Is there any advantage in replacing existing standard rockers with either 1.3 or 1.5 lift roller rockers as against a full resto on the existing for a 1275 LS engine, apart from one being a lot cheaper to do.

rollers are supposed to reduce side loads on the valve guides thereby extending their life.

My feeling is that they increase top end power at the expense of low down torque. At lease thats the impression I got when i broke a roller (broken adjuster) and replaced them witha set of standard S items.

Cheers, Ian

I liked the minispares 1.5's (non-roller forged steel) I had on my 1330. Apart from the top end benefits, they had the extra advantage of reducing run-on to just about nil.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I agree with 1071 about the extra top end.
I run the `MSC forged 1.5' ones (actually 1.58:1) in my 1360 with a 282 cam, valve lift is 0.493". Power hits at 2900 and then there's a marked extra surge from 5000. It spins to 8K if I'm inclined.

The wife's 1293 runs a Tighe 104 cam- but as it only had .320" valve lift I bunged a set of my ToyoMini (Corolla) rockers in. They measured 1.46:1.
With twin HS4s it revs well to 7K.
Low down torque is still good, it pulls nicely in 4th gear thru roundabouts at 40KMH in 4th....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Another benefit is getting a uniform lift across the valves, the newer sets are made to tighter specs, and don't have 40 years of wear.

I have 1.3s in the deluxe (1310cc) and the difference is noticeable. Made the power come on a little earlier, and broadened the torque range. Or it could have just been in my head

I have a HR255 cam, which has the same lift as the RE13, but is a bit milder. I'll have to take you for a drive some time

The standard rockers are around 1.2 ratio, so even the slight difference will help, without stressing the valvetrain more.

Matt

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68 Deluxe.... it's shiny..... I like shiny!!

I had my 1293 dynoed prior to fitting Titan 1.5 : 1 roller rockers, then again on the same dyno a few months after fitting them. After re-jetting the carb to suit, there was a very noticeable improvement in power from 4000rpm upwards to over 7000 where the increase was in the order of 7KW at the wheels. Torque was only slightly down below 5000rpm but higher from there upwards. The engine runs a valve lift in the order of 0.510".

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Curly
'64 Cooper 'S' (Group Nb spec)
'67 Mini Marcos GT www.mm7056.wordpress.com

You haven't got a spare set sitting around getting in the way do you Curly????

I know someone that would look after them for you...

Same here -running with the forged steel 1.5- I'd heard about a few failures with the roller rockers over the years.

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