VP MD5A experts, cylinder head

[etxee]

Hello everyone

I am new to this forum, so big hello from Bilbao in Biscay Bay NorthSpain, I am the owner of a 26ft swedish Hellmans sailboat.
It is powered by a trustfull VP MD5A, which I am about to restore. I have acquired some spare parts including a second cylinder head and to my surpirse, even though they both came from MD5A's, their reference number differs, i.e. 838121 vs 838181. The diameter of the valves are also different 40 vs 35 and 30 vs 25 (all in mm). Also one of the water exits varies its position slightly. I wish I could attach pictures, but do not have the cylinder heads with me now...

any one can give me any hints on operating differences?

many thanks in advance
Ibon

 

[greeny]

Are you sure the spare head is off a 5A.
From a long ago distant memory, I think the head for the 5A and 5B were the same. The 5C was different.
Volvo Penta MD5A;MD5B;MD5C | 21 Engine | Volvopentashop.com
This link seems to show different valves for the 5A 5B compared to the 5C.
No doubt one of the engine experts will be along soon to help more.

 

[etxee]

Many thanks Greeny for your support. I did check all available diagrams in the web but could not find any differences.
So I have decided to do the whole cylinder head. Unfortunately but not surprisingly each valve is around 200euros each, the guides around 100 euros each...
My question is whether I can find non OEM parts from any other manufacturer that will suit my MD5A cylinder head.

Dimensions are as follows
Inlet valve:
40mm valve head diameter, steam 8mm diameter length 100,4mm one single groove for the spring and a seating angle/bevel 45°

Outlet valve head diameter 33,1mm, steam 8mm diameter length109,5mm one single groove for the spring and a seating angle/bevel 45°

 

[Bilgediver]

I discovered many moons ago by accident that the valves in my Volvo MD2B were the same size as certain car engine valves. The only diofference with them was the seat angle as those Volvo valves were a slightly different angle. to the 45 degs of BMC. However I was able to get a Pikavand valve seat cutter for BMC engines which had cutters of the correct size and an angle of 45 deg.

The original valves were not worn to a great extent so I recut my seats to 45 deg and machined the valves to the correct differential angle of about 1/2 deg. Are your valves definitely NOT recoverable as there are many engineering shops around the country that can recut/regrind them to profile. Such a machine shop could deal with the guides as well.

These companies can also at reasonable cost rplace the valve seats using inserts

 

[etxee]

Many thanks Bilgediver, your solution is heading towards the goal I am looking for. I have been trying to search for similar valves but there is hardly any "valve searching tool" available so it is quite hard to find even similar valves.
I will keep looking, shall I find anything I will surely let you guys know