AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

[paperklip]

Long story short, I got a good deal on a 21' cabin cruiser with a Volvo 4 cylinder OHC (AQ125B) in it which turned out to have a severely corroded head, exhaust manifold, and eventually a blown head. This was all due to raw water cooling an aluminum head, but for more detail, read the discovery thread here.

I did lots of searching for another engine or even a donor boat, but no luck (at least nothing of any quality). So, this project is to swap the complete engine with a marinized automobile engine. The Volvo Penta AQ125B is a B230F block (2.3 Liter) which can be found in many Volvo 240 cars between 1985 and 1993. I believe a comparable 4 cylinder OHC can also be found in the Volvo 740 (1985-1992) and Volvo 940 (1992-1995).

In addition to helping me along with my project, I hope this thread helps anyone in the future who might be considering this for their boat.

So here we go...

I picked up a 1992 Volvo 4 cylinder engine (out of a 240) with 168K miles, in really good condition for cheap from a junkyard. I plan to use the original marine intake/carb and a brand new marine exhaust manifold. I will also be adding a closed cooling system with a raw water heat exchanger and antifreeze expansion tank.

Here's the auto motor fresh from the junkyard shelf:

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Fuel injected intake side:

And then here it is broken down and skinny.

About to pull the head and take it to the machinist for inspection.

Ordered and waiting on shipment of the following:

- Volvo De-carbonizing Head Gasket Set New 876302
- Volvo Heat Exchanger (housing & insert) Used 831890/831713
- Osco Exhaust Manifold (with mounting kit) New V0418

 

[RogersJetboat454]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Looks fairly clean. You will be able to see what the holes look like when you pull the head too.

Just outa curiosity, is that heat exchanger including the tubes and an oil cooler?

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Doesn't include the tubes, and I'm not doing an Oil Cooler. According to my Workshop Manual (which is for both the 125 and the 145), the 125 doesn't have one, but the 145 does.

 

[bruceb58]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

You are also going to need a marine distributor and starter.

 

[Luhrs28]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

I was about to launch into a 6 paragraph lecture on why you should go diesel, but I don't know what kind of diesel engine would mate up with your tranny bellhousing.

So just forget I said anything.

 

[johnmorgan]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

I have a marinized b20 motor in my boat, almost the same motor just older, but I had problems with the carb sloshing around and killing my motor so i am going diesel now md21a. a oldie but goodie. on a foot note my motor had a crappy closed cooling system, the raw water pump was huge and the cooling was still atomotive. are you getting the waterpump that attaches to the cam and a marine cam also. theres some pictures of my motor

 

[captmello]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

View attachment 106045View attachment 106046View attachment 106047I have a marinized b20 motor in my boat, almost the same motor just older, but I had problems with the carb sloshing around and killing my motor so i am going diesel now md21a. a oldie but goodie. on a foot note my motor had a crappy closed cooling system, the raw water pump was huge and the cooling was still atomotive. are you getting the waterpump that attaches to the cam and a marine cam also. theres some pictures of my motor

The motors are really not the same...your b20 was not overhead cam, and came stock with raw water cooling. B230 blocks are overhead cam and always had fresh water/closed cooling.

 

[sqbtr]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

The 125 water pump is also a marine only unit and very pricy, the 131 can run a auto pump but is a totally different heat exchanger.

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

I'll be using lot's of marine parts from the old engine.

 

[sqbtr]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Take a picture of your old water pump, you might be better off using a 131 heat exchanger. Have you looked into cam requirements yet?

Seeing how your old engine was automotive look close at all your components

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Yes, I'm definitely seeking info on the cam change. Any tips appreciated.

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

The auto cam is stamped with "A" and I checked the one that was in the old engine, also an "A"

Anyone know the grind for an original AQ125B? I'm guessing it was "K" based on the following link:

http://www.turbobricks.com/resources.php?content=camspec

 

[RogersJetboat454]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

The auto cam is stamped with "A" and I checked the one that was in the old engine, also an "A"

Anyone know the grind for an original AQ125B? I'm guessing it was "K" based on the following link:

http://www.turbobricks.com/resources.php?content=camspec

According to that source, it looks like it. Just remember if you get a new cam, you are also going to have to re-shim the "valve depressor" with "adjusting washers" so they are with-in specifications.

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Thanks, good tip on the shims! I can't find anyone local who does cam grinds, but I'll keep hunting for a "K". I may end up running the "A" if nothing pans out. I have the second cam to send off for a grind if need-be.

In the meantime, the head is off. Cylinders, head, and valves all look good. Taking the head to the shop for a checkup and probably a valve job. Draining the pan tomorrow and flipping the motor to take a look at the other side of things. Other than that, mostly in a holding pattern waiting on the decarbonizing gasket set and other parts from the brown van.

 

[PiratePast40]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

The auto cam is stamped with "A" and I checked the one that was in the old engine, also an "A"

Anyone know the grind for an original AQ125B? I'm guessing it was "K" based on the following link:

http://www.turbobricks.com/resources.php?content=camspec

Check for a part number on the cam and compare that against the Volvo OEM part number. You could also take the cams to a shop and have them compare the two.

I'm not so sure about the list from turbobricks. Notice that they don't list any specs for the marine cams for any of the engines. Here's an experience I had: For the B20 engine, they list the 'P' grind but it's not available anywhere. The cam in my marine B20 engine had the correct part number and was stamped with a 'C' which is the standard performance grind. I bought an Isky 'C' grind and it's identical to the original.

Just be careful about some unverified list.

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

Check for a part number on the cam and compare that against the Volvo OEM part number. You could also take the cams to a shop and have them compare the two.

I only see what looks like a casting number 1000132, and also 2967.

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

The 125 water pump is also a marine only unit and very pricy, the 131 can run a auto pump but is a totally different heat exchanger.

Is there a difference between the AQ125A and AQ125B water pump?

I see two different part numbers in the diagrams on volvopentastore.com, but I wonder if they are interchangeable.
AQ125A - Part# 828023 Replaced by 3587508
AQ125B - Part# 855566 Replaced by 3856036

 

[PiratePast40]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

I only see what looks like a casting number 1000132, and also 2967.

What I see in the schematics is part number 1336767 for the cam.

 

[paperklip]

Re: AQ125B Engine Swap with a Marinized B230 Auto Engine from 92 Volvo 240

What I see in the schematics is part number 1336767 for the cam.

Interesting link here with the different Volvo cam grind specs. If that's right, the 1336767 is an A grind, which is what I already have (2 of).