Pearson Yachts Forum
Pearson Boats - Common Systems => Engine and Drive Train => Topic started by: Alma on December 01, 2019, 02:40:18 PM
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We got ALMA's Atomic Four out of the boat without any issues last week.
We used the technique shared by vessel CHANCE #10 and it worked perfectly!
Now the venerable marine engine is in my workshop and getting the royal treatment.
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I hadn't thought about removing utensil box to access engine. Good to know.
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My Atomic 4 is setting on salon floor. Picking it out tomorrow with a crane. I'm on a cradle and am not comfortable trying to use the boom to lower it to the ground. It seems like too much weight pressing down on the rear cradle pad. I've had "oil-canning" issues in the past as it is. I left the V-drive attached. I see you removed yours.
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We didn't use boom to lower to ground- just to get it into cockpit.
Then we had yard pick it from the cockpit with a jury-rigged setup on the travel lift.
The load is on the mast and topping lift and halyards not the boom.
I've seen an Atomic Four pushed up an extension ladder into the cockpit with 3 strong folks.
If you have access to a crane to lift from salon floor that should be cake.
Good luck with your build- Alma's A-4 runs much better than new.
.010 over pistons and CNC bored cylinders make for a better block than what came out of the factory.
Even with many NOS parts from eBay the cost was over $1500.
Pistons, rings, valves, guides, crank and cam polished, valve seats cleaned up and balancing...
IT was a real Covid-Project last Winter and Spring. It kept me out-of-trouble.
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Thanks for the info. The crane is $107 plus I may have to pay a guy to operate it. I may consider using a halyard/boom setup to put it back in. I may scrounge up a few jack stands to ease the pressure on the cradle pad. Looks like I'll have to remove the V-drive in order to attach the engine stand I just bought.
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Yes- I paid $100 each way and was happy to do so.
We already had a system to get it into the cockpit and when finished back into the salon.
I have a generic engine stand and an adaptor for my 911 engine- I never saw an elegant way of attaching the A-4.
I stripped the A4 on a pallet style fixture on the floor and went from there on my bench.
You may have trouble finding a competent machine shop- I did. When I was young there were auto machine shops in every town... Now not so much. Make sure they have experience with small cylinders. I got into a speed shop and they did a lot of motorcycles so they had fixtures for the tiny A-4 cylinders. The result was spectacular.
I got the genuine NOS Universal pistons on Ebay at half price- Popular A-4 parts houses sell after-market. Be sure to match them when they arrive- I waited and one was different- Luckily the seller had a few and was happy to send me a match. One was curiously 180 degrees different- crazy. I never saw anything like it- It had its own different part number suffix.
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I removed the flywheel/bell housing and tried attaching my stand to that end. The shaft flange got in the way and the bell housing bolt pattern was so narrow I couldn't manipulate the stand arms enough to attach them. I had to make an adapter out of 3/4in. plywood to interface between the engine and stand. So far so good! I want to be able rotate it upside down to remove crankcase pan for easy access to connecting rods.
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Sounds good!
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I've attached a picture of my head. There are five coolant holes that seem to be filled in somehow. I don't think they are simply plugged up with gunk. I tried drilling one out and just hit metal. I circled the holes. Does this sound right? Also, how did you get the studs out? I've tried double nutting without success. I'll look for a stud remover sometime today to see if that works as well as some YouTube vids make it out to be.
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I can't see the detail in the picture. If you hit metal stop and investigate.
You'll need some patience with the studs if this is their first time out.
It's worth taking a break and ordering some Aero Kroil.
Then use a little Kriol, tap on them lightly to distribute and wait.
If you can borrow or buy the genuine Snap-On collet stud remover that's the best tool. Pricy.
I had success with the double nut and also additionally a vice grip on the stud. Bottom line is you will want to release the corrosion before you get a tool that has the grip to gall or tear the stud.
It is counterintuitive which of the doubled nuts to apply torque to to get the most grip without slippage. Test and experiment. It is a 25/75 difference.... Amazing.
And patience, Aero Kroil and a little tap tap tap to distribute and patience is the best way to get the studs out with minimal damage to the block.
Patience being the most important.
Remember fumes from a torch (not recommended) burning Kroil or any other rust-buster are very toxic.
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A collet stud remover worked like a charm! Pistons and valves are out. Pistons and rings seem to be in decent shape. Valves are very sooty. Micrometer readings indicate minimal wear. I may have an expert take a look. I've reached a point where I'm quite unsure how to proceed.
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Good news. Your machine shop can make the measurements and guide you.
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I replaced rings and cleaned and lapped valves. My measurements of cylinders and pistons seemed good enough not to require reboring. I've reattached the head and was hoping to compression test and can't get any compression whatsoever by handcranking. I did not remove cam or crankshaft. I staggered ring gaps. I must be doing something wrong. Could it be that hand cranking isn't fast enough or cranking "dry" has something to do with it?
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Its hard to say.
How did you hone the cylinders?
Are you sure the camshaft and crankshaft are in sync?
You should get some pressure against your finger at ta spark plug hole no matter what the cranking speed.
Are you sure you're cranking in the right direction?
Check rotation against the firing order.
My pistons ring lands were so bad that I used a quart of oil in just a few hours- still the engine ran acceptably.
Of course now it has far more power. It also will burn much more fuel-
But oil consumption is unmeasurable.
Make sure you're spinning her correctly first.
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I used a drill driven hone to remove a little glazing on the cylinder walls.
I didn't remove either crankshaft or cam shaft so syncing should be ok. The crankcase is not installed nor is valve inspection plate so I can visually check positions of pistons and valves.
I am cranking counterclockwise. Later today I poured a bit of oil in cylinder #3 and was able to register 15 lbs. I'll install starter and figure how to wire it up to a battery and crank it that way to increase revs in case that helps somehow.
I may try forcing air into spark plug holes at TDC and look/listen for leaks.
Maybe I have a bad tester!
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Block is out for machining. What type of hose is suitable for cooling water? Will heater hose suffice?
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Good news!
You can use QUALITY automotive hose everywhere the water is under pressure (from the pump on).
The suction half from the raw water inlet on the hull and to any strainer and from the strainer to the pump needs to be QUALITY (expensive) marine hose with a spiral stiffener so it doesn't collapse if you get up against plastic debris at the hull inlet.
ALMA came with no onboard strainer. I think it is just another set of several fault points that can suck air, cause an impeller burn-out and create havoc. Anything that gave me a clog in 25 years was at the inlet over the side before a strainer could help.
I once got a clog in my engine inlet so I substituted the raw water through-hull that goes to the saltwater pump in the galley sink. It was good enough to get us to the yard where ALMA was getting pulled for Winter.
You may want to use an inlet hose that is longer than necessary so you can reach a substitute inlet in an emergency.
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Engine is remounted in engine compartment. I should have taken the mounts out. Instead I chose to lift the engine off the mounts and dropped it back in over the the mounting bolts. That was silly and a real pain. I left the mounts in as I was afraid of messing up alignment. Compression ranges between 75-80 which is a great improvement but not what I was hoping for. I had the valves and seats reground. Head surface ground slightly. Cylinders honed. Kept pistons and replaced rings. I installed Indigo PCV and raw water cooling systems. Also placed a timing pointer on the auxiliary pulley to enable easier timing with a gun. Pics are attached. Bench tested. Runs great!
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Beauty! Nice test set up too.
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WoW nice job!
You might see those compression numbers rise after a careful break-in. Be sure to run the first couple hours at all different speeds and loads. Don't worry about ignition timing yet. You'll be able to get the optimum timing running at cruise speed and slightly turning the distributer for best performance. The same goes for carb mixture. Did you get or already have an adjustable main jet on the carb? The idle and cruise mixture can be set while running just like the timing. Built in dynamometer! I never ran a compression test. These flat head engines don't have a lot of compression and don't need a lot to perform well. If all cylinders are similar you're all set.
I'll be looking forward to seeing how that Indigo thermostat works. I've had several different setups through Moyer and all of them rely on expensive and hard to find thermostats. The Indigo thermostat checks several boxes for maximum engine life.
Where did you get that nice exhaust mixer? It is similar to the one I had when we got ALMA. It was green and was ONAN brand for their generator. I'd like one like yours.
Well done!
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Exhaust elbow: It was with the boat when I bought her. I simply cleaned it up. It is Onan P2833.
Timing: Yes, I'll recheck/adjust timing when I launch in the spring. I really like using a timing light to take out some of the guesswork. I've attached a pic of rather crude timing indicator installed next to the auxiliary pulley. I punched and painted a notch in the pulley that references TDC of piston #1.
Adjustable main jet: No, I don't have one. I'll revisit that.
Indigo thermostat: I'll let you know. I bench tested without temperature gage and could definitely tell when it opened. The bypass loop is quite sensitive to air pockets so I have to be careful to purge air otherwise exhaust gas doesn't get cooled when the engine is cold. I melted my makeshift exhaust hose. It was sump pump hose so it didn't take much heat.
Indigo PCV: My engine has a history of "exhaust fumes" escaping out of the engine compartment. Turns out the shifter cable was pinching off the rubber breather tube which allowed crankcase fumes to escape out both oil fill tubes. I didn't catch this until I removed the breather tube in my garage. It was actually torn. I had ordered the PCV kit by then so I just went with it. Added bonus of the PCV kit are fuel hose and fittings to replace the copper loop connecting the mechanical fuel pump and carburetor.
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I have Tom Steven's original PCV and when my engine was worn I had a lot of oil consumption. The Indigo PCV kept the interior salon blow-by free. I was using 1 quart in 3.5 hours running! Still the engine ran well, idled smooth and spark plugs were satisfactory. That oil consumption is equal to a two-stroke yet there was no smoke. The engine was down on power- but I never knew better.
I haven't been able to measure any oil consumption with the new engine.
Some experts state that PCV isn't a good idea for constant speed engines like boats and aircraft...
I don't see a problem and I kept mine on the overhaul.
PS HA!
I had also filed a small mark on the auxiliary pulley for TDC also!
Great minds think alike!