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Ice cream maker, Gas to Diesel conversion

41K views 99 replies 16 participants last post by  bindermike 
#1 ·
Here it is with the gas engine


And here's the new Diesel engine


It's a Volvo Penta model MD1, late 60's I think, about 7HP, direct injection, hand crank with optional electric starter/generator.
When swapping engines I'll also put it all on a cart/wagon so it'll be easier to move around. Engine in front, existing pulley arrangement over the output shaft with a short belt, and ice cream maker behind that.

Have almost everything except a good fuel tank and some sort of water tank for the engine. For the water tank I'm thinking about 8" round x 24" tall would be suitable.
I also have a second ice cream maker I'll probably add later on.

Grigg
 
#56 ·
Nope, just a 90* shutoff valve. If I were to use a glass bowl filter the bracket would have to be much taller and unstable with as much as this thing shakes around. It has a much oversized primary fuel filter and probably won't burn but a gallon or two a year so I'm not going to miss the glass bowl filter, although it would look nice.

Grigg
 
#57 ·
Well it looks like you should checked your own stash:) Either way nice job, how does it sound now with the muffler? That muffler is quite popular out here at the tractor/thresing bees!
 
#58 ·
Not the best pictures but here is the new tank and muffler installed.



I did have the muffler, the tank came from a neighbor, I made the bracket for it.
Pulled it out of the garage last night and it seems to work just fine, sounds a little quieter but certainly not silent with the new muffler, pretty good I think.
Only trouble is the exhaust pipe wants to unscrew from the head as the engine shakes, I'm going to try pulling it apart, clean the threads, and use some Loctite. It supposedly lets go at about 400 degrees F but I think the exhaust is running pretty cool, and the head might keep the flange cool enough. Worth a try anyhow.
Looking for a throttle lever next and it'll be done. Well I'd like to raise the whole thing 1" above the axles so the wheels can fit under the rails to turn more, tighter turning radius. Then sometime I can add the second freezer if I want, shaft is already there to run it.

Grigg
 
#59 · (Edited)
It's ice cream season again, I think we've already made close to 2 dozen gallons in the past couple months.

Ready for a few improvements and it has a few troubles, mainly slobbers a little soot and fuel or oil out the exhaust.
-I've tried restricting the exhaust some to help it get and stay warm, no real improvement.
-Pulled the injector and had it tested, sprays fine and pops at the right pressure
-compression is great, starts on the first couple revolutions of hand cranking every time.
-Checked timing and it was within spec, even so I retarded it a little out of spec, slight to no improvement. I'll set it back within spec but retarded as much as that allows.

Next on the list is make an exhaust pipe that turns down and points at the ground, then while I search for an answer to the slobbering it at least won't make a mess of its self. Might also be quieter.

I'm also trying to improve the cooling and engine temp. Being a marine engine the thermostat is relatively cool, close to 165F, and with such a light load I think it's struggling to get even that warm. Went to NAPA and picked a thermostat that almost fits and is 180F. Had to turn the outside diameter down a little to fit. I'll give it a try but not sure if it'll have trouble overheating... Unfortunately I couldn't find a replacement thermostat that would block the water passage and force the cool water into the water jacket. The way it is supposed to work is the raw water pump picks up fresh lake/ocean water and pumps it to the thermostat housing where if the engine is cool it keeps going straight through the housing and is discarded. If the engine is warm the thermostat opens and also closes the water bypass, cool water then must enter the water jacket and exits through the open thermostat and is discarded. What I have will not close the bypass, some some cool water will always bypass and I hope some will enter the water jacket when the thermostat opens.

I also made a new Micarta insulator for the thermostat housing because the old Bakelite one was cracked and I had stuck it together with superglue, I didn't trust it.

Any ideas on the slobbering or where to find a higher temp thermostat that works like the original Volvo one?

Grigg
 
#62 · (Edited)
Thanks guys, The old thermostat is presumably adjustable by unsoldering the disc on the end of the stem and threading it on or off some.

I tried the new one and it's not going to work, water in and out of the housing is dead cold and cylinder/head temp is hot. If it were working I'd have some warm water exiting the thermostat housing. As I suspected the thermostat has to block that port to force the cold water to flow into the cylinder, wishful thinking that enough would flow to keep it cool.
So I tested the old thermostat on the stove in a pot of water with a thermometer. It begins to open at 165F and fully open at 175F I put it back in and tested, works as its should, warm water exits thermostat housing when the engine is up to temp. ~170 isn't bad, not worth the risk attempting to adjust as I haven't found even a stock replacement and if I do I'm sure it's expensive.

Really I'm grasping at straws trying to figure out why it slobbers. Thought a thermostat change would be easy and running 180F couldn't hurt even though I knew it wasn't the real problem causing the slobber.

During testing yesterday I lost water flow, suspected the Jabsco rubber pump impeller had died, which it had. Luckily I had ordered a new kit on ebay last week to have as a spare, looks like I need to get another. The old one was something like 30 years old and I knew it'd die at some point, lucky it didn't die in the middle of a batch of ice cream, and lucky I finally ordered a new one. I'd been foolishly putting off buying one because they cost $20-$30, kept thinking I'd find one at a better price somewhere...

Also this weekend I got the new exhaust made for it, 1" sch 10 stainless with 1-1/4" NPT ends, fit pointed down between engine and frame. It might be a little quieter I think and certianly won't cover the whole thing with specs of fuel/oil and soot while I figure out the real problem.

Tonight I hope to get the timing changed back within spec. Sometime I'll have to pull it all apart and see what I have, what's really going on, and if nothing else fix some oil leaks in the process. In the meantime I have 2 batches to make for a party tomorrow, two more for different gathering the next day, and 3 or 5 batches for next weekend...

 
#63 · (Edited)
Adjusted the timing back to within spec last night and it seems to still run fine/the same. Made a batch of ice cream last night and not nearly as much (any?) slobber with the new exhaust and possibly the other changes. It does however still smoke just a little, which it has always done.

One thing I noticed is I could pump the priming pump and pick up a few RPM, which means the fuel pump probably isn't doing all it should. The manual said gravity feed 6" higher than inlet on fuel filter is enough pressure, I used one of these pumps and it seemed to work when new. Pulled the cover to check last night, no apparent problems, looks perfect inside.


It sure would be simpler to have the fuel tank up high and gravity feed but there's nothing good to mount a full size tank to. Now I'm thinking of a little "day tank" sort of thing mounted on the head above the injector that would be filled by the fuel pump and or the priming pump, then gravity feed from there, overflow back to tank. A pint of fuel would last a while even if the fuel pump gave up and had to fill it with the priming pump.
Or can anyone think of a suitable non electric fuel pump?

Grigg
 
#64 ·
Is there any kind of eccentric on the outside of the engine you could drive an automotive fuel pump off?

If there is (or you feel handy enough to make one) you cold use the pump off a 6.2.

It's mechanical, comparatively inexpensive and easy to come by (basically a diesel rated Chevy gas pump).

If you have to add, maybe add it to the "ice cream" end of the drive (opposite side of the pulley though) as it wouldn't likely need that much volume; slowing it down might be a good idea.

If that's not too much pressure (Mikuni pump like that is what, 1.5-3 psi?).

I don't know if the smaller diesels used a similar pump.

Old I4 VW gassers had a block mounted pump when they were carbureted, dunno if the diesel variant used that for a lift pump or not. :confused:
 
#65 ·
There's not a real clean way of using an automotive eccentric actuated diaphragm pump that I can think of. like you said something on the belt and pulley end of the contraption might be a reasonable method. The later model of this engine does have provision for one...

As much as the whole engine shakes I wonder if I could sue one of these to pump fuel... I'll have to make something up and give it a try. Nothing more than a check valve in the fuel suction line coming out of the tank.
http://www.superjiggler.com/prestashop/store/9-super-jiggler-plastic-siphon-pump.html

I kept scratching my head on how to mount the whole tank up above the engine but didn't come up with much.
What I did figure out was a little fuel can solidly mounted to the head that gravity feeds the filter/injection pump and overflows back to the main tank. It is filled from the main tank and primary filter by the Mikuni pump if it would work, and the hand primer pump on the filter when it doesn't.

It seems to run better (more through testing to come this afternoon) and unfortunately the Mikuni pump doesn't seem to do anything right now. It'll run for a long time on a can full and easy to hand pump the fuel up there every now and again.



 
#70 ·
I kept scratching my head on how to mount the whole tank up above the engine but didn't come up with much.
What I did figure out was a little fuel can solidly mounted to the head that gravity feeds the filter/injection pump and overflows back to the main tank. It is filled from the main tank and primary filter by the Mikuni pump if it would work, and the hand primer pump on the filter when it doesn't.
Since it only takes a small head pressure of gravity to make it run better, perhaps you might consider pressurizing the fuel tank from a low pressure (regulated?) source. My initial thoughts take me to an air pump for a aquarium, but that's just the idea. Must be many others. Maybe even sourced from the exhaust manifold with a flame arrester and inline cooling ahead of a regulator. Just thinking out loud...
 
#69 ·
It does seem to run a little bit cleaner with the constant gravity feed fuel. I'm still going to disassemble and check everything soon.

Made a little inline check valve yesterday, that was fun just making it up as I went.


Then slid a sleeve over it with some green loctite




For now I installed it in the outlet of the primary filter as that's about the lowest place for it and it's more or less vertical. It might help the fuel pumping situation but it's not real obvious. The thing will run for more than an hour and still have a half full fuel can and I can't tell if it's properly refilling on it's own and sloshing the top half of fuel into the overflow pipe as it runs and shakes or if it's sloshing and consuming fuel and NOT being topped of automatically. The way it shakes and splashes you can't tell by opening the lid and looking. I need to pull the fuel line off the fill tube and check for flow there.
 
#73 ·
Yes and no.

...I used one of these pumps and it seemed to work when new. Pulled the cover to check last night, no apparent problems, looks perfect inside.
Thanks for the ideas on pressurizing the fuel tank but I think I've found a decent solution with the gravity feed fuel can mounted high on the engine, that has been working well.

On another pump idea I made that little check valve and it works as it should but not as a fuel pump as the engine shakes, no surprise there.
Here's a real short video https://picasaweb.google.com/lh/photo/K-oNR4_6VwQJrimQdFVIbdMTjNZETYmyPJy0liipFm0?feat=directlink

So I think something along these lines might work yet. The spring loaded belt tensioner vibrates pretty good with every power stroke, perhaps a little check valve or two arranged just right and mounted to that arm with flex hoses coming to and from?

In any case the fuel can on the head is working fine and holds enough fuel for a batch of ice cream, and the primer pump is easy to operate and doesn't take long to fill it. Eventually I'll figure out and or make a pump that works to fill the fuel can automatically.
 
#74 ·
Moving on to the ice cream maker part of it.
I've been less than pleased with the quality of the "country Freezer" brand freezer head from the start (though I do like the wood bucket). First issue was the dasher shaft rubbed where it goes through the lid and causes little pieces of metal to fall into the ice cream. Sent it back for repair early on, it's just poor alignment and machining, or lack of it. They put a couple shims in but didn't solve the problem at all. Later I got a second set of gears and still same issue. I put a leather washer in there to catch the dust and kept using it.

Recently I heard about Immergood, another brand of hand crank freezer that is a copy of the White Mountain; just like Country Freezer is a copy. Seems logical that the Immergood head would interchange on my existing wood tub/bucket and canister and dasher, a call confirmed that it would.
Here's the whole thing, I just bought the head. All these brands can be bought here http://www.cottagecraftworks.com/processing-equipment-ice-cream-freezers-c-53_184_59.html


And here's the Country freezer and an old White Mountain for reference.


Have a look at the country freezer guts side by side with the Immergood.

Country freezer is ince in that the housing is bronze, but that's it. the gears are zinc, poorly fit, essentially no machining done to fit it all together, just as cast.
Immergood has good fit and finish, stainless steel gears, delrin or nylon bushings, machiend parts, and cast iron housing (good quality casting) then zinc plated.

This is a little video comparison.


This evening I get to make 3 batches of ice cream, first try for the Immergood head.

Grigg
 
#75 ·
Sure have enjoyed this thread and your ingenuity Grigg.

I bought a old cranker just to have around because of the fond memories at our family picnics.

Jeff
 
#76 ·
The new Immergood head is holding up just fine, turns smooth and quiet. Here's an action shot.


Made a holder for the hand crank so I don't loose it one day. Need to take a picture if it installed.


Vanilla Swiss Almond from yesterday
 
#78 · (Edited)
oh, and I moved the throttle lever where it can be reached with the rest of the levers and while standing behind the machine as I do while checking on the progress of the ice cream, then easy to shut down when done. Also turned the oil pressure gauge to see from that position.


The fuel can seems to be working fine and the pump might be pumping again. I only pump the primer a couple times while running just because I don't want it to run out of fuel, and at the end of a batch the can is still half full, probably sloshes out the overflow and might stay half full even if the pump works all the time...

It seems about the same as far as load, I wouldn't expect any real difference.
It is hard to tell it's being loaded as it churns except when you disengage the clutch and the RPM picks up a few RPM. Well if you let it set up real hard you can hear it but that's unnecessarily hard on things, I try to stop when it has good body but still just a little soft, the deep freeze takes care of the rest.

Grigg
 
#80 ·
Update on the fuel pump and "day tank".
They seem to be working fine together, I think the pump is pumping enough to keep it "full" which is really just half full because the rest sloshes out the overflow as the engine shakes. I forgot to use the primer to fill it up during the last batch of ice cream and checking the level when done was still half full, pretty sure the pump is working.
Apparently the pump alone wasn't working well or consistently enough to supply the fuel pressure needed but now with the constant gravity feed to the injection pump all is well.

Grigg
 
#81 ·
Helped the local fire dept make ice cream last night for the celebration on Labor Day.
This is not the best picture but they had about 16 of these aggrivating little electric machines going and my machine in the background.
In one evening we filled a very large deep freezer, I ran 4 batches of chocolate through my machine.


Fuel system is still working good on it's own.
Still blowing oil out the exhaust and the oil level is now noticeably lower, which is a good thing because I wasn't quite sure if it was fuel coming out the exhaust and good that fuel is not making it into the oil. One more batch to make on the 17th and then I'll pull it down for inspection/rebuild.

Grigg
 
#82 ·
Last week I managed to make a replacement lid for the ice cream freezer part.
It's 1/8" thick brass and the center is bronze. It fits a lot better both on the can and in the drive housing. I hope it eliminates the dasher shaft rubbing where it exits the lid and the resulting metal flakes that try to end up in the ice cream.



Sunday I made a little road trip and fetched a replacement engine which as the sorry goes and from what I can see has never been installed or run more than a few hours at engine shows.
Same model engine a little older than mine according to the serial numbers.


Also yesterday a few miles from where the new engine was found I discovered at a flea market some parts for a White Mountain 20 qt (5 Gallon!) ice cream freezer which has been on my wish list for a couple decades at this point.

 
#83 ·
Nice piece Grigg but I would expect anything less from you! Sounds like you were in the right place at the right time, great finds. This should keep you out of mischief for a little while:) GW
 
#84 · (Edited)
Thanks,

This past weekend I prepped and painted the new engine. It was nicely painted with a shade of blue with metal flake in it, not original and not something I could easily match with a spray can. because I removed some parts and needed to fix a few things it needed at least some paint, so I elected to paint the whole thing "alpine green" also not an original color but not very far off.
Before

After (did not repaint air cleaner)



Then Sunday I removed the old engine and put the new in.


It runs, flushing the cooling system here.


Made a little "dashboard" for the oil pressure gauge.
Also I found a new place to get the crankcase pulses for the fuel pump (I forgot to modify a cover prior to painting). See the hose going to one of the bolts on the water pump, it's a hollow bolt with a piece of 1/4" tube silver soldered in the head of it. This way uses a much shorter hose and it looks a little cleaner than the previous method any how.
Sorry for the shaky picture, it must have been running....


That's all good.
The bad part is it's not "new and never installed" like I was hoping and as the seller thought, as he had been told by the previous owner. While prepping it for the swap I had to rearrange the shifter on the transmission, remove thermostat housing, water pump, and remove the injector, change the oil, and chose to look in the crankcase. Most every part of it has been assembled with the old gaskets and a small amount of clear silicone. In the crank case I found a little water and some metal flakes (I made and installed a magnetic drain plug as a result). The injector however looked pretty near brand new, but signs that it had been removed at least once if not several times, the hold down clamp had also been installed upside down. The water jacket had some rust and crust in it and the thermostat and housing had white deposits on them, perhaps calcium. The head surface where the thermostat housing attaches is pretty well rusted and pitted. On the outside of the crank case are some severe rust pits mostly filled in and painted over, were hard to see when it was in it's wooden stand.
Worst part is the transmission has a little noise, perhaps the source of the metal flakes, and something I'll have to swap out soon, the other/old one seems quite good.

On the plus side is the whole thing even with a few hours on it appears to have had much lower use in comparison to the old engine. Between the two of them I should be set for spares and such for years to come, and I still think the price was reasonable given the apparent condition.

Now how it runs,
This one seems to also have good compression while hand cranking. But when starting it struggles to run, like the children's sorry about the train "I think I can. I think I can. I think I can...." eventually it will get up to speed. However if I press the cold start button, which allows more fuel to be injected, either prior to starting or while it is "thinking it can" then with a little black smoke it quickly starts and or gets to speed.
It also seems to me that it won't idle down as low or as smoothly as the other engine.
Could these be signs of overly advanced timing?

Grigg
 
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