New Motors almost ready to go back in Help Exaust-gctid378167

[Guest]

OK so I'm not as smart as I think I am. The new 5.7 motors with Vortec heads are almost ready to go back in.

Here is the problem the vortec heads with the volvo exhaust manifolds don't work. You cant get the spark plugs in. I am being told I need to go with the mercruiser manifolds.

Here is where I need help. is there an easy mod to hook the mercuiser manifolds to the volvo Y pipes? Or can I go with a through transom system that is not overly loud and will clear the power steering ram?

Has any of you done this before?? :hammer

This is in my 82 conquest with volvo 280 drives.

[2850Bounty]

Scott, this is one manifold/riser whereby the other exhaust manifold makers are able to copy the foot print of the OEM.

IOW, another maker's riser will fit an OEM Volvo Penta manifold, and visa-versa.

Osco on a Barr..... Barr on an Osco..... either on Volvo Penta, and so on.

Because of this, perhaps not all manifold castings are the same near the spark plug area.

Are yours Volvo Penta/OEM, or other?

NOTE: the Volvo Penta riser "down angle", for this stern drive system, is rather unique. Plus it's 95mm OD (95mm ID hose)

I think that you'll have trouble with Merc or other.

I'd shoot a PM to Doug, and ask if he'd change your thread title to sump'n like; AQ 260 w/ Vortec Heads... exh man/spark plug issues????

Some of the other guys may have run into this before.

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[Mikalkc]

I have an issue with plug clearance on the Volvo BB225B/MS3C install on my 3270. Over the years I just gave up trying to find a plug socket that would clear the manifold. I can still put the plugs in by hand then tighten them with a wrench. When it's time to change I break them off then use a socket. I just bought Osco manifolds and risers for both sides and noticed they are slightly different shaped where the plugs clear. I haven't put them on yet so I will have to see. My intent was to repower with 350's in a couple of years and reuse these new manifolds. I'd be interested on what you decide/ end up doing.

[2850Bounty]

Mikalkc wrote:
I have an issue with plug clearance on the Volvo BB225B/MS3C install on my 3270. Over the years I just gave up trying to find a plug socket that would clear the manifold. I can still put the plugs in by hand then tighten them with a wrench. When it's time to change I break them off then use a socket. I just bought Osco manifolds and risers for both sides and noticed they are slightly different shaped where the plugs clear. .......

The BB V-8 engines, in this year range, use the same exhaust maniold/riser as does the AQ series.

However, I believe that Scott's issue is with the Vortec cylinder head spark plug angle.

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[Mikalkc]

So did Volvo make a change in their casting after 1994 or so whenever the vortec engines came out? Would a newer Volvo (or equivalent) fit the different plug angle? I ask since I am considering vortec heads but may not if the overall expense of replacing the manifolds again is there.

[2850Bounty]

Mikalkc wrote:
1... So did Volvo make a change in their casting after 1994 or so whenever the vortec engines came out? Would a newer Volvo (or equivalent) fit the different plug angle?

2.... I ask since I am considering vortec heads but may not if the overall expense of replacing the manifolds again is there.

1... When Volvo Penta went with the SX and DP-S Gimbal system drives :thumb the exhaust manifolds did change, and are no longer similar to the BB or AQ exhaust manifolds. Several years into this, the Vortec engines showed up.

The best of the AQ series drives ran along side of the SX/DP-S for several more years, and the BB and AQ style exhaust continued.

Unfortunately, our Bayliner boats never saw this engine/drive package!

2... I'd give this some thought before spending my money on the Vortec cylinder heads. They do not really perform to their true potential until the quench style piston is used with them.

If you go the quench piston route, you can do as well with one of the D shaped wedge cylinder heads, and not have to deal with some of the Vortec cylinder head issues.

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[yachtman]

Scott i hope you get this solved easily. As I have learnes when ome thing is changed another thing needs altered.

Hey I havent forgotton about the anchor pulpit. I am maybe passing through portland memorial day weekend. If you are still interested ill bring it with me.

[Guest]

Dave,

That would be great. I should be in town that weekend.I live in Corbett just off 84.

Back to the Vortec heads. I took the old volvo manifolds and bolted them to the heads and I dont see a problem with the plugs. how ever my nice new fancy valve covers wont fit.

I am thinking that maybe what Dennis Moore was talking about is the GLM after market manifolds he sells are cast different. He is really recommending the mercusier manifolds. and a thru transom setup I need to figure this out.

I like the design of the GLM's but I may need to go with Barr or some other model.

[Guest]

What would be wrong with sending the exhaust through the transom? Is there an advantage to sending it through the sterndrive, or is that just to keep from cutting holes in the transom.

[yachtman]

I prefer through a hull exhaust but with straight exhaust iut of the transom it will be loud you will need to put some kind of muffler system on it. You will.also need to cap the existing y pipe.

[yachtman]

I prefer through hull exhaust but with straight exhaust close to the transom it will be loud you will need to put some kind of muffler system on it. You will.also need to cap the existing y pipe.

When i say i prefer it its because it creates more power. Less to deal with the out drive but when its a outdrive system i dont usually do it because of the noise.

[Guest]

Dave,

Did you go thru the transom on yours?

Is the power steering ram in the way?

[2850Bounty]

Scott, Dave's is an I/B boat. His exhaust would either exit the transom or the sides... not sure.

I did some quick checking on the other style exhaust mans for you.

I also just looked at a boat yesterday that was using the Volvo Penta SX style mans with elbows that made it work with a DP-C1 drive.

The top of the Y-pipe had been slightly modified, but nothing that couldn't be done easily.

I have photos if interested.

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[yachtman]

My motors are inboard and in the middle of the boat so i do have through hull but i have long exhaust runs and mufflers

[Guest]

Yes Pictures would be great