Race Engine Forum UK

Below are the statistics for my engine and the results from a recent rolling road session at Northampton Motorsport.

Key issues were the throttles not fully opening and the timing too far advanced.

The session took 3 hours during which time the oil and water temperatures remained good, though I cannot remember the exact figures.

Fueling is a little lean, but not problematically so, low down. But picks up at the higher rev range

Peak power is 167.6 BHP at 7,500 rpm. Peak torque is 142.7 lb/ft at 5000 rpm. More important to me is it reaches 120 lb/ft torque at 3,750 rpm and stays above that till practically 7,250 rpm giving a lovely long flat torque curve.

These figures are slightly different from expectations and is most probably due to the custom exhaust system utilising twin tail pipes, just because I like them. The result is a very fast Morris Minor and a huge grin from me.

Guy Croft Head No. 02.021.1
Head: 130 Abarth 8v head
Valves: 43.5mm inlet; 36mm exhaust
Cams: GC 3A inlet and exhaust
Pulleys: GC vernier type
Valve springs: triple
Head work: Guy Croft
Plugs: NGK B9EGV

Fueling
Carbs: 2 * Weber 45 DCOE using 38 chokes, F16 emulsion tubes, 145 main jet and 175 air corrector
Pump: Facet red top

Timing
Timing 23° at idle* and 33° at 4,500rpm
* this figure is taken from the printouts and needs to be confirmed.

Guy Croft Block No. 03.043.1
Block: 2 litre Fiat 131
Pistons: GC Forged Race
Rods: GC Race

Exhaust
Custom built 50mm stainless 4-2-2 system with Magnaflow main box and Scorpion back box

Others
Lightened flywheel by GC
Uprated clutch and plate
Moroso Accusump
13 row oil cooler
Modified Fiat 131 sump
1” Cam belt
GC Head bolts

[img]morris%20rr%20northampton%2020100509%20graph%20colour%203.jpg[/img]

Stephen hi,

thanks very much for this informative and interesting post, great result and well done indeed!

I give this MODEL POST not because it mentions my name a lot but because I do like the 'bullet point' style with which you set out the engine spec.

My attention is drawn to the influence of split secondary pipes on the torque/power as you know, insofar as the layout generates an unusual curve, ordinarily peak torque would be at 5500 and peak power at 7200.

I've remarked to you on the ignition timing, it really should be 10 deg at 850 and 35 deg at 5500, this certainly wants checking out. I mention this merely for the guidance of others who read this.

I look forward to one or two pics of the installation and the car (incl the fabled twin-exit tailpipes!)

Here is your block in build at my works 3 years ago.

GC

compression?

Nah, fracture.

GC

Cos,
I don't know the exact compression ratio, probably around 10:1 maybe a bit higher given the pistons. Guy might have a better idea.

However I know there is no problem as I measured the cylinders when the engine was put together and all the readings were between 14.75 and 15 BAR (215 and 220 PSI).

I'll try and post some picys of my "odd" exhaust, though I have to say it sounds great and twin pipes really suit it.

Regards,
Wal