring different spring tension in the metering unit. I'd be pleased to receive advice as to how best check the current setup and what course of action I should take if the metering unit still has the CR spring(s) etc. I'd also be interested in comments as to any adverse effects that a lead substitute may have on the injection system as the engine rebuild did not include the fitting of hardened exhaust valve seats. Quote Link to post Share on other sites
Andy Moltu Posted September 5, 2016 Report Share Posted September 5, 2016 Not sure of the exact mods to the metering unit that are required - you may benefit from having it recalibrated by one of the injection specialists - I presume you are still running the CR inlet manifolds so it won't just be a straight swap for a CP calibrated unit. (Although it will probably run pretty well on the CR metering unit) AFIK there haven't been too many reported problems with using unleaded additives on the PI system. Years ago there were concerns about the impact of the unleaded fuel itself on the metering unit - early unleaded fuel being damaging to the seals, however there are few units out there that haven't been rebuilt with viton (or other compatible seals) by now. It used to be claimed that the lead "lubricated" the metering unit rotors but time has shown this to be largely testiculation. Quote Link to post Share on other sites
Steves_TR6 Posted September 5, 2016 Report Share Posted September 5, 2016 I'd recommend you talk things over with one of the PI experts, Neil Fergussen or Prestige Injection perhaps. Go armed with as much info as possible, ie engine spec, cam, ignition, exhaust. The Lucas PI can run really well, and tends to stay 'in tune' for years once set up right and if used regularly, so its worth getting it right. Steve Quote Link to post Share on other sites
TriumphV8 Posted September 5, 2016 Report Share Posted September 5, 2016 No "normal" person would mix these items up. If there is something wrong the reason would be elsewhere. The CP has two springs, the CR has three of them. You can open the dome with the four screws and have a look. Take care not to spoil something. Most metering units I set had been treated badly before and are completely set wrong before. There are the read and green book for this injection availiable. Sometimes they pop up as a PDF-file. They are the bible to read first. Very often misbehaviour is related to air in the fuel hoses or damaged non return valves or damaged o rings in the injectors. Also a good clean of the injectors might be invisaged first. Neil does a very good job. Quote Link to post Share on other sites
John L Posted September 5, 2016 Report Share Posted September 5, 2016 I'm also interested in this topic, I would like to understand what the differences are in the metering unit of a CP original without the airbleed, and with the air bleed and what vacuum is recorded for both of these. I know there are different springs, red and silver these are in pairs, but I've never heard of three springs, which application would these be used for? Currently my CP vacuum is 12"Hg with no air bleed, how would this compare to a CP with air bleed? Then perhaps I will understand the difference in spring setups, will I need heavier springs for the higher vacuum or is it the other way round? I understand there is a third of set blue springs which I understand were fitted to the 2500 saloons. There is of course no mention in any of the Lucas books on this subject which doesn't really help. It only mentions calibration details of CP and CR MU's Any information on this subject would be gratefully received John Quote Link to post Share on other sites
k_raven_smith Posted September 5, 2016 Report Share Posted September 5, 2016 Hello all who are interested in this subject I offer a of open invention for you to give me a call on 07977001571 . I can then explain the difference between all the different types of metering units. Neil Quote Link to post Share on other sites
astontr6 Posted September 5, 2016 Report Share Posted September 5, 2016 Hi Kiwi! Take up Neil offer but make sure if you change MU/Injectors etc. that any of the 'O' Rings/ Seals are fully compatible with modern fuel formulation i.e. Viton B grade or higher. I had a very bad experience 2 to 3 years ago, where they were not! It caused me no end of aggro! Bruce. Quote Link to post Share on other sites
KiwiTR6 Posted September 5, 2016 Author Report Share Posted September 5, 2016 Thanks everyone for your comments. I'll take up Neil's offer and give him a call to discuss. Regards Gavin Quote Link to post Share on other sites
Andy Moltu Posted September 6, 2016 Report Share Posted September 6, 2016 I don't think there is any fundamental difference between the metering units for the very early CP cars and the CP cars with the air bleed screw. The air bleed makes it easier to adjust tickover -without it you have to adjust the butterflies to be minimally open to set the idle speed and as that's about a fag paper thick it's a pain. the air bleed allows the throttles to be shut at idle and then all you have to do is balance the three sets of throttle bodies. Working on the theory that the inlet manifold pressure should be the same - the air bleed should be letting in a certain amount of air to achieve a certain idle speed, the same speed achieved by adjusting the throttle bodies should do exactly the same to manifold pressure. CRs have different cams, different ignition curve, different inlet manifolds so have a metering unit that is calibrated and timed slightly differently. his is achieved by different springs and (probably) a different fuel cam and settings of the 3 rings on top of the metering unit.. Quote Link to post Share on other sites
k_raven_smith Posted September 6, 2016 Report Share Posted September 6, 2016 There is a difference between the two cp units. They are fitted with different springs and the calibration is different between the two units. Neil Quote Link to post Share on other sites
matttnz Posted September 6, 2016 Report Share Posted September 6, 2016 Hey fella-where are you? If in Aucks: There's a good garage in New Lynn for Triumphs and a bloke in Tauranga who sorts out the MUs. Plus the local TR register has some v good sources of info & parts. PM me for details if you need/want. Matt Quote Link to post Share on other sites
JohnG Posted September 6, 2016 Report Share Posted September 6, 2016 Hi All. A new member here who has been fortunate enough to purchase in the last few days a beautiful body-off restored car that has undergone a comprehensive refurbishment to a very high standard. However, one of the issues that the previous owner has encountered is poor running at low revs and similarly poor starting. The motor has been fitted with a CP camshaft and I'm aware that because this cam has more overlap than the later CR, it produces less vacuum thus requiring different spring tension in the metering unit. I'd be pleased to receive advice as to how best check the current setup and what course of action I should take if the metering unit still has the CR spring(s) etc. I'd also be interested in comments as to any adverse effects that a lead substitute may have on the injection system as the engine rebuild did not include the fitting of hardened exhaust valve seats. Kiwi Certainly take up Neils offer, he helped me in times of need. My 6 is a CP car It has a 'TR5'camshaft Manvers fitted a CR metering unit when they sorted out my poor starting and rough low revs running. Conclusion to my meanderings: Talk to them that know and be prepared to spend some money, it can be put right Quote Link to post Share on other sites
KiwiTR6 Posted September 7, 2016 Author Report Share Posted September 7, 2016 (edited) Hey fella-where are you? If in Aucks: There's a good garage in New Lynn for Triumphs and a bloke in Tauranga who sorts out the MUs. Plus the local TR register has some v good sources of info & parts. PM me for details if you need/want. Matt Hi Matt. I'm in Taranaki and I've just purchased Chris Daker's Pimento TR. I'm trying to get a handle on what might be causing the slow running problem he's been experiencing, but will not be doing anything to the injection system until such time as I've thoroughly checked out all the basics as the car is quite usable despite this issue. Also in the process of joining the local TR register and happy to PM you for details in the future as and when needed. Gavin Edited September 7, 2016 by KiwiTR6 Quote Link to post Share on other sites
matttnz Posted September 7, 2016 Report Share Posted September 7, 2016 Taranaki?-lovely. V v jealous. The Register will be a v good way of troubleshooting and hopefully can recommend a good local garage if you're not doing the work yourself. Re: lead. I squirt one of the syringes in every 2nd tank, although the boys at Hyde auto do note that at the miles it does, valve recession would take quite some time & I can fit hardened seats at that time anyway. Use 98 if you can-mine is not overly fond of 95. Also-if the poor starting is after a week or two not being driven it may be that (like mine) there's a small leak in the injector valve (?) so that fuel runs back to the MU and needs pumping back to the injector again before that cylinder catches. Apparently quite common. Quote Link to post Share on other sites
KiwiTR6 Posted September 7, 2016 Author Report Share Posted September 7, 2016 Taranaki?-lovely. V v jealous. The Register will be a v good way of troubleshooting and hopefully can recommend a good local garage if you're not doing the work yourself. Re: lead. I squirt one of the syringes in every 2nd tank, although the boys at Hyde auto do note that at the miles it does, valve recession would take quite some time & I can fit hardened seats at that time anyway. Use 98 if you can-mine is not overly fond of 95. Also-if the poor starting is after a week or two not being driven it may be that (like mine) there's a small leak in the injector valve (?) so that fuel runs back to the MU and needs pumping back to the injector again before that cylinder catches. Apparently quite common. A bit chilly here at the moment, but summer is on the way! I own a motorcycle shop here (we don't actually sell many motorcycles though - mainly quads and Jet skis) and I and my technicians all play around with cars so I'll be doing most of the the work myself. I'll try the 98 octane as you suggest although I'll have to drive out of town to get it - not too much of a hardship... I've also ordered some Valvemaster as its been around for a while, got a good inbuilt dispenser and easy to remember mix ratio. I'll also check out the injector valve tip as you suggest. Quote Link to post Share on other sites
cp7535he Posted September 7, 2016 Report Share Posted September 7, 2016 You may want to check out your distributor type they have different advance curves Your distributor number is stamped on the casing eg 41306 B 21-70 41306 is the spec and 21-70 represents the 21st week in 1970 it was made For Lucas Cr Tr distributor its 22D6 41501E The Cp Tr would be 41219 A further check with the Distributor Doc may be advantageous Quote Link to post Share on other sites
Colin White Posted September 7, 2016 Report Share Posted September 7, 2016 There are many Lucas distributor numbers - my 1974 CR TR6 distributor number is 41542B ( original distributor). Car is export model shipped to Australia. Quote Link to post Share on other sites
KiwiTR6 Posted September 7, 2016 Author Report Share Posted September 7, 2016 You may want to check out your distributor type they have different advance curves Your distributor number is stamped on the casing eg 41306 B 21-70 41306 is the spec and 21-70 represents the 21st week in 1970 it was made For Lucas Cr Tr distributor its 22D6 41501E The Cp Tr would be 41219 A further check with the Distributor Doc may be advantageous The car is running a Pertronix electronic ignition system purchased from Moss or Rimmer Bro's (not sure which) so I doubt this is likely to be the issue(s). I'll be starting with the basics and checking the pulley timing marks in relation to TDC, timing advance, cam timing etc before I do anything else. Quote Link to post Share on other sites
Guest ntc Posted September 7, 2016 Report Share Posted September 7, 2016 The car is running a Pertronix electronic ignition system purchased from Moss or Rimmer Bro's (not sure which) so I doubt this is likely to be the issue(s). Wana bet Quote Link to post Share on other sites
KiwiTR6 Posted September 7, 2016 Author Report Share Posted September 7, 2016 (edited) Wana bet Explain please?? I've read about issues with this system, but from memory it related to complete failure rather than timing advance. Edited September 7, 2016 by KiwiTR6 Quote Link to post Share on other sites
Colin White Posted September 8, 2016 Report Share Posted September 8, 2016 I believe the Pertronix electronic ignition system (and others like Lumenition which I have) just replaces the contact points but does not affect the timing advance curve which is still as set by the weights and cam inside the distributor. Different distributor model numbers dictate the different centrifugal advance curves used. (The Lucas PI system does not have a vacuum advance). If you do an archive search on the forum someone previously listed a table of the different advance settings for the various Lucas distributor numbers used on different model TR's. Sorry, I can't remember who or when it came up. By the way I lived in New Plymouth for 4 years on Maui gas back in the '70's and had 2 kids born there! Great place to live! Quote Link to post Share on other sites
KiwiTR6 Posted September 8, 2016 Author Report Share Posted September 8, 2016 Thanks for the info on the Pertronix Colin. I assumed (incorrectly it seems) that such a unit would have an inbuilt advance curve as do most of the motorcycle systems such as Boyer. I will definitely check out what you've suggested. Yes, New Plymouth is a little warmer than here being coastal, but we don't get the onshore winds that they do thankfully (can't stand the wind). Not so many months ago I was looking at bringing a TR in from Australia as they appeared to be far more plentiful there, but suddenly I had a rush of local offers and ended up spoilt for choice. I eventually purchasing the first car that I had been offered - an absolute beauty. Gavin Quote Link to post Share on other sites
Dennis Devon Group Posted September 8, 2016 Report Share Posted September 8, 2016 Hi to our friends in NZ. I lived in NZ in the 60s 70s and have a very good friend John Parker who lives at the Mount, he overhauled and set up most of the pi equipment in your home country. He recently gave up and sold all the equipment to the NZ TR register if you would like his phone number PM me, I am sure he would point you in the right direction. He and his wife are Triumph enthusiast they started the Triumph Stage club in NZ and were very involved in the TRs Dennis Quote Link to post Share on other sites
KiwiTR6 Posted September 8, 2016 Author Report Share Posted September 8, 2016 Hi Dennis. You have a PM. Quote Link to post Share on other sites
Alec Pringle Posted September 8, 2016 Report Share Posted September 8, 2016 Hi Gavin, in case you're not aware, my old pal Martin Jay, aka Distributor Doctor, adores New Zealand . . . . and would be only too happy to advise and assist you, and any other Kiwis in need, of that I am quite sure. He's well versed both in TR dissies and the vagaries of Pertronix, don't hesitate to contact him and feel free to mention I suggested it ! http://www.distributordoctor.com/ Cheers Alec Quote Link to post Share on other sites
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