Head Off Rb25t

[skidkid]

I got the head off our 98' Stagea yesterday to replace blown head gasket (80k). While the head is off I thought its a good time to give the ports a tickle. Are people match porting out to gasket sizes on both inlet and ex. or just make sure gases are not hitting a shoulder? Are people removing lump in exhaust? Also are people replacing head bolts??

Edited January 3, 2009 by skidkid

[Dale FZ1]

I found the R33 spec factory manifold gaskets pretty well matched already, but checked and touched up both sides where necessary.

That lump in the exhaust port I smoothed out the sharp leading edge considerably and blended them in to the overall port shape.

The short radius in each port, leading onto the seat was where I spent a fair bit of time. Ex-factory that really was an abrupt edge and needed work.

Overall, not much material taken out but quite a bit of finishing work that the factory doesn't do. I'll have an idea later this month if I'm happy with my work

New head bolts not essential, but aren't expensive and should be replaced if the engine will see a bit of work.

[skidkid]

Any more hot tips? Cheers. Happy boosting!!

[NYTSKY]

A set of drop in cams would be good.

Tomei Poncams 260deg i think they are for NEO heads.

I hope your head gasket is not over 1.2mm in thickness?

[skidkid]

I am going to buy a genuine vrs gasket set. What would expect to pay for cams? You say drop in. No lobe relief, different spings or anything?

[NYTSKY]

Drop in meaning no other modifications required ie:valve springs.

[wolverine]

valve clearances need to be checked and may require shims (with neo head).

Edited January 4, 2009 by wolverine

[skidkid]

Can anybody quote neo valve clearances?

[wolverine]

the Tomei recommended valve clearance with type B poncams (260 deg) is 0.45mm cold.

the lifters are a touch noisy at this clearance on my car so i reckon something a little tighter might be better?!?!?

[jay1]

drop cams would be great

[lachlanw]

and yes use new head bolts . they are torque to yield . eg snap if you re use them

[skidkid]

Looks like I will go new head bolts. Are standard NEO valve clearance going to be 0.45mm cold as well? Won't be able to afford poncams.