Loud Exhaust Leak AQ131A

[peradetlic]

Hi,
I searched forums, to my surprise couldn't find similar experience, except one post from 2010 with no answers.

It is Bayliner Capri 1987, 19feet with Volvo Penta AQ131a and 275 outdrive. Purchased it about 4y ago, in very good to excellent shape.
Last weekend I started noticing very loud exhaust leak. Removed exhaust manifold and exhaust hole #3 on the head, counting from the heat exchange, or rusted out or some electrolysis was happening, and about 3/4in of it is gone (like mouse ate it away). I can almost put my thumb flat there. I noticed that other exhaust head openings/channels have some ring or sleeve inside, but not this one. or it was never there, or it rusted away.

Without replacing the head, how can I fix this problem?
If I'm not mistaking, the head is aluminum (manifold cast iron). Can liquid metals do the job?
Is there a sleeve/insert, like what I am seeing in other exhaust openings that I can pres in, maybe combine with liquid metals?

I planed to go boating with my friends this weekend, and thought this was just a gasket... HELP!

THANKS!!!!

 

[Bondo]

Re: Loud Exhaust Leak AQ131A

Hi,
I searched forums, to my surprise couldn't find similar experience, except one post from 2010 with no answers.

It is Bayliner Capri 1987, 19feet with Volvo Penta AQ131a and 275 outdrive. Purchased it about 4y ago, in very good to excellent shape.
Last weekend I started noticing very loud exhaust leak. Removed exhaust manifold and exhaust hole #3 on the head, counting from the heat exchange, or rusted out or some electrolysis was happening, and about 3/4in of it is gone (like mouse ate it away). I can almost put my thumb flat there. I noticed that other exhaust head openings/channels have some ring or sleeve inside, but not this one. or it was never there, or it rusted away.

Without replacing the head, how can I fix this problem?
If I'm not mistaking, the head is aluminum (manifold cast iron). Can liquid metals do the job?
Is there a sleeve/insert, like what I am seeing in other exhaust openings that I can pres in, maybe combine with liquid metals?

I planed to go boating with my friends this weekend, and thought this was just a gasket... HELP!

THANKS!!!!

Ayuh,.... Welcome Aboard,.... Got any pictures,..??

If yer Head is eroded, ya need a new head,.....

There ain't no fixin' what's gone,...

 

[peradetlic]

Re: Loud Exhaust Leak AQ131A

Ayuh,.... Welcome Aboard,.... Got any pictures,..??

If yer Head is eroded, ya need a new head,.....

There ain't no fixin' what's gone,...

I'll make some pictures today. For now, as a rough idea what is going you, there is a picture in post
http://forums.iboats.com/volvo-pent.../volvo-131-head-rear-exhaust-port-401668.html

My problem is half or third of a size of the problem in above picture. And picture shows cyl4 mine is on #3

Don't know enough about it, but I was hoping that there is some liquid metal for aluminum and high temperatures, maybe even some welding process that can bring on material...

Thanks

 

[captmello]

Re: Loud Exhaust Leak AQ131A

What you found is much more common in at the fourth cylinder like you found in your search. I have no first hand experience but I've heard that the heads can be fixed. Or replaced like Bondo mentioned. either way the head needs to come out.

 

[peradetlic]

Re: Loud Exhaust Leak AQ131A

Would high temp "cold weld product" like Blue Magic Quick Steel Hi temp (Extreme) work? Whitstands 2500F/1300C. Is it worth a try?

 

[jerryjerry05]

Re: Loud Exhaust Leak AQ131A

Would high temp "cold weld product" like Blue Magic Quick Steel Hi temp (Extreme) work? Whitstands 2500F/1300C. Is it worth a try?

NO!! Those products are ok.
But won't work very well in that situation.
The "bond" won't hold.It will heat up and expand then cool down and contract.
Then pop out when the bond is broken.
New head.I'd replace the manifold while your at it.

 

[peradetlic]

Re: Loud Exhaust Leak AQ131A

I apprechiate all the comments and suggestions. What I just noticed is that third exhaust, the one that rusted away, was missing the steel sleeve. Don't know how that happened, where did it go, but other exhausted have it. Can I get that sleeve somewhere, that would allow more strength for the bond. Trying this doesn't hurt much, no further damage will be done, might postpone head replacement.
BTW, manifold was about 40% passable, I bored it out, and used acid to clean it up, now it is about 95% passable. So it will wait next rusty chance to be replaced...

 

[axisg]

Re: Loud Exhaust Leak AQ131A

a "good" engine repair shop can bore out the manifold, insert and weld in a sleeve ( fairly complicated process with cast iron ), Then the whole unit is machined flat again. Cost will be in the hundreds in machine time alone.

I would say ebay is your friend here. For $250.00 plus shipping you can get a good used replacement and swap it out in an hour or so.

855387 Exhaust Manifold Volvo Penta AQ131A 4 Cyl OHC | eBay

 

[peradetlic]

Re: Loud Exhaust Leak AQ131A

I called "local" Penta service. For older engines they used a hand tool to machine a 4th channel on the head. (Similar like for faucet seats). Then they would insert the steel ring and fix it with liquid metals. However and older engines are mostly gone, they don't have the tool any more. I got the ring, and decided to machine it myself. The outer ring diameter is some acquard dimension like 1 and 15/16 in. All bigger milling tools are 1,3/4 or 2,1/2 in. So I got a 1&3/4 grinder disk, then 3/4 in milling carbide tip, used a drill and carfully, over a span of 6h mile dit exactly to side. Easy to say, VERY hard to do it. Somebody smack me a few times if i decide to do something like this again!
Then I used that high temp liquid metal and sealed it in place. I'll post some pictures before and after. Now I need to apply another layer of liquid metal to build up where the aluminum is missing so the manifold seal can sit flush.
And I inspected exhaust manifold again, and there is a leak in the separation plate, right at 3rd cylinder
Beside eBay, what would be the cheapest place to get manifolds for 131a? Preferably new...
Thanks

 

[captmello]

Re: Loud Exhaust Leak AQ131A

Exhaust Manifold for Volvo Penta 855387-7 834438-4, GLM 51610, Barr VO-1-855387 - Sierra

These are the aftermarket manifolds from iboats. I would try googling the aftermarket brand and part numbers and see what you find. Cheapest isn't always best, but...

 

[jerryjerry05]

Re: Loud Exhaust Leak AQ131A

"LOCAL" where's local?
Cobe Marine in Pasadena,Md.
They sell aftermarket. OSCO and Barr manifolds.
They ship too.
I think this site sells them too.

 

[peradetlic]

Re: Loud Exhaust Leak AQ131A

Local is San Diego I thought, that beside my name it says where I am located...
Thanks!

 

[peradetlic]

Re: Loud Exhaust Leak AQ131A







Fixed it with steel ring and high temp metal mentioned above. Held for two fishing trips, so far (fingers crossed).
Before pic, bored and "glued" pictures. The ring is flush with aluminum edge. Has to be, cannot stick out or in. Afterwards I added more liquid metal where head material was missing, and to seal the ring. light sanding , installed new gaskets and new manifold.

 

[jerryjerry05]

Re: Loud Exhaust Leak AQ131A

Supposed to get San Diego from peradetlic???

 

[peradetlic]

To knock on the wood, the fix is still holding. About 2 trips/rides every week. Each trip lasted for about 2-3h of engine use. About 30% high speed at 4500rph the rest at 2000rpm.