5 replies to this topic

[1977 Loud_Mini]

Hi all, i have just got my mini back on the road with my newly aquired 998cc engine. It has a 12G295 cylinder head with new valve stem seals and guides etc, it also has red TITAN roller rockers and therefore i am asuming they are 1.5 lift? It also has an uprated timing chain etc possibly duplex. Pistons are flat top standard size. Also it has a 65DM4 electonic ignition fitted.
Compared to my other 998cc i had peviously this is quick, the gear ratios are a lot taller and will hit 60mph in 2 and around 80mph in 3rd, is this right for standard 998 gears? It also makes a whining noise in all gears but not as loud as i have heard s/c gears, is this a worn diff etc or can s/c diff gears be purchased?
Also people on here say the 1.5 roller rockers will be too much for a 998 and lose me 5-10bhp so is it worth using my standard rockers for better power? Oh and the car is lumpy on tickover i'm asuming this is the rockers.

In the future i will be getting some 1.25" twin carbs to suit (if anyone has a set give me a shout) and an LCB or cooper 3into1 exhaust.

Any help on any aspects of this engine will be very much appreciated.

[Bungle]

yes 1.5 rockers are to high for a 998

[1977 Loud_Mini]

Is there anyway of checking if my rockers are 1.5 lift because places like minisport sell 1.5 rockers and the colour is red, whereas the rockers on different sites are 1.3 lift in the colour red.
Why are 1.5 lift roller rockers too much for a 998 then, is it because it needs revving a lot to draw out the power? It runs fine with the rockers i have and is a lot quicker than my other 998 even though this one has taller gear ratios.

[bmcecosse]

I wouldn't use the 1.5 rockers - but since you have them on there - may as well keep them! They won't 'lose' you any power - but I seriously doubt they will gain more than ~ 1 bhp, and they will cause more wear/tear on the valve train. If it's going well - don't fiddle with it! Twin 1.25" SUs are a waste of time - go for a larger single SU - although I assume you have an HIF 38 at the moment - which is quite sufficient for your engine. Check your speedo against a GPS - sounds like it may be just a tad optimistic! Whining could be the drop gears

Edited by bmcecosse, 21 February 2010 - 11:37 PM.

[1977 Loud_Mini]

I was going to change the rockers to my standard ones from the other 998 engine and see how they were. My carb at the moment is an HS4 with the mixture adjustment underneath. About the whining noise, could it be worn out gears as it isn't too loud but sounds a bit like a supercharger and i don't think it has drop gears but i can't be certain. They usually sound really loud on videos i have seen with minis and s/c gears. Oh and it doesn't whine when not under power. Sounds good though. The speedo could be out, but i usually keep with traffic on 30mph roads which suggests its fairly accurate. I will try the mile a minute at 60mph test and see what i come up with because it did 65mph in 2nd today and still had more.

[matty121]

I was going to change the rockers to my standard ones from the other 998 engine and see how they were. My carb at the moment is an HS4 with the mixture adjustment underneath. About the whining noise, could it be worn out gears as it isn't too loud but sounds a bit like a supercharger and i don't think it has drop gears but i can't be certain. They usually sound really loud on videos i have seen with minis and s/c gears. Oh and it doesn't whine when not under power. Sounds good though. The speedo could be out, but i usually keep with traffic on 30mph roads which suggests its fairly accurate. I will try the mile a minute at 60mph test and see what i come up with because it did 65mph in 2nd today and still had more.

hi did you try using the standard roller rockers as opposed to the 1.5 alloy ones? i am going to do the same thing but am beginning to regret buying 1.5 as everyone says they are too big for a 998.

I have a 998 with stage 1 exhaust alloy inlet manifold stage 3 head with larger inlet valves.