27 replies to this topic

[DILLIGAF]

When I fitted 1.5:1 rockers on my 1293 'S' with a 286 I gained 2 bhp at over 5700 rpm up to about 7000 rpm, but although I didn't measure it I'm sure I lost torque at lower revs, like at 3000 to 4500. 

 

How'd you measure the horsepower without measuring the torque ?

[Cooperman]

Because the car had been fully set up with 1.3 rockers earlier, then I 'happened upon' a roller set at 1.5, so fitted them, with a new head gasket and stopped off at the rolling road on my way to an event. All we were interested in was re-setting fuelling and checking timing for full power as time was limited. It gained 2 bhp at 5700 up to around 7000 rpm when compared to the graph done 2 weeks earlier. The torque was not of interest at that time. My perception was a slight loss of mid-range torque, but that was unimportant as we won the event anyway.

[DILLIGAF]

Rolling roads measure torque...........Then a mathematical equation is applied to get the horsepower figure

Edited by DILLIGAF, 14 August 2013 - 06:47 PM.

[Cooperman]

Good.

[DILLIGAF]

Good.

 

OK

[oltonlad]

if you are considering changing the cam then why not try the minispares evolution001 cam, I have recently fitted one of these in my 1275 with a 37x31 well ported head and the car goes like a stabbed rat!...............loads of torque and power right from 1200rpm to well over 6000rpm........I really cant fault it and would recommend that camshaft to anyone, I've had kent 266/276 and 286 cams in my engines in the past as well as the morspeed PH3 and the minispares cam is better than all of them for road use.

[Spud_133]

Spud,
First of all decide what you want to use the car for. The decide where you want the peak power to be. If you want to rev to 6800 all the time when using the power, then go for a 286 cam and suitable induction 7 exhaust system. The 286 gives fantastic power at 6400 rpm and is strong right to the optimum change up point of about 6800 rpm. It is truly a beautiful competition cam.
However, if you don't want to be using such high revs all the time, and if you fit that cam and don't use those revs then you have the wrong cam, go for the 266 or 276. The 266 will give peak at 5700-ish, whilst the 276 peaks at 6100 rpm.
Higher lift rockers really won't make a heap of difference, but 1.3:1 roller rockers will reduce valve guide wear.
When I fitted 1.5:1 rockers on my 1293 'S' with a 286 I gained 2 bhp at over 5700 rpm up to about 7000 rpm, but although I didn't measure it I'm sure I lost torque at lower revs, like at 3000 to 4500. But then, my 'S' is a competition car, so it's no issue. I strip & rebuild it after every 6 or 7 rallies.
A hotter cam requiring more revs will need more frequent rebuilding.
For the road, if you are looking for more power, you may not want to be revving at 6000 or over whenever you want top power. In fact, on the road, better mid-range torque is what is needed.

Thanks for the comprehensive answer, I have a 276 fitted, and I'm more than happy with this. I think I'll leave it for now. It definitely has more than enough power to play with traffic and have some fun on the back roads, but it's a trivial thing but as when it was rolling roaded, I put out 93bhp, whilst it was still tight, so I just want to get into 3 figures. Silly I know.
Cheers, Spud

[jaydee]

if you are considering changing the cam then why not try the minispares evolution001 cam, I have recently fitted one of these in my 1275 with a 37x31 well ported head and the car goes like a stabbed rat!...............loads of torque and power right from 1200rpm to well over 6000rpm........I really cant fault it and would recommend that camshaft to anyone, I've had kent 266/276 and 286 cams in my engines in the past as well as the morspeed PH3 and the minispares cam is better than all of them for road use.

 

Do you have the timings of this cam by chance? Is it £68 supplying an exchange cam?

[phil hill]

From AC Dodds info : 

 

The Minispares Evolution 1 Based on 1 new example only;

 

Checking height:   0.016" @ lobe

 

Timing:                   (Intake):  20/54    (Exhaust):  65/29

Nominal lobe lift:     (Intake): 0.263"   (Exhaust): 0.285"

Duration                 (Intake):  254       (Exhaust):    274

Lobe centre angle (Intake):  106        (Exhaust): 109

Lobe separation angle:  107.5

Lift on overlap:   0.054"

 

Accuracy:  Good

 

Yes I'm sure it's on an exchange basis.

 

Phil.

[minilee94]

All this arguments go on for a few bhp that you won't actually notice instead of rockers try and have bigger valves fitted ,polished ported head . The only way to get more power other than that will be change the cam etc wich you clearly don't want to do so there no other way of power increase really. my advice is if your happy with the power just leave it because you may go and do a few upgrades and not be happy with it

[KernowCooper]

I'll second that if your happy then pointless if your looking for the magic 100bhp figure, and then end up with a 100bhp+ and then find its only a few more for 15% of your driving.

[oltonlad]

 

if you are considering changing the cam then why not try the minispares evolution001 cam, I have recently fitted one of these in my 1275 with a 37x31 well ported head and the car goes like a stabbed rat!...............loads of torque and power right from 1200rpm to well over 6000rpm........I really cant fault it and would recommend that camshaft to anyone, I've had kent 266/276 and 286 cams in my engines in the past as well as the morspeed PH3 and the minispares cam is better than all of them for road use.

 

Do you have the timings of this cam by chance? Is it £68 supplying an exchange cam?

 

yeah, its £68 exchange, I took an old cam with me when I bought mine so they waived the surcharge as someone checked the cam while I was there, I also bought an offset woodruff key but it turned out that the cam was spot on at dot to dot (107 degrees).....happy days....

[oltonlad]

 

Spud,
First of all decide what you want to use the car for. The decide where you want the peak power to be. If you want to rev to 6800 all the time when using the power, then go for a 286 cam and suitable induction 7 exhaust system. The 286 gives fantastic power at 6400 rpm and is strong right to the optimum change up point of about 6800 rpm. It is truly a beautiful competition cam.
However, if you don't want to be using such high revs all the time, and if you fit that cam and don't use those revs then you have the wrong cam, go for the 266 or 276. The 266 will give peak at 5700-ish, whilst the 276 peaks at 6100 rpm.
Higher lift rockers really won't make a heap of difference, but 1.3:1 roller rockers will reduce valve guide wear.
When I fitted 1.5:1 rockers on my 1293 'S' with a 286 I gained 2 bhp at over 5700 rpm up to about 7000 rpm, but although I didn't measure it I'm sure I lost torque at lower revs, like at 3000 to 4500. But then, my 'S' is a competition car, so it's no issue. I strip & rebuild it after every 6 or 7 rallies.
A hotter cam requiring more revs will need more frequent rebuilding.
For the road, if you are looking for more power, you may not want to be revving at 6000 or over whenever you want top power. In fact, on the road, better mid-range torque is what is needed.

Thanks for the comprehensive answer, I have a 276 fitted, and I'm more than happy with this. I think I'll leave it for now. It definitely has more than enough power to play with traffic and have some fun on the back roads, but it's a trivial thing but as when it was rolling roaded, I put out 93bhp, whilst it was still tight, so I just want to get into 3 figures. Silly I know.
Cheers, Spud

 

i'd say that you would already have a sorted cylinder head to get 93bhp out of a 1293 with a 276 cam......either that or the rolling road that you used was a bit "optimistic"....