Is there noticable difference changing from the standard pressed steel version to the 1.3 roller rockers?

What about the forged rockers? I have the forged ones in my car (Cooper S only??)

_________________
1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

Minispares dont make them anymore. Nope, zip nada.
Aaron, make that 2 people with the same ones now


As for wether roller are better, yadda, yadda... DONT go buying them if you have enough lift.
I have bugger all lift and mods to my head mean that even the 'best' standard/ forged, whatever rockers wont give me enough lift.
I NEED more lift cause my peak is about 5500rpm...

If you can afford about $100 per HP in the top end (thats very expensive) then go for it... otherwise stick to normal rockers.

Peter.

_________________

Click here for the Turbo Conversion Thread!

1.5's on a small bore, not worth it. Just get a bigger cam. I ran 1.5's on my 1152cc which had a BIG head and extractors and dellorto 45mm with ported intake and it ran like a pig. Put the 1.3's back in and it suddenly had 10ft/lbs more through the rev range.

Measure the ratio/lift in your current set of rockers, if they are crap (which I hear many are) buy a set of 1.3's

_________________
Lillee - 1969 Morris Mini K

Just for the record, Graham Russell got his 1100 smallbore project to close to 100HP and 90+ft/lb torque with 'standard' rockers.

You only need to go to 1.3 if you NEED more lift.

I have an RE-13 but DONT have enough lift... in fact, bugger all lift.

Check first, if you just throw in 1.3's you might see NO improvement (depending on your motor) and if you whack in 1.5's you might see LESS power... as Doc explained and Chong has experienced.

Peter.

_________________

Click here for the Turbo Conversion Thread!

This engine already has a pretty big cam -- the 731, which Vizard considers the biggest cam suitable for road use. I've not driven anything wilder, so I can't judge, but this cam is still pretty drivable. I hear a lot of people raving about the RE13, how does it improve on the 731?

Basically, although this engine is pretty strong already I'm looking for ways to improve it further without spending a small fortune. It's currently running the 731 cam, a 295 head (although I don't know if it's been modified in any way..), twin 1-1/4" SUs, and 3-1's into a 1-3/4" exhaust. Adding the twins made a big difference to the top end, but I'm looking for more grunt basically everywhere so I can throw in a taller diff to make the car more comfortable at freeway speeds (this is where a 5-speed with an overdrive 5th would be perfect...).

I was kinda hoping the higher-lift rockers would be an easy bolt-on improvement, but if it ain't so, it ain't so..

(I can hear the calls of SC12!!! already )

_________________
Simon

The adventures of an owner builder in the Tallarook Ranges

From what you describe it should be nearly as good as it gets for a smallbore. Maybe some headwork will give you more ponies if it hasn't already been ported.

Taller diff will be at the detriment of accelleration. In my opinion 3.44 diff is probably the best all round road diff. I run a 3.44 and although I don't drive freeway daily, she is happy to sit at 110km/h without much trouble at all.

By the sounds of how big the 731 is, your engine may not run well at too low of an RPM anyway. Like for me, below 2300 is a no go zone. It will run at that rpm but she's much happier at 3000rpm say. So on 4th at 60km/h is exactly 2300rpm and for me, it's slightly lumpy. If I want to take off in a hurry I shift back to 3rd...

If you want to run on the freeway at 110 @2500rpm, buy a commodore

_________________
Lillee - 1969 Morris Mini K

Yeah, that's what I'm starting to think...



That's why I'm looking for more grunt I'm pretty sure the car's running a 3.44 now (that's the standard K / 1100 ratio, yes?) and it gets pretty tiring running at over 4000rpm for long periods. An overdrive 5th would be absolutely ideal.. the engine's got plenty of grunt at 110 km/h, it's just revving too hard. If I could drop the revs to say 3500 at that speed, it'd be perfect and would be a much nicer cruise.



It's actually pretty drivable, but it's had the 731 in it for as long as I've known the car so I can't say what it would be like on a standard cam. It most definitely does come "on cam" at around 3200rpm, and now that it has twin 1-1/4"s, she loves to rev.. although I'm too much of a wuss to push beyond 5000rpm.



Yeah, over long distance I'm with you (actually, over long distance I'd stick the Mini on a trailer ). Maybe the SC12 is all the options I've got left...?

_________________
Simon

The adventures of an owner builder in the Tallarook Ranges

What would the SC12 do?

Do you just want big hp? I would suggested starting with a 1275 and working from there, but since you've gone so far with the smallbore stick with it, and from what I've seen, really good hp can be made with them.

The SC12 would give you all round more torque and power but to expect fuel use to go up a lot!

However after all the trouble I've had with tuning it and fitting it all in and making it work I'd say it's worth it, above 3000rpm it goes really hard!

<edit> Forgot to say, most important, I don't know about your cam but is it good for boost? Some cams don't suit boost very well, from what I've heard, RE-13, but also from what I've heard RE-13T (T for turbo I assume) is great.

_________________
1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

There is some way you can go but not without spending some serious dosh...



MiniK/1100 ratio is actually 3.66 diff. It's running higher revs at 110km/h. If you are running a stock 998/1098 3 synchro box then this is probably what you have now. This could be why you are revving more at high speed. The 3.44 diff only came on Cooper S's and later rodchange 4 synchros in Leyland models. if you can find a taller diff that would make it more liveable if you do alot of highway miles. Although even then I think a 3.44 is still the money...



This is why we like the RE13. It's got balls all the way to 7500rpm and comes on quick at about 2300. It's a good allroung fast road cam and quite sedate considering it's output potential. Sounds like your 731 is way too big! You've have nearly no torque below 3000 which is where you want it on a road car...

In a road car, what you want is alot of torque for as long as possible, starting as early as possible. This is why the stock cams were good for road cars, as they start producing torque from idle. Race, different story and hence I think the 731 sounds abit big for road IMO.

[/quote]

SC12 is not the be all and end all. It is an expensive route too. For starters you may need to lower your compression for Supercharging which will involve $$$ (don't quote me, I am an NA man so no idea about hair dryers).

If you are pulling out your engine anytime soon, my advice is, bore it out to get more CCs, throw in a milder fast road cam like an RE13, and port the head. If you have a perry 3into1 you may want to try a maniflow LCB system instead. Port the intake to the twin SU's and get ramtubes/stub stacks. All this costs $$$! (and possibly $$$$)

_________________
Lillee - 1969 Morris Mini K

Yeah or as slinky says, get a 1275! 120hp will get you from A to B in a hurry!

At 4000rpm on the freeway, Lillee feels like she's going for a leisurely walk

_________________
Lillee - 1969 Morris Mini K

The larger lift rockers take care of a great deal of run-on as well on a 1275 if it can't be cured with different sparkplugs.

_________________
SooperDooperMiniCooperExpertEngineering

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

That's interesting.. this engine does tend to suffer a little from run-on, especially if the idle is set anywhere over 800rpm...

_________________
Simon

The adventures of an owner builder in the Tallarook Ranges

I don't know the history of the engine/box before I bought this car 10 years ago.. and all I've done to it in that time was to throw the carbs at it. I'm likely to get the car back (after gifting it to my father as a resto project, but now he's finished it he's bored with it apparently ) but I really want the car to be better behaved on the freeways. Lots more of them around these days than when the car was designed

It currently has a rod-change 'box, I have NFI whether the K was fitted with those (it's a June 1970 build).. so it may well be a non-genuine box. All I can tell you is that it does near as damn it to 4000 RPM at 100 km/h.


Hmm.. may have to look into that one then.



Yeah, I'm not real keen about bolting on a blower, nor replacing the motor with a 1275 (as attractive as that may be). Better the devil you know, IMHO. Maybe in the project car in a few years



Yeah, all of the above methinks. The $$$ don't really scare me, I was planning to buy a resto'd car but it looks like I'll end up saving that money and spending it on my old car

I'm pretty sure the extractors *are* the Perry's, I'm also reasonably sure the head hasn't been worked over, so I think I'll do that and throw a 3.44 diff at it at the same time. Gotta get it back to Melbourne first, though..

_________________
Simon

The adventures of an owner builder in the Tallarook Ranges

I think it reduces the compression a little at the low speeds that the engine runs-on at because of the exaggerated lifts. Stops the dieseling a little. It was very pronounced when I put them on the difference it made.

_________________
SooperDooperMiniCooperExpertEngineering

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