Volvo B5244S3 B5244S4 B5244S7 Conversion Engine Swap

Volvo B5244S3 B5244S4 B5244S7 engine swapping - interchange and conversion

Case study of a 2006 S40. Rod bearing failed at 60,000 miles. The car had a B5244S7 engine and there wasn’t one available locally but there was a B5244S3 from a wrecked low miles 2004 S40. Both were non-turbo.
Checking the part numbers of pistons, valves & head gasket I decided to make the engine swap using the cylinder head from the 2006 B5244S7 car.
The short of the story is that the lower end of both engines is the same, although there are two different timing tensioner bearings used. The cam cover of the B5244S7 engine has two cam sensors and the B5244S3 just one. I used all of the sensors & fuel injection components that went with the car we were putting the engine into so there wouldn’t be any conflicts.
The top of the B5244S3 cover is machined for one sensor but the place for the other sensor is easy to machine as the mounting surface is machined and the mounting hole threaded. The bore for the sensor is 19.5mm at the top and 18mm at the base of the sensor. I machined it myself but you could take the cover to a machine shop and have them machine the new hole to match the other one.
Note that you can’t just swap the camshaft covers as the covers are machined with the head so they are a match.

A little nervous to start it up ... but hitting the starter it roared to life and ran like a clock. One happy customer I might add ... saved several thousand dollars over the next best option.
Some notes on the parts used:
Camshafts in B5244S3 engine: exhaust cam 0009497736EA135 aka 9497736 (I think this number has since been changed to 30650585.)
Intake cam 000867014711063 aka 8670147 . The 2006 B5244S7 had a 30677832 tensioner bearing and the 2004 B5244S3 had a 30637955 tensioner bearing. Both use the same timing belt 274338.

To install a B5244S7 in a B5244S3 car is simpler because you don't have to machine the port for the sensor. You would probably have to swap one of the cams though or it be perpetual "check engine" lights.

More articles like this coming as I convert scraps of paper notes into web pages. If you copy this to your website please provide a visible link and credit to the .

October 7, 2011 update from an email from Brad:


Just finished up my motor swap last night and all went well. I replaced a B5244S7 engine with a B5244S4 engine. The major differences I encountered were similar to yours. Here are a list of the differences I noticed between the 2 engines:

1: Exhaust manifold on the B5244S4 engine has no 02 sensor bungs while the B5244S7 engine had 2 of them.

2: My B5244S4 engine did not come with the bracket for the driveshaft bearing support so I had to use the one off my B5244S7 engine. By doing so the lower hole on the bracket had to be opened up. For some reason they felt they needed a larger bolt on the block there.

3: The cam cover needed to be machined similar to what you had posted. The hole was already partially in the casting and the tapped hole was even still tapped and ready to go.

4: I used the cams on the head that cam with the B5244S4 engine. By doing this I also had to pull the cam pickup gear off my B5244S7 engine so the new cam sensor would have something to read. The B5244S4 engine cam on the backside was missing this pickup for good reason, it didn't have a cam sensor there to begin with.

After all of these modifications and such the motor came to life without a single check engine code. All is good and I really appreciate you posting that article. I wouldn't have even considered risking this without hearing that someone else had done it already.
The engine I bought was $1900(us) shipped so I would essentially be taking a $1900 gamble had you not posted the article.

Maybe you can add this info to your website so others that are in our situation can benefit from our results as well.