oldtuckunder

I agree if I was after absolute maximum gain then Webers or EFI would be the way to go, however the down side is that would bump me up a class and my target bogey times would drop to the point where any extra power delivered would be eaten and then some, hense the desire to achieve the maximum I can from the standard set up. Is also a personal challenge to see what's possible from a pair of twin CD's with the tools available these days, as as your comment indicated most people gave up on them long ago! I think there's still a few more unexploited horse power left in them. Alan

Yes I played with those, the problem is that the only place you can fit a magnet in a common place is on top of the piston damper tube, which means you can only have a circular magnet about 2mm thick and 2 mm tall otherwise they interfere with the operation of the damper, and all the magnetic contactless sensors I found require a very strong magnet pull even when the magnet is very close. I even tried flex sensors inside the chamber, the problem with those is that they have a memory and very rapidly loose their range response, well way to quickly to leave in there! I think I have all the bits now for my solution so hoping in a week or two to be able to post some logs. Alan

Nah! not since the Loon Pants in early 70's, and its embarrasing looking back at old pictures

Hi many thanks, and I did look at solutions like that which are way better than nothing, but the problem is that they completely mess up the damper action, and the most misunderstood thing about (semi)Constant Depression Carbs is the effect of the damper at snap WOT, Standing Starts and very rapid gear changes, which are the real problem areas. Setting up for cruise isn't too much of a problem. The other oft quoted falicy (even in the expert books) about the dampers is that they only have an effect on piston lift, whereas it only takes a few data logs of AFR's using different weight oils to show that is completely untrue, and how fast/far the piston falls can have a dramatic effect on transient mixtures during WOT gear changes. I can show the effects the only thing I don't know is exactly where the piston is and how fast its rising and falling, hense the desire to have a mechanism that can data log exactly what is happening all the time without affecting the operation of the carb. Alan

No not going to Spa :-( Just looking at MAP sensors, do you happen to recall what manifold vacuum ranges you were typically seeing? just seeing if I can find one that I can fit remotely and just run a short hose to the manifold, rather than fit the sensor direct into the manifold, some of the GM Vauxhall ones look like they may fit the bill. Alan

What's this traffic stuff? Fairly amazing stuff you were working on. I'm currently logging to an Innovate LM2 so apart from AFR's anything that I can generate a 0-5 volt analog signal from I can log like TPS and the piston lift sensor I'm working on. I'm assuming that you were logging manifold vacuum? what kit were you using to do it, as I may as well add it as part of the current work as it looks as though it may well be usefull. I had only got as far as wanting to know where the needle is, whereas as it seems you are on the next rung off the ladder working out the changes required to the needle! I joked to Nick at Gurston that playing with oil weights and springs and logging AFR's you can play tunes with CD carbs, and that if I knew where the needle was I thought that given a standard needle with a straight taper proved the low and high points were correct anything else in between was almost irrelevant :-) In reading your text, it keeps reminding the difference between the SU and the Stromberg in that on the SU you have that funny choke jet movement thing to factor in, I could never work out why people keep talking about needle profiles way beyond the range that the piston moves. i.e. on a 1.5" carb there are 13 1/8" dimensions, whereas in operation a 1.5" carb only moves the piston about 1&1/8th of an inch i.e. only 9 of the 13 needle positions are ever operative. Do we really think the designated choke points on an SU needle ever see use? its just that you need an awfull amount of piston lift for them to be effective, and with a cold engine that's one hell of a lot of manifold vacuum to get that amount of lift which basically means flooring the throttle on a stone cold engine? Sorry gone off track :-) Alan

Sorry I meant that a lot on this forum had switched to Petrol Injection, and thus the sub forum on Carbs didn't see much traffic My dissertation in computer science was pretty much on this before i started my PhD the other year, well on SU carbs and tuning using piston position with an SU carb against AFR. I can share most parts of the writeup with you and the Software if you want via private message. I cannot share it all as my uni was a bit funny as I signed a bit of paper that said that they owned my intellectual property so it means they wanted to market it and sell it and i said no so it sits there in a stale mate for 7 years. Did quite a bit of testing on the rolling road and it all worked very well. Using a base sequence you can them map upper and lower limits of vacuum against needle as every car is different, use then the base map to map against needle position and AFR One question though what is the PI forum? Really impressive/interesting your work on SU digital tune, and that you were using vacuum readings (from the manifold?) And I can see that with a rolling road you could map and then match to AFR's, one of the problems I have been struggling with which is why I wanted real time logging of needle position (apart from not having a rolling road) is that if you change spring rates or damper oil, where the piston is and how long it takes to get there for any given throttle opening changes (I deduce from AFR's). I have also found that how hot the carb gets can also dramatically affect its transient responses as the oil thins, I now duct air to ensure that my carbs stay as cool as possible when driving, another reason I want the oil/water heat exchanger fitted as I discovered that idling for 25 mins to get the engine oil up to temp also raised the carb body temp by 25C which completely buggered the lift response I had engineered. After the first run at MIRA I had to suck all the hot oil out the dash pots and refill them with fresh cool oil just before the next run to get things working correctly. When I've got the logging working, I'd love to contact you and see where the data between measuring lift and AFR's correlates to your data set. Alan

I know at somepoint that I need to go to 1.75" but I'm a bit perverse and want to find out what you can get from points and standard carbs, before changing. The problem with an over rich mixture is that you can get it for two reasons, either fully lifted and still too much depression sucking too much fuel out because the carbs won't flow enough air, or not enough lift causing too much depression and too rich a mixture, and as soon as your AFR's go below 11 everything goes to pot as the engine efficiency get worse and power drops, even worse on a hill as on the flat you can quite often accellerate through the problem and everything comes back into balance, especially as on the flat holding WOT for more that a second or two without needing to change up again is almost impossible. I have more springs and magic weight oils that I have tested and data logged than you can shake a stick at, and I can put together combinations that will do perfect standing starts, but go rich in mid range, or will give over rich or over lean starts, are perfect up to 4K WOT and then go off track, but with all of these I never know where that piston was and what part of the needle is in play. I'm not deperately unhappy with my current settings, but know there is a fair bit more to be gained, I also know if I upgrade the carbs I'll be back in the experimentation stage, whereas if I know what's happening it becomes more of a science than an art form. Alan

Well this forum section doesn't seem to get much traffic these days as you have all switched to PI Well as I now have the engine running again, I get a chance to pick through the data logs from a couple of recent events and can see that the age old problem of CD carbs going over rich at prolonged WOT is still lurking there. I'm data logging each carb individually for AFR's with a WB sensor in each exhaust branch, and I'm also logging TPS, but all that really tells you is what I was asking for "TPS" and what the end result is "AFR's" what you never know is where that dam air piston is and thus what position the needle is in. Now I've seen people set up video cameras to record the piston lift and then try an tie it back to a data log (but you need to remove the filters and inlet ducting to do that, and I've seen people drill holes in the carbs and drive about with the bonnet off to try and watch what happens (although not on a Vitesse, GT6 or Spitfire!). And I've also seen how a Manometer can tell you lift at one specific time point. So I have been playing with a project for a couple of years to tie exact piston lift into the data logs, in a way that it can be installed and left without affecting the operation of the carbs. Lets say I've worked on dozens of idea's and prototypes to try and find a method that would work with all types and sizes of SU and Stromberg's, and the current one I have on the bench seems to do it, but I need some scrap SU carbs to check out a few final things. So does anyone have any scrap SU's? I'm happy to pay postage. I have every size of Stromberg and HIF SU's but could do with a 1.25, 1.5 and 1.75 H and HS SU. It can be broken, chipped, damaged, it doesn't need a float bowl, or butterflies just a body, dome, piston, damper rod and cap, ideally with a spring (but not necessary). If anyone has one please PM me! Alan

Completed MIRA Sprint at the weekend, and with my hindsight hat on I think that the failures that I have been getting at Shelsley Walsh in early July each year were actually symptoms of a cause laid down at prior events. And I think MIRA might be it, now that I'm watching everything! its funny how you can look at things in a completely different way. MIRA is a Bitch of a track the sprint circuit is on the super grippy tarmac test surface, and it starts with about an 80yd straight and then a long constant radius LH semicircle that according to my data log last for about 10 secs, which I think without a properly baffled sump the oil is going to way up the RH side of the sump, this leads into another long sweeping LH and a straight where I'm reaching 80mph through the trap (the very very quick cars are reaching 106mph) and then its a very hard brake and tight RH turn that in my minds eye (without the baffling and windage tray) I can now see the oil hurtling forward and up the LH side of the block, then towards the end we have another straight where I'm reaching about 75mph going into another constant radius LH semicircle where I'm sure the same oil surge as occurs on the first bend is repeated, before the dash for the line. Now its all guess work what was happening before to the oil in the sump, and to some extent even now with all the baffling and the windage tray preventing forward surge, but I did observe at the end of one run that there was a wiff of petrol, and noticed that there was a tiny drop of petrol on the ground when I stopped. Now I have a 40ltr slab tank over the rear axle that is baffled and filled with explosafe mesh that also prevents surge, on the highest RH point of the tank I have a vent tube that then goes up in a loop and then down to below the bottom of the tank externally (the thought being if I ever roll the thing I don't want the tank emtying out through the vent. Anyway with only half a tank of fuel somewhere on the MIRA circuit there is a LH bend thats good enough to push all that fuel over to the RH side (despite baffling and filling) and on up higher than the tank so that a tiny amount got ejected through the vent tube. Extend that thought to the oil in the sump, and the fact I now know that I never had the oil warm enough, and the host of other potential oil flow restrictions I have tackled on this rebuild, and its not suprising that at an event shortly afterwards the engine has said enough is enough. Now I haven't got to Shelsley yet, but I'm far happier now that I have done my best to engineer out potential weeknesses. Finally made up the Tube so that I can fit the oil/water heat exchanger this week and get that oil up to temp quicker, will hopefuly stop the jokes about me having money to burn from fellow competitors as I have the engine running for 25 mins before the first run just to get the oil up anywhere near a working temp! Alan

Only by way of input, a couple of circuit racers who have driven my Vitesse have commented on how quick a turn in it has (which is what I actually want for hill climbs) compared to their track set up GT6's and Spitfires. I'm running 480lb front springs but the Vitesse engine has to weigh 50% more, and the original 5/8" ARB at the front, with AVO's on about mid setting, with 1deg neg front and 1.5deg neg rear and tracking parallel front and back. I do have a very firm specially set rear spring and rear camber compensator so have very little rear induced roll. I also am running an LSD this year but not sure if I can dercern any handling difference from it yet, the tight hills have yet to come! I don't do tracks (other than the odd sprint) but from what I understand from those that do, they prefer understeer which is normally induced by toe in, stiffer ARB's and springs. Autosolo's and hill climbs I think favour an oversteer set up. Alan

As it worked well in the TR7, I was wondering what is different with Ian's set up. I don't have the car here anylonger but can get info from current owner, it might be worthwhile if Ian did a schematic of the installation and I could compare.

If you can be assed to try anything more try removing the centre of the thermostat just leaving the outer ring, i.e. just slow the flow a bit. I suspect with the larger radiator you have a lot of flow through it and the engine, and thus over cooling, as an alternative remove the thermostat and put a clamp on the feed hose to the radiator and try slowly tightening it to reduce flow until you find a point that gives good results, and then just put a reducer in the hose. Alan

I was also impressed with the TR7 compared to a couple of other 2Ltrs I tried. I think getting rid of the huge viscous fan assembly helps, also makes it a lot quieter! and also the water pump itself is probably taking an odd bhp or two. NB. Running cooler (within reason is also good for power output) not quite so good I believe on fuel consumption. After trying the TR7 with one, fittting an EWP is something I have on the probable list for the Vitesse if the engine survives this season intact. Alan

Yes this one is actually an expansion tank for a small hot water boiler, rated for 10bar operation and 15bar max (both way out side any pressure I hope to see) and for continuous 99C and max 115C. Also came with a 1/2" BSP fitting so easy to plumb in. The solenoid valve is proving interesting. I knew from some prior research that most of these cheap valves are really one directional, i.e. they have a feed and supply side, and the valve will shut flow from feed but that it will allow leakage back even if shut if the pressure is higher on supply side than feed side. In hydraulic circuits one is supposed to fit a nonreturn valve on the supply side to prevent this happening, but as when its open I want the flow to be from engine (supply side) to tank in this instance it doesn't make much difference as long as when shut it holds the charge in the tank. Anyway what is interesting is that with the engine running and the valve shut, the leakage back to the tank is actually quite high, i.e. just running on tickover with the valve shut it will still charge the tank within a couple on mins, which means that even if you forget to open the valve, by default you will still find the tank charged at next start up. The valve from feed to supply side does however appear to hold good with no leakage, but the longest I have left it charged so far is about 24 hours. Alan

I had a TR7 here for 6 months last year with the DC system fitted, with I'm sure the 8020 controller. It seemed to work faultlessly We had the the pump in the bottom RH hose, and the temperature sendor in the top hose above it. There was no thermostat fitted. I think the top LH hose (that goes to the heater matrix? sorry cant quite visulise) had a T in it that went to the expansion tank. I think we set it to 80C, and it seemed to keep it on track around that, I did notice that the fan didn't cut in that often, but we weren't doing much road work with it, so it would cut in when in a queue on a hot day, or at the top of a hill after a good blast! If the fan wasn't running you could certainly here the pump running at different speeds. NB, when we had a few other wiring gremlins I temp wired the fan to a switch and had the pump wired full on, now then the engine did take an awfull long to time to heat up and barely reached 80. WHich I think sounds a bit like your problem, it the pump running flat out all the time? If I remember the controller adjusts the pump speed by adjusting the voltage to it, can you just put a meter in the feed to the pump and check the voltage, when the engine is cold the pump should only be running slowly. Alan

The temperature gauge has been an eye opener, but at least with it I know what's happening. Haven't got the oil/water heat exchanger fitted yet as I need to find a 1.5" die holder so that I can make the adaptor pipe to fit it to the remote filter head, threaded 3/4" UNF tube appears to be unobtanium so I'm going to have to make one. But have made progress on some other bits to try and make sure I don't break this engine by ommision. Fitted the adjustable pressure warning sensor today, managed to find one at 17mm dia that just fits in the machined hole on the block at the back of the engine mounting plate. Currentkly have it set at 35psi which means its just flicking when the oil is above 80C and the engine is on tickover, may just reduce it by a couple of psi so I don't get used to seeing the big red warning light I fitted on the dash top flashing, so that if it comes on in anger I really notice it! The Warning light was a bit of a disapointment I got one promised to be visible (as what good are they if they aren't?) mounted it on the dash top right in line of sight when driving, so hopefully would spot it if it ever comes on (mind you with all the other mods I'm hoping this is a completely wasted effort/expense) Now unfortunately or fortunately depending on how you look at it, after fitting the warning light I had the car out side in daylight and the for about the first time this year we had bright sunlight and it was right on to the dash top, guess what the sun picking up on the big red lense made it look as thought it was on! So magic I have a warning light that on a bright sunny day I don't know if its on or off! Solved the problem by dropping it into a black painted tube, so now I can really see if its on. Tight fit but it goes adjustable pressure switch Please excuse the spot of rust on engine bracket, I had just about every part of the car CAD plated about 35 years ago (when it was legal, and I had open access to a plating plant) but that rust stuff is tenacious and here's a coupe of shots of the mega bright warning light, one on and one off but in bright sunlight, see if you can spot the difference! Also got my version of the Acusump installed and working, something I really wanted before MIRA next weekend. I really must thank Marcus for a thread he had on the CT and TR Register Forums late last year that got me started on designing my own. Its really very simple, I have used tapping into the block just above the old oil filter position where the oil feeds to the gallery goes, put in an adaptor to 1/2" BSP, then fitted a manual check valve so I can isolate if needed, then there is the solenoid valve ( with a switch on the dash) and then a short feed to the tank. Unlike the ones that Marcus was inventively creating I went for an off the shelf item actually designed for central heating systems. It has the advantage that it has an internal nitryl bladder that in nitrogen filled, so I can preset the pressure (just like the Moroso and Acusump accumulators) and decide if I want more oil at a lower pressure or less oil at a higher pressure. And boy is it wonderfull!, turn the ignition on, flick the switch and watch the oil pressure in the gallery immediately climb to 50psi, hold for 30 secs, slowly drop to 25psi and hold for another 30 secs and then slowly fall away to nothing, all before starting the engine! ITs also fun simulating how I hope it might work when running if there was a sudden oil starvation at the pump, have the engine (and oil) hot at 80C, with the engine at tickover and oil pressure at 30ish psi, then just flick the switch and watch the oil pressure in the gallery instantly jump to 50 psi. So my intention is to turn it off before stopping the engine so that I have a load to pre-oil the engine before starting. But when competing to just leave it open so that its charged at running pressure, and if all those baffles and windage tray still don't prevent a a surge starvation, it will instantly kick in. I think all the parts came out at less than £50, and its a great toy! I hope with all the other mods its never going to do anything in competition, but its certainly going to make starting the engine after standing a much more enjoyable experience, as at the moment everytime I engage the starter I envisage #5 Big End turning without lubication and ripping the surface off the shell! The storage tank I'm using is 2ltrs, I'm currently using a pre charge of 10psi, which seems to allow it to store just over a litre of oil, or the difference between the full and low marks on the dip stick. Anyway its starting to look a bit like a plumbers nightmare under the bonnet, and the oil/water heat exchanger to come! Alan

I am in awe!

Have sent you PM about a couple of MK1 engines I know of. Alan

From the Vit6 bit I'm assuming that its a Vitesse 2ltr with the 308778 cam (which isn't actually a bad cam as Stanpart Profiles went) So also assuming that this is the original cam so may be a few years old? From your comment to Nick I'm also assuming that your not looking to open a vein in your wallet and start on the endless pursuit of power, but rather are looking for a measured improvement. Lots of the more power producing cams tend to rely on some serious improvements in the head, induction, fueling, ignition, exhaust etc, and are likely to be a disapointment. If it was me and I had a nice road 2ltr running Strombergs or SU's and just wanted a bit more oomph without breaking the bank, I'd be looking for a cam near the 308778 profile, with a reworked inlet manifold (around #2 & #5) and if you can run to it a good exhaust manifold. In my 2ltr I'm actually using a Witor CW3021 cam which is basically a 308778 with higher inlet lift. And whilst there is a lot of other work gone into the engine with that cam its just about maxing out what its possible to make with twin 1.5 Strombergs, and as I think Nick would confirm from Gurston it is on the quick side. Alan

Hense the expression "Fram here to enernity"

Thanks for the input guys, been doing some digging... Marcus sent me a link to a long tread on Mann filters on the CT site http://www.triumph.org.uk/cgi-bin/forum10/Blah.pl?m-1373532310/s-0/ And a lot of further searching led me to the conclusion that there is a lot of rerepeated regurgitated crap on the web, where a lot of people obviously believe that if something has a go faster badge on it it must be better, but there are people out there digging for answers. Found a long piece of filter investigation that has a few nuggets of useful info on an american V8 site, it is actually worth a read even though its not about Triumphs, although incorrect in some detail http://www.shoclub.com/lubrication-oil/lubrication-oilpart1.htm Anyway by the start of today, I felt I had learnt a lot, but also had been subject to a bunch of myth and misinformation, like the popular and much repeat factoid that if an engine is moving 2gals per min at 1k rpm then at 6K rpm it was pumping 12gals per min and thus the oil in your sump was being completely recycled every 17 secs and that oil filters spend a huge amount of time with their relief valve open circulating dirty oil, both of which it seems many recount as gospel all over the place. Now I may be a novice in the field of oil filtration but I know when something just doesn't make sense. So I decided I needed to talk to someone who made filters, to help me sort out fact from myth and help me choose a good filter for my application. So as I have a Mann filter fitted, and they seem to generally have a reputation for making good filters, both under their own brand and for OEM supply. They don't publish any technical contact details or services on the web, so I just phoned the main number and said could I speak to someone in Technical Support about oil filters. Got bounced through a couple of people, who as soon as I asked any questions said they would pass me on to someone better qualified, until someone said Ah you need to speak to Fred, but he's in a meeting I'll get him to call you back. An hour later I get a call from Fred! Who turns out to be quite senior and appologises that rest of the technical team are out at some event. Start explaining why I was calling, background to my problems, half expecting at some point to be told to go away, but no Fred in interested and as I find out also involved in motorsport. Ok as Nick and flatter4 have pointed out pressure relief valves only work on differential pressure, when do they cut in? cold thick oil, blocked filter, are they open at high revs, very very unlikely unless the main system pressure relief valve is faulty, or there is a sudden loss of pressure downstream of the filter. A new filter is the best filter? No the best filter is one that getting towards the end of the expected service interval when the oil and filter are due to be replaced. A filter is designed to become more efficient as it becomes slightly clogged, i.e. as the oil gets dirtier towards the end of the planned service interval the filter actual starts hitting its maximum efficiency at cleaning the oil. Then the oil and filter get changed, the oil is nice and clean and the filter is actually working below maximum efficiency, but it not as important as the oil is clean. Serious recommendation to me given limited mileage, change the oil by all means if you think you have been working it hard, but don't change the filter! in fact given a total mileage of under 1K per annum, seriously think about keeping the same filter for two seasons! An engine running at 6K rpm could be pumping 12gals per min through the filter? Ah that old chestnut! In theory given a displacement pump yes! but as the pressure relief valve post pump and pre filter will have opened way earlier, flows like that through a filter are complete myth, a correctly sized filter when clean or in fact within its designed service life (i.e. getting dirty) will easily flow more hot/warm oil than pums will throw at them without opening their own internal relief valve. A bigger filter is a better filter? Yes within reason in that when the oil is cool/cold a bigger filter will flow more oil without opening its relief valve if you gun it, but your not going to do that anymore are you? not know you know about getting oil up to temp before working it hard! and also remember that a bigger clean filter isn't as efficient as it will be when its starts getting dirty, and a bigger filter is going to take longer to get dirty! Drain back valves do you need them? do they restrict flow? Virtually no restriction on flow circa 1%, if you have a filter that's hanging vertically then they aren't going to do anything, any other orientation yes you need them! Do you need a pressure relief valve in a filter? Yes unless the oil system in the car is fitted with a filter bypass that in effect does the same thing. i.e. the oil Triumph Canister with replaceable filter had its own inbuilt oil bypass, replace that with a spin on filter head and filter without a pressure relief valve and the filter could be toast on the first cold oil start up, like the first one when you change the oil and filter! Anyway with help have now sized a filter that should meet my requirements and installation, and which if I can keep my nerve may do two seasons (somehow I think the little doubt gremlin will creep in before then) Oh and of course there's the huge hurdle of not blowing the engine halfway through the first season to overcome. But at least I think I understand a little more! Alan

Just going through the Mann Filter Catalogue, well actually using the online one which is a bit of a pain as you need to specify a make model then it will tell you all about the filter, whereas I really want to search on size, thread, anti drain back etc. as I'm trying to find one that will fit the oil/water heat exchanger. Anyway I'm getting puzzled, most of the filters I look at which according to Mann meet/exceed OEM requirements, they all have inbuilt pressure relief valves but they all have setting like 1-1.5bar which means at 20psi or below these filters start sending un filtered oil to the engine! I thought the idea of a pressure relief valve in a filter was to start diverting oil if the filter starts getting clogged, not to start diverting if the engine is running hard and putting out 50-75 psi. I'm assuming that 20psi at the filter roughly equates to 20psi in the oil gallery Or am I being stupid? Alan

Many thanks, just what I needed to know! Alan

Hi Anyone got a Vitesse/GT6 or I suspect most straight Triumph Water Pump Housing lying around they could take a look at for me? Looking at fitting the oil/water heat exchanger and the best place to take the water feed from is from either the inlet manifold to pump feed or return circuit. I was wondering if I could swop the manifold feed pipe and the temp sender around i.e. side to side, know I may need an adaptor or to tap the housing to do it, but before I pulled it off a running engine I wanted to check that the manifold feed pipe and the temp sender are actually in the same chamber in the housing, I'm fairly certain they are, but confirmation would be good. Alan