Head valve leakage

[Luchitosan]

Hello, I will try to detail this the best I could so need go chronologically.

1- When the engine was rebuid someone suggested use ordinary/ economic oil at first 1000/2000 kms.
to clean all the dirt which can remain in it. So I did...
2- One lifter of cilinder 1 had a leakage (I think was intake). So change it for another used but good shape.
3- Engine work fine for a few kms
4- Change the oil for Motul 10-40w turbolight , some say it cause it bad oil (has a leak when I fix it goes with 300v)
5- Engine was better, but still has a failure the sparks plugs on cilinder 1 looks like these compare cylinder 1 and 2


DSC04678 por Luchitosan

DSC04679 por Luchitosan

6- Check the compression and cyl 1 has 20 psi LESS that the rest
7- Pull out the 4 lifters to disassembled for cleaning and found this in one of them...

DSC04662 por [url=https://www.flickr.com/photos/luchitosan/14578704216/]
DSC04660 por Luchitosan
I forget which of 4 was

8- Need the car so change the shim of the lifter, assemble all and has the same problem...
(see video to listen and "feel" the engine failure inside the car, vaccum, oil press, etc)
https://www.youtube.com/watch?v=59DNLak ... e=youtu.be

The thing is I,m rebuilding another head with solid lifters, custom cams, etc, etc but by now
NEED this works fine and WANT to know WTF is goin on....
My idea is measure and compare with the other valves and "SCABBLE" the steam of the valve is leaking
to allow the lifter close properly.

A- Can be wrong another thing ? What ?
B- How Fix it ?
C- Feel free to review and ask

Thanks...

[float_6969]

Have you done a leak down on that cylinder with all the lifters out? Maybe the blockage caused the lifter to pump all the way up and open the valve enough to damage it by contacting the piston, of if it was on the exhaust side, burn out due to not closing all the way.

[Luchitosan]

Yes, tested w/o lifters and all cylinders are equal. No leak at all.

[float_6969]

Is just replacing it an option for you?

[Luchitosan]

I switch places each to other from diferent cylinders and then change the lifters and still the same.

What I didn't do is measure the long of the steam of the valves yet.

What you think ?

[float_6969]

I can't imagine why that would be off... unless when the head work was done they didn't grind the valve stem down to account for the change in height for grinding the seats and valves. Then maybe it would be too tall and not close all the way.

[Luchitosan]

Thats what I suspect, but need to make sure before, for that I create is this post.

[float_6969]

I talked to a reputable head shop yesterday and he said that what you're describing is possible, but that would be pretty poor machine work. He said that for them to remove enough material off of the valve and seat to cause the valve to move up enough to not allow a hydraulic lifter to close and leave the valve open would be A LOT of material. He said that when he see's something that far out, he tells the customer they need a new valve and/or seat. He said it had something to do with the way the valve sat in the head when they were ground that much made them flow poorly. At least I think that's what he was trying to tell me, LOL.

Anyway, it sound like you got some crappy machine work. The head is going to have to come off to pull the valve out. I would pull it, put the cams back in and see if you can see the valve(s) lift on that cylinder. If you can, I would take it back to the machine shop that did the work, show them what's happening, and tell them to fix it PROPERLY this time.

[Luchitosan]

Thanks Float !

That's what I inquire arround here, so now it's confirmed.

A- The machine shop was recommended for a "friend" and do this work in early 2012, It has 35 years of work, but last year become bankrupt. So no tears, no refounds, no warranty, just f*** Me. It's long story of this car and engine (I if want and have time I can tell you)
but the block and all bottom end was machined in another place that specializes in race engines and developments, so I'm cool with that at least.

B- I'm gonna' measure the valves (I'm guess goin to notice a significant difference in the "bad" valve) to confirm how much difference
then gonna lift up the head or something.

C- The head in this motor looks very bad treated in the past, cause of that now I have 3 heads 4 ports in stock, just in case.

I'm ANGRY now, but I thank you for the trouble you took and the research.

[float_6969]

That sucks that you don't have any recourse for having it repaired properly, but I hope you keep working on it and get it all sorted out!