Is this normal? Cylinder wall (pic)

[trickie]

I just got my head off to replace some valves and wanted to know if this cylinder looks ok to the trained eye. Thanks!

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[Old Mitsu Tech]

First, I would like to know a little more about your vehicle. Update profile.

If you can't feel the lines you probably are ok. If the lines can be felt with a fingernail you may have problems.

Is this the only cylinder or are all of them the same?
Just out of curiosity, why did you pull the head?
What are your goals when going back together?

Give us some more information and we will do likewise.

 

[trickie]

This is a 92 galant vr4 134k miles engine may or maynot have been rebuild about 30k ago. I purchased it with a "blown head gasket"
It was a good price and came with the top end gasket kit so I decided to do the work myself.

While taking it apart I found the belt for the front balance shaft missing (still not sure if I should leave it like that or not )
When I removed the head I found that the head gasket was ok and one of the exhaust valves on the #2 cylinder was missing a chunk.

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So I bought a set of exhaust valves on ebay and will have them as well as the new seals etc put on that head.

I just want to have the car running solid for a good winter car, I dont plan to boost the crap out of it or race it.

Here is a picture of the rest of the cylinders, they dont exhbit the same lines. I rubbed my finger across the wall and I can feel the scratches if thats what they are.

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I guess what I need to know is what kind of problems if any will I have with this cylinder if I leave it? I got good compression 150 psi before i took it apart.

Thanks

 

[98evoIIIpwr]

Well like he said above, if you dont feel the lines w/ your fingernail you are probably ok. I would definetly recommend honing the cylinder though. When you hone it you will want to put cross hatches in it with the hone. When I rebuilt my motor I had the same thing on my cylinder walls. Its not a problem as long as the rings seat w/o gasses passing through of course.

OK just realized you said you can feel them. I could feel some of mine also but they were very faint. After honing the cylinder it ran fine. I would definetly make sure to check clearances when you get it back together. Better safe then sorry

 

[funniegus]

Theres a special tool you use to get those ring grooves out. But as stated above if you dont feel it you should be alright.

 

[trickie]

about the balance shafts, will leaving the rear one hooked up and leaving the front one disconnected cause more vibration than if there were nothing at all?

are the balance shafts working against the engine vibrations individually or are they (balance shafts) working against each other to quell vibrations.

 

[RoasT BeeF]

The balance shafts run in sync to cancel out vibration. Leaving the front one disconnected will cause major vibration and is not recommended.

I would also recommend not just replacing the exhaust valves but the intake ones as well. I believe they are only about $8 per valve and the labor of putting them in will be minimal since they are taking them out anyway to do seals. Also check/replace any guides if necessary.

 

[RoasT BeeF]

I noticed that it appears your valves kissed your pistons. That's what those little notches are on the pistons. Really the only way that could happen is if something was out of time somewhere back down the road. Most likely it's from when the previous owner had it because you just got the car. The pistons should be fine, but it's just good to know everything that going on.

Those in-dents on the pistons are meant for valve clearance and they come that way straight from the factory.

 

[selmerguy]

is that that same cylinder with the bad valve? if so some of those lines in the wall could be from pieces of the valve. i would get the valve job done and put it togeather and see what happens. since it wont be a race car you should be ok.

 

[ArticNemesis]

is that that same cylinder with the bad valve? if so some of those lines in the wall could be from pieces of the valve. i would get the valve job done and put it togeather and see what happens. since it wont be a race car you should be ok.

Definitely doesn't appear to be. The cylinder he posted in the first picture is either 1 or 4, and the valve chunk that is missing is either cylinder 2 or 3. So that rules that out. The scratches in the first picture **almost look like that of a piston with excess sidewall clearance.

In the first pic, the hone is completely gone, where as the pictures with cylinders 2 & 3 look to have the hone still somewhat visible (can't tell from the distance). If you can feel the grooves then something is definitely wrong. Of course, we are speaking of the actual scoring along the middle of the cylinder wall, and not the top ridge of the cylinder deck.

***edit. The cylinder with the scoring is piston #1.

 

[trickie]

ok, a little more info. The pic of the questionable walls is cylinder #4 where I was able to get 150 psi when i did a compression check pre head removal i'll probably just leave it be. The cylinder that had the broken exhaust valve was #2. Im wondering if the use of only 1 balance shaft may have contributed to that. I will make sure to buy a belt and hook up the front one as well.

 

[ArticNemesis]

ok, a little more info. The pic of the questionable walls is cylinder #4 where I was able to get 150 psi when i did a compression check pre head removal i'll probably just leave it be. The cylinder that had the broken exhaust valve was #2. Im wondering if the use of only 1 balance shaft may have contributed to that. I will make sure to buy a belt and hook up the front one as well.

If you say it's #4 then I'll take your word for it (#1 is closest to the timing belt side).

If you have the block out of the car, you might as well eliminate the balance shafts! It gets rid of the chance of the b-shaft belt ruining something down the road. (Just my opinion)

You should really check the piston to cylinder wall clearance on that cylinder, something is definately not right to get that kind of wear and tear on only that cylinder! Find the problem and fix it now, before you have to tear it back down again later to fix it.

 

[Defiant]

ok, a little more info. The pic of the questionable walls is cylinder #4 where I was able to get 150 psi when i did a compression check pre head removal i'll probably just leave it be. The cylinder that had the broken exhaust valve was #2. Im wondering if the use of only 1 balance shaft may have contributed to that.

No, it could not have. The balance shafts are only for driver comfort.

 

[trickie]

ok bad cylinder wall was #1 then if closest to timing belt is #1.
that would make broken valve cylinder #3, i'll get the clearances checked.

Thank you all for your help!

 

[SinaiTSi]

Those in-dents on the pistons are meant for valve clearance and they come that way straight from the factory.

Do you say this because you know or because you think so. I just took my head off the other day and I have those dents, but only on the intake side and that is because the intake valves were smacking against the pistons, I don't have them on the exhaust side and my car is bone stock internals wise. It should really be no big deal anyways, because most likely his pistons are still fine, but it's not like the valves on a 4G63 have never smacked the pistons. Don't get me wrong, I do hope you're right for his sake, but what, only some of the pistons from the factory got those dents for valve clearance.

 

[trickie]

With what little I do know about these cars and cars in general I am confident in saying those dents were molded into the pistons & those are not the stock pistons.

I do not think that my valves are strong enough to make those indentations without bending a single one.

 

[RoasT BeeF]

Do you say this because you know or because you think so. I just took my head off the other day and I have those dents, but only on the intake side and that is because the intake valves were smacking against the pistons, I don't have them on the exhaust side and my car is bone stock internals wise. It should really be no big deal anyways, because most likely his pistons are still fine, but it's not like the valves on a 4G63 have never smacked the pistons. Don't get me wrong, I do hope you're right for his sake, but what, only some of the pistons from the factory got those dents for valve clearance.

I am positive those are from the factory meant for valve clearance. I dont guess on this stuff. It is completely impossible for your car to only have them on one side and not the other unless they are aftermarket pistons.

With what little I do know about these cars and cars in general I am confident in saying those dents were molded into the pistons & those are not the stock pistons.

I do not think that my valves are strong enough to make those indentations without bending a single one.

Those are STOCK pistons. Trust me. They most likely are new from the looks of them, especially if your motor was rebuilt 30k ago. But I am absolutely certain they are stock.

 

[ArticNemesis]

Come on guys, trust roastbeef! They are completely stock pistons.

http://www.dsmtuners.com/classifieds/data/7/110322g_piston_5-large.jpg

Though it's a 2g picture, 1g & 2g pistons have the indents for valve clearance. You will find them on all stock, aftermarket OE, and aftermarket forged designs.

My guess is someone messed up on a ring gap, or piston to wall clearance on that one cylinder, and that's what you have. I don't know what to tell you on the valve, if it collided with the piston, both valves would more than likely be broken.

Possible heat stress, or an improper head rebuild. Was the motor rebuilt due to a snapped timing belt the first time? Or what reason was. I'm curious, because from your pictures only certain valves were replaced.

164psi is the standard limit for a 1g, and 121psi is the service limit. If you have 150 across the board, then obviously the rings are holding compression.

I'm curious though, how did compression in cylinder#3 come out to 150psi with a broken valve like that. Are you sure it was done right? I'm not trying to accuse you of not doing in correctly, just trying to cover bases.

However, if you just want to replace the valve, and throw it back together, it **should run. There is no telling for how long, especially since the scoring on the cylinder wall is like that. Granted 150psi shows the rings are holding compression.

It's your motor, so you have to decide what you want to do, and what your budget is on fixing it.

 

[trickie]

Artic, #3 cylinder showed 0 psi when i did the compression test, the other 3 were anywhere from 140-150 #1 being the highest. Im probably going to let #1 stay the way it is because I dont have the money or the knowledge on removing pistons to fix it.

The reason it was rebuilt in the first place is unknown to mas as this car changed hands a few times it may have just been a low quality job seeing how they just left the front balancer shaft belt off without removing the rear.

 

[Spyderman7]

It looks like the oil rings are shot on the pictured cylinder.You can get good and sometimes better compression readings,It's like doing a wet test all the time.It will however burn tremendous amounts of oil(a quart every 20 to 30 minutes)You're wastjng your time if you don't pull the pistons.The block is not that bad,hone it and put in new rings and bearings.The balance belt being off,you need to see if it spins freely and if there is any up and down play.Sometimes the balance shaft starts to seize breaking the belt.You can leave the front balance shaft in place with no belt so long as the bearings have not spun out of place and you remove the oil pump balance shaft and replace it with the oilpump driveshaft from a 1989 to 1992 mitsu mirage 1.5 .They don't have balance shafts but use the same oilpump.Part #md098626 $10.00 .This is the part that comes with most balance shaft removal kits.You don't need the whole kit unless your bearjngs have spun out of place.You should replace the oilpump.You can not just remove the front shaft without doing something with oil feed holes.

 

[Defiant]

it may have just been a low quality job seeing how they just left the front balancer shaft belt off without removing the rear.

That's a fairly common practice. Do you know if the rear balance shaft is in the engine?

 

[trickie]

yea the rear shaft is still in

 

[SinaiTSi]

I am positive those are from the factory meant for valve clearance. I dont guess on this stuff. It is completely impossible for your car to only have them on one side and not the other unless they are aftermarket pistons.



Those are STOCK pistons. Trust me. They most likely are new from the looks of them, especially if your motor was rebuilt 30k ago. But I am absolutely certain they are stock.

I believe you, when you say that those are the factory pistons. It just didn't make sense to me because I thought that my car had the factory pistons in it, but apparently not. I don't have any notches for my valves on them, till my intake valves smacked them and put notches there. The owner before me had them replaced sometime apparently by pistons that didn't have clearances.

 

[compression]

the special tool for cleaning cylinder walls is a engine honer i believe, and the "dents" in the piston are called reliefs. most engines look like that internally, like has been said as long as you cant feel it , and everything else looks decent.