MD17C in A25

[DesertAlbin736]

Yes, things can go South quickly in heavy seas. Don't ask me how, but I know, been there, done that. I'm all in with the Department of Redundancy Department. Glad you had a good summer. Time to start dreaming/planning for Gulf Islands and Desolation Sound next year.

[WillieC]

Oh, I'm dreaming, believe me. Yesterday was such a peaceful day on the Canal, but the forecast was spot on and today it is like a different body of water, whitecaps and the Willie C. straining at the anchor rode. (I pulled our mooring ball and its 150 lb. anchor earlier in the week.) I guess I did a good job setting that tiny anchor because she hasn't budged. Hope the winds abate before the Starfleet Commander returns. She has bad memories of rough water.

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[DesertAlbin736]

Actually, right now we are RV camping near Fort Pierce on Florida's SE coast. Little canal or stream runs behind the camp site, and a sign advises campers not to feed the alligators. Our boat is at home, 2,300 miles away. Rainy & muggy as the dickens, hookups to run the A/C a necessity, not a luxury.

[WillieC]

I could start a new thread, but since there are not too many MD17Cs left in these A25s I'll just add to this pile.

I decided to buy a new, cam driven water pump for the old beast. No problem, readily available Johnson F4B-9. Only it comes with with R3/8 threads, allegedly the same as BSP tapered threads. I knew there was something fishy on both of my Volvo Penta engines, since every time I tried to do anything with pipe fittings, threads would only engage for a thread or two, then bind up. I suspected things metric, but nothing blew out as long as you don't over torque things.

Now that I am looking at actually buying a new pump, I would like to find BRONZE R3/8 to hose barb fittings that actually fit the pump. One of my old pumps has stubs cast as part of the pump that 5/8" hose readily clamps onto. But they are only stubs, not real hose barbs. As Pat Paulsen used to say, "Picky, picky, picky..." And the whole point is to start with a NEW pump. All mine have obvious wear patterns in the impeller cavities and probably need new bearings and shafts and seals. One new thing on this engine would be good.

I'll find them, maybe in the UK. ASAP Supply has been helpful in the past. I would also like to install the speed seal quick-o change-o cover, and it also comes from the UK. So close, so close but yet so fa-a-aar.

On a similar note, I plan on installing a NEW fuel lift pump, since all the ancient ones I have leak. But only a little. Kill me now. ASAP has a sealed replacement, also cam driven that I am considering. Forget NOS Volvo Penta. And I have been unable to locate a rebuild kit (which could easily cost more than the ASAP replacement.)

I would go with an electric fuel pump, but I like the concept of an engine driven pump that varies output with the engine rpm and uses no electricity. I already have a couple of the inline fuel transfer type pumps that use some kind of internal solenoid instead of a motor driven pump. Not sure about using these relatively cheap pumps for continuous use. They work great for priming the fuel system. And the electric fuel pumps I have been looking at deliver about ten times the fuel these engines sip. Not optimal. The additional noise would be unnoticeable, but also unwanted. I already have enough noise. Also, would some kind of pressure relief/bypass valve be needed with this kind of set-up? Probably some kind of custom hose to fit the original filter canister as well. We are talking lift pump only here, low pressure.

Feel free to weigh in if you have any suggestions regarding these two issues. Thanks.

[dkirsop]

Richard, here's what I know about my engine, not a Volvo product but manufactured next door to Volvo in Sweden. All the hose fittings on my engine have a fine thread that bear no resemblance to anything I have seen in North America. My recommendation is get a metric thread gauge and find out what you are dealing with. If it is anything like the Albin you know where to buy the fittings. If it isn't then I guess the search is on. Hopefully the female threads have not been destroyed by previous owners.

My fuel pump is a Type J AC cam driven fuel pump with priming lever. It is made in England and I am willing to bet any shop that sells parts to British car collectors can source one. Not sure what was on your Volvo but this pump would easily meet your fuel demand. I have one spare, one on my current engine which I rebuilt and one on the engine that is waiting to be rebuilt. Service kits are also available. When I bought the boat the PO had installed an electric fuel pump but had left the cam pump in place. When I serviced the engine guess what - the electric pump was dead as a doornail and the cam pump had been pulling the old girl along even with the additional drag on the fuel supply. His spare electrical pump in the locker was equally dead. The cam driven pump is highly reliable and I am sticking with it.

If you go electric Walbro makes a fuel pump with a pressure bypass that would meet your engine's needs without oversupplying it. I researched this before deciding to stick with the original pump.

[kerrye]

Totally agree on the cam pump. No need to introduce an electrical requirement to an engine which has no need of electricity to run. I wish my Westerbeke had a mechanical pump.

[WillieC]

Thanks, Kerrye and Dave. I have contacted ASAP Supplies in the UK and have high hopes for new, bolt in replacements. The water pump is easily sourced just about anywhere, but all suppliers point out that the threads are R3/8, which I understand is 3/8" BSP. 3/8NPT darn near fits, so I think I know what I have. They are not the oddball English Norton motorcycle thread. I am asking ASAP to scrounge a couple fittings and send them in the box. Wish me luck.

I agree with the comments on the mechanical fuel pump and ASAP has a direct replacement brand new unit available for less than repair kits, if you can find them.
Will keep you posted.

[Beta Don]

The little $10 electric 'solenoid pumps' are actually quite reliable. A friend uses 3 of them on his offshore Shannon 28. He has a day tank the engine runs off of and uses a large Racor filter to pump fuel through a loop into the day tank, spilling over back into the main tank. This runs anytime the engine is running, circulating the fuel through the big filter to keep it polished. He uses a second pump from the day tank to the engine and a third pump with a 2' length of copper tubing to pump fuel out of 5 gallon jerry cans into the main tank when he refuels. Since they're only $10 each, he does carry a couple spares, but I don't think he's ever had to replace one. Don't recall how many hours he used them with his old 2 cylinder Yanmar that came in the boat, but he now has more than 2,000 hours on a new 3 cylinder Yanmar

Anyway, I wouldn't hesitate to use one. My Kubota diesel garden tractor uses a very similar pump. They're not known to be problematic. I actually prefer them to the mechanical pumps because some of those will pump diesel into your engine oil when the membrane fails - You don't see many mechanical pumps on new diesel engines these days

The quick change water pump covers are very nice - Couple that with an impeller puller and making a change is very simple . . . . but I still pull them and change more based on hours (750 or so works for me) so I don't have to do it unexpectedly . . . . and worry that pieces of the old impeller are plugging up the heat exchanger

Don

[WillieC]

New pumps and speedseal kit are in the mail! AND, properly threaded hose barbs. Wow. That will cure the biggest of my reliability issues on the engine. If only I hadn't created a run in the engine block paint...

[DesertAlbin736]

Great! And now that you have a heavy duty tow vehicle & the fuel pump issue solved you'll be ready for Desolation Sound next summer, right? The sailing friends from our club who recently purchased this Alden 44 (ALDEN, not Albin) sailboat in Virginia and had it shipped overland to Anacortes are at this very moment in the San Juans on their way to Sidney where they plan to keep it from now on to avoid WA state taxes (and to do so will have visit a US port at least once every 365 days). Hoping they will be able meet us & do Desolation Sound next summer. Plus we have our other friends with their O'Day 25 that cruised with us last time may also go up next summer. And who knows, maybe dkirsop? That would be such an adventure. We HAVE to stop at Montague Harbour on Galiano along the way & take the bus up to Hummingbird Inn Pub. We could have quite a little fleet going on. I for one would also like to make to one of the Albineers of BC club's rendezvous.

[WillieC]

Long story, I’ll post more details later...
Right now I am installing my rebuilt heads and have a question for those in the know about installed spring height.
This has to with the closing(closed) pressure on the valves. It has been suggested to me that I may need to install shims under my brand new springs. Note that I also have brand new valves and guides. All holes. Valve seats were re-usable.
I find no info in the MD17C engine manual so I am tempted to just slap it back together (along with the brand new pistons and liners, yeehaw).
The camshaft is original and the new springs are back to original spec. No racing cam or 8000rpms here.
Any wisdom out there on this subject? Thanks!

[dkirsop]

These old engines are generally slow revving. Mine tops out at 2200rpm, so no need for NHRA Type A dragster high pressure double-helix spring ratings. The spring only has to close the valve before the compression stroke begins. I have noticed the existing springs on my engine can be compressed by hand if you need to (hard but doable).

[WillieC]

I have worked on more engines than I can recall and never considered installed valve spring height. Thanks to the internet, I now know what a fool I have been...then again, my experience has been limited to low power, worn out, derelict, and abandoned equipment that I try to wring a couple more years out of. No Isky racing cams in my toolbox.

But, the question remains. I think what I'll do is try to measure and compare them all to each other and see if there is a large discrepancy. Hopefully, not. When I first tore this engine apart, there were a couple springs that had shims under them. I thought it was compensation for weak springs, each of which was a full eighth of an inch under spec when relaxed. So much for a .015 shim, so I thought. Really, they are to compensate for the valve seat depth or recession from original, which affects the actual pressure on the valve when closed. Obviously, much more important on any kind of revving engine. Not exactly the description of the MD17C. Thanks for your input.

[WillieC]

Just talked to the machinist. Installed spring height is actually in the book, just not called out as such. It gives three readings: at rest, loaded with 66 pounds, and loaded with 125 pounds, or close to that. Well...the unloaded (at rest) reading is no, duh.
The second reading, 66 pounds, is valve closed...i.e. the corresponding length in the chart, 39mm, IS THE INSTALLED SPRING HEIGHT!
The third measurment, 125 pounds at 32 mm is valve open, top of cam lobe.
Problem solved! They just don't call it out for mere mortals to understand.
And my mechanic DID check the new springs against the book. Perfect.

Now to figure out how to measure it with any accuracy and no fancy micrometer valve height measuring tools. It sort of is like rocket surgery.

[dkirsop]

Well I have learned something today which is what I like about this site.