Exhaust Port on Head

[kkuhia]

I am installing a new exhaust manifold and when I pulled off the old one I found that the #4 exhaust port in the head is rusted and has a chunk of metal out of it (see attached pics).

By looking at the pictures, do you think the chunk of metal missing will cause probs? Also, what is the best way to get the rusted surface cleaned up and flat to get a good seal between the head and exhaust manifold? Finally, I know exhaust manifold gaskets usually go on dry, but should I use Permatech Permatgasket here if I can't get the surface perfect?

 

[kkuhia]

Re: Exhaust Port on Head

I tried to attach the pic, but it didn't seem to work. Anyone know how to attach pics to a post?

 

[Boatist]

Re: Exhaust Port on Head

I do not see your picture but a very common problem with
saltwater boats is exhaust manifold rust out and plugs the riser ports.
This causes the engine to over heat.
Also when the exhaust ports rust thru water runs thru
the manifold and runs down hill to the back cylinder.
This water rust the exhaust valve and gets into the number 4 cylinder.
Very soon after that the #4 exhaust valve starts to leak and the valve in burned.
This causes a low RPM engine miss.
Water in the # 4 cylinder gets to the rings and cylinder also into the oil.

Before I put the new exhaust manifold on I would do a compression check.
If number 4 cylinder is low or any for that matter squirt some oil in and check again.
If still low may as well pull the head and have a closer look.
Likely needs a Exhaust valve and maybe a lot more.

Also when replaceing the Exhaust manifold I would also replace the riser.

 

[kkuhia]

Re: Exhaust Port on Head

Thanks Boatist! I did a compression check before I pulled the exhaust manifold and it was actually a little higher than the rest of the cylinders:

1: 160
2: 165
3: 165
4: 170 (this is the one with the rust/chunk of metal missing)

I also didn't see any water coming out of the spark plug holes when I turned the engine over. I do have water in my oil though.

 

[kkuhia]

Re: Exhaust Port on Head

Alright, I think I figured out how to add an image...

Any feedback on how bad this is and best way to get rust to shiny/flat surface without removing head?

 

[Boatist]

Re: Exhaust Port on Head

Compression looks good to me.
You may have gotten away with no real damage.
Your picture still too blurry to tell much about it.
If the sealing surface for your exhaust gasket is in tack,
then I would just clean it up as much as possible.
When cleaning up turn engine until that exhaust valve is open.
put an air hose in the spark plug hole and clean as good as you can.
Apply an oil like WD40 and wipe with a cloth.
Most of the oil will burn off as soon as you fire it up.
Does the Spark plug look rusty?

Make sure you put some engine oil in the cylinder and with the plug out give it a few turns.

Make sure you change the oil a couple of times.
Last thing you want is SaltWater in the oil pan.
Also keep a close eye on the oil for any sign of new water.
If Riser is bad will still get water in the cylinders.
Make sure you use the sealer for Exhaust manafolds.
Some gaskets may not require a sealer.
Check all your bolts and any thing that does not look brand new replace.

Funny no one else responded.

Good Luck

 

[Reel Poor]

Re: Exhaust Port on Head

Isn't that an aluminum head on that engine. I believe the rust is from you exhaust manifold and not the head. Any damage to the gasket surface would be caused from corrosion, not rusting.

 

[kkuhia]

Re: Exhaust Port on Head

Thanks for the replies...the spark plugs don't have any rust on them. The head is aluminum. There seems to be corrosion/rust on the metal inside the aluminum part (like there are cast iron liners for the exhaust ports?). Either way, there is a bit of corrosive/rusted debris on the flat surface where the gasket needs to go. I guess I will just file that down to be as flat as possible. Also, think I'll put the other ones on dry and this one with Permagasket to ensure it doesn't leak. I'm using brand new bolts as well as they had corrosion/rust on them too.

I plan to change the oil at least 3 times to get rid of the water and I'm putting some cleaner stuff in the first time to clean out the foamy stuff. I'll keep an eye out for the water in oil again.