Problems with worn valves. Need good advice

[Donal]

@swathdiver what they sometimes do is change the valve seats, but not the valve stem seals. And the ones they used were too short, which caused the disintegration of the valve stem seal housing, so to speak, from the seal itself.

@rockola1971 how should over tighten rocker arms, wear the valve stem tip cover? The rocker arm assembly sits on the cylinder head. If you use too much torque, then you may damage the threads, but you will not get movement or too much pressure on the valve stem tip. The pressure on the valve stem tip comes from the spring and the camshaft. And there is a supplement from GM that the rocker arms of the aluminum heads should not overtighten 24nm which can cause the threads to fail.

But thank you both for trying to think about that with me. That makes a forum good, to exchange with people with the same afficination.

For me at the moment, I can only see two reasons for that wear. Too much friction, because of a lack of lubrication, or less quality of the valves.

Too much friction I would denie, because oil pressure was all the time good. I used good quality oil and changed it regularly. As well. Why only the intake valves are affected? I mean, if the intake and exhaust valves have the same quality, the exhaust valves must wear more, because of the higher temperature.

So I think, when they did the cylinder head, and the former owner told me, that they did the valve seats, they probably used cheap intake valves, which are not hardened enough.

Fact is: I cannot drive that engine anymore, until I do the cylinder heads, because if this small rest of the tip breakes, the valve spring releases and the valve falls into the combustion chamber….

Then the engine is for sure ready for the junk yard.

Valve is not correct for valve for the engine. Pull the head, replace valve. retainer, seal, locks and rocker arm. Verify that all other valves are correct length.

 

[nonickatall]

I had a friend here today, he is a professional technician and he saw that the valve stem seals are not broken, they cut it and used some universal seals. So they took the base from the old seals probably to prevent the spring to work into the aluminium of the head.

What morons...

And he has as well the opinion, that the intake valves where to weak from the material and wear out for that reason.

So i need to disassemble the enginge and rebuild it.

Not a good timing now... But what is a good timing for a failed truck engine.

But I am an optimist.
I am glad that i found out, before an intake valve failed and ruined the engine.

As the British say:
A pessimist says: All women are bad. An optimist hopes they are...

 

[rockola1971]

If the engine is not stock and the cylinder heads were machined smooth this essentially puts the rocker arms closer to the valve stems. The fix for this is buying correct length pushrods but if someone just stuck the originals back in then that would cause irregular wear. Could have been just the affected valve got a mixup of pushrods or the others are slightly bent. Need to take atleast the worn valve's pushrod out and check its length. How is the roller on that rocker?

 

[nonickatall]

I understand what you mean. I saw some rebuilt videos from the LS/LQ engine. Isn't the risk not rather, that if you have too long pushrods that your valve is going to contact the piston? So the clearance of the piston is the problem, with the lengths of the pushrods from what I understand?

As far as I have saw it until yet. My pushrods from the intake and the exhaust Valves are the same.

The rollers of the rocket arms seems to be in a very good condition. As far as I have seen, the rocker arms looks absolutely brand new.

As well the two Tipps of the pushrods look brand new.

 

[nonickatall]

I removed today all rocker arms, inspected all valve tips and as well made a pressure loose test on all cylinders.

Six of eight intake valves are worn in. All more or less the same.

Only two intake valves look ok. All exhaust valves are not affected.

Pressure loos test was on all cylinders nearly 100% good. But when I put pressure on cylinder 2, coolant comes out of the coolant line, that I disconnected for better handling.

So it seems that i also have a problem with the cylinder head gasket.

Ich werde nicht darum herumkommen, den Motor komplett zu zerlegen und neu aufzubauen.

Two month before my ex wife leaves the house and I now have to bear all the costs myself. She also takes the second moving car with her.

Perfect timing.

I think she's a witch and put a spell on my truck...

i always wondered why she leaves the house in the night and dance with the bats before she eat them.

My wife always said that all women do that.

I'm starting to have doubts...

 

[SilverSport]

I know mine did...

Bill

 

[Mudsport96]

I removed today all rocker arms, inspected all valve tips and as well made a pressure loose test on all cylinders.

Six of eight intake valves are worn in. All more or less the same.

Only two intake valves look ok. All exhaust valves are not affected.

Pressure loos test was on all cylinders nearly 100% good. But when I put pressure on cylinder 2, coolant comes out of the coolant line, that I disconnected for better handling.

So it seems that i also have a problem with the cylinder head gasket.

Ich werde nicht darum herumkommen, den Motor komplett zu zerlegen und neu aufzubauen.

I don't think a complete engine disassemble in required. I would just remove the heads and repair them. Or if you can find some already machined or remanufactured heads. Remove yours and put the new ones in their place. With new gaskets of course. But I don't think a total rebuild is needed. It could also be that there is a cracked head and that is causing the coolant bubbles.

 

[nonickatall]

I don't think a complete engine disassemble in required. I would just remove the heads and repair them. Or if you can find some already machined or remanufactured heads. Remove yours and put the new ones in their place. With new gaskets of course. But I don't think a total rebuild is needed. It could also be that there is a cracked head and that is causing the coolant bubbles.

Yes thats true, but i have also the problem of a weak compression on cylinder 5 and i would as well check the camshaft, the main bearings of the crankshaft and piston rod as well, as i would change main crankshaft sealings and clean and check the piston rings, and look for the barbell.

And my experience is: it is much more comfortable to work on a pulled engine, than working hunched over the high side of the truck the entire time.

And i am also afraid, spend all the money and time just to find out, that i still have a weak compression, because of stuck or worn out piston rings.

And i have a garage with two lifts, a motor crane, and a motor stand for comfortable working.

And i would give the block a painting, clean everything and give the truck the love it deserves, when my wife refuses my love i have to spend ..

And i am looking foreward to work on that engine. I am so common with working on that Audi, BMW and Mercedes shit, that this will be like Holliday...

 

[nonickatall]

So today drove 900km through Germany to get two used 317 cylinderheads in a very good condition, a rebuild automatic transmission and some other spareparts for realy good money.. So it was worth to go that long trip..
..

Now i need gaskets and time and then the rebuil will start...

 

[Mudsport96]

Those look to be in very good condition. I am glad you were able to find a good set.