bore wear - look for lips at TDC, BDC - carefully remove a top ring from each piston and put it down the bore, tap it in with a piston top so it's square - check the end gap at top, middle, bottom - make sure you use the rings from the piston that came out of the same bore - do this one at a time so you don't get em mixed up.
Big ends & mains - look for scoring/wear - think about replacing the big ends anyway as they're not expensive.
Oil pump relief valve - have it out - considering replacing it if the valve or it's bore is scored - a nylon relief valve kit is a wise precaution.
Check the valves for obvious oil contamination - this most likely means a stem seal needs replacing.
Thanks Gary, I dont quite get the Bore thing with the pistons, but ill try and suss it out,
You did my head a few years back on the White GTE 16v I had, and now im going to do the same with this one, I have the Dremel kit, so what bits do i need to smooth please? Im confident of doing it myself, its just a matter of knowing which bits to "gas flow"
blend valve seat inserts into the port throats and open them up a little - radius them over into the throat as well, but be careful to avoid the actual valve seat itself.
knife edge the inlet splitters
exhaust ports bend over sharply - there is a lot of scope for taking out metal to smooth the transition from port to chamber
after that it's basic gasflow - take out all the imperfections - open up the inlets a little all around - but don't take any out of the large radius of the port entries (roughly where the valve guides are)- this slows down gas speed more than anything else.
If your doing a proper head rebuild anyway, you might as well strip it totally and use new stem seals.
rememeber to get it properely cleaned afterwards - that head I did for you was chemically cleaned - you can see how well it came up
Oh right Ok, head looks fine, dont think it needs skimming, so thats knocked off the list of things to do..... right wheres me tools, gotta get the cams off, and the valve springs realeased - BTW how easy is that to do??
vauxhalls gasket set doesnt have stem seals. get one from SBD, cost about 50 quid for the whole upper engine set, you get seals and gaskets for everything. even a little copper one which i never found a home for.
My local Cafco, motor discount place sells the gaskets for £38 I think includiong the seals so Ill get some of them. on the Cams, am I jsut checkin for scoring (heavy) and the same on the lifters?? Should ireplace any of theose bits, eg springs, retainers, tappets etc??
check the cams for scoring - if you find any that's a sign something nasty has been circulating.
lifters - these can be dismantled and cleaned out - I recommend you do this - whack em down hard on a flat wooden surface and the plunger should pop out, allowing you access to the insides - theres a little bearing inside the plunger as well which needs pushing in to let the old oil out.
lifter contact faces should be checked for pitting or wear, and relapped using valve grinding paste if they're ok - if you find bad ones replace em, obviously.