Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

[GilligansIsland]

I am replacing my '97 Volvo 7.4 GL and would like to add a Full closed cooling system. I know Volvo does not offer this as OEM, but I thought, "hey, why not?". Here are some details that may help solve this:


The boat is an '85 Contessa Command bridge
The boat is fitted with through hull exhaust so Y Pipe alignment will not be an issue
The boat is also fitted with a through hull raw water intake (not using the drive leg. don't know if that matters)
I will buy a "universal" manifold/riser set from Barr that has the proper porting
I will be buying my closed cooling system from San Juan Engineering of the proper size
I will be buying the New Long Block from Doug Russell, (who will deal with SJE and send the entire package)
My original alternator was mounted high (like OMC), but I'm sure another bracket could be used to set it low

So, there ya go. I can't imagine I am the first one attempting to put a fully enclosed system on a Volvo and hope you guys can steer me in the right direction.

Thanks in advance.

 

[Capt Ken]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Its not a problem until you attempt to cool the exhaust manifolds. Then you will have a cooling problems. Most systems on sterndrives do not attempt to FWC the manifolds, just the engine. Those things put off a lot of heat for a heat exchanger to soak up.

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Maybe I'm wrong, but I thought many of the Merc systems use the full system.

I realize that raw water is rather cold and while I'm sure that aids in the removal of heat, I thought E/G was really good at heat transfer.

Of the systems that do include the manifolds, do they not work well or have a bad reputation?

 

[Bondo]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Maybe I'm wrong, but I thought many of the Merc systems use the full system.

I realize that raw water is rather cold and while I'm sure that aids in the removal of heat, I thought E/G was really good at heat transfer.

Of the systems that do include the manifolds, do they not work well or have a bad reputation?

Ayuh,.... It'd need a Much Bigger heat exchanger...

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

SanJuan can probably get you the right size heat exchanger for a full closed system. You will need to find a thermostat housing used with a full closed system, there are more ports on the full system. You will also have to manufacture your own block off gasket plates between the manifolds and risers if using Volvo manifolds.
You might even be able to use Mercruiser manifolds and risers if they line up with your exhaust. Might even be able to use the newer dry joint, but that would be even more expensive.
The old 740A Volvo's used a full closed system, but those things were a nightmare, but it did prove the engine mounted pump was enough for the cooling.
It would be a battle with the plumbing, but not impossible.

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Thanks, Don. That's exactly what I thought and glad to have it confirmed. I will be using Barr manifolds and risers so they are ported and block off plates are available.

Please explain the other manifolds you mentioned - sounds interesting.

Also, what was such a mess with the old closed system volvo used?

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

I was thinking more of the 5.7's when talking about the dryjoint type. There are similar setups for the Mercruiser 496, but a bit different. Let me do some checking and I will post back.

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

I was thinking more of the 5.7's when talking about the dryjoint type. There are similar setups for the Mercruiser 496, but a bit different. Let me do some checking and I will post back.

Thanks Don but as I look they seem considerably more expensive, but interesting concept.

What was wrong with the old Volvo closed cooling system you mentioned. Would it be a problem Iogjt encounter?

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

What was wrong with the old Volvo closed cooling system you mentioned. Would it be a problem Iogjt encounter?

If you are referring to the 740, How does $1600 per side sound? Exhaust Manifold For Cooling System With Heat Exchanger 740A/MS5 - 7745660 - Volvo Penta

Want to hear any more about that awful system.

Look at this and all the hard (formed copper tubes) plumbing in it. The manifolds are also designed for seals flat pipes, not hose barbs.

Cooling System 740A - 7745660 - Volvo Penta

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Here is some diagrams that shows how Merc used the full system up to 97, they never used the full system on any of the big blocks after 97.

View attachment Full closed 74.pdf

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

If you are referring to the 740, How does $1600 per side sound? Exhaust Manifold For Cooling System With Heat Exchanger 740A/MS5 - 7745660 - Volvo Penta

Want to hear any more about that awful system.

Look at this and all the hard (formed copper tubes) plumbing in it. The manifolds are also designed for seals flat pipes, not hose barbs.

Cooling System 740A - 7745660 - Volvo Penta

WOW! Talk about cost prohibitive! And you're not kidding about about all that copper... sheesh

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Here is some diagrams that shows how Merc used the full system up to 97, they never used the full system on any of the big blocks after 97.

View attachment 181982

More interesting reading... thanks. Why did they stop after '97? It seems to be relatively easy but maybe I'm missing something. I'm assuming you (Don) would not like to do what I am suggesting, right? The Barr set is only costing me 600 for both sides, and I'm assuming that my manifolds will suffer MUCH LESS deterioration over the years. But again, am I wrong?

Thanks for the conversation.

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

My only experience with the 7.4 manifolds usually found the manifold flaking off from corrosion where the manifold bolts to the engine, long before they failed at the water passages and gasket surface between the manifold and elbow. So even with the the inside in perfect shape, the outside goes away. Doesn't seem to be a problem on any of the small blocks, just the big blocks.

So why save the inside at great expense when the outdside fails first. Of course this is all salt water boats, but you wouldn't be looking at a full system for a fresh water boat.

 

[bruceb58]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

When I was thinking about adding the San Juan Engineering system to my Volvo 7.4L, a full system was not available. Don't even attempt to use the heat exchanger for a half system on a whole system.

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

My only experience with the 7.4 manifolds usually found the manifold flaking off from corrosion where the manifold bolts to the engine, long before they failed at the water passages and gasket surface between the manifold and elbow. So even with the the inside in perfect shape, the outside goes away. Doesn't seem to be a problem on any of the small blocks, just the big blocks.

So why save the inside at great expense when the outdside fails first. Of course this is all salt water boats, but you wouldn't be looking at a full system for a fresh water boat.

Very interesting observation, about the "failing point"... any speculation as to why that is, or how it can be avoided?

And yes, this is a salt water boat as you surmised.

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

When I was thinking about adding the San Juan Engineering system to my Volvo 7.4L, a full system was not available. Don't even attempt to use the heat exchanger for a half system on a whole system.

A full system is still not available. At least in the traditional sense of the statement. This is not OEM and if you call SJE, that's what they will tell you. There is no prescribed kit for a full system Volvo. However, the larger H/E that is used on the Merc application will work because it's sized appropriately, and appears that it will bolt up if I can get my alternator down and out of the way.

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Very interesting observation, about the "failing point"... any speculation as to why that is, or how it can be avoided?

And yes, this is a salt water boat as you surmised.

Lot of heat in that area, plus any salt water leaks that might start from the manifold/riser gasket. Just found it normal on customers boats with 7.4's. Never see it on small blocks.

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

Lot of heat in that area, plus any salt water leaks that might start from the manifold/riser gasket. Just found it normal on customers boats with 7.4's. Never see it on small blocks.

I see. This is only my second boat, first one had the AQ 260 which I loved and now this is my first experience with the big block. I've come to learn that there are some differences in them but overall, I LOVE the performance of the big block.

You seem to know the BBC so let me ask this, if you don't mind. I see I have a tensioner pulley below the alternator. If I move the alternator down low, could it take the place of that tensioner pulley, or do I need to keep the tensioner pulley and work around it?

 

[Don S]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

First, let's make sure which engine you have for sure, what is the full model number of your engine? Need all those letters after the 7.4GL

 

[GilligansIsland]

Re: Can it be done?...Adding a FULL / COMPLETE closed cooling system on a Volvo I/O

First, let's make sure which engine you have for sure, what is the full model number of your engine? Need all those letters after the 7.4GL

Model 7.4GL INCS
Spec No. 3868283
Serial No. 4110132937