New member - A-4 in a 1974 Sabre 28

[wagner]

Hello everyone!

New member here, but have been "lurking" here and there on this forum for a few years as I became the owner of "Bubble" a 1974 Sabre 28 Mk1 with an original raw water cooled A-4. Believe it is a direct drive late model A-4.

Bubble was an inexpensive vessel because the owner didn't have any one to sail with any more and the motor was "tired" (meaning not running, unknown whether it would run).

Being resourceful and optimistic, I said, motors aren't "tired"--they have something "wrong" with them that needs to be fixed. Armed with the boat owners manual, the MMI A-4 manual, a pile of parts from MMI, a multimeter and a heat-shrink connector kit, I somehow got the A-4 running with some semblance of regularity and even maybe some smooth-ness.

In the initial season, I replaced the following and had only one occasion of total engine failure (apparent corrosion on the points...):
-plugs
-wires
-cap
-rotor
-condenser
-points
-wire between alternator and coil

The A-4 ran remarkably well (shifter was nearly seized...but liberal application of some kind of oil and elbow grease freed it up) until late in the season when a sudden loss of power nearly caused a collision with beautiful Hinkley in Manchester, MA Harbor in 15-20kts of breeze. (This is only part of the story of a very long day...the dinghy motor was also not running that day).

The power loss appeared to be periodic and attempts to diagnose were limited to diving to examine the prop (brrrrr....no wet suit!). Had something hung up? NO. Stuffing box too tight? NO.

Not to worry...it IS a sail boat primarily and we sailed on and off the mooring mostly. Our home harbor has a lot of room to maneuver.

But the problem nagged at us (three of us own the boat) and we intended to "check things out" in the off-season (2019-2020). Well, 2020 turned out to be not so great. We did not launch at all, but DID determine that the rhythmic tapping sound while the engine was running was a stuck valve. A thumb test showed no compression on cylinder 3. A foray into the valve spring gallery showed a stuck exhaust valve on #3. No amount of Marvel Mystery oil and gentle taps availed any movement of the recalcitrant valve.

With winter looming and no break in my professional life (residential construction), we decided to lay her up for the winter again. I put the valve gallery cover back on with the used gasket and ran the engine. Some gallons of RV antifreeze and a few minutes of run time and we put her to bed. Fingers crossed that the coolant made it into all the nooks and crannies....

Which brings us to today! Clearly the head had to come off to unstick the valve...

Head is off. Thermostat is caked in black gunk. Cylinder three is cased in black gunk. Cylinder three exhaust valve is stuck way open and caked in black gunk.

The goal is put the engine back together and running for the season, knowing our mooring is easy to sail on and off and having a small outboard on board as a backup. We only do very close coastal sailing. No offshore work. Like everyone else, we are trying to avoid a full overhaul at this juncture. Time will tell!

The plan:
-knock the valve down carefully
-(probably) pull all the valves, clean and lap
-clean up head, block
-new head studs
-new head gasket
-new thermostat
-new temp sensor
-new oil pressure sending unit (none of the gauges work)
-rebuild carb
-new impeller in water pump
-Oil change
-fuel filter change
-plugs, points
-test motor on the hard for water in the oil etc
-Go sailing

Thoughts on the plan?

[ronstory]

Welcome to the forum!

Pretty good plan. I would continue to soak the errant valve with PB blaster or the like and let sit a day before lightly tapping.

I'd recommend would also convert to ignitor electronic ignition and buy a new coil (on principle and not expensive) from MMI (correct resistance) and keep the old one for a backup. Don't forget to check and lube the advance mechanism.

Lastly I would look at Indigo Atomic4 thermostat housing, my engine(s) have ran with more consistent temps with one of those. Before, the temp seems to fluctuate more with the old thermostat and diverting valve setup.

Fresh water cooling is always nice too.

[wagner]

Forging ahead

Thank you Ron for the warm welcome.

Going to forge a head later this week and get things cleaned up to see what we are working with. Then a parts order! Lets see if I maintain this level of excitement.....

[ronstory]

The worse part (IMO) is when the project is at maximum entropy and still needs cleaning and painting. Once everything is cleaned-up and a painted ready-to-go... it just like childhood. But with larger Legos and erector sets.

[Al Schober]

Welcome to the forum. We'll try to help.
Sounds like you want to do what obviously needs doing, but avoiding any lower end or piston/ring stuff. Not a bad way to go. Sounds like you're committed to removing the head.
Definitely pull all the valves. Take them to the shop and have them professionally faced and cleaned. While they're out, get a suitable sized pistol cleaning brush and do the valve guides.
Refacing the valve seats would be nice. Talk to the shop doing the valves - they may have a portable tool. They could do the job or loan you the tool. If not, lap the seats using the refurbished valves. Exhaust seats are likely to take more work.
As for cooling, I'm an advocate of glycol cooling. You'll do it eventually - do it now and be happy. I'm also an advocate of no thermostat - run the engine cool.

[Dave Neptune]

Did you rotate the engine before trying to move the valve. If the cam is still in contact the valve won't move. IE be sure the cylinder is on TDC of the compression stroke ~ then the valve should be easy to get unstuck.

Your plan of attack is pretty good, but be very careful as you are playing with many separate systems that work together.

While your at it I would recommend new fuel lines from the "tank" and adding a cheap fuel pressure gage which can be priceless when trouble-shooting fuel related issues.

Dave Neptune

[wagner]

Thanks Dave, Al and Ron!

Excited to do this. The ratio of engine work to research and discussion is currently about 1 hour engine work to 4 hours of research and discussion!

All good points - planning to pull the manifold and valve spring gallery plate next as it is fairly obvious that I am pulling all the valves this weekend and measuring them for wear and eccentricity and run out.

Any one know of a good machine shop for valve and head work in Eastern Massachusetts?

[ronstory]

Well, we are close on latitude but I'm really off on longitude to help with a referral. However, there is a classic post from lat64 (Russ) on what to look for in a shop for an A4.

https://www.moyermarineforum.com/forums/showpost.php?p=12067&postcount=7

[TimBSmith]

Welcome to the forum....

If you look at a lot of the manifold or head removal stories here you will often see experience with broken studs, helicoils, tap dies, etc. (most of which I have learned about on this forum). It appears that you removed your head and manifold without breaking a stud...is that right? If so, congratulations.

I have been rebuilding my exhaust and will make final tests this spring. I mention this because I thought I might need to have my manifold off and I was planning to have it reconditioned if I did, spoke to a machine shop in Allston, MA that would do it well and affordably. Might be a good time to give the manifold and exhaust system some TLC.

All the best with your work, sailing, I sail out of Salem, MA maybe we will cross paths this season.

Here is a link to contact information for my machinist in Allston. (Out of your way, maybe he has referral?) He mostly works on race cars though does a lot of side work. His shop meets requirements I have seen posted here. (viz. hard to find entrance, shop owner communicates in single word answers, cash business, no answering machine or other communication assisting technology, etc....).

https://photos.app.goo.gl/tR2vGQEwWvNWxkqk7

Stay well.

[wagner]

Next step...

Tim, thanks for the intel on the machine shop in Allston...will check it out. I got referrals to a couple shops up my way in peabody and Beverly

After discussing and researching and meditating and supplicating, I went back out there and started turning wrenches again today....

Began by considering removing the manifold, thinking I am in for a complete valve job and need to get it out of the way. Reconsidered this after a) first stud starting coming out with the nut and b) noticed all the "other" stuff that comes off with the manifold. Changed course.

Removed valve spring gallery cover (it has been on and off a couple times already in this adventure). Access is OK but not awesome once the breather tube comes off and the throttle linkage is disconnected. I removed the cover to be able to see when the #3 exhaust valve lifter is at bottom. Success on the removal. Noticed several other random fasteners and parts on a slow but eventual course to the bilge when I dropped one of the bolts. Maybe a valve cover stud kit is in my future...opened beer.

Next, soaked #3 exhaust valve (stuck. the whole reason for this repair) in various lubricious libations (MMO, PB Blaster). Said various incantations. Sipped a human libation (Bent Water Brewing's Thunder Funk IPA - highly recommend if you are into such things). Found an appropriate small block of wood and after confirming that the lifter was at its low point, I gently tapped the valve down, turned the engine over by hand to raise it again and repeated this process about 17 times until the valve dropped on its own consistently. Sipped additional libation.

After getting the valve working, I set up cleaning up the mess of carbon and sludge from the block. I pulled all the studs. looks like I have at least three different kinds of studs (some larger bottom threads, some longer than necessary) and two different kinds of nuts. It appeared that I had two head gaskets. Is that normal? I have to reread the moyer repair manual on that.

While sipping aforementioned cold beer, I considered the brevity and preciousness of my time here and on earth and counted my blessings, among which is the time to fuss around with 47 year old engines in 47 year old sailboats.

The questions for the forum are:
1. Is it worth getting a set of replacement studs? Or just reuse the ones I have? It looks like at least three of them have some bulging and as noted above there are several different sizes which I assume means that someone has been in here before fussing around and breaking/stripping things.
2. Can a full valve job be done without pulling the manifold? Remember, we are trying to contain the scope on this particular adventure.
3. With the valve unstuck and operating, should I just put her back together and fire it up and do the major rebuild next year? As my next door neighbor (retired machinist and hot rod builder) says, all you've got to lose is a head gasket and a few hours work if you decide to broaden the rebuild scope after.

[ronstory]

Great progress and congrats on the valve! Yes, two head gaskets is normal, original gaskets were thicker and new modern gaskets are much stronger... but you need two to keep the same thickness.

The studs are different lengths due to the longer lengths needed for the thermostat housing and extra thickness for the lift plate. If they look to be in good shape (the threads look fine) you can just clean them up and reinstall. I might be worthwhile to get new nuts depending on their state.

As for the valve job, it really would be easier to just pull the manifold. Have the manifold stud some out is not a big deal and you will need to reseal the threads anyways. Those threads penetrate the cooling passage.

[wagner]

Bulging stud holes?

Any thoughts on the bulging stud holes?

It appears that this motor was run without the thermostat (max cooling) which is good from my perspective on winterization the last two winters (i.e. the glycol antifreeze got 'everywhere').

I'm inclined at this point to clean everything and put it back together and see how she runs. If she runs great/better, I will end this year's adventure and focus on other boat projects (rudder head replacement, mast rewire). Still plan to replace impeller, change oil etc, normal spring start up stuff and check for any water in the oil.

The major rebuild could be next year....or next week if things don't go back together right...

[Dave Neptune]

Wagner, while you are at it I would suggest that you take care of the manifold too. A compromised stud can allow either air (which screws up the air fuel ratio) or water (seizing, fouling and dying) into the manifold.

Be sure of the head studs and be careful torqueing thing down.

Also if you do bolt her up and she runs add some top oil to the gas and no other additives, perhaps some stabilizer if you want. Mix the "top oil" either MMO or my preference TCW-3 grade 2-stroke synthetic at around 100:1 or a bit richer. Another is to shut the engine down with the choke, this will pull some extra fuel and oil to the valve stems and the cylinder to keep them lubed and free of rust.

Dave Neptune

[edwardc]

Any thoughts on the bulging stud holes?...

I don't know about the others, but those bulging stud holes in the block would bother me. The studs penetrate all the way into the water jacket, so the ends of them slowly corrode away. To me, those have all the look of studs that were corroded down to three threads or so being overtorqued and beginning to pull out. In one of your pics, it looks like there already is a crater around one of the stud holes where one did pull out.

At a minimum, I would suggest replacing any studs that are down to around three threads in order to get the most gripping surface. At the other extreme is drilling out all the damaged holes and installing threaded inserts (NOT helicoils, they leak). All this assumes that there is enough thickness left in the walls of the water jacket.

[wagner]

Hybrid approach?

Edward, totally agree that the "bulging" stud holes are concerning!

Having a confab with the two boat partners (neither is involved in the engine besides turning it on and off) tonight about the engine, the rudder and the mast wiring.

Having made an offer on Ebay for a used atomic 4 (Serial 178260) from a fresh water location, I plan to present a hybrid approach:

-Put the current a-4 back together as best as possible, knowing that it will likely run well enough to get the boat back in the water, but that it DOES need to be rebuilt in the next year or so.

-Buy the ebay motor as a "drop-in" after a tuneup and bench test. Previous owner says it runs fine. Drop the motor in later in the season during some time at the dock. Rebuild the current one at my leisure in the shed.

That's the best I've got for the moment. Will continue with updates as we go!