16 replies to this topic

[minisam92]

sorry for the noob question but would pressed steel rockers and a hif make a difference at all to a 998 thats got a stage 1 kit (cooper freeflow stainless straight though mini sport inlet cone filter) and a 59d4 distributor ?

and how are why better ?

p.s sorry if its a stupid question

[MRA]

It depends on which pressed steel rockers you have...... is the "pad" (the part that pushes on the valve stem) round or oval ?

[minisam92]

erm not sure as i havent bought them yet he said there the early type pressed steel rockers ?
also what advantages are there with using a hif 38?

[dklawson]

You are not likely to see a major performance increase with the early rocker arms. The ratio will still be pretty close to whatever is on your engine now. As for the pads, small bore engines had "round" pads on the ends of the rocker arms while the 1275 used oval pads. I think the biggest argument for the stamped steel arms is that they are more "uniform" with regard to their ratio.

Since you are contemplating changing to an HIF38, I assume your engine came with a HS4 carb. The two carbs will breath about the same so changing the carb isn't going to make much difference. However, you could change the needle in the carb you have to perhaps get a bit more out of your engine.

[minisam92]

thanks mr dklawson i reckon ill leave it and just try a few needles
and thanks mra minis

[lrostoke]

shouldn't really need change the needle if you have a stage 1 kit, they normally come with a different needle to standard anyway.

[jakejakejake1]

It may be worth getting a rolling road tune, this should include a re-profiling of the needle to match the engine, also they will sort out the timing and mixture etc to really get the most from your engine. As most standard needles will be fairly close, but this will get it spot on, which should help improve power and economy. So if you do many miles you will make up the cost of the tune over time.

Jake

[minisam92]

shouldn't really need change the needle if you have a stage 1 kit, they normally come with a different needle to standard anyway.

shouldnt but i dont really trust the guy i bought the mini from

It may be worth getting a rolling road tune, this should include a re-profiling of the needle to match the engine, also they will sort out the timing and mixture etc to really get the most from your engine. As most standard needles will be fairly close, but this will get it spot on, which should help improve power and economy. So if you do many miles you will make up the cost of the tune over time.

Jake

#

i think this is what i will do once its on the road just too make sure everythings ok

once again thanks for all the advice

[bmcecosse]

Stick in an AAA needle - with 3 in 1 oil in the damper, advance the timing till it 'pinks' - then take it back slightly. Now go spend the RR money on something useful.......

[minisam92]

ive got the 3 in 1 oil as i cleaned the carb will try and get a aaa needle and will get me boss who used to race minis to help with the timing

[MRA]

The ratios are different for pressed steel 1.28:1 is common against 1.22:1 for sintered types....

[Cooperman]

I seem to remember running a line of weld over the top of the pressed steel ones to prevent 'spreading' when used with heavier valve springs and higher revs.
The pressed steel ones are certainly lighter, but most people stopped using them when the original 'S' forged rockers arrived.

[twrminisport]

Stick in an AAA needle - with 3 in 1 oil in the damper, advance the timing till it 'pinks' - then take it back slightly. Now go spend the RR money on something useful.......

This man speaks sense.
I only ever took my car to a RR once. I paid £120 for him to gain 0.3bhp over what i could myself with my own tools and ear.
Yes alright i do have a few good tools like the genuine SU balancer etc but yeah. Waste of money

When i put the full rally head on it i just looked up in vizard the rich mix for my car put those needles/springs in and it was much better. Obviously.
Then just some fine tuning on the mixture by looking at different revs and dropped the needle to sort it out then had a quick fiddle on the mix screw and perfect.
Fuels beautifully across the rev range in all gears IE i can stamp on the throttle when im in 4th gear at ~20mph and it pulls neatly and cleanly with no stuttering.

Oh and back to the OP. Dont change your rockers unless you go for the MED 1.3.1 ones. but thatll give you a whack in the wallet.
Skip this and the £220~ you save will go a long way to a recon 12G295 head.
The HIF38 will give you an increase but if your plans are to put a big valve head (Either a cooper or 1275) then you should go for a HIF44 instead really.
Or even better than both of these get Twin HS2's modified as per Vizard.

Jesus

Edited by twrminisport, 11 October 2011 - 07:45 PM.

[minisam92]

thanks for the advice and twrminisport i think im going to do what bmcecosse said and change the needle for a aaa needle i actually didnt no that about a hif 44 if i but i doubt ill mod it that far as im just using the 998 as a daily/ runaround and my 1275 will be more performance inspired thanks for the advice though has saved me a few pennies

[jaydee]

The HIF is downdraught so no lean-off issues when hard cornering.