Hi there,

in the quest for some engine bay bling I have been busy polising my intake manifold plus cleaning / spray painting all parts of the intake side of the engine.

While I was planning to put everything back I've noticed the gasket between the lower and upper plenum doesn't match the runners at all, so I thought what the hell, I have it off now anyway so lets see if I can improve the transition from upper to lower plenum a bit. Not sure if it will make a noticable difference, but heck, what to loose right?

I made the lower plenum black there where the gasket goes on, and scratched with a nail folowing the gasket.

http://simotion.dnsalias.net/fotos/sr20det/inlaatspruitstuk/portmatch1.jpg

Then I used my dremel tool to open up the lower plenum.

http://simotion.dnsalias.net/fotos/sr20det/inlaatspruitstuk/portmatch2.jpg

As you can see I also removed the cast marks deeper inside the runner.

After that I placed the gasket back on, fastended the bolts and used a knife to cut away the gasket where some parts of the runners where bigger then the holes in the gasket, wasn't much but the gasket and runners now sit completely flush.

http://simotion.dnsalias.net/fotos/sr20det/inlaatspruitstuk/portmatch4.jpg

I also cleaned up the cast marks of the runners further further down:

Castmarks
http://simotion.dnsalias.net/fotos/sr20det/inlaatspruitstuk/portmatch5.jpg

And cleaned up
http://simotion.dnsalias.net/fotos/sr20det/inlaatspruitstuk/portmatch6.jpg

The problem I have is my dremel tool doesn't get deep enough and in the middle of the runners there still is a bit of this castingmark left, any tips on how I can get to clean these deeper areas?

Also, I have used a sanding paper on the runners where I have opened them up to smooth everything out as much as I can, but how smooth do I want to go for this? I have now used P180 on it, and I know that polishing it to a mirror finish will only hurt the flow, but what would be to rough, what to smooth and what would be perfect?

Sorry if these questions sound a bit stuppid, but it's the first time I'm atempting to do something like this, so I thought I'd better ask a stuppid question in stead of being sorry ;)

Also, the upper plenum's runners are now smaller then the lower plenum's runners everywhere, is it best to match them up to the gasket so lower and upper plenum have a complete smooth transition, or should I leave it as it is and is it enough that the air will not bounce against any steps now?

Thanks in advance.

PS: I will not match the plenum to the head because it's still on the engine and wouldn't like any allow swarf to get into the engine itsself. If I ever have to replace a head gasket I will do that part.