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I have a set of new 243 heads, when I was porting them I slight nicked a valve seat. it was the top of the seat, so when the valve was lapped in, it still showed it sealed, but only halve way up the seat. I did a leak down test and no liquid came through.
I don't have any pictures, do you think it will be ok?
There is no way to know if that will cause a problem in the future. You need to fix it. Maybe the engine would run 200K miles without fixing it but it might also run only 10K miles without fixing it. Why wait to find out and then have to tear the engine down again. Fix the potential problem while it is easy to fix.
Bill
Last edited by Bill Dearborn; 08-26-2020 at 09:58 PM.
Me personally i wouldnt worry about it ,but if your asking your going to lose sleep over it. So get it fix. Maybe the machine shop can tell you what needs to be done.
OK, lets say I get it fixed, Im in the UK and no one really knows about LS engines. Is there somewhere I can get the specs and dimensions of a standard 243 zo6 with sodium valve seat? its the exhaust seat.
Im guessing they have to press in a new seat and machine to same spec?
That would clean up with just a touch of the stone. So would need to find a shop with that older equipment.
That looks like a nice valve job actually. Done with a cutter, not a stone.
But the right shop could fix it.
Typically a 45 degree angle. 8mm pilot to fit the guide.
You could get more aggressive with the lapping and maybe improve it.
My concern would be that there's now a "weak spot" there. At some point in the future, it will start to blow by, then you will end up with a burnt valve.
I would find an automotive machine shop and see if they can recut it without losing too much metal. Hard to see from the pic how "deep" the groove is. Otherwise, it's time for a new valve seat.
Last edited by jackthelad; 08-28-2020 at 10:28 AM.
OH brother!!! there is some bad info in here... hey bud... professional ASE certified mechanic and aircraft mechanic here.... the nick is "clean" no high metal and a nice radius.... so zero chance of cracking... your next step is to get some valve lapping compound and lap the valve.... if it still shows a seal (which that low, I'm sure it will) then...... (I know its cliché' but if it seals)... "SEND IT!"
Hi, thanks for all the feedback. I have taken the valve back out again to have a look. I had forgotten it looks a little better after it was lapped in. As I said I did a leakdown test and didnt get a leak. I have contacted a few engine places over here and I think it will be ok.
OK, lets say I get it fixed, Im in the UK and no one really knows about LS engines. Is there somewhere I can get the specs and dimensions of a standard 243 zo6 with sodium valve seat? its the exhaust seat.
Im guessing they have to press in a new seat and machine to same spec?
No, just take it to a machine shop and have them touch up the seat. Not a big problem.
It's easy to replace the seat now. If it were mine, I'd have a new seat installed. My friends call me Mr. Overkill but when I fix something, it's fixed so I never have to fix it again. You might get away with it the way it is but there's a lot of heat there. Whaddya' think, maybe $50 or $60 bucks now and you know it's good. Consider the cost and inconvenience if you have a problem and have to tear it down again. I'm callin' it cheap insurance. AND, you'll always be worrying about it. It may never give you a problem but you'll always be looking for one.
w/psint...I think its fine. Try pressurizing it with some air, or get some fluid in there then do the same.
One of those situations it should be fine for some time but youll be thinking about it while the wife wants to talk about feelings or some chit "you arent listening". wait maybe this is a good thing
08-26-2020, 10:37 AM
I nicked a valve seat when porting, is it ok?
