burnt valve

[86ranger4x4owner]

I have a 1986 ford ranger 2.3l. I have a burnt exhaust valve on cylinder one. Was wondering what all I have to to do the replace it. Can I just replace valve and put new head gasket on or do i need to rebuild anything just to replace one valve?

 

[4b316]

You can just replace the one but not good practice.At least pull the rest of them and check and maybe reseat them as long as it is off

 

[kimcrwbr1]

How did you determine it has a burnt valve, did you do a leakdown test? If you pull the head I agree have all the valves ground at the same time or you can lap them yourself and put in new seals and check for warpage.

 

[RonD]

The valves on the 4cyl can "tulip" from heat as well.
This usually happens on the intake valve.

After removing cam, check valve stem height on #1, if it looks higher than the others that's what you have.
With cam out, so all valves are closed, and exhaust and intake manifolds removed, remove all spark plugs except for #1, rotate crank manually to see which valve has the leak, exhaust side or intake side, if there is no leak now then valve is tuliped, no cam means valve can close all the way.

This thread has some pictures and good info
http://www.therangerstation.com/forums/showthread.php?t=134664

Yes you can replace just 1 valve if you can ID the reason just the 1 valve failed
Pinging causes overheating in the cylinder and these engines are known for pinging, pinging can soften a valve or burn it

Not sure if your engine has an EGR system, but the EGR system helps prevent cylinder overheating.
Running too lean also causes cylinder overheating.

 

[86ranger4x4owner]

I took it to a mechanic he did a compression test and found the exhaust valve bad. Also said it needs two fuel injectors but he wanted a lot of money to pull head so am going to pull head. How can I find out how it got burnt?

 

[RonD]

Which cylinder and was it one with a faulty injector?

Burnt valve means a hot spot in the cylinder.
Running too lean causes hot spots, so a faulty injector could do that.
Blocked cooling passage near that valve can cause a hot spot, hot tanking head will usually clean it out but could be a casting flaw if head is low miles, under 100k, probably not on an '86

The exhaust valve runs at a higher temp than the intake because intake is cooled by incoming fuel/air, so exhaust valve is most likely to get burnt but they are also made of stronger compounds.
The valve seat for each exhaust valve is very important, the valve seat is cooled by the coolant, the exhaust valve is then cooled by its contact with the seat, 75% of valve cooling is done by contact with the seat, if the valve and seat are not matched then full contact isn't possible, so full cooling isn't possible.

Valve defects are know issues, one replacement valve manufacturer, claimed 1 on 5 OEM valves could be defective, not sure it would be that high, lol, but I know it does happen.

Best thing you can do is to check all possible external reasons for that 1 valve to fail and if nothing can be found then "defective valve" is what you are left with.


I would check with a few local machine shops and get pricing on valve job + cleaning and surfacing, they can check and reseat valves not replace them all, although replacing all the exhaust valves might be a good idea.

 

[86ranger4x4owner]

Which cylinder and was it one with a faulty injector?

Burnt valve means a hot spot in the cylinder.
Running too lean causes hot spots, so a faulty injector could do that.
Blocked cooling passage near that valve can cause a hot spot, hot tanking head will usually clean it out but could be a casting flaw if head is low miles, under 100k, probably not on an '86

The exhaust valve runs at a higher temp than the intake because intake is cooled by incoming fuel/air, so exhaust valve is most likely to get burnt but they are also made of stronger compounds.
The valve seat for each exhaust valve is very important, the valve seat is cooled by the coolant, the exhaust valve is then cooled by its contact with the seat, 75% of valve cooling is done by contact with the seat, if the valve and seat are not matched then full contact isn't possible, so full cooling isn't possible.

Valve defects are know issues, one replacement valve manufacturer, claimed 1 on 5 OEM valves could be defective, not sure it would be that high, lol, but I know it does happen.

Best thing you can do is to check all possible external reasons for that 1 valve to fail and if nothing can be found then "defective valve" is what you are left with.


I would check with a few local machine shops and get pricing on valve job + cleaning and surfacing, they can check and reseat valves not replace them all, although replacing all the exhaust valves might be a good idea.

Exhaust valve on cylinder one is burnt. Also have two injectors that don't work all the time. Cylinder one has a new injector not more than a year old. So what should I tell the machine shop I want done? I want everything fixed right and not have to go back in there and also dont want to rebuild bottom end. But I almost got head off just the head bolts and it'll be off.

 

[Mark_88]

Well, the good news is you should be able to use your head bolts again...but you might want to go to a local yard and pick up more of the same if the ones on there are badly rusted.

I just replaced my head last month and happened to have picked out five extras from the engine I took the head from...the ones on the driver side tend to get oiled whereas the passenger side were dry and coated with rust.

Have you ever had the head off this engine before?

 

[RonD]

Exhaust valve on cylinder one is burnt. Also have two injectors that don't work all the time. Cylinder one has a new injector not more than a year old. So what should I tell the machine shop I want done? I want everything fixed right and not have to go back in there and also dont want to rebuild bottom end. But I almost got head off just the head bolts and it'll be off.

You want a Valve job
What they do:
Remove valves and re-grind them for seating
Re-grind seats to match valves
Generally check valves condition, they will call you if if any need replacing, you know 1 will, valves are around $12, machine shops often sell them cheaper than auto parts stores, intakes are usually OK, so worst case would be $40 for new exhaust valves

For a 4 cylinder head with 8 valves, a Valve job should be under $80, add hot tank(cleaning), pressure test and resurfacing for about $80 more.
If you buy your head gasket set it will come with new valve seals, drop these off with the head and they will install them, usually free but maybe $10
You need to call a few shops this is a labor job and if they have the newer machines they are looking at about 1 to 2 hours labor max.

I have seen ads for 4 cyl. valve job, hot tank, pressure test, and resurfacing for under $100


Most larger towns have places that rebuild injectors, $25-$45, walk in with your old ones walk out with rebuilt ones
On-line rebuilders offer 4 Ford injectors for $60/exchange

 

[LIMA BEAN]

You want a Valve job
What they do:
Remove valves and re-grind them for seating
Re-grind seats to match valves
Generally check valves condition, they will call you if if any need replacing, you know 1 will, valves are around $12, machine shops often sell them cheaper than auto parts stores.

For a 4 cylinder head with 8 valves it should be under $60, add hot tank(cleaning), pressure test and resurfacing for about $80 more.
You need to call a few shops this is a labor job and if they have the newer machines they are looking at about 1 to 2 hours labor max.

1+ on pressure testing. I've seen shops charge to magnaflux them and tell people they are good to go and they were not, both valve and casting wise. Rep to you RonD for the good info you have given to him on this thread.

 

[86ranger4x4owner]

You want a Valve job
What they do:
Remove valves and re-grind them for seating
Re-grind seats to match valves
Generally check valves condition, they will call you if if any need replacing, you know 1 will, valves are around $12, machine shops often sell them cheaper than auto parts stores, intakes are usually OK, so worst case would be $40 for new exhaust valves

For a 4 cylinder head with 8 valves, a Valve job should be under $80, add hot tank(cleaning), pressure test and resurfacing for about $80 more.
If you buy your head gasket set it will come with new valve seals, drop these off with the head and they will install them, usually free but maybe $10
You need to call a few shops this is a labor job and if they have the newer machines they are looking at about 1 to 2 hours labor max.

I have seen ads for 4 cyl. valve job, hot tank, pressure test, and resurfacing for under $100


Most larger towns have places that rebuild injectors, $25-$45, walk in with your old ones walk out with rebuilt ones
On-line rebuilders offer 4 Ford injectors for $60/exchange

OK thanks. I'll call around and check prices. Is there anything cheap to do while I have the intake and head off like port and polish them? Something for a little more power just not really expensive.

 

[86ranger4x4owner]

Well, the good news is you should be able to use your head bolts again...but you might want to go to a local yard and pick up more of the same if the ones on there are badly rusted.

I just replaced my head last month and happened to have picked out five extras from the engine I took the head from...the ones on the driver side tend to get oiled whereas the passenger side were dry and coated with rust.

Have you ever had the head off this engine before?

Yes it is. All my heads bolts are covered in oil. Anyone know what type of socket it uses for the head bolts? I put a 1/2 inch 12 point and it fit but I don't want to break anything.

 

[Mark_88]

I'm pretty sure I used the same 1/2" 12 point to remove and install mine...just make sure you have a 3" extension because the sockets don't clear the towers and it makes it easier to remove and install the bolts...

Also you will need a good torque wrench...the torque specs are 60 ft/lbs on the first go and 80 - 90 ft/lbs on the second.

It's also easier to do if you remove the hood completely...easy to do even with one man...but with help it is better than trying to prop up the hood and loosen/tighten the bolts.

 

[86ranger4x4owner]

I'm pretty sure I used the same 1/2" 12 point to remove and install mine...just make sure you have a 3" extension because the sockets don't clear the towers and it makes it easier to remove and install the bolts...

Also you will need a good torque wrench...the torque specs are 60 ft/lbs on the first go and 80 - 90 ft/lbs on the second.

It's also easier to do if you remove the hood completely...easy to do even with one man...but with help it is better than trying to prop up the hood and loosen/tighten the bolts.

Thanks. Is there a certain sequence you have to go in or just tigthen them to the torque specs? Like on 350 heads you have to tighten bolts in a different pattern.

 

[Mark_88]

Yes, and if you have a Haynes manual it actually shows the sequence. If you don't have one you simply start in the middle of the head and work out towards the ends cris-crossing from the driver side to passenger side for each bolt and end to end where you go front right, back left, front left, back right...

Haynes has a diagram in the 2.3 section but it is not obviously placed.