I have my vortecs apart and I noticed some strange markings on the valve seats, mainly the intake. They have these small pockets or indentations right behind the area that the valve was sealing against. Also, it didnt look like the valves where really mated to the seats properly as there was only a pencil thin line around each valve face where it was contacting the seat. Are these due to the valves not sealing properly? It almost looks like something just scoured the seat away in those areas.

 

Have you ever done valves before? You are only supposed to have a thin sealing line -- not the whole valve face. The thinner the strip where the valve to seat contact that occurs, the higher pressure the seal will withstand (good!). Of course you need a wide enough strip to transfer heat from the valve. Looks normal. If you are re-doing high mileage heads, you need a valve job anyway.

 

No, this is my first time through a set of heads. These only have around 30k on them and Im porting them. My main concern is why the depression there right on the seat? It doesnt seem like they'll seal to well the next time around with a gap like that. Its not just this valve seat, but several of them have these strange patterns of craters on the seat. I could see if they where high milage, but these are relatively new.

 

That picture is so high resolution and so close up I can barely tell what i'm looking at. That's definitely the other end of the spectrum of pictures on TGO
You should be able to lap that out. Usually lapping will give a solid ring, not a pencil thin ring - no?

 

I don't know what to tell you ,that is a very hard pic to look at. I'm sure they are fine w/ that kind of mileage.

 

LOL! My bad... Yeah, I scored at a pawn shop near Camden, NJ and got a nice 10 zillion megapixel professional sony camera with zeiss lenses and all that happy jazz...

Heres the overall picture. That litte booger there is actually a sunken area on the seat that looks like it goes right into the chamber. IOW, the valve appeared to not be sealing at that one spot. Most of the seats have strange marks like this on them. Any ideas as to what they might be? My worry is that these where caused by the valve not sealing properly and allowing hot combustion gasses past the valve. Or, theyre some defect thats allowing the valves to leak.

 

Heat, fuel, carbon deposits... lot of stuff going on at the seat. Having some areas like that in the seat arent totally unusual, but yes they can cause a sealing issue. Are you doing a valve job? No worries then. If you are reusing those seats, lap the valves and see if the marks go away or not.

 

They look like theyre at least .005" deep. Too much to take off by lapping? Its weird that theyre not in the exhaust seats as well. Maybe because theyre hardened? Sort of an off the wall thought, but could some fuel additive do this?

 

Oh I see, the pits. I would not think they will lap out. The thing with lapping, is that you will quickly make the sealing surface concave, instead of flat, because of the way the lapping compound squeezes out around the edges of the valve but stays in the middle. Do not lap too much or you will ruin the valve faces anyway. If ~10 seconds of lapping won't take them out, you need a valve job.

Has a beaver been chewing on the bowls of those heads or did someone attempt to port them?

 

Normal. Dirt, crud, carbon, etc. gets hammered between the valve and seat when the motor has been running for a while (thousands of miles)- there's always crud that gets in there somehow. It leaves little pits and scratches over time. When it gets bad you need a valve job. Yours don't look too bad, but certainly not perfect.

Also, the contact between the valve and seat won't be across it's entire width. It will always contact towards the outside edge of the seat's 45* angle. Seats and valves aren't cut at exactly matching 45* angles. Usually they cut the seat at a degree or two less than the valve so you get that contact around the ouside edge of the valve seat. Also normal.

 

Funny... but NO.

I had just started work on that port, but stopped when I noticed the pits on the seats.

Damon, yeah, I took a look at pits and they still have teh machining pattern in them, so it looks like they where just hammered in rather then melted or anything like that.

 

Are you using carbides or just stones? It looks like stones/sanding rolls from the pic. If you are intent on removing enough metal to really increase flow, I'd recommend getting a good set of carbides. They are easy to work with, and you won't be able to take material off fast enough w/ stones alone. I picked up a set of 8 carbides on ebay for like $30. Well worth it. If those pits don't lap out, I would get the valves redone. It's not worth putting your time into porting if the valves are not sealing as well as they could. You don't want to leave power or longevity on the table.

 

Im probably just going to get a valve job at this point. They look too deep to get out just by lapping alone.

More then anything else, Im just removing the ridge from teh core shift (this one had it bad) with stones/carbide cutters on the bad ones (as you mentioned) as well as the ridges from the bowl cutter and then following up with the sanding rolls for finishing the entire port and removing all the junk.

 

Good move. You'd regret it later if you ended up having to take the heads off (been there done that)

 

Just out of curiosity, how much effort is it to step up to a 1.6" exhaust valve? With the 1.5" exhaust valve and tiny port, the exhaust and intake flow seems like theyre really unbalanced with the vortecs.

As far as the porting goes, I just wanted to clean up the crap. It seemed like Stevie Wonder was laying out the cores that day they where cast. Some of those ports where MESSY. Here are some pics of the head thats nearly completed, aside from cleaning up the chamber. I did this one, the beaver has me covered with the other head. I'll be sure to pass on some of your tips to him

Damon,

BTW, are there any good machine shops over in the Philly area? Im only about 15 minutes away from Philla.

 

Someone else sure can chime in, but you cant always just go from 1.5-1.6 valves without replacing seats. Its going to depend on the head so I cant answer that since I've never dealt with those before.

 

For a simple valve job there are tons of shops in the area. I have my favorites, but there are probably plenty near you than can do the job just as well.

For porting or installing larger valves..... that's my secret. Find a shop that knows what they're doing with Vortecs specifically. Porting is something you can pay a ton of money for and end up with crap anyway if the guy doing the work doesn't know what he's doing. Larger valves require that the port be opened up to match so consider that hand-in-hand with porting (if you want it to work well, not just physically fit larger valves).

 

That was my concern since the exhaust seats are hardened and I have no idea how far in that penetrates.

As far as the porting goes, Id just do that myself, but one thing I was worried about is how thin the castings are. Wonder if theres any chance of it becoming *too* thin when Id be done with upgrading the exhaust valves and enlarging the bowls around the valves. Maybe its easier to just leave it and just do a valve job.

As far as the machine shops go, I didn't remember seeing that many advertising locally here in NJ the last time I cracked open the yellow pages to get some machine work done. I also need to have the stock spring seats cut deeper as well as having them machined for screw in studs and the shop I went to had a hard time just swapping out the pressed on bearings on my 9-bolt axles.

 

not trying to hijack your thread dimented but i was wondering if you had a pic of your intake ports... specifically the sealing face... i have 2 sets of vortecs where the bottom of the wall between the intakes is only about .180-.160 wide... no sealing problems so far but it makes me nervous... maybe some detailed pics of your bowl work.... those looked good...

as far as the 1.6 valves i have seen mixed reviews... some say they helped... some proffesionals say they dont and can hurt flow...

here is a good thread about vortecs
http://www.nastyz28.com/forum/showthread.php?t=56505

 

In the thumbnail above, the intake ports are shown next to the bowl. The ports are near stock dimensions as I didnt really remove any additional material except for what was needed to clean up the intake ports.

 

On one of the heads, I happened to notice a void with carbon in it on the head gasket surface that runs about 3/4 of the way across the area where the fire ring sits. Surprisingly, it didn't cause a blown head gasket, but I should probably get the heads milled as well.

Just out of curiosity, how much would all of the following machining typically cost: milling the heads, valve job, machining for screw in studs, and having the exhaust spring pockets cut to the same depth and the intake ones? $300 dollars? More? Less?