mr fixit Posted August 4, 2016 Report Share Posted August 4, 2016 AS I've been learning my way round the new 6 I have noticed that i have a CP engine but with a CF injection system (4 balance tubes). Would this make any difference?? If so I'll be looking for a new inlet/injections so any ideas as to where I might get one ? The other thing I was thinking about was going onto Carbs again thoughts please? Nick Quote Link to post Share on other sites
Bodiam Posted August 4, 2016 Report Share Posted August 4, 2016 Hi, Nick, I think you will find the 4 balance pipes identify a CR PI system. I too have a CP block with heaven knows what head and CR throttle bodies. I raised the same question as you on the forum some time ago. The general consensus at the time was that the gain from changing to CP throttle bodies was unlikely to be noticeable for normal road use (I believe the shape of the ports is different, circular on a CP and squarish on a CR). As regards changing to carbs, I guess they may be easier to balance and maintain but the PI models seem more desirable and so your resale value may suffer. Having said that, once a PI is well set up, it seems to stay that way so worth putting in the effort. Good luck with your new car, lots of help on here as I have found! John Quote Link to post Share on other sites
mr fixit Posted August 4, 2016 Author Report Share Posted August 4, 2016 https://www.dropbox.com/s/rjltfz4v2xfjgqc/2016-07-06%2010.44.04-1.jpg?dl=0 PIC FYI Looking at a red rotor and a recon Dizzy from the DD as well as some new plugs so lets see what that brings! Quote Link to post Share on other sites
Bodiam Posted August 4, 2016 Report Share Posted August 4, 2016 Nick, Judging by the heater flap, your car appears to be a CP series, which should normally have only single balance tubes on the throttle bodies, as I understand it. Seems very odd that someone would fit CR throttle bodies, with that awful throttle linkage. DD very good choice for anything associated with distributors - Martin was very helpful to me when my car was running like a bag of nails, he found that, although my engine had been changed for a CP, the dissy was still a CR, so the centrifugal advance was way out. John Quote Link to post Share on other sites
mr fixit Posted August 4, 2016 Author Report Share Posted August 4, 2016 Thanks Dizzy will be off to him in a few days! I changed the plugs tonight and found that the three nearest the bulk head were really sooty while the other three looked correct . Ideas or is this the butterflies out Nick Quote Link to post Share on other sites
Ragtag Posted August 4, 2016 Report Share Posted August 4, 2016 It isn't unheard of for the rear two plugs to soot up,(I'm assuming it is soot, not oil) something to do with the Plenum design starving them of sufficient air. Some people have constructed larger diameter Plenums to solve the problem and others run with a grade hotter plug in 5 and 6. Quote Link to post Share on other sites
TriumphV8 Posted August 5, 2016 Report Share Posted August 5, 2016 Two balance lines instead of one give better sync even with slightly incorrect butterflies setup. On the other hand idle with hotter cams suffers. Thats the biggest difference, the rest is a myth. Both need proper bearings for the spindle without any play. Disadvantage of the CR is that the "signal" is guided through the spindles and play adds up and the left body suffers most from that. Giving up and swap back to carbs is quite bad because you loose power and fun. That is not noticed from all who did so because a well set carb system outperforms a rotten PI system. All the brain should not be put into carb swap or swap to another PI system but refurbish of manifolds with ball bearings and proper setup of MU with wideband Lambda. Quote Link to post Share on other sites
Chilp3 Posted August 5, 2016 Report Share Posted August 5, 2016 Nick It is possible to have your CR bodies modified with CP shafts. This will allow you to fit an after-market CP throttle linkage kit either overhead or underslung depending upon which exhaust manifold you have fitted. I have this set-up fitted to my CR TR6 with the Revington CP throttle linkage. They also offer parts to allow you to connect the original 'double cam' throttle opening mechanism which will compensate for the sometimes 'snappy' throttle created by the higher vacuum from the CR cam. I have personally experienced difficulties setting all of this up which is probably due to me rather than the parts. I have my car booked in next week with Revington TR to hopefully sort the issues once and for all. Best regards, Peter Quote Link to post Share on other sites
mr fixit Posted August 5, 2016 Author Report Share Posted August 5, 2016 Plan so for is to get the Dizzy sorted through DD, I have new plugs fitted 9need to see what delta this makes) and will change the fuel just to be sure. I have found a CP inlet so was going to get this and refurbish!. I also have electronic ignition but the dizzy has the VA so i don't know what the set up should be as the VA is not connected (assuming the electronics sorts that 0 so now that I have a nice new shiney timing light will have a go. Could somebody give me an idea of what the start point for timing would be with the Electronics? Nick Quote Link to post Share on other sites
Peter Cobbold Posted August 5, 2016 Report Share Posted August 5, 2016 (edited) Nick, The rich rears are caused by the rear butterflies not opening fully due to slop in the linkage, as Andreas says. The fuel squirts are OK, the air flow too little. The PI has to run rich to avoid pinking upon suddenly flooring the throttle, due to lack of a throttle pump. So leaning for cruise was not possible and so the vac advance was never used either, from the factory. Slide 100 gives the stock curve and a modifed curve that a professional motor engineer devised, and which allows running on 95RON without pinking upon wot. https://supertrarged.wordpress.com/2016/07/21/iwe-2016-technical-seminar/ Peter Edited August 5, 2016 by Peter Cobbold Quote Link to post Share on other sites
peejay4A Posted August 5, 2016 Report Share Posted August 5, 2016 If you're asking what the static ignition timing should be then you should start at 11 degrees BTDC. Quote Link to post Share on other sites
mr fixit Posted August 6, 2016 Author Report Share Posted August 6, 2016 well set the timing as it was out at 11-12 degrees and its better but still rough, idle now at 800 ish so Ok. She also has a tank of 98 ron now (well half)!! I have noticed some slack across the butterflies so that's next to look as as I need to sort out the sooty plug element. During the setting up we noticed that she really smoothed off at some 18 degrees advance;- could this be right with the electronics? Is there any adjustment to the fueling though the metering as i probably need to get my head round this next. Nick Quote Link to post Share on other sites
TriumphV8 Posted August 6, 2016 Report Share Posted August 6, 2016 Nick before you investigate in the wrong direction you should check that 18 degrees are really 18 degrees. Will say check the timing mark for TDC to be correct. 11 to 12 degrees idle advance is only correct if the rpm advance is in proper order. You should check that, too to achieve about 30 degrees advance at 3000 rpm or higher. Quote Link to post Share on other sites
peejay4A Posted August 6, 2016 Report Share Posted August 6, 2016 (edited) +1. 18 degrees at what RPM? If it's at idle and your pulley TDC mark is correct then I'd expect it to be pinking under the slightest throttle opening under load. Edited August 6, 2016 by peejay4A Quote Link to post Share on other sites
Peter Cobbold Posted August 6, 2016 Report Share Posted August 6, 2016 18deg BTDC static would be good for a late-USA head with 8.5 or lower compression ratio. Could the head have been changed ? Quote Link to post Share on other sites
mr fixit Posted August 7, 2016 Author Report Share Posted August 7, 2016 Given that I have a CR intake I suppose that could be the case although the engine number is definitely CP (CP53949HF);-, how would I know which head I have ? Nick Quote Link to post Share on other sites
mr fixit Posted August 7, 2016 Author Report Share Posted August 7, 2016 Juts reading some of the other comments;- RPM was at around 800. I will check the pulley set up and the new gun means you can dial in the advance digitally so when we were mucking about moved it further back, Will check the pulley and that shortly and there is an initial set up where you set the gun to zero and then check the pulley is in the right place! Quote Link to post Share on other sites
Peter Cobbold Posted August 7, 2016 Report Share Posted August 7, 2016 Given that I have a CR intake I suppose that could be the case although the engine number is definitely CP (CP53949HF);-, how would I know which head I have ? Nick Nick, Measure its thickness: http://www.goodparts.com/tech_docs/TR6_Compression_Ratio.html -from the rocker cover land to the base. A convenient place is just above the engine number stamping. Peter Quote Link to post Share on other sites
Peter Cobbold Posted August 7, 2016 Report Share Posted August 7, 2016 there is an initial set up where you set the gun to zero and then check the pulley is in the right place! Cant see how that can compensate for the marks being in the wrong place. Quote Link to post Share on other sites
peejay4A Posted August 7, 2016 Report Share Posted August 7, 2016 +1 Quote Link to post Share on other sites
mr fixit Posted August 7, 2016 Author Report Share Posted August 7, 2016 Just measured the head and got 85 mm exactly (inc gasket) so this is 3.346 Inches and if i have this right from the table so looking like a lower compression engine then! Nick Quote Link to post Share on other sites
Guest ntc Posted August 7, 2016 Report Share Posted August 7, 2016 Just look at the half moon on the head , how big is that? Quote Link to post Share on other sites
Peter Cobbold Posted August 7, 2016 Report Share Posted August 7, 2016 (edited) Just measured the head and got 85 mm exactly (inc gasket) so this is 3.346 Inches and if i have this right from the table so looking like a lower compression engine then! Nick '...lower...' ????????? Head thickness minus gasket thickness would be 3.346 - 0.035 = 3.311 inches From the table for standard bore that corresponds to compression ratio around 11:1 - its off the bottom of the table. That's a very high compression ratio - the head has been heavily skimmed. If that measurement is correct than it will be very difficult to make the engine run on 97RON fuel without pinking badly. It will need serious attention to the ignition timing Best check the measurement. Peter A rough check is to examine the thickness of the flange at the bottom of the head on the disy side, seen in bottom right of this photo: http://tr6car11.bravehost.com/myPictures/FUEL%20INJECTED%20CIRCLE%20B%20HEAD.JPG Look at this flange at the rear corner. If there is say 1/8 inch of vertical edge the head may be normal. If skimmed to 11:1 there will be little vertical flange left. Edited August 7, 2016 by Peter Cobbold Quote Link to post Share on other sites
mr fixit Posted August 8, 2016 Author Report Share Posted August 8, 2016 Timing checked and assuming we have the marks right (rotation was the issue!) we now have 30 degrees advance at 3000 rpm and this results in around 18 at idle. She is running much better and little or no pinking aside from when stalled pulling up into the drive so may reduce the advance a little more. Bit more to do and fancy a 6;2;1 manifold!! Nick Quote Link to post Share on other sites
mr fixit Posted August 8, 2016 Author Report Share Posted August 8, 2016 What's the Half moon?? Quote Link to post Share on other sites
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