Bad heads, China valves

[BigMikeIT]

Hi,

I was looking into all sorts of information about DIY head porting. I found this link about a guy speaking about bad valves (China Valves), advice on what things should cost if buying a complete head, or just buying it bare and doing it up.

Anyone try porting their heads or run into poorly seated valves, etc?

[magnus77]

I lightly ported my gt40p heads, got rid of the bumps and flash and all that. Just smoothed any imperfections out and am likely going to lap the valves myself with the grinding compound either this week or next before I put them on the car.

[BigMikeIT]

I lightly ported my gt40p heads, got rid of the bumps and flash and all that. Just smoothed any imperfections out and am likely going to lap the valves myself with the grinding compound either this week or next before I put them on the car.

One guy online showing using a drill at slow revs rather than hand lapping them.


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[gadget73]

If you're buying aftermarket heads, I'd go with something like an AFR. They don't sell crap. If they're real cheap, they're usually made offshore and may have questionable parts. I've heard of people bolting on cheap "high performance" heads that were no better or worse than factory castings.

Still, dude isn't wrong. Better to verify its right before it goes on than to find out its crap after.


I have done a stock rebuild on E7 heads. A guy I knew that had a valve grinder helped me grind the valves and seats, and I lapped them in by hand. Its real easy to verify they seat properly. You can do it with nothing more than magic marker, though high spot (bluing) compound works a little better. Just color the valve seat and drop the valve in. Spin the valve, and pull it back out. If its right, the marker will wipe off evenly and transfer to the valve. If you get high and low spots, you'll see where it hits or doesn't hit.

[merc91]

I have yet to actually come across these "china" valves that are junk. I doubt many valves are made in north america any more as china gets the exact tooling/process just cheeper labour/business costs really.

I have a 3-5lbs pressure spring i use to lap valves and a drill with a flex attachment. Just kinda let the drill float and keep oil in the guide to lap it exactly as it wants to sit without side loads. Highly reccomend fine lapping compound vs the coarse grinding compound if just touching up as routine maintenance.

Do lots of reading about the specific head you are doing and where people have removed material to gain flow #'s... Oem heads are really weird where they like and don't like material removed.

[knucklehead0202]

Some heads are very obviously cheap junk but people still use them and make power with them. Look at all the jerks out there with Pro-Comps and a cheapass On3 turbo setup doing 10-second and lower 1/4's. I personally wouldn't buy that shit but the Chinese stuff at this point is not THAT far off in quality from the major guys and at a fraction of the price. I actually did buy a Pro-Products intake because the price was ridiculously low. It's almost a dead-ringer for a genuine Edelbrock, not quite as cleaned-up but no notable quality defects.

Worst case, if you buy cheap heads, get them bare and buy good valvetrain components. You may not save as much in the end but have more peace of mind that way. Your experience may vary.