10 replies to this topic

[Joshua.w]

Hi not 100% sure if this is the right place this is my first post.

 

I want a little more out of my mini and have been told that changing the cylinder head is probably the best thing to do on a standard 998. I am pretty good at using a spanner and have done plenty of work on my mini before but have never ventured that far just need a bit of advice as i'd pretty much like to do a straight swap. and only really have to readjust the carb. so just wondering which head i could use to just do a straight swap, rough price and how much power it would give? I do not want loads of power but just a bit more that the normal mini has. Ive recently fitted a stage 1 kit so that should also improve it.

any advice would be much apreciated. 

thanks Josh

[Icey]

Tuning a 998 is a well covered topic on here and the usual consensus is that while the 998s are fun to drive (they rev rather well and can take some punishment) you're better off fitting a 1275, it's the best bang-for-your-buck.

 

That said, usual rules apply. Make the engine breath well and you'll make more power. Do the simple stuff first though - make sure the engine is in good health, any issues spend the money there first.

[Anthony30]

You need to make the decision. Either keep the 998, or swap for a 1275. So many options.

[Joshua.w]

You need to make the decision. Either keep the 998, or swap for a 1275. So many options.

I wanted to keep the 998 really and just thought a head change would be the quickest and easiest thing to do. not after a massive increase in power just a little to give it a bit more oompf...

[Joshua.w]

Tuning a 998 is a well covered topic on here and the usual consensus is that while the 998s are fun to drive (they rev rather well and can take some punishment) you're better off fitting a 1275, it's the best bang-for-your-buck.

 

That said, usual rules apply. Make the engine breath well and you'll make more power. Do the simple stuff first though - make sure the engine is in good health, any issues spend the money there first.

I have been told that fitting a 1275 is best however id prefer to keep the 998 (probably me being a lazy tight git ) really just want to fit a better head and leave it at that with the stage 1 kit.

[gazza82]

Plenty of tips on here but a 12G295 is best head ... If you can find a good one.

Edited by gazza82, 08 April 2016 - 08:12 PM.

[Fast Ivan]

Surely a standard 998 head appropriately modified would be the best option?

[Joshua.w]

any ideas how much such modification would cost roughly? or anywhere i could get a 12G295? 

also can i just say how helpful this forum is ive always used it when im stuck on something but its really good that everyone helps each other out!

[mk1leg]

I had a 998 with a stage 3 polished and ported double spring head and a 731 camshaft on a std box with LCB and 1-3/4" exhaust went well.all work done with engine in bat ......tappet chests are good

Edited by mk1leg, 08 April 2016 - 09:25 PM.

[Icey]

I have been told that fitting a 1275 is best however id prefer to keep the 998 (probably me being a lazy tight git ) really just want to fit a better head and leave it at that with the stage 1 kit.

Nothing wrong with a 998, you just have to keep in mind what your end goal is and how much it's going to cost you to get there. Just changing the head by itself will show some moderate improvements (how much, I don't know, it depends) but to make the most out of it you'd really want to put a warmer cam in.
 
Nothing wrong with doing that either but do you see how it starts to add up? The same amount of money could just as easily be spent on a 1275 and get you to the same power level but you're only at the start of the road at that point.
 
If you don't have a copy already, get a copy of Vizard's 'Tuning the A Series'. He has some example builds and covers key areas for making power - not all of them expensive.
 
And don't get me wrong, I'm not down on 998s - I have one on my bench at the moment which is to be modified. It's just such a common question with one very clear answer that will satisfy most peoples needs/wants it seems negligent not to make sure it's understood.

 

Plenty of tips on here but a 12G295 is best head ... If you can find a good one.

 

Again, good advise in general if your aim is to kit out a 998 as it is a better head regarding valve sizes etc.. but because the CC is larger it'll need skimming and/or D-top pistons. Not just a drop-in improvement so if your 'want' is just a little more power will that work plus the cost of the head be more or less than just replacing the engine wholesale?

Edited by Icey, 08 April 2016 - 09:57 PM.

[Ethel]

The 12g 295 is the best casting, even if you ground away all the extra metal from a cam4180 you'd still need to cut bigger valve seats and avoid breaking through in to pushrod holes etc.

 

a 12g202 is an option in the middle, or you might manage to fit a 1275 head if you could get the valve seats recessed enough to avoid the need to pocket the block.

 

There's a fair chance, if you find a 295, it's already been skimmed.