1975 volvo AQ225A cracked exhaust riser

[dozer59044]

Newbie here,
I searched archives but, have found nothing on my engine(the A model) The exhaust doesn't look like any of the others. Is there any to be found? Can I change it out with a new set up, with out a whole lot of problems? I am in Montana and not finding much info here. Thanks for any advice. I have built a lot of autos but don't have much marine experience.

 

[captmello]

Re: 1975 volvo AQ225A cracked exhaust riser

Do they look like these?

Exhaust Manifold: A AQ200B : A - 7740880 - Volvo Penta

One piece mani? If so, I don't think you're going to find many. You could use the newer center rise manifold with a seperate riser, Like these.

Exhaust Manifold: Aq255b.AQ200D, AQ225D - 7740890 - Volvo Penta

But the riser may not line up with the exhaust y pipe...

Post some pics if you can.

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Thanks for input. My exhaust isn't like either one. i will try uploading a pic.

 

[captmello]

Re: 1975 volvo AQ225A cracked exhaust riser

Risers Elbows Spacers | Exhaust | Chris Craft | Basic Power

Have a look at this link, halfway down there are some that appear very close...Check around the site, you never know...

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Thanks, it looks close. I will check out. Does any one know if I can update to the newer style center riser? What all would need to be done if I can. I can get the complete kit for around $500. I just dont want to put $300 in my old system just to have an other part fail.
Thanks

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Well, I took a closer look at the riser and it has been welded before on both sides. So this would be the third time it has cracked. The boat is new to me so I am finding and solving issues It looks like the last is the exhaust. I am leaning towards replacing the whole set up and going with a complete kit.(center riser style) Has any one done this before that can give me advice on what set up and install issues. I am wondering how I will have to re-plumb the water lines. Any advice is very much appreciated. Thanks.

 

[jerryjerry05]

Re: 1975 volvo AQ225A cracked exhaust riser

Contact Cobe Marine in Pasadena,Md.(on the net)
They were the place to go for ANYTHING Volvo when I lived there.
What you need to look into is possibly replacing with the original stuff?
You've got the old style Chris Craft manifolds.
Cobe should have the stuff you need.
Gonna be costly.

 

[captmello]

Re: 1975 volvo AQ225A cracked exhaust riser

Jerryjerry05 mentioned the chriscraft manifolds, which are the type I linked, but they do not sell the manifolds, only the risers...

After some more thought, converting to center rise manifolds could create a few necessary changes.

For sure you'll need a new thermostat housing, that will hopefully solve the extra hose issues. You've got a ton of hoses there. You could find that on ebay...This one's new, but you may find a used one cheaper...Volvo Penta AQ 225 260 570 Thermostat Housing 857068 | eBay

Also You'll need to figure out if you can get hoses and fittings to connect to the existing ypipe...that could be tricky. One option would be to bypass the ypipe and go to a thru hull fitting if it fits on your boat and you don't mind the noise.

Heres a link to iboats aftermarket exhaust...there are some elbows that may work for you. Just need to check your diameters, etc.Volvo-Penta Exhaust Manifold Elbows - iboats

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Thanks for advice. I am trying to weight out which direction to go. I would like to go with a more modern set up. but I haven't even had this vessel in the water yet. So I am a little reluctant to spend a large sum until it proves it's self. I really need to learn about marine exhaust any ideas of sources? Again all of your input is appreciated.

 

[jerryjerry05]

Re: 1975 volvo AQ225A cracked exhaust riser

The guys at Cobe sell TONS of manifolds every year.
Good prices,etc.
They make, sell aftermarket thermo housings.
If you buy Volvo parts it's gonna HURT!!!

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Thanks Jerryjerry05. I did check out their site. I decided at this point to patch what I have and see if this is my only problem. Then if every thing else checks out I will replace the Riser with new ones. Any ideas why I would have Chris Craft exhaust in a 1975 Fiberform 19' cabin cruiser? I am finding out that boats are very different compared to auto. hard to track models and engine set ups. Seems like they just grabbed what they found and put it in.

 

[jerryjerry05]

Re: 1975 volvo AQ225A cracked exhaust riser

You'd be amazed at what you find in a boat.
The previous owner probably got the motor for free and changed the valve covers and said lets GO!!!
Saw a Chrysler 440 hooked to a Volvo drive.
Saw a pair of early 70's Olds big blocks in a older wood boat.You could water ski behind that bugger.

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Well,
I patched the starboard side riser using JB weld as a temporary fix. It held during test. now I see that I have a crack in the port side as well. It too has been welded on twice. Some one didnt like pulling the drain plugs. I am patching it for now. I also have a over heating problem so, I pulled the t-stat and it was rusted up so I will replace and test again. I just might get this thing in the water before snow flys.

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Now I have the riser leaks taken care of for now with temp. patches. Now I am dealing with engine temp. hitting 210 and holding. I changed the t-stat. put in a 140 degree. I checked the impeller and it looks good. I would even say it looks new soft and pliable.When i pulled the outlet hose off the pump it was pumping water.
Can any one educate me on the cooling/exhaust on this beast. I am trying to understand the flow. I know that it is pulling water to the motor. What is the running temp of marine GM motors.(block ser#SO5234UJ)I cant find any other ID plate on the motor. I feel like I am learning mechanics all over again.
Thanks

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

OK, I checked for blockage in line from out-drive to pump all clear. Checked several other lines all seem to be clear. I decided to pull the raw water pump and check the impeller. Turns out that two of the fins are cracked. Now how do I know which impeller to buy? Its a Sherwood pump.

 

[captmello]

Re: 1975 volvo AQ225A cracked exhaust riser

How are you cooling it now while you work on it? The system can leak in the outdrive causing the system to suck air. Even though it appears to be pumping, you could be pumping a lot of air. I would pull the hose off the intake fitting under the ujoint bellows and look for corrosion where the hose connects. It can also suck air from the gasket below the fitting.

FYI, your raw water pump is pulling water through the outdrive, through the fitting i mentioned above, through hose to the tramsom shield, then up to your raw water pump, then to the themostat housing. Thats where your setup gets confusing. Where does the hose coming off the rear of the risers go? You have a different raw water pump than most V8s we see. Most are on the harmonic balancer...but whatever works, right? In the end, assuming all flows where it is supposed to, the water goes out the exhaust pipe.

Keep in mind, the exhaust manifolds can crack internally, allowing water to get into the cylinders and corrode the cylinder walls and pistons. I would do a compression test on the motor as well before spending a bunch of money on it.

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

I disconnected the hose from the out-drive and hooked the garden hose directly to the raw water pump. Still had heat issue. There are no signs of water in the engine block. I check every time I run it. Engine runs great just gets hot?(190-200) There is ampule water from exhaust and even water running from secondary discharge tube that runs out beside (gimbal mount???). How do I figure out what impeller I need. I have the pump in hand but all I see are casting numbers. I think the next step would be to replace impeller(two fins are cracked) then if that doesn't fix the heat problem then I will start dismantling the exhaust looking for blockage. Maybe the temp. sensor is wrong I don't know. I have a lot of automotive building history but the marine cooling/exhaust is very different. researching engine and parts is very difficult. Who knows maybe this isn't even a Volvo engine. I know its a GM v8. The only thing marking it as a Volvo is the valve cover. I will take the pump and impeller into the local marine shop and see what they say. Problem I have found being in Montana is that if its older than 10 years must don't even want to look at it.
Thanks.

 

[captmello]

Re: 1975 volvo AQ225A cracked exhaust riser

When I first bought my boat, the temp gauge wasn't working. I picked up an inexpensive mechanical gauge at napa, and screwed it into the intake, been there ever since.

The impeller should be replaced immediatly before those fins break off and plug up the cooling even worse.

Go to this link:
Engine database - Engine database : Volvo Penta

in the "engine type" box, type in aq225a. Its your motor all right. Lots of info to be had.

 

[jerryjerry05]

Re: 1975 volvo AQ225A cracked exhaust riser

Hooking up the hose direct doesn't mean it's gonna cool any better.The system needs to be complete to operate.
The impeller is a standard Sherwood imp. There should be a # stamped on the housing or look on the end of the impeller.
There might be a # on one end or the other?

 

[dozer59044]

Re: 1975 volvo AQ225A cracked exhaust riser

Thanks Captmello. The site was very helpful now I have some info on what I am working on. I still can find a number on the impeller. I tried to search the numbers on the side of pump but nothing comes up. I will keep trying. Thanks you both for the input.