Andy K Posted June 5, 2007 Report Share Posted June 5, 2007 Evening all. (And good afternoon to our New World cousins). A question for you all...... Excess engine heat can be disposed of by the use of front wing vents. The rally TR4s had ducts with grilles set into them. Iain Rollo's well-modded (c/o Racetorations) TR6 (see recent TR6 forum) has ducts with louvres let into the outer wings. I sure I have seen correspondence about the inefficiency of louvres elsewhere. I also recall something somewhere about the area between the front inner and outer wings being a low pressure area aerodynamically. So if one wanted to vent hot air out of the underbonnet area, why not just open up the triangular pressed area and put a small shroud on the leading edge on the external side of the new inner wing opening to stop the water and road dirt getting in directly. On the move, it extracts actively, and whilst stationary allows convection to do the job. Also, as a bonus, avoids cutting up the outer wings. Any thoughts? Quote Link to post Share on other sites
Tom Fremont Posted June 5, 2007 Report Share Posted June 5, 2007 Hi Andy, Sounds like it might work fine, but I'm not qualified to advise w/r to where louvers might be located. Since you posted on the TR5/250 heading I would surmise this to be the model under consideration, and would urge against " customizing " the sheet metal on any of these rare examples. If your car is intended for competition use it would be best to consult specialists on this point as I haven't heard of any solid evidence/reports to confirm actual benefit from any of the various louvers I've seen , though several aficionados clearly like the appearance. Quote Link to post Share on other sites
Andy K Posted June 7, 2007 Author Report Share Posted June 7, 2007 Hi Tom. I would agree that cutting up a 5's metalwork could bring on tears, but this car is a tidy but not a concours example and I do have a heat problem with the triple Dellortos in very warm weather, particularly if the car stands in full sun after a long run (bigger problem still on mainland S. Europe). I've rerouted the fuel line away from the engine, some is in reflective tubing. The cast manifold will be going away for ceramic coatng, but this may not be enough. What I'm wondering is if attacking the inner wing only would be an adequate stragegy for losing this problematical hot air, and avoiding holes of any sort in the outer panels. I do appreciate your sentiments though! Quote Link to post Share on other sites
stuart Posted June 8, 2007 Report Share Posted June 8, 2007 (edited) Hi Tom.I would agree that cutting up a 5's metalwork could bring on tears, but this car is a tidy but not a concours example and I do have a heat problem with the triple Dellortos in very warm weather, particularly if the car stands in full sun after a long run (bigger problem still on mainland S. Europe). I've rerouted the fuel line away from the engine, some is in reflective tubing. The cast manifold will be going away for ceramic coatng, but this may not be enough. What I'm wondering is if attacking the inner wing only would be an adequate stragegy for losing this problematical hot air, and avoiding holes of any sort in the outer panels. I do appreciate your sentiments though! Andy a couple of small 12 volt Boxer type fans in the RH side of the rad shield may help to dispell a lot of the heat and fit a stainless heat shield under the carbs as well. Also if you run an electric radiator fan wire it up as per the modern cars so that it runs on after you switch off the ignition. Stuart Edited June 8, 2007 by stuart Quote Link to post Share on other sites
Andy K Posted August 30, 2007 Author Report Share Posted August 30, 2007 An update on the heat dispersal arrangements as of last week........ One ceramic coated cast manifold (c/o Camcoat) S/S downpipes lagged with thermal tape Dellortos have a Revington airbox, with 30-odd mm rampipes inside the box, cork gaskets from K&N Duct to original filter housing K&N filter within filter housing, inlet pointing at 4 o'clock looking from front No shroud around radiator, electric fan on stat and oil cooler all as before Car will now pick up fine after lengthy idling in traffic and restart after standing without the coughing etc. previously encountered. Big test will be the Italy & Greece trip, especially if the latter is still on fire in three weeks time Only problem was working out how to fit the airbox/rampipes/carbs combo. together. due to bolt access problems since I don't have a 3ft forearm to go under the assembly. Which leads to one minor grumble over the design of the airbox...I think there must be a better engineering solution to access inside and closure than just having a lid held on by eight tiny self-tappers. Finally,no holes in the wings! Quote Link to post Share on other sites
jean Posted August 30, 2007 Report Share Posted August 30, 2007 Andy, I got the same airbox on my TR6 combined with 6 EFI throttle bodies mounted on TWM manifolds, same layout as Webers/Dellortos. I was unable to reach/tighten the lower bolts in the box under the trumpets, wonder who designed such a mess In addition I worked a whole day on the box to give it an acceptable appearance, completely de-polished it with a soft rotating wire brush. The next step will be to apply some isolation material as it heats up like hell. If you have a look at the TWMinduction website you will see that they now produce a fantastic carbon airbox for the 6 cyl the downside is the price Quote Link to post Share on other sites
JohnC Posted August 30, 2007 Report Share Posted August 30, 2007 <snip>No shroud around radiator, electric fan on stat and oil cooler all as before <snip> I know you're trying to solve underbonnet heat, but removing the shroud really reduces the effectiveness of the radiator. Just something to bear in mind if you're planning to drive around in hot weather... Cheers, John Quote Link to post Share on other sites
Iain Rollo Posted August 30, 2007 Report Share Posted August 30, 2007 Hi Tom.I would agree that cutting up a 5's metalwork could bring on tears, but this car is a tidy but not a concours example and I do have a heat problem with the triple Dellortos in very warm weather, particularly if the car stands in full sun after a long run (bigger problem still on mainland S. Europe). I've rerouted the fuel line away from the engine, some is in reflective tubing. The cast manifold will be going away for ceramic coatng, but this may not be enough. What I'm wondering is if attacking the inner wing only would be an adequate stragegy for losing this problematical hot air, and avoiding holes of any sort in the outer panels. I do appreciate your sentiments though! Hi Andy. I think that you will need to go right through to the outside as with my car to get any reasonable flow. What you need to do is to create an eductor effect and this is caused by the flow of air over the openings, louvres in my case, which causes a low pressure area to develop and thereby encouraging the flow to the outside. For sure without the radiator shroud fitted the flow of air will tend to go around the rad rather than through it thus reducing the efficiency of the heat exchange. It's a moot point as to how effective the ducts are for cooling and if I'm honest when I was designing my car I decided on louvres because I really liked the looks of them. However having decided that that was what I wanted they were then engineered to be as effective as possible. I suspect that I will have made a greater contribution to cutting down under bonnet heat by the recent fitment of roller rockers as the reduction of friction that these give over the standard design should lead to quite a lot less heat generation. BTW I'm sure everyone is well aware that Racetorations built my car. I commissioned them for a reason. They were able to bring far more skill and experience of building the sort of car I had designed and commissioned than I could ever hope to do. The last thing I would want is to be hammering into Mansfield to find the suspension give way or some such because some numpty (me) didn't torque up something correctly or something similar. In my proffesional capacity I design process plants and then I do the start-up and commissioning. I hand over the building to guys that know that end of the business inside out. Same deal with the car. Also given my working pattern it meant that the car was able to be driven and enjoyed while I was still of an age to be able to get in and out of it without the aid of one of those hoist contraptions that some unfortunates use to get in and out of the bath. I am however considering one for fitment into the garage for later years The road test finally appeared in this months Octane and I'm pleased to say found in favour of my car over the Talisman (just) based on the more standard appearance of mine even though the Talisman has a bit more grunt. Wish I'd asked for another 50 ponies now Some buggers are just never satisfied, actually I am, very, picked it up again today and had a very enjoyable couple of hours on the way home, lovely weather lid down.....perfek. Iain. Quote Link to post Share on other sites
North London Mike Posted August 31, 2007 Report Share Posted August 31, 2007 Andy a couple of small 12 volt Boxer type fans in the RH side of the rad shield may help to dispell a lot of the heat and fit a stainless heat shield under the carbs as well. Also if you run an electric radiator fan wire it up as per the modern cars so that it runs on after you switch off the ignition.Stuart Andy Ref Stuart's last point, Manvers set up my elec. fan to run on as Stuart suggests, and, as mine has the wing vents as per the works cars, this has the effect of pushing the heat soak air out of the engine bay. Stand by the car and you can feel the hot air pouring out, wouldn't like to think of it sitting there cooking the engine and carbs . Runs on for about 3-4 minutes much to the ammusement of the lads down at the Royal Oak who think the switch is U/S Works for me though as she starts on the button even on very hot days and stays in the zone whilst running Quote Link to post Share on other sites
Andy Moltu Posted August 31, 2007 Report Share Posted August 31, 2007 I'm not convinced the use of roller rockers makes that much difference to the overall heat generated by the engine. (I've played with them on & of for 10 years and found no real difference & it's hard to see why the reduced friction on the tip of the valve stem cam make that much difference. Yes it does help to reduce loading on the valve guides to an extent however there is debate as to whether the bearing between the rocker shaft and the rocker arm truly benefits from being on needle rollers as against the standard where they run on a film of oil similar to the way the crankshaft bearings do. (Indeed may makes of roller rockers only have the roller on the tip. Compared with the heat generated by the combustion process the rockers must be insignificant. Quote Link to post Share on other sites
Tom Fremont Posted August 31, 2007 Report Share Posted August 31, 2007 Andy, I got the same airbox on my TR6 combined with 6 EFI throttle bodies mounted on TWM manifolds, same layout as Webers/Dellortos.I was unable to reach/tighten the lower bolts in the box under the trumpets, wonder who designed such a mess In addition I worked a whole day on the box to give it an acceptable appearance, completely de-polished it with a soft rotating wire brush. The next step will be to apply some isolation material as it heats up like hell. If you have a look at the TWMinduction website you will see that they now produce a fantastic carbon airbox for the 6 cyl the downside is the price I've pondered the airbox question myself for years now; looked at the Revington box and a Racetorations example too and rejected both for technical and/or cosmetic reasons ( cosmetic being the principal motive in my case; K&N filters doing fine actually ). In the case of the early wheelarches, through '71 TR6 I think, space is lacking for a decent transition to a large bore inlet. Later cars could be done much more easily, as in GOODPARTS' triple Stromberg/S.U. airbox which won't go on the earlier cars. I may yet get a nice stainless box made per my own design, embossed with TRIUMPH letters a la the P.I. plenum but it's not a high priority. I did make allowances on the RH wheelarch on my emerging project to easily accommodate the 2-1/2" K&N filters Quote Link to post Share on other sites
Andy K Posted September 2, 2007 Author Report Share Posted September 2, 2007 I know you're trying to solve underbonnet heat, but removing the shroud really reduces the effectiveness of the radiator. Just something to bear in mind if you're planning to drive around in hot weather...Cheers, John As far as I'm aware the 5 never had a radiator shroud. The car has never had a heating problem when on the move even in very hot weather, the gauge sits fixed at six o'clock. At rest it warms up to about four-thirty (on a clock face) and then the electric blower fan cuts in to bring it down to five o'clock and cycles every couple of minutes until we're off again. I had imagned that given the main problem was cooking the carbs, letting air run over them while on the move was a good idea, and that fitting a shroud would reduce the airflow (on the move) into their area. Quote Link to post Share on other sites
Andy K Posted September 2, 2007 Author Report Share Posted September 2, 2007 Andy, I got the same airbox on my TR6 combined with 6 EFI throttle bodies mounted on TWM manifolds, same layout as Webers/Dellortos.I was unable to reach/tighten the lower bolts in the box under the trumpets, wonder who designed such a mess In addition I worked a whole day on the box to give it an acceptable appearance, completely de-polished it with a soft rotating wire brush. The next step will be to apply some isolation material as it heats up like hell. If you have a look at the TWMinduction website you will see that they now produce a fantastic carbon airbox for the 6 cyl the downside is the price I finally ground down the heads of the bolts for the lower fittings to a couple of mm, just enough to get a spanner head on and secured the trumpets off the car with those bolts.then using three NEW carb cork gaskets (from K&N, lovely people), bolted the box to the carbs using the top bolts only. The gaskets seemed thick enough, the box appears adequately sealed, and I would imagine the cork insulates the box from some of the heat transfer. The assembly seems solid enough, and I could not see any other way of doing this. I am disapponted with having to resort to this sort of bodge because of the poor original design. Also I do wonder what the airflow is like into the front rampipe, and why the engine breather inlet has to be vertical (the pipe has to be restrained somehow to prevent it rubbing the paint off the underside of the bonnet because of this position. Quote Link to post Share on other sites
Tom Fremont Posted September 4, 2007 Report Share Posted September 4, 2007 Also I do wonder what the airflow is like into the front rampipe, and why the engine breather inlet has to be vertical (the pipe has to be restrained somehow to prevent it rubbing the paint off the underside of the bonnet because of this position. Not sure if I got your post right, but conventional wisdom for the Webers is to ensure a minimum distance from the nearest surface, i.e. airbox, to the edge of the trumpet. In my case I use the 16mm trumpet and a 2-1/2" K&N filter. This is the minimum, as I understand it, and it barely fits within the RH wheelarch. With paper carb gaskets rather than MISAB rubber/aluminium seals the clearance is better. I don't believe any performance advantage is to be had from an airbox though noise and appearance could be improved... Quote Link to post Share on other sites
marvmul Posted September 4, 2007 Report Share Posted September 4, 2007 (edited) Very simple and very effective for lowering the underbonnet temperature is making an air dam by lowering the front spoiler and thus preventing the air to build up the high pressure zone under the car. When the pressure under the car is lower than the pressure at the radiator grille, the underbonnet air will escape under the car. At the same time, this will stop the lifting of the front of the car at high speed. Don't know if it is practical though : perhaps the spoiler has to reach very low? But maybe the high pressure under the car is making the wing ducts (official TR4 rally car style) rather ineffective : it is possible that these ducts are only relieving a bit the high pressure under the car... Edited September 4, 2007 by marvmul Quote Link to post Share on other sites
Andy K Posted September 7, 2007 Author Report Share Posted September 7, 2007 Not sure if I got your post right, but conventional wisdom for the Webers is to ensure a minimum distance from the nearest surface, i.e. airbox, to the edge of the trumpet. In my case I use the 16mm trumpet and a 2-1/2" K&N filter. This is the minimum, as I understand it, and it barely fits within the RH wheelarch. With paper carb gaskets rather than MISAB rubber/aluminium seals the clearance is better. I don't believe any performance advantage is to be had from an airbox though noise and appearance could be improved... The current arrangement is an effort to get cold air to the carbs principally when stationary/in slow traffic, since they do seem to warm up when hanging around in queues, and then spit and stutter as we move off. The noise with the box fitted is different from the K&Ns, but still quite nice! The box will never make the Tate Modern, though. The Revington airbox seems at least as deep as the biggest K&Ns that will fit, the K&N filtration now residing in the original filter housing. I have been given to understand that the longer the rampipe, the further down the rev range the torque appears (within reason), but also appreciate that the air needs to be able to get into the carbs! The old setup used K&Ns with the same 30-odd mm rampipes and under both arrangements the car pulls like a train from low down and onward. I assume therefore that the air is getting in OK, albeit not via the regulation clearance. Perhaps all this damp air really can get in more easily! My gripe was over the anatomy of the front of the airbox, where the exit duct gets quite close to the mouth of the front rampipe and must cause some turbulence. Finally, apparently the MISAB seals are important since they reduce fuel frothing by isolating the carbs from the engine vibration, so perhaps really shouldn't be omitted Quote Link to post Share on other sites
jean Posted September 8, 2007 Report Share Posted September 8, 2007 Andy, the Revington airbox on my 6 has 35mm rampipes and allows for a 45mm clearance in side the box. Yes the front pipe might give reason to a turbulant suction, will have to see how the nr1 plug will look. Here is my box don't know if it's the same as yours, and the DIY filter box fitting in the front grill opening infront and beside the rad Quote Link to post Share on other sites
Andy K Posted September 14, 2007 Author Report Share Posted September 14, 2007 Andy, the Revington airbox on my 6 has 35mm rampipes and allows for a 45mm clearance in side the box. Yes the front pipe might give reason to a turbulant suction, will have to see how the nr1 plug will look.Here is my box don't know if it's the same as yours, and the DIY filter box fitting in the front grill opening infront and beside the rad Jean, Hi. Yup, it's the same item, same size rampipes. It looks like you've been spot welding the rampipes on. I think there is enough space for the air to get drawn in effectively. I don't know why the breather pipe mounting has to be vertical. I do like the DIY filter box - I stuck with the original. Quote Link to post Share on other sites
Tom Fremont Posted September 14, 2007 Report Share Posted September 14, 2007 The current arrangement is an effort to get cold air to the carbs principally when stationary/in slow traffic, since they do seem to warm up when hanging around in queues, and then spit and stutter as we move off. Finally, apparently the MISAB seals are important since they reduce fuel frothing by isolating the carbs from the engine vibration, so perhaps really shouldn't be omitted Racetorations have a purpose-sourced electric fan for the idling-in-traffic mode. It's fairly recent so may not be know to many yet. Never needed it myself in 13 years of triple Weber service on a '250, but I do have the original plastic fan on mine which moves a little air at idle. The 6-cylinder engines don't seem to need vibration isolation. I did without for a while without incident. Next, I had O-ring grooves machined into the inlet manifold and employed 1/8" diameter O-rings until switching heads to the wide-spaced port style, around which time I discovered MISAB plates which just barely stuff into the space allowed. These are aboard on principle rather than proven need in my case. Quote Link to post Share on other sites
jean Posted September 15, 2007 Report Share Posted September 15, 2007 Andy, I received the box like shown, the rampipes are welded into the plate and have no bolt-ears. If they would have, it had allowed me to rotate them in order to reach the lower bolts but now I had to fix the box with screws inserted from the opposite side Quote Link to post Share on other sites
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