MD1B or not MD1B, that is the question!

[James W]

Morning all,

Discovered a very strange problem this morning. I acquired 2 VP MD1B engines that came with my new boat and i've just started working on them. However, despite both being MD1B's (both stamped to confirm this), they appear to have different cylinder blocks, cylinder heads and exhaust manifolds!

The engine on the boat has a lot more cooling channels in the block itself (pictured with rag inserted) and the studs go through the block itself. The spare has almost no cooling channels and the studs run externally.

The serial numbers are 18405 (external studs, small cooling channels) and 20230 (internal studs, bigger cooling channels)

Please can someone shed some light on this please?

Thanks loads,

James

View attachment 40679View attachment 40680

 

[scottie]

I think you have a MD1B but one has mid block and head grafted on

See marine parts express volvo schematic sorry can't give link on ipad

 

[James W]

I think you have a MD1B but one has mid block and head grafted on

See marine parts express volvo schematic sorry can't give link on ipad

Thanks Scottie,

From what I can see on the schematic, the one on the engine with the proper cooling channels is the original and proper MD1B. But where would the other one have come from? Surely someone hasn't just machined up an entire cylinder block? And do you think it would work properly with the limited cooling channels?

Thanks, James

 

[Bilgediver]

Thanks Scottie,

From what I can see on the schematic, the one on the engine with the proper cooling channels is the original and proper MD1B. But where would the other one have come from? Surely someone hasn't just machined up an entire cylinder block? And do you think it would work properly with the limited cooling channels?

Thanks, James

Does the one with smaller channels have six stud positions and same bore? It sounds like MD1 which had smaller bore.

 

[scottie]

Which is on boat?
is it running ?

 

[James W]

Does the one with smaller channels have six stud positions and same bore? It sounds like MD1 which had smaller bore.

Hi Bilgediver, this is the one with smaller channels but it's 4 stud positions.

View attachment 40683

 

[James W]

Which is on boat?
is it running ?

Hi Scottie,

This is the one on the boat but it's not running. This has the head that should be on the MD1B View attachment 40684


The boats been laid up for 20 years and the engine was never winterised. It's not seized though and i'm working through the cooling system first and then the fuel system.

I'd preferred the other one simply because the cooling channels aren't so blocked up but I'm sure I can make the original one work with a bit of engineering help and some graft.

Other than that i'd better start saving....

 

[James W]

Cylinder heads

Further to this, here are the respective cylinder heads.

This is the one that matches the MD1B on the boat and matches the description of the engine in the manual:

View attachment 40685

And this is the one from the spare engine. Note the different (tiny) cooling pathways and the slight differences where the exhaust manifold bolts on:

View attachment 40686

I'm sure there's a sensible explanation to all this, it's just puzzling me whether both heads and blocks will work on the engine?

Thanks

 

[[448]]

I used to know a lot about MD2B and MD11c engines. At first glance it looks as if you have a MD11c block and head fitted to a MD1b bottom end. Not sure if this is possible though, but I think the MD2B block and head will fit the MD1b.
Check out the Md11C parts lists etc.
Main difference is the MD11c has separate cylinder liners and the outside headstuds.
Was ther a single cylinder version of the MD11c?
Dave

 

[James W]

I used to know a lot about MD2B and MD11c engines. At first glance it looks as if you have a MD11c block and head fitted to a MD1b bottom end. Not sure if this is possible though, but I think the MD2B block and head will fit the MD1b.
Check out the Md11C parts lists etc.
Main difference is the MD11c has separate cylinder liners and the outside headstuds.
Was ther a single cylinder version of the MD11c?
Dave

Dave,

You've cracked it, thanks for that! It definitely looks like a MD11C according to the manual.

Now the next question is.......is there any reason at all why that wouldn't work when bolted onto the MD1B crankcase? If it cools sufficiently on the MD11c, why wouldn't it on the MD1B?

 

[Bilgediver]

Hi Bilgediver, this is the one with smaller channels but it's 4 stud positions.

View attachment 40683

That looks like an MD 1 (A) casting. Has it been overbored to the same bore as the one fitted???? It has no provision for the two studs next to the tappet space so these studs could not be used! Also those drilled cooling passages could be in the wrong place to match those on the MD1B head. I suspect it is of no use and been bought in error.

 

[[448]]

Dave,

You've cracked it, thanks for that! It definitely looks like a MD11C according to the manual.

Now the next question is.......is there any reason at all why that wouldn't work when bolted onto the MD1B crankcase? If it cools sufficiently on the MD11c, why wouldn't it on the MD1B?

See Bilgediver's reply about cooling passages. Does the existing setup look as if it has ever run?
Despite what many on here might say, these MD1(b) and MD2(b) engines were great and almost unburstable. If you get one going well you will get a lot of service from it. Blockage of cooling passages is a common ailment.

Dave

 

[James W]

See Bilgediver's reply about cooling passages. Does the existing setup look as if it has ever run?
Despite what many on here might say, these MD1(b) and MD2(b) engines were great and almost unburstable. If you get one going well you will get a lot of service from it. Blockage of cooling passages is a common ailment.

Dave

Hi Dave,

I'm now pretty certain it's an MD11c cylinder block and head. I've discovered a chap who successfully used one as parts for an MD1B and i'm going to contact him to find out how it went and if he can share his experiences.

I'm hoping i'll get to the point soon where it all comes together. Who knows, I might yet fall in love with the old Volvo.

One thing's for sure, I'll know the engine inside out!

Thanks again for your help.

James

 

[[448]]

Hi Dave,

I'm now pretty certain it's an MD11c cylinder block and head. I've discovered a chap who successfully used one as parts for an MD1B and i'm going to contact him to find out how it went and if he can share his experiences.

I'm hoping i'll get to the point soon where it all comes together. Who knows, I might yet fall in love with the old Volvo.

One thing's for sure, I'll know the engine inside out!

Thanks again for your help.

James

James, keep us updated with the results. I have a MD11C bottom end and 1 block, piston and conrod (no heads) if you need them.


Dave

 

[James W]

James, keep us updated with the results. I have a MD11C bottom end and 1 block, piston and conrod (no heads) if you need them.


Dave

Will do Dave, and thanks again for the help.....I may well take you up on your kind offer.

All the best,

James