1959 TR3a Dyno Run

[Hamish]

Hi

Took my 1959 Triumph TR3a to WGT Auto Developments for a Dyno run as I wanted to see if I had cured an intermittent top end fuelling issue. Pity it was pouring with rain on the way when my passenger was filming.   Final results of 93hp at the wheels with 138ft/lbs torque at 3500 ish rpm. 

(And no fuelling issues manifested itself )

This is about 117bhp at the flywheel according to our championship regs calculator. This is 123bhp/tonne.

Thanks to Pip at WGT for his time and expertise in looking after me and my old car.

And some screen shots of the output data  ( the arf data is from the tail pipe of the exhaust system)

 

Edited June 25, 2019 by Hamish
Added pics

[Nick Jones]

Quite a decent max torque number but surprised how pronounced the peak is. Would have expected flatter, though happy to admit I know little about these engines.

[Hamish]

Nick

unfortunately I don’t know what cam is in the engine.

and also I changed the exhaust and manifold during the winter and I think it’s a very big bore on the manifold that has affected the torque and where it peaks, further up the Rev range, that’s what it feels when driving anyway.

[oldtuckunder]

some observations. a bit like nick i was intreagued by the steep/short torque curve(although one has to be careful just looking at a picture not to jump to false impressions). however as th he  a reasonable standard 4pot 2100 engine i think makes around95ftlbs at around 4500rpm, your approx 140 at 3500 is a good number and slap bang in the middle, however it did make me ponder your comment from earlier in the year about number of gear changes you were making, as from that torque curve i suspect there may be a feeling of pulling strongly and then dying, changing up or going into overdrivethen dropping you back into the torque band and away you go again. that sort of torque at 3500 is goog(wish i had had anything near that on the vitesse, but probably not if the band was so short around it. 
another thing i noticed was the similarity between the torque curve and the AFR curve, assuming i'm reading it right the throttlr is being opened smartly at around 2k if you look at the afr trace you will see that they start heading for the floor dropping to towards 11(i would consider that a tad rich, infact if you the compare the AFR curve with the torque one you will see that as the afr's lean up towards 12.5/13 the torque starts coming in strong and follows the same profile up to max at up around 3500, where afr is around an ideal 12.5/13 for power acceleration.now of course we can't go on getting leaner to extend flatten the torque curve, but it did make me wonder if the fueling was better from 2500 it torque would be building sooner and the curve flatter.
unfortunately as you say you don't know what cam is fitted or i assume timed, but with a dial gauge you could get a reasoable measurement and compare with some regular TR CAM numbers, your not after finding out its exact profilebut more a couple of critical lift points and their timing, may give you an idea if something radical has been fitted. on the fueling whilst without being able to measure afr's its all seat of the pants, from that afr curve i might be playing with initial piston lift damping to see if i got better WOT response, but also just to be contrary rather than playing with the damping i might also be playing with the timing a bit and watching the afr's a degree or so more advance can sometimes give a much better burn. unfortunately you have now reached either the trial an error point or you need more data about what is happening, as they say"information is power" from those graphs there is more to be had from that engine without trying to turn it into a reving fragilescreamer, just something with a good power band upto your i think sensible low 5k limit. i wish you luck 

alan   

[HARVEY S M]

Back in the 70s when my friends at the MG shop in Manchester were racing MGBs in the BCV8 

championship. Bill Hewitts standard class winning  MGB produced 93bhp at the rear wheels on Harry Ratcliffes

rolling road. The only mod. was bored out to 1860cc, all other parts carbs camshaft, exhaust & cylinder head

all standard as per the regulations ( as a point off interest we always used the 3 bearing engine to reduce

friction loss ). I did build a 5 bearing standard engine for racing that produced 87 bhp at the rear wheels

still on Harrys rolling road.

 

                                        Harvey  S. Maitland

[Hamish]

Very mix day for me. At Aintree sprint yesterday. 

We normally have 4 runs. 2 practice and 2 to count in competition 

My first 3 runs I suffered really bad missfire and in between worked so hard changing things to try and fix it. Checked all elecs. Carbs. Fuel in float chambers. Rerouted couple ht leads. And LT leads. Changed plugs. All without joy. Very frustrating. Esp as I had had the car on a rolling road after loads of changes to fuel pumps and ignition etc etc and the miss fire never appeared.

problem manifested itself after the first left hander thus thought could be elec short. 

Plenty of fuel in the tank- more than normal to rule out fuel surge away from pick up point.

Even fellow competitors felt sorry for me a stepped in to help - thanks Steve Small with the white v8 wedge.

70 odd second runs of missfire for 3/4 of the run. Times Usually very low 60’s. ( a bogey of 58 secs!!!!)

I taped over the numbers and gave it a motorway run at lunchtime. Fine on the A roads to Mway but misfire happened at Mway speed without bends so in my mind fuel starvation. 
Then decided to put my cheap Aldi elec type pump on the fuel line from engine to fuel tank. It must have cleared a partial blockage and I did a 60.98 run. 
As there was time they gave us another run and I broke the minute ( just) with a 59.98. Best time ever there. 
Could have been more if the other runs worked !!!

a very mixed day. 

I have in the past, trying to fix this misfire, siphoned the tank out x3 and it’s very shiny inside (steel).

the engine bay pipe work is new and correct size.

the only thing I can see is an old 3” length of (rubber?) pipe joining 2 metal sections up in the left chassis area forward of the axle. 

I cant believe the issue is the metal pipe ?

i am now thinking that this small rubber pipe is breaking down and causing a partial blockage. Rather than something in the tank.

so this is my next task to replace that pipe at the risk of petrol flow from the tank. That I will try and drain.

fingers crossed for me. 

The car in its home awaiting that 50pence fix that I hope will sort things. 

 

Edited July 1, 2019 by Hamish
Added detail

[mpbarrett]

Is it an old rubber hose? Could be effected by the ethenol in the fuel and swelling inside? Or is it before the pump and the pump is sucking in air from the hose or joints

.

Mike

[Hamish]

Before the pump.  It looks like it should be a compression fitting

no 30 in this picture.

the rubber pipe looks like a PO  modification