2 replies to this topic

[Mad Max]

Hi

I've just pulled out my 998 engine from my minivan due to its ill health and am going to attempt a rebuild. I've done lots of bits before on engines from clutch,timing chain changes to headgaskets so i'm ok with how it works but i'm struggling trying to work out where to stop with the rebuild.

I intend to keep my van for a while and therefore want a good run-about which is quite with good mpg but with enough torque to allow me to cruise easily on a motorway.


So initally the plan was going to be put a better final drive in for economy when i rebuild the gearbox and then use everything standard with a stage 1 kit. I think i can live with the little extra noise that a RC40 would produce unless someone can recommend a quiter good performance exhaust.

But

I have the tools and equipment to have a go at porting the head myself and increase the compression which since i'll be skimming it anyway wouldn't cost me extra. I've also read vizards book and could play with the chambers. The other point is that i'm probably going to need a new cam as i know atleast one of my current followers is knackered so do i upgrade this while i'm at it.


The final aim is a reliable engine with good usablility, good mph and what i would call a safe amount of power to use on motorways i'm not chasing all out power. What do people think?

[MRA]

And cam bearings.... oil gallery plugs, core plugs, to enable the block to be cleaned after boring and honing.

[blacktulip]

i think you should get some flat top pistons unless you dont already have them, this will allow a 12g295 head that wouldnt need skimming past the oil gallery to achieve the right compression ratio. also in the minimag where they tuned a 998 they used a cooper 997 cam with a stage 1 kit plus a 12g295 head and it was a great cruiser plus achieved a very decent mpg as well, i think it was an average of 45 odd mpg. be carefull with cam choice as some are bad for mpg. the sw5 cam claims to be good for 40mpg average.