kagato

During my cleaning process I noticed this!

What do I need to look at/check? I assume this was caused by over revving and valve float maybe? Car seemed to run fine before I had it apart.
The heads are not going back on since its apart for a head/cam swap but want to make sure the shortblock is ok and the stock heads as well if I ever sell/reuse them.
I cant see any obvious damage to the valve faces or evidence of the contact point

98z-28redcamaro

iTrader: (3)

thats not too bad... i have a t-rex cam and my pistons all have a kiss from the valves.... Tick Performance told me that ls1 cars with big cams have usually show up with a kiss from the valves on the piston.

kagato

My car is stock internal up till now!
Understandable it happens with a big cam but I would think its still not good to have happen.
Any thoughts on what I should do about this guys?

Grimes

iTrader: (3)

what springs are you running and what kind of mileage do they have on them?

Duffster

iTrader: (103)

Yes you kissed and it's most likely fine. Check your valves for that cylinder and go from there if needed. IF they're still straight and fine, forget about it

vettenuts

iTrader: (4)

On a stock motor the springs get weak with miles and will float well before redline. Likely the cause.

kagato

Everything internal is stock as of now. 53K on the car/motor
Will check the valves sometime, thanks duffster (not in a rush with head inspection since new heads are going on)
So I shouldn't be concerned about the bottom end/pistons then?
thanks for confirming vettenuts
Thanks guys

technicalninja

iTrader: (1)

Quicky test for bent valves that doesn't require taking head apart. You can brace the head with the port upright and fill it with a testing fluid. antifreeze works well as it has almost no surface tension and will tend to leak through tiny cracks. Ever seen a ceramic coffee cup with stress cracks in it that holds coffee fine. It won't hold anitifreeze.
Fill to top of port and walk away. Check it after some time has elapsed. Still full, You may be fine!

The only correct way IMO to verify valves are not bent (without a trip to the machine shop) is to hand lap test them.
Dissemble and clean the valve seat surface and the valve face that meets this seat; wire brush is fine, I use a bead blaster. You can use the dykem-blue if you have it but a permanent wide tip black magic marker works equally as well. darken both mating surfaces and place a TINY bit of fine lap compound on the seat in 4 equally spaced spots. Oil stems/guide with thick oil (think 50 w or 90 w gear lube) this helps center the valve in the guide. Wipe oil off of the installed valve tip and shove a 8mm/5/16 peice of fuel hose on valve stem almost to the guide. 15 seconds of "trying to start a fire with a round stick in a hole" type action with very light down pressure will remove the marker ink all the way around the seat and on the valve face. Lift the valve off of the seat every couple of seconds. If your valve is bent you will be able to see it. one side will be clean and one side will still have marker on it. If it was bent even the smallest amount I'd replace the valve as the head to stem area will have already been "stressed" once and be far more likely to break down the road.
The head needs to be held upside down (combustion chambers up) on a set of cylinder head stands for this to work properly. if it's on its sides gravity will tend to pull the head of the valve down one direction and this test is in-accurate. Your "floating" the valve head into the valve seat using this method.

Don't have lap compound? You can make some out of tooth-past or grease and a fine abrasive (comet, sugar, cigarette ashes, superfine sand).

The above method is what I use to check a used head for valve contact pattern anyways. If I was to the point of having them off I'd check all 16 even without evidence of valve contact to see If I needed to have a valve job done. I'd replace the stem seals at this time as well.

If it all looks ok but you have minor pitting (more common on seats than the valves) you can clean them up using this same method with greater down force/more lapping time. Get real lapping compound for this job. All I use is the fine compound. If the seats/valves are to the point that the coarse is needed they need a real valve job.
I also check fresh valve jobs from machine shop using this method. You'd be suprised at what you find. Not all machine shops should BE machine shops. Always verify machine work if you can.
hope this helped.

garygnu

I like the home made lapping compound .

kagato

Thanks a ton Ninja!
Will do this when I get the time

orangeapeel

iTrader: (18)

Cigarette ashes is a new one to me! lol. I have used comet in toothpaste.

technicalninja

iTrader: (1)

Ever need to remove permanent marker from a surface you don't want to put a serious chemical on? (think 3 year old with a marker assulting a brand new $1500 refridgerator)
Cig ashes and spit work perfectly!
Smells a bit weird but works great!

Yep I'm a smoker and I know I should quit!
I'm pretty smart about most things,
and dumber than dirt at others.

samdogmx

iTrader: (14)

all 8 of my pistons looked like that when I pulled mine apart for the head & cam swap. I also was on stock cam & stock springs.