(18-11-2018, 06:30 PM)Michael D Wrote: Hi Michael,
What road speed are you reaching having accelerated hard in 2nd and what has it dropped to by the time you find 3rd? if the drop is significant your acceleration will be rather sluggish.
Looks a nice car.
I would also sugest your ram pipe with mesh isnt helping you much.
Paul N-M
here's an update on the SU on my Rosengart.
Yesterday at last we had some time to test drive the car with the new ALR 30 degree inlet + exhaust manifolds cum SU. ’t was some 8 degrees Centigrade but sunny so the Missus donned a warm coat and gloves to share the drive with me….. She kinda liked it. A lot
Mind you....The exhaust manifold is a bespoke item that’s not available off any shelf….
I’ll post some more pics separately hopefully showing the space they take up.
The top of the float chamber is approx 14 cms above the engine’s head.
The intake ram pipe just fits within the space underneath / inside the bonnet; it lines up more or less with the left front chassis member
We’ve measured the entire arrangement protrudes appoximately 20 to 22,5 cms ‘sideways’ from the engine block [font=system-ui, -apple-system, BlinkMacSystemFont,
Testing this was a mixed-emotion experience ; it pulls okay in 1st and 2nd (even though not quite as lively as I had hoped for) reaching revs that to my ears sounded like more or less the max advisable (fitting a small OS tachometer to the dash is one of the next jobs on the list) but when finding 3rd gear (which is still a bit of a struggle as the ‘3rd gate’ is a bit hard to find) there is a huge drop in revs and no ‘pull’ whatsoever, the car taking ages to ‘accellerate’ (i.e. Crawl) beyond the speed attained in 2nd gear.
Yes I did replenish the scuttle mounted fuel tank to over 3/4 so that should be of no influence; fuel supply should have been sufficient.
Judging by the little farts firing back now and then from the exhaust when double declutching the mixture is rich enough.. (may be a tad too rich???) No fuel pump has been fitted as yet as the one I had arranged is a bit too bulky to fit together with the Malpassi filter king cum pressure regulator as there just is not enough space under the Bonnet
So I’ll have to settle for a small Facet style 6 v pump instead. Nevertheless I’m puzzled; Is it customary with these 3 speed boxes that 3rd is such a long one that the engine will hardly pull after shifting up from 2nd or is it me losing too much momentum finding 3rd gear as the Missus so kindly suggested ….. I've had it confirmed that there's quite a gap between 2nd and 3rd but that there's nigh to no discernible acceleration in 3rd seems a bit odd... so if anyone has a spare 4 speed gearbox lingering around that 'll fit my LR4N2.... drop me a message and make me an offer I can't refuse[/font]
Paul NM.. can't answer that question as the speedo didn't work....the missus says it felt like some 50 kp/h in 2nd
and what's wrong with the ram pipe with mesh??? do you mean I should run it without a ram pipe of without mesh?
I've run similar ram pipes on my TR2 with even finer mesh and that one outran my friend's TR4 (admitted.. It had 86 mm Mahle pistons and a fast road camshaft)
Fitting mesh over the ram pipe had a significant negative effect when I tried it on an SU fitted to one of my Sevens some years ago. I imagine that effect could be overcome by adjustments to the carb and/or needle but I never bothered trying.
22-11-2018, 06:03 PM (This post was last modified: 22-11-2018, 06:10 PM by Michael D.)
Reckless Rat and Jim thanks also too.. a guesstimated 50 kp/h in 2nd is more or less 30 mp/h ain't it???
as mentioned the inline fuel pump I had was too bulky to fit together with a malpassi filter king due to lack of space under the bonnet so there's a low pressure facet type 6 volt pump on its way from Blighty...
I'll try the 'remove the spring' ghist and have a look at the throttle / butterfly opening properly as well... the car is still at my friend's workshop and he'll join me for a drive this Saturday to experience what I'm complaining about.... I want to get this cleared before fitting one of the HC heads.
Having said all this.. we had a bundle of laughs with the car in 2nd in 3rd; it steers and brakes a lot better than we had expected, the Missus was. surprised that. it was far less. bone-shaking than she had expected, had. no fear of falling out over the low cut passenger door (remembering my cornering frantics in the TR 2) so its not all gloom and doom
@Steve.... Replacing air fillters with a ram pipe gave my cars beter breathing in the past (and. indeed it asked for some mixture adjustment) but I consider running a rampipe without any mesh on rural roads through the agricultural shores like were the Missus and I live nowadays unwise.
(22-11-2018, 05:47 PM)Michael D Wrote: Paul NM.. can't answer that question as the speedo didn't work....the missus says it felt like some 50 kp/h in 2nd
and what's wrong with the ram pipe with mesh??? do you mean I should run it without a ram pipe of without mesh?
I've run similar ram pipes on my TR2 with even finer mesh and that one outran my friend's TR4 (admitted.. It had 86 mm Mahle pistons and a fast road camshaft)
Yes and what did the speed drop to by the time you found 3rd? That could be the issue with your sluggish 3rd gear pick up.
Re the ram pipe. Nothing wrong with a ram pipe but any benefit will be severely comprimised by the mesh restricting and also disturbing the air flow.
Best to fit a pipe of good proven design with no filter, which will let in dust etc, or put a filter sock over it if you have concerns about FOD. The quickest way to set up the carb properly on a rolling road.
Paul
Carb checks- too thick an oil in the in damper will cause poor acceleration use 3in1 oil or similar. check piston lifts and falls freely if not centralize jet or clean dashpot, to centralize jet screw jet nut up until jet is level with bridge piston without damper should drop with a slight clunk on to bridge if not release nut above jet spring and tap lightly to centralize check after retightening you may to do this several times. To check float level remove dashpot and piston with jetnut screwed down 8 flats turn on fuel or pump, fuel should not flow over the jet operate choke to lower jet fuel should flow over jet. A blue spring is correct the needle could be AN,4,5,or 6 depends on any engine tuning. Basic setting is usually
8 to 10 flats on jet nut when engine is at running temperature lift piston slightly if dies too weak if speeds up too rich adjust one flat rev engine
then check again, for overall setting you need to check on road.
Took the Rosengart out for a llttle spin again yesterday with my friend mechanic (he almost declined as it was some 4 degrees centigrade and off course we would drive with the top down......) to demonstrate to him the sluggish accellaration in 3rd. The oil pressure gauge on the dash of my LR4N2 Indicates approx 2.5 / 3 psi when stationary (and I dare not revert my eyes towards that hard to read gauge when driving) so I'll stick with he old fashioned absence of an oil filter for now... The rev. counter is now fitted (A small OS from Techni Tacot with a 12 to 6 volt converter) but I scared back of going over an indicated 3000 rpm that sounded quite 'busier'... However getting to grips with the 'box and having les loss.of momentum when changing to 3rd learned that some slow acceleration actually did occur. The speedometer although connected to the gearbox doesn't work so I still have not got a real clue as to the speeds attained. Over coffee with some more petrol headed friends present I unpacked the Ricardo and Whatmough Hewitt heads and it seems my friend warmed up to the Ricardo head's design so I left both heads and a HC gasket with him to fit when he has the time as several pre war cars in his workshop were attending his urgent attention a.o. a Lagonda 3 litre, 2 Bugatti's and some Alvisses.... my little Rosengart does not take up too much space in comparison so those so he didn't mind me leaving it at his garage for a few more weeks. The small low pressure Facet type fuel pump arrived from the UK on Friday but although the label on the box said FPU6V it contained a 12 v pump....
(25-11-2018, 12:29 PM)Michael D Wrote: Took the Rosengart out for a llttle spin again yesterday with my friend mechanic ... The rev. counter is now fitted (A small OS from Techni Tacot with a 12 to 6 volt converter) but I scared back of going over an indicated 3000 rpm that sounded quite 'busier'... However getting to grips with the 'box and having less loss of momentum when changing to 3rd learned that some slow acceleration actually did occur...
As a matter of course I will take my standard low compression/3-speed 'box RM to 30mph in second, which equates to approx 3500rpm; if necessary I have no qualms about extending that to 35mph+, which is a little over 4000rpm. 3000rpm in second equates to 27mph, which would mean engaging top at perhaps 23/24mph or 1600rpm - I wouldn't expect much acceleration at that sort of speed!
Michael the oil pressure reading is quite normal for a splash fed engine. Forget about it. With the standard low compression head don't expect much more than 45mph in 3rd (70kph) on a flat road.
