Bent valves, using used valves ok?

[Janky]

I recently posted about an AWM engine that needed pulled because of a broken connecting rod. I got a used long block and the head had a bitched up intake cam bearing surface. I decided to pull the head and found out the used long block head also had a single bent intake valve. I pulled the head off of the original motor(with the broken rod) and it too had a bent intake valve and the piston looks like it may have barely contacted both exhause valves. They appear to be seated properly under valve spring pressure.

Now I have two long blocks and only 1 head is useable. My problem is that I need to replace an intake valve and possibly 2 exhaust valves. I just ordered the tool to remove the valves and it will be here Tuesday and I can get into pulling the valves.

What are some of your thoughts on using used good valves out of the head with the bad bearing surface? Is it blasphemy to not replace the guides? I am kind of on a budget at this point. This rebuild is adding up quickly.

[Scotty@Advanced]

I recently posted about an AWM engine that needed pulled because of a broken connecting rod. I got a used long block and the head had a bitched up intake cam bearing surface. I decided to pull the head and found out the used long block head also had a single bent intake valve. I pulled the head off of the original motor(with the broken rod) and it too had a bent intake valve and the piston looks like it may have barely contacted both exhause valves. They appear to be seated properly under valve spring pressure.

Now I have two long blocks and only 1 head is useable. My problem is that I need to replace an intake valve and possibly 2 exhaust valves. I just ordered the tool to remove the valves and it will be here Tuesday and I can get into pulling the valves.


What are some of your thoughts on using used good valves out of the head with the bad bearing surface? Is it blasphemy to not replace the guides? I am kind of on a budget at this point. This rebuild is adding up quickly.

As long as the valves are in spec and straight I'd have no problems using used valves. Just make sure you have a proper valve grind done.

[Janky]

Just make sure you have a proper valve grind done.

By that you refer to lapping the valves or actually having the head machined?

[walky_talky20]

Yeah, regrind the valve/seat. You can DIY this with a drill and some valve grind compound. This would be the hill-billy way to do it. Obviously the right way is to have the machine shop do it.

[guy022077]

take all of the valves and the head to a machine shop and have them see which ones are straight and which are bent. and hope that they get an entire set when they are done.

[redline380]

i would replace the exhaust valves with stainless ones.

[EErie B6]

I would do this with the exhaust valves:

i would replace the exhaust valves with stainless ones.

I would do this with the intake valves:

take all of the valves and the head to a machine shop and have them see which ones are straight and which are bent. and hope that they get an entire set when they are done.

if it were me.

[Scotty@Advanced]

i would replace the exhaust valves with stainless ones.

Depends on what the car is going to be used for, big turbo plans then yes replace the Exh valves with some good stainless ones.

[redline380]

I disagree. Even on stock motor I say replace with stainless. They're only 10 bucks a piece. The problem with the sodium valves is they don't bend, they snap. And when they snap, they ruin the combustion chamber and piston. Go the the thread labeled about to put my motor together by jaychen, and look at what sodium valves can do, even on a stock motor. It ruined that head.

Oops. I meant look at the photos I posted in the thread am I getting yanked

[034Motorsport]

Intake valve? You will probably be fine throwing in a used stock one. Exhaust valve? No. Your car only has 8 exhaust valves; if you are going through the labor of replacing a valve or two, and your guides are fine, replacing the exhaust valves won't be that expensive overall and will give good piece of mind.

If the motor is staying entirely stock forever, I wouldn't worry about it much. If you have any plans of running a bigger turbo or even a tune, I'd go for inconel exhaust valves (stainless at the minimum), or at least new OEM. High mileage OEM exhaust valves likely have very little to no sodium left in them.

[andyrew]

Exhaust valves bend pretty easy... You CAN use used valves but how long will they be good for? I replaced some slightly belt valves in a honda (you know, cheap as you can car...), Bought a set of 8 used off ebay and 3 of them were good. Ran them on a drill and put them up against a piece of metal, If they bounced at all or more than a fraction of a MM then I tossed them. I was short one so I bent a valve back with some heat and some ingenuity. Finished it off with lapping the valves and then surfacing the head (after installing it the first time and having leaks..)

Been going good for 5k miles.

[Scotty@Advanced]

I disagree. Even on stock motor I say replace with stainless. They're only 10 bucks a piece. The problem with the sodium valves is they don't bend, they snap. And when they snap, they ruin the combustion chamber and piston. Go the the thread labeled about to put my motor together by jaychen, and look at what sodium valves can do, even on a stock motor. It ruined that head.

Oops. I meant look at the photos I posted in the thread am I getting yanked

To each his own, but there are several 200,000+ mile 1.8t's with stock exhaust valves that continue to work just fine. If you got the money then I say yeah change the exhaust valves it won't hurt you unless you happen to get a new defective valve.

High mileage OEM exhaust valves likely have very little to no sodium left in them.

They will have the same amount of sodium in them when they were made. There's no way for the sodium to escape.

[jaychen]

They will have the same amount of sodium in them when they were made. There's no way for the sodium to escape.

so, who's right?

[redline380]

To each his own, but there are several 200,000+ mile 1.8t's with stock exhaust valves that continue to work just fine. If you got the money then I say yeah change the exhaust valves it won't hurt you unless you happen to get a new defective valve.

let me explain my position a little better now that i am on a computer instead of a damn phone. obviously, stock valves work just fine for most people and most applications. sodium valves do have the obvious advantage of being light, hence why they are used by the factory. my position is coming from seeing what those sodium valves can do when they break, i would run stainless just because they have much less chance of snapping and damaging internals. but for op, running used valves is fine i guess. but if he had the money, stainless would be the way to go, and they are fairly cheap. i do have a local guy though who is always looking to buy scrap heads to take the good valves out and put them in heads with bent valves.

as for the whole sodium leaking out, i got no idea, but i did try cutting one open to see if there was any sodium left, and there wasn't any left. i got no idea how it would leak out

[M-Hood]

let me explain my position a little better now that i am on a computer instead of a damn phone. obviously, stock valves work just fine for most people and most applications. sodium valves do have the obvious advantage of being light, hence why they are used by the factory. my position is coming from seeing what those sodium valves can do when they break, i would run stainless just because they have much less chance of snapping and damaging internals. but for op, running used valves is fine i guess. but if he had the money, stainless would be the way to go, and they are fairly cheap. i do have a local guy though who is always looking to buy scrap heads to take the good valves out and put them in heads with bent valves.

as for the whole sodium leaking out, i got no idea, but i did try cutting one open to see if there was any sodium left, and there wasn't any left. i got no idea how it would leak out

It doesn't have to leak out, it changes forms over time when the valves get too hot. This is why you found no sodium in your valve when you cut it open.

[*Blue-Angel*]

Smacks Forehead..