TOPIC: Mark 58 interchangability...

...if that's a word.
Hi All, Is a powerhead and carbs from a Mark 58 compatible with let's say a 58A or a 58E. Looking at oldmercs.com it looks to me as if the mark 58 was only built in 1958 and 1959. Is that so? Thanks in advance.
Shipster

The power heads are all Identical The e designates electric start & the A was just a redesign of the cowling.

most of the 4 cyl parts are interchangeable depending what parts are you wanting to swap but there are 40 cubers & 44 cubers
but you can still run a 40 cube powerhead on your mk58 setup your less limited than you think...not just restricted to mk58 parts

Thanks guys.

Be careful here. There are many small differences between the years that can trip you up, but the biggest thing to remember is that the year 1965 brought a completely new powerhead for the 44 cube engines, and they will NOT interchange with anything built before that. Keep it in mind if you are looking for a donor engine for parts.

I believe George is referring to the block not being able to be retro-fitted to the earlier mid or lower pan 44ci Mercs - or - visa-versa, but lots of the small parts will interchange still - like pistons, crankshaft, carbs, ignition (until adi), etc.
This may create some arguement, but I am a frankenmerc'r at heart.

Thom

This may create some arguement, but I am a frankenmerc'r at heart.

Im with you Doc , I took to these old mercs because they are just like my old harleys, mix em match em & swap em

That is true Doc they won't swap out but it does not end there, as there are internal differences as well. Some of the 44" cranks are longer and will not swap out, they will bind and interfere when you try to put the end caps on, measure what you have first! We ran into this on a recent build, and found that one crank was a little bit longer than the other but looked identical at first blush. We swapped out the crank from an earlier engine and all was well again. Piston pins are also smaller on the early engines and use different rods and the lower endcaps have different bleed holes drilled in them. Inspect carefully before you swap!

I had a 1970 50 hp and for what ever reason I smeared a piston on the cylinder wall. I tore it down and found out it didn't score the wall. I took it to a machine shop and they cleaned it up for me. I then started digging through a box of old Mark 58 A parts that I had and found out that the bore was the same. Since the wrist pins were smaller I just used the rod and the needle bearings from the Mark and it worked great. I put a in new set of rings, ect since I had it apart anyway. I ran it hard for several years then sold it. As far as I know it is still running great to this day. That is one thing I like about old Mercs - the parts don't change much, unlike just about anything you buy now days!!
Bill

Yes, there are similarities between the years and you can mix and match...sometimes. Thing is, always measure everything and check stuff like water jackets, end cap holes, crank length, journal size, flywheels, starter teeth etc etc. While there are many similarities, there are differences as well, so never assume anything, check first and avoid disappointment.

Once more, thanks. You guys are getting into details that are way over my head but it gives me a good reference point. Does anyone have a line on service manuals? Thanks.

Now that you mentioned starters, that reminds me that the 50 hp didn't have electric start or a charging system. I had a flywheel, stator, and starter from the Mark 58 A. They all fit perfectly, with the timing marks lining up and everything. It looked like it came from the factory and worked great.
Bill