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Grinding Valve with head on engine
Topic Started: Aug 17 2014, 12:18 AM (1,908 Views)
wanderingturtle
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yes this is crazy but it just might work..

My problem is a burnt exhaust valve on cylinder 3.

My idea is:
Disconnect exhaust manifold from exhaust pipe (to keep from getting oil into cat). Ensure the cylinder is TDC. Remove the camshaft and the valve lash adjuster. Hold the end of the valve stem with vice grips, compress the springs in some manner, remove the valve keepers. Release vice-grips, hold the valve stem in some manner, and remove the retainer and spring. Fill the cylinder with oil (through the spark plug hole). Tighten an electric drill onto the valve stem. Spin the valve while pulling it upwards to apply pressure tot he seat, also letting it down frequently to keep the valve and seat covered in oil and to flush away metal, and ensuring that the cylinder stays full of oil. After turning the valve for a presumably sufficient time, release the valve. Flush the cylinder with oil to remove any metal flakes. Reassemble in reverse of disassembly. Test compression. Maybe wait until after running engine to reconnect exhaust, to burn the oil out of the exhaust manifold.

Do you think this will do any good? Yes, even if it did work it would be a very temporary fix. So you don't need to tell me how wrong it is. I just want to know, could it work?
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geogonfa
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All this work and to think your only a few more steps away from pulling the head...and just my $.02 this will not help... :type
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David95237


Have you ever seen a burnt valve? They have pieces missing. You have to change the valve.
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wanderingturtle
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Yes but pulling the head means head gasket set. If I'm gonna do that I'm gonna replace valves, rings, etc. Right now I just want to kick the can down the road. So what I want to know is, fundamentally, will spinning the valve in oil like this be likely to help reseat a burned valve?
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wanderingturtle
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David95237
Aug 17 2014, 12:34 AM
Have you ever seen a burnt valve? They have pieces missing. You have to change the valve.
Ok.. dangit
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rv93
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no. it wont. one, a burned valve is not just a slightly messed up sealing surface. burned is a bad term for it. cracked or broken are better. it happens when a chunk literally falls off the valve. second, everything else thats wrong with what youre doing. no, you cant grip the valve in any manner while the spring is still on. the retainer and keepers are more or less flush with the top of the valve stem (there is a trick with rope you could use to get past that particular obstacle, so well leave that alone for now). second, when grinding a valve, you need to use a grinding (or lapping) compound. this is what actually does the work. spinning the valve against the seat wont do anything. at all. listen to these good people. take the head off. if you wanna go cheap and reduce the chance of success, do it smart. number one, you can reuse the head gasket. no, its not a good idea, but if you coat it with copper sealant spray on both sides, and clean the mating surfaces of the head and block properly, id say you have a decent chance of being ok. second, you can reuse the head bolts. they are not torque to yield. clean up the threads on the bolts and the block when its all apart, and *lightly* coat the bolts with oil whhen you put them in. that last one i actually did. third, changing the rings is a separate job from messing with the head. whole different game. dont mess with them if they work fine now. you also wont have the replace the other valves, but the burnt one will have to be replaced. what i just told you would take you around a full day if youve never done it before and you have some mechanical ability and common sense. if you try to cut more corners than that, you will fail.
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geogonfa
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So I dug up a pic of a Metro head with a burnt valve so you know what your dealing with...

Posted Image
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Hanuman
"The Almighty Grounds Cleaner"

rv93
Aug 17 2014, 12:44 AM
no. it wont. one, a burned valve is not just a slightly messed up sealing surface. burned is a bad term for it. cracked or broken are better. it happens when a chunk literally falls off the valve. second, everything else thats wrong with what youre doing. no, you cant grip the valve in any manner while the spring is still on. the retainer and keepers are more or less flush with the top of the valve stem (there is a trick with rope you could use to get past that particular obstacle, so well leave that alone for now). second, when grinding a valve, you need to use a grinding (or lapping) compound. this is what actually does the work. spinning the valve against the seat wont do anything. at all. listen to these good people. take the head off. if you wanna go cheap and reduce the chance of success, do it smart. number one, you can reuse the head gasket. no, its not a good idea, but if you coat it with copper sealant spray on both sides, and clean the mating surfaces of the head and block properly, id say you have a decent chance of being ok. second, you can reuse the head bolts. they are not torque to yield. clean up the threads on the bolts and the block when its all apart, and *lightly* coat the bolts with oil whhen you put them in. that last one i actually did. third, changing the rings is a separate job from messing with the head. whole different game. dont mess with them if they work fine now. you also wont have the replace the other valves, but the burnt one will have to be replaced. what i just told you would take you around a full day if youve never done it before and you have some mechanical ability and common sense. if you try to cut more corners than that, you will fail.
"third, changing the rings is a separate job from messing with the head. whole different game. dont mess with them if they work fine now. "

:banghead no! no! no! no! no!
if you do the head on a suzuki G-series engine you must change the rings!
for some reason when you do the head even if the rings are in great condition, the engine will pull oil past the rings.
unless, you enjoy replacing your valves on a regular bases!

ask me how i know. :D
ask many, many other members on the forum how they know. :D :D :D
:thumb
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wanderingturtle
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Posted Image

Ok, I guess it wouldn't have worked. Funny thing is, cylinder 2 had better compression than 3. BUT, compression was tested before I drove it 25 miles on hilly terrain running on 2 cylinders. So no telling what the compression was after that.
Edited by wanderingturtle, Aug 17 2014, 04:16 PM.
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wanderingturtle
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Took a little over an hour to pull the head. You guys were right, these things are easy to work on. I haven't had an engine that I could easily turn the crank by hand. The head bolts were very tight. But once I had them off, the head just came loose. I bet I can reuse that gasket, it just fell off, no damage.
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wanderingturtle
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And yes, I am gonna do the rings, too. But probably not rod bearings, since I read on here that it's hard to get the right clearances, anyway. On the head, do I need to replace valve guides too? Or can I just replace the valves and valve seals? I searched but it wsa hard to find any info related specifically to valve guides.
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geogonfa
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Again...just my $.02...replace the head gasket...Auto Zone...felpro 90 bucks...as well as the head bolts...they are TTY...big chance they will :die
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Cubey
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geogonfa
Aug 17 2014, 04:46 PM
Again...just my $.02...replace the head gasket...Auto Zone...felpro 90 bucks...as well as the head bolts...they are TTY...big chance they will :die
$90 for a head gasket at Auto Zone?!?!

They're $49-53 at O'Reilly depending on which brand you get:
http://www.oreillyauto.com/site/c/search.oap?keyword=head+gasket&year=1993&make=Geo&model=Metro&vi=1141771

The bolts are $20-33 depending which brand you get:
http://www.oreillyauto.com/site/c/search.oap?keyword=cylinder+head+bolt&year=1993&make=Geo&model=Metro&vi=1141771
Edited by Cubey, Aug 17 2014, 06:04 PM.
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geogonfa
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Not just the head gasket...every gasket needed to do a good job...
http://www.autozone.com/autozone/parts/1996-Geo-Metro/Head-Gasket-Set/_/N-j5039Z8znn4
and the head bolts...
http://www.autozone.com/autozone/parts/1996-Geo-Metro/Head-Bolt-Set/_/N-j5039Z8znp2
:type
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Memphis metro


Clean and lubricate the head bolt threads in the block before putting it back together and do not loose the oil check valve in the block. Replace the head gasket with a new one. Make certain you use the correct torque values on everything. Hone the cylinders.
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