[Battle_918]

OK so first off, thanks to the guys who showed me where to get a service manual for my goodwrench 350. Like I said before I was going to take my heads off, have them rebuilt, and put them back on myself (with the help of that manual of course). Again, this is the first engine work I've done EVER, but I figured it was pretty straight forward. But I've heard from more than one person that "If you rebuild the top end of the engine without rebuilding the lower end, then that could create more problems and you will risk having the bottom end going out and needing repair". If that is true then wouldn't I be better off replacing the engine all together or is that something I should take with a grain of salt. The engine is about 3 years old, the mechanics I had look at it all said that it was in great condition minus one valve and valve spring that they said needed to be replaced along with whatevers under all of that so they insisted that I replace both heads to be safe and they all know thier engines but they never said anything about the lower end of anything and for the job they are asking way too much so I said Ill do it on my own, with help. So if possible could someone elaborate what was meant by "the lower end could go out" and if so how could I find out if that is the case. Thanks and as you all can tell, I'm still learning about all of this so a lot doesn't make sense to me yet. thanks again.

 

[EdontheBeach]

the gm bottom end is solid as a rock, but then so are the heads - i would just replace the valve and spring. HOWEVER, since the head would be off, you may as well do a complete head job

 

[steelybill]

Having the bottom end fail after replacing heads, or doing a valve grind, is an old wives tale, which is popular in BS sessions. If the bottom end is like you say, you can do anything you want to the top end. Removing the heads is the only way to know what's going on with the valves etc Maybe just getting the heads re-done at an automotive machine shop is all you need.
Of course if you want new heads & can afford it, that's OK too....

 

[80v6]

cylinder head rebuild

Bottom end going out means once you repair the heads etc. and reassemble the engine that the new found performance will accelerate any issues with parts in the short block. if you had good oil pressure, strong, stead vacuum readings and no fluid issues such as oil burning, chances are youll be safe by repairing the heads and reassembling the engine.

 

[SINISTER]

Mileage?
Heads really make an engine.
Bottom will last if you don't turn a ton of rpm's.
Swap the heads and cam and have some fun.

 

[fixitman1]

stead vacuum readings :dontknow:what the heck is this ??? new one on me after 35 years of building engines .

 

[woody31]

Mileage?
Heads really make an engine.
Bottom will last if you don't turn a ton of rpm's.
Swap the heads and cam and have some fun.

X3 :texas:

 

[Battle_918]

Thanks guys, thats really what I needed to hear. and yeah oil pressure has always been fine along with everything else. Ill start with having the heads rebuilt and reassembling to the engine and go from there. I honestly would rather do it on my own anyway it seems more satisfying and all I hear about is how these are the easiest engines to work on. thanks again. Maybe after I a while I'll be able to actually give some advice. :nanawrench:

 

[fauxrs]

OK so first off, thanks to the guys who showed me where to get a service manual for my goodwrench 350. Like I said before I was going to take my heads off, have them rebuilt, and put them back on myself (with the help of that manual of course). Again, this is the first engine work I've done EVER, but I figured it was pretty straight forward. But I've heard from more than one person that "If you rebuild the top end of the engine without rebuilding the lower end, then that could create more problems and you will risk having the bottom end going out and needing repair". If that is true then wouldn't I be better off replacing the engine all together or is that something I should take with a grain of salt. The engine is about 3 years old, the mechanics I had look at it all said that it was in great condition minus one valve and valve spring that they said needed to be replaced along with whatevers under all of that so they insisted that I replace both heads to be safe and they all know thier engines but they never said anything about the lower end of anything and for the job they are asking way too much so I said Ill do it on my own, with help. So if possible could someone elaborate what was meant by "the lower end could go out" and if so how could I find out if that is the case. Thanks and as you all can tell, I'm still learning about all of this so a lot doesn't make sense to me yet. thanks again.

My first reaction is to suggest you find new mechanics, because these guys are out to hustle you out of money. I cannot conceive of 1 valve and 1 spring in an otherwise acknowledged good 3 year old motor being able to remotely justify two new cylinder heads. Even if you grenaded one head there would be no reason to discard the other.

To be safe from what? The red menace? even if one head had to be replaced the most you would have to consider on the other is a lapping of the valves just to refresh the seal those valves deliver in comparison to the new head.

 

[fauxrs]

the gm bottom end is solid as a rock, but then so are the heads - i would just replace the valve and spring. HOWEVER, since the head would be off, you may as well do a complete head job

I totally agree with this, if the problem is all on one valve, fix that valve. Surely if you want to do a valve job on the entire head now would be the time but for a 3 year old motor, it really shouldnt be necessary.

 

[Battle_918]

My first reaction is to suggest you find new mechanics, because these guys are out to hustle you out of money. I cannot conceive of 1 valve and 1 spring in an otherwise acknowledged good 3 year old motor being able to remotely justify two new cylinder heads. Even if you grenaded one head there would be no reason to discard the other.

To be safe from what? The red menace? even if one head had to be replaced the most you would have to consider on the other is a lapping of the valves just to refresh the seal those valves deliver in comparison to the new head.

That is EXACTLY what I thought and I asked if they could just do the one or at least just the valve springs and valves and they told me that there was some type of leak in in the cylinder, I can't remember exactly but I think he had said there was a little bit of oil so there may be a leak in the one cylinder? thats what they made it sound like. they said the others were fine but if one is going the others aren't too far behind. which is why the mechanics said to replace both.

 

[Battle_918]

That is EXACTLY what I thought and I asked if they could just do the one or at least just the valve springs and valves and they told me that there was some type of leak in in the cylinder, I can't remember exactly but I think he had said there was a little bit of oil so there may be a leak in the one cylinder? thats what they made it sound like. they said the others were fine but if one is going the others aren't too far behind. which is why the mechanics said to replace both.

Also to make it clear. With everything that was said to me by the mechanics, the ONLY thing that I was told that needed to be repaired/replaced were the Heads, even with whatever leak they were talking about. If it helps to describe the issue with the one cylinder thats misfiring, when everything was tuned down to where it was supposed to be, everytime the engine was ran for a few minutes, it burned out that one spark plug, and kept doing it.

 

[EdontheBeach]

OK, here's the deal - it sounds like the engine is coming out and that is something you can do yourself. once you take the head off with the bad valve you'll be able to see all the other combustion chambers on that side. if everything looks good on that side except the offending valve, just replace it grind it in and carry on. it is not likely the other side has a problem at that point. however, if you find something ugly in any of the other combustion chambers, go ahead and do a head job on both sides - new valves, seals, guides; re-grind and re-install.

here's the next thing - re-installing those heads takes, at least some, know how. if you are comfortable with your skill level at installing the heads, setting push rods and rockers, getting the intake back on and so forth, then go ahead - if not have them re-assemble everything for you and you can re-install the engine between the rails yourself.

 

[BOOSTED-SS-ELKY]

"If you rebuild the top end of the engine without rebuilding the lower end, then that could create more problems and you will risk having the bottom end going out and needing repair".

LMAO!!:laughing4:

Find new Mechanics..

 

[fauxrs]

That is EXACTLY what I thought and I asked if they could just do the one or at least just the valve springs and valves and they told me that there was some type of leak in in the cylinder, I can't remember exactly but I think he had said there was a little bit of oil so there may be a leak in the one cylinder? thats what they made it sound like. they said the others were fine but if one is going the others aren't too far behind. which is why the mechanics said to replace both.

There are only two ways oil gets into the combustion chamber.

1. past the valve seals - little $2 parts that sit over the top of the valve guides inside the springs. even if all of them were going out it would NOT require replacement of the head.
2. past the rings - which has nothing to do with the heads and probably isnt the case since they said replacing the heads will fix it.

It still sounds as if all your problems revolve around a single valve, I'd pull that head, have that valve repaired, since its off have all the seals replaced on that head - I personally would leave the other head in place and get on with enjoying my car.

If it gives you a level of comfort to remove both heads and have valve jobs done to both thats fine too.

 

[80v6]

Stead vacuum

Steady vacuum. sorry guys. Oldshiemers :banghead:

 

[ccc]

it isnt a old wives tail but it certainly doesnt apply to a 3 year old engine.in the 50 and 60 s the engines were lucky to make it to 100,000 miles and if you did a valve job on a 80 or 90,000 mile motor it would start smokeing 80% of the time .that is no longer a consideration,with better oils and better build materials you can put fresh heads on a 200,000 mile modern motor with no effect other than it will run smooth again.for sure do both heads because they were both put on at the same time and built with the same batch of parts