23 replies to this topic

[Trials_Chizz]

Heyy,

Currently running a 1275 but looking to upgrade it a little more.
It's had it's valves done and a new carb on it.
What else off I'm not too sure.

Although it was suggested to me that I should try high lift rockers?
Does anybody run these and what do you think?
And what are the major power gains?

Aidan.

[twrminisport]

Camshaft will give you a good "bang for your buck" value.
You will have to take the engine out though because although you can fit one in situ its pointless as you cant replace the followers.
A new camshaft kit could cost about £200 but this will give you good performance boost for your money. Arguably the best Power/money mod you can do to an a-series

High lift rockers. From the sound of it unless your going mental spec you will wasnt 1.5.1 roller rockers. MED Engineering are the kings here but you will pay the money for the goods. Advantages here are major. SMall to meduim increases but literelly half hour to fit them rather than the engine out malerkey of a cam change


Jesus

[wmc1]

If your not running a mad cam, 1.3:1 rockers will be better.

[Trials_Chizz]

So 1.5.1 or 1.3.1?

Also what does this mean?

[Stevee]

Camshaft will give you a good "bang for your buck" value.
You will have to take the engine out though because although you can fit one in situ its pointless (Unless You have a 850, 998 or 1098 engine) as you cant replace the followers.
A new camshaft kit could cost about £200 but this will give you good performance boost for your money. Arguably the best Power/money mod you can do to an a-series

High lift rockers. From the sound of it unless your going mental spec you will wasnt 1.5.1 roller rockers. MED Engineering are the kings here but you will pay the money for the goods. Advantages here are major. SMall to meduim increases but literelly half hour to fit them rather than the engine out malerkey of a cam change


Jesus

[1977 Loud_Mini]

I've got TITAN 1.5 lift roller rockers on my standard 1275 and i must say it made it a damn sight quicker. It pulls for longer through the revs and has that little bit more power. Basically there like going up one level on a camshaft (so if you had a 266 it would be like a 276, so i've heard). Also the 1.3 ones are lower lift than the 1.5's and you won't notice much over the standard rockers as the standard lift is near 1.3 anyway. They just hold the valves open for a longer duration.

Evan.

[Cooperman]

When I fitted the 1.5:1 rockers I gained 2 bhp at over 5700 rpm and nothing below that.I think I lost a bit of bottom-end torque, but we didn't measure that. If you think that those rockers cost more than a decent cam they might be seem as too expensive in terms of bhp-gained/£1 spent.
The key to better power is better head, better cam, better carb(s) and better inlet & exhaust systems.

[lawnmowercrap]

I fitted 1.5 roller rockers to my 1275, and its made a huge difference. Before it's run out of pull at about 4k but now it'll quite happily pull at full strength to 6k.

[AndyMiniMad.]

When I fitted the 1.5:1 rockers I gained 2 bhp at over 5700 rpm and nothing below that.I think I lost a bit of bottom-end torque, but we didn't measure that. If you think that those rockers cost more than a decent cam they might be seem as too expensive in terms of bhp-gained/£1 spent.
The key to better power is better head, better cam, better carb(s) and better inlet & exhaust systems.

Totally aggree with the above. But once you have done these mods a decent set of 1.5:1 roller tip rockers does make a big difference to the engine, maybe not in overall power gains, but in my case they smoothed the tick over (a bit) and gave a much sharper throtle response. also the power delivery was much smoother, not such a big off cam/on cam jump.

[Bungle]

i had good results with my cooper and standard cam and 1.5 rockers

[Cooperman]

It does seem as though the hotter cam you have the less you gain with the 1.5:1 rockers. To gain only 2 bhp for around £100for the rockers didn't seem like any sort of result. Maybe with a standard cam the benefit of greater lift is more evident.
I gather 1.5:1 rockers are not much good on a 998, but I've never tried that.

[twrminisport]

I know there are exceptions but as a general rule you want 1.3.1 on a 998 as the 1.5.1 lift TOO much and lose powerr
1.5.1 on a 1275
you dont need 1.7.1 until you get to mental 1380 specifications

Like i said before though. Your money is better spent on a camshaft though but you will have to take the engine out

[Ethel]

To answer the "what does it mean"

Valve rockers are like an off centre see-saw: if the cam lifts one end by 1cm then the other end opens the valve by 1cm multiplied by the rocker ratio. That's about 1.25cm for a standard rocker & 1.5cm for a 1.5 roller tip jobby. Actually, even the wildest cams won't open a valve that far, but 1cm makes the maths easy

Hi-lift rockers don't increase the duration like a sporty cam would, but the valve opens at a faster rate so the effect is similar.

[M44K TS]

So would 1.5 roller rockers make much difference to a 1275 that's already got a 266 cam and a stage 1 kit or would head work be the better route to go down for a bit extra power?

[AndyMiniMad.]

So would 1.5 roller rockers make much difference to a 1275 that's already got a 266 cam and a stage 1 kit or would head work be the better route to go down for a bit extra power?

I would defo spend the £200 on head work first. Then a decent exhaust system. The biggest gains in bhp are made with head work. Other than overboring of course.