Volvo MD21 replacement

[KimCrocker]

I purchased my Hallberg Rassy 352 with a seized Volvo Penta MD21(shaft drive) fitted, I now have the engine in pieces on my garage floor it looks to be too far gone to salvage. I have an opportunity to buy a 5000 hour MD22(sail drive). Has anyone out there had any experience of doing this transplant ?

Thanks, Kim

[glenn.225]

Well there isn't much of a transplant as long as the bell housing and fly wheel bolts match on to your existing transmission and of course your engine mounts. It's a straight forward engine swap.

[KimCrocker]

Thanks Glenn, I had checked the measurements/mounts and thought they would be ok but it was the bell housing and flywheel I wasn't sure about. I can't seem to find any info on them.

[DougR]

Can’t help you with drawings of these two engines as I’m not at home for awhile, but a couple of thoughts about this job.....

- the MD21 had a rather small diameter flywheel housing and if the existing engine beds were really close to the housing, then you might have a problem getting the MD22 housing between the beds without some modifications. Of course this will apply to just about any other engine as well

- Both the MD21 and MD22 were available with transmissions that used the six hole “Borg Warner” bolt hole pattern (SAE 7) so you should be able to bolt the old gearbox to the new flywheel housing. However the gearbox input shaft splines on the MD21 transmission options used the 26 tooth involute spline, and the saildrive used a different input shaft diameter and spline count. So, you will need to source a new flywheel torsional damper or spring plate. You can get this from VP or ZF or most any component transmission supply house. Also it is necessary to carefully check the transmission for interference between the front of the transmission case and the spring plate.

-Some careful measuring might be in order with the oil pan on the MD 22 engine...as I recall the MD21 has a fairly shallow oil pan, and the MD22 had a rather deep cast aluminum pan. There might be some interference from that pan.

Hope this is helpful.

[KimCrocker]

Many thanks Doug, it is all as you explained.
I haven't started fitting the engine yet but it seems the main issues are the rear mounts and the spring plate.
There is quite a big difference in flywheel weight, the MD21 was a lot heavier, not sure why.
Again, many thanks for your input, Kim