md3b vs md17c differences

[cruisingtime]

Is there a volvo guru that knows the differences between a volvo md3b and a volvo md17c. I have a feeling that the bore and stroke is the same soooooo the block including the crank and rods are the same....but the heads are different and this difference is compensated by the bucket (cylinder). Thing is I dont know all this for SURE. Can anyone HELP.
Mitch

[bob p]

Give Dick Vosbury of Vosbury Marine in Annapolis MD. a call or email. He can be reached at 800-427-3451 and vosburym@aol.com. He has rebuilt a volvo engine and done other work for me. I've heard from reliable sources that he is the most knowledgeble Volvo guy on the east coast.
Hope this helps.
Bob P.

[Wavehopper]

Are the exhaust manifolds the same

[WillieC]

I have one of each sitting in my shop right now. The 3B is pretty much intact, but the 17C is down to the block. I'll take a close look at the manifolds, at least externally since the 3B is still on the engine, and get back to you.

Yes, same bore and stroke. but the 3B 6 bolt heads means 6 studs. The 17C is a four bolt head, as you know. So the crankcases are not the same. The 17C is sleeved and that also makes for differences where the cylinders mate to the crankcase. The exhaust manifold could very well be interchangeable, since the injectors are. There is a water port in the ex man for cooling the injector sleeves.

It is pretty easy to use the Volvo Penta part blow up on line to check numbers, but I'm not entirely sure a different number rules out swapping. It is all about fitment since the water circuit is identical. HOWEVER, there was some kind of change in the thermostat/housing, one using a bellows type thermostat with slight difference in the bypass function. I spoke with one of the east coast gurus whose name slips me, He still works in the shop (as of a couple years ago) who was adamant about not screwing up the thermostat as it closed one port as it opened...it got a bit long winded, with a bit of Swedish added further confusing me. I think the earlier 3Bs had this oddity. All three (four, I lose count) of my tstat housings are the same, regardless of engine.

Stand by, maybe check the parts list online.

[WillieC]

They look identical, bolt spacing matches, I'd swap 'em.

IMG_2216.JPG

[uptank001]

Do they use the same thermostat housing? I have a spare manifold with a three port housing? Can I plug the third and use it on my 1973 MD3B?

[WillieC]

Are you fresh water cooled? Do you have an aftermarket heat exchanger?

I ask because I got into a discussion with the VP expert back east who had a very definite opinion about the tstat housing. Where we landed slips my stable genius mind.

I have both engines sitting in my shop (and a fully functional 17C in the boat) and all three have the same stat housing and exhaust manifolds.

Maybe we should compare actual parts because I am quite certain there were two quite different housings.