New Cylinder Heads = No Compression???


FATHERnSON

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These valves have not been used at all... I installed them into the head... My mechanic friend said I didn't need to grind the seats as both the valves and heads were new. Sorry for the confusion, but I did the warm water test just with brake clean as it is thinner and my friend said to... I poured them in the same place and had no leaks. As for the installed height I'll check that... Was the new lifters a good call??? My dad thought it was (I'm sixteen)
 


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RonD

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Yes, check the valve stem heights with rockers removed to make sure they are all the same height
Just a straight edge across the top is fine, actual length is not the issue, yet, lol, all just need to be the same height

Well new lifters can only be installed with heads off, so its a judgement call at that time, hydraulic lifters do fail/collapse and that causes a tapping noise and slightly lower power on that cylinder, but engine is still drive-able
If over 100k miles then I would probably put in new lifters on speculation
 

FATHERnSON

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The valves have never seen use in an engine. They are unused castings. I purchased the bare heads and assembled the valvetrain myself. I am sorry about the confusion on the liquid test. I did exactly what you did 55Trucker with the only difference is that I used brake clean because my mechanic friend told me to do so as brake clean is thinner. I also poured brake clean on where the valves sit (I am not sure of the technical term) on the bottom side. There were no leaks. I then cleaned everything down and did what you mentioned. We ended up purchasing new lifters as they are pretty stiff. After some reading, my dad and I (I'm sixteen) think that could be holding the valves open since they didn't have to compress as far to close the valves because the rocker arms were pitted on the side it comes in contact with the valve stem. Was that the right call and do you think that could solve my problem. The lifters are the only part of the valvetrain I haven't replaced. Thanks a lot guys!
 

FATHERnSON

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My apologies for the double post - technical difficulties
 

RonD

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Did you test the valve stems with a straight edge yet?

You have established that the valves don't leak liquid, so that's done

What you need to establish is that the valves are all seated at the same height, some are not higher than the others
So just put a straight edge on top of the valve stems and see if they are all the same height


Yes, lifter springs are hard to press down, they are suppose to be, but they are NOT as hard to push down as valve springs
So a rocker/lifter can't push open a valve until lifter is fully compressed, which is about a 1/4" travel
When rocker assembly is torqued down, lifters will be compressed about a 1/8" about 1/2 full travel
Yours are being compressed more on some valves so valve is being held open

Pitted rocker, on either end, won't cause your issue, it can cause "ticking" when engine is running but not loss of compression
 
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55trucker

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a little more clarification needed.........you have purchased a new set of lifters but they have not been installed?.......*We ended up purchasing new lifters as they are PRETTY STIFF. *....is this a reference to the old or new ones?
New lifters with no oil in them will compress as far as the plunger will go, the lifters currently in the engine will not as they are *pumped up* (full of oil), seeing as all else appears to be within spec the old lifters may be gummed up internally & are literally seized & cannot bleed off. With a used set one disassembles them & cleans them in kerosene to free them up, seeing as you have new ones install them, and that's an involved task.
 
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FATHERnSON

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I purchased new lifters and am waiting for them to arrive. I cleaned the old ones in kerosene when I took the heads off the first time, but they are still very stiff.
 

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Straight edge test yet?
 

FATHERnSON

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When installing the lifters is there any special steps to "prime" them with oil or fill them with oil or just slip them in the slots and they are filled with oil in the process of oil cirulation???
 

FATHERnSON

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Sorry... At school right now... couldn't do it it yesterday because I had a HUGE paper due... Imma do that after school today
 

FATHERnSON

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Did the straight edge test; all are level. Just for clarification, can failed lifters cause zero compression??? As well as what should my next steps be???
 


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