Pulled head off, need experienced eye.

[Wote]

So I pulled the head to get a valve job done, I think I've got a burned exhaust valve.

Got everything just fine up to here, and this is what I see:

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Obviously it's a mess, but is there something I should do besides clean it up? Am I hosed here?

Thanks for your advice, folks.

[Wote]

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And this is the bottom of the head. Lovely, no?

Off to the machine shop shortly.

[geezer101]

Your head actually looks - well, pretty good dude! Normally I see coolant gallery ports munched out by corrosion but a swim in the hot tank, a pressure test (just to make sure), a light skim and the valves + seats recut and it should be rockin' good as new. If you're not in a rush I strongly recommend you do some work on tidying up the inlet and exhaust ports yourself before sending it off to the shop. I've said it plenty of times - but it really does make a noticeable difference to how your engine will run. The piston bores however are looking very 'loved'. It's not ideal but if it was running fine before the valve cooked, you could glue the head back on and keep driving. If you have lateral movement of the pistons in the bores it means you won't be getting away with a hone and some new rings. Remember you're only looking at the block from the top. If you're going to pull the engine down be prepared for all sorts of horrors...

[Wote]

Thanks, Geezer. I poked around and the bores look very smooth, no marks at all to speak of. The #3 cyl wasn't firing for a month or so, and that discoloration in the bore is just some film of liquid, my guess is coolant.

What do you suggest I do with the ports? I already took it over to the machine shop but I could do something when it comes back. Just polish it up real good or..?

[geezer101]

First up, you don't need air die grinders and carbide tips to do mild port work. The idea is to take out all the sharp edges in the ports and turn them into nice rounded edges (I'm talking about the inside walls of the ports - don't mess with the outer edges especially with the exhaust ports). Get the walls of the ports looking even. You won't need to take out great chunks of metal, just a little buzz here and there to smooth them out. I put up a post somewhere about how I tackled the porting on my 4G63 but I went a little (read as 'very') OCD porting my head and cleaning up the castings/previous bad repairs...:scratchheadyellow:

[geezer101]

O.k. found my post on head porting and manifold preparation. All of the porting work I performed was done with a rotary die grinder (Dremel thing but cheaper version), a power drill and a flexi-drive attachment. I also made a special lapping tool from a dead screwdriver with a bit of folded medium grit sandpaper to dress the port walls - http://www.mightyram50.net/vbulletin/showthread.php/2566-Intake-manifold-porting-question?p=31683&viewfull=1#post31683

[LSR Mike]

use some machinist dye to help mark what you want to take. The gaskets were used to make the circles for matching. you can see how far off the factory casting is...

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[geezer101]

It's bizarre that the quality of the castings on my 4G63 head were absolute garbage but the ports were nearly perfectly aligned. OOC Mike, would it be worth opening up the ports that much on a stock engine or simply tapering the port openings so the air/fuel charge gains some velocity going into the head?


...the gaskets were used to make the circles for matching. you can see how far off the factory casting is...

That's taking into account if the gasket is a direct copy of an OEM gasket too. No guarantee of that.

[Wote]

Whoa, awesome. I'll get on that just as soon as I have the new timing belt and water pump in.

Looks like I'm going to have the jet valves plugged while it's at the machine shop, and the machinist said it looked in pretty good shape. Bonus, he's worked on these engines before and had some things to say about the condition of the head and the valves that aren't burned.

[LSR Mike]

Remember, I was going all out with the turbo, The head was ported, chambers re-worked, full on race prep. Gasket matching has always been a step one on a performance rebuild in my experience.

[geezer101]

...should be step one in any build! :thumbup: No excuses for poor fitting manifold gaskets.

[Wote]

Well, crap. The head is cracked, right between the valves on the #3, the one that had the burned valve.

Where's a guy look for a new g63b heads round here?