Disassemble A4 onboard?

[Trés 30]

Firstly,

Thanks to all the frequent and knowledgeable posters who make this site such a great resource. I've gleaned a lot of info and hope to be able to offer likewise assistance in the (near) future.

I was about to replace a decrepit water lift muffler with a new standpipe, but realized deeper issues need attention. Given the state of the mounting flanges (?), among other things, I'm thinking a total rebuild is in order.

The boat is in the water & I'm not planning to have the yard crane the engine out.
Is it possible/advisable to remove the engine in components instead of whole? Then I'd have it boiled, machined, etc., as needed. (I do have the overhaul manual and PO installed a few MMI upgrades.)
Is rebuilding also possible onboard?

Attached are a couple pics of what I'm working with.

Thanks much!

[marthur]

It would be possible to disassemble the engine on board. It is a little messy and you will want a work bench of some sort. You will have to lay the block on it's side to remove the oil screen and pistons / crankshaft, among other things.

Before you disassemble the motor, tell us why you think it needs a rebuild. The mounting flanges (and external corrosion in general) are not a good indicator of the internal state of your motor. What I see on the exterior of your motor can be addressed with a wire brush and fresh paint.

I have a motor on my work bench right now that was corroded worse than yours in spots. Even so, the internal components are in excellent shape--measurements are well within spec and many parts look like new. No need to rebuild. Removable components can be replaced or renewed without a complete rebuild.

[Al Schober]

Tres,
I have to agree with ma - what symptoms (other than some rust) make you think a rebuild is in order? In New England, this is definitely the wrong time of year for such a job - just go sailing!
Yeah, rebuilding is a fun thing to do - in the off season. Find a parts engine (eBay, craigslist, local boatyards) and do up a spare at home in the shop. I've got one in the basement now that I bought for $250 as a block and several boxes. It's ready to install. I like having a spare, and the wife has learned not to complain - she likes to sail too!
Doing the swap isn't hard. Last one I did the dead engine came out one day & the rebuilt went in the next. Done deal - go sailing. It's easier in the water with the mast in - you can use the main halyard as a hoist and the boom will allow you to swing the engine to a dock. Recommend removing the heavy stuff first - starter, alternator, flywheel, manifold. You can get that beast down to about 200# without much effort. Oh yeah, pump out the oil.

[Trés 30]

Bad timing (for a rebuild)

Y'all are very right about the "just go sailing" part of it! Been kicking myself for not noticing things sooner.

The idea to rebuild was due in part to the condition of the plugs & muffler & other rust (not to mention my boat-induced OCD). I figured if I had to readjust valves, might as well get to the bottom of it all, so as not to do it twice.

These plugs are less than a year old with very few hours on them, it's a real short run to the lake. But it looks like there may be some moisture getting in there (?). The #2 is the only one with near normal wear. Also, couldn't get engine to start last couple times I tried, worried I overdid it & messed things up.

Just can't stay away from that rabbit hole!

Whatya think?

[marthur]

Here are some thoughts:
Exhaust:
She's dead Jim.

Condition of the Plugs:
Plugs are a little sooty, but that is common with these motors. I am not overly worried about what I see and there is a long list of things to check before going to the nuclear option. Carb mixture, temperature, exhaust pressure, adjustment of valves and timing come to mind. None of these require a rebuild. The bold items are easy and common issues.

Rust on Plugs:
The rust is on the part of the plug that is outside the cylinder. Look for a source of water dripping onto the motor. Next worst scenario, you have a leaky stud or cracked head. Most likely repair not rebuild.

Valves:
Adjustment of the valves is maintenance not rebuild issue. It is a relatively easy thing if you have access to the port side of the motor.

The others can weigh in on valve jobs, but we don't have any information suggesting you need one yet.

Not starting:
Spark, compression, fuel. These are maintenance issues with the possible exception of compression.

REBUILD?
What I look for when deciding to rebuild is wear or damage to the internal components of the motor. I decide this after removing the head and inspecting (i.e. look at and measure) cylinders, removing the oil pan and inspecting bearings and crank, etc..

The others on the list can help with some suggestions, but here are some common symptoms (short of catastrophic failure of a component): Low compression due to worn cylinders and rings. Low oil pressure due to excessive bearing clearances. Noise indicating excessive play in bearings or bushings. Excessive blow-by.

If an A-4 runs and produces decent power, has OK oil pressure and is not sounding like it is on death's door I would sail and worry about it later.

[lat 64]

You have been given good advice. This engine may just need some love.

And if we're wrong, keep taking things apart. I doubt it will come to that though.

I see you have the good water pump

Russ

[TomG]

Tres,

I have a T-30 as well and replaced the old waterlift with the MMI Standpipe. You can read the thread here: New MMI "Tartan" SS Standpipe install

Since the old waterlift is out, you can't really tell what your exhaust back pressure was, but I'd look closely at the exhaust hose and waterlift for obstructions. This will really cause problems with performance. The exhaust hose on my A-4 was nearly completely closed off probably caused by and overheating situation with a prior owner. If you don't know already, the Tartan 30 has a common issue with water getting into the engine (especially the number four cylinder) due to the location deep in the bilge with very little room between the exhaust manifold flange and the top of the waterlift. During hard starting with the thru-hull open, flooding the engine is almost a certainty with a waterlift muffler on the T30.

There is a wealth of knowledge on this forum and as a newbie, I defer to their wisdom. I will say that your engine looks to be in pretty good shape and like marthur says, a wire wheel and some elbow grease could make a big difference. If it were me, I'd be very curious about the compression in each cylinder. If you have a stuck (or even several stuck) valve, I'd try to loosen it up with MMO and an allen wrench first before pulling the engine. A compression test would tell you a lot.

[Mo]

I agree with the guys...a little TLC on the engine, rebuild the exhaust, and you may be golden. A compression check is worth it once you get around to it.

If you are either bit mechanically inclined this is a beauty little motor to play with. They do develop their quirks if left unattended for too long, but once you know what you are doing with it, they just run and run.

[yeahjohn]

That engine looks cleaner than most... Sail away!

[Mo]

That engine looks cleaner than most... Sail away!

Certainly has more paint intact than mine....and mine runs like a top.

[marthur]

Certainly has more paint intact than mine

+1 to that. My spare engine looks great but my "runner" could use a little paint here and there. I have been waiting for 10 years for a reason to pull my engine out of its cubby hole and paint it (not a lot of access for cleaning one up in the cata lina 27). It is just too darn reliable for its own good!

[Skywalker]

Last year I was in your spot. I was ready to pull her out and rebuild.

These guys walked me off the ledge, told me to keep going, and two weeks later I was in the water and the A4 has been purring along.

Stay with it...

Skywalker

[Trés 30]

Off the ledge! It's gonna be alright

Thanks all for the proper advice!

I'll take the path of least resistance on this one, following marthur's plan for inspection/maintenance. Tom, the standpipe thread is what convinced me to spring for the MMI standpipe. (PO had warned against water backing to the engine & suggested keeping thru-hull closed until started. I may not have followed to the letter those last couple times.) I'll be ordering exhaust later today. Then get engine going & check compression. Then go sailing!

[TomG]

Tres,

Having recently done the standpipe project, I'll offer this free advice:

If you are ordering from Moyer, I would strongly recommend getting the Exhaust Pressure Kit (it's an exhaust flange pre-tapped for a pressure gauge) and the exhaust wrap at the same time. The standpipe is quite robust and reliable, but being able to rule out exhaust back pressure as a causal factor in performance issues could save you a ton of time one day in the future. If you don't have a source of supply for the wrap, ordering from MMI makes it simple. You WILL need some kind of wrap as the hot section is quite long and clears the bulkhead by an inch or so. I found it MUCH easier to assemble the hot section to fit, then remove the exhaust flange with the hot section still attached and then wrapping it, leaving just enough at the end to wrap the connection to the base of the standpipe.

Good luck and shoot me a note if you have any questions!

[Al Schober]

Going with the Moyer mixing can is a good move, as is the new flange with the pressure tap (even though you may never need it). I use stainless bolts to attach the flange to the manifold - others have gone to studs and nuts.
On my T30 the system comes fwd out of the flange with a nipple, 45 elbow, another nipple, then another 45 elbow and another nipple. Final nipple should snug up as horizontal, allowing a 90 elbow to give a vertical shot into the mixing can. I recommend a union in the leg up to the mixing can - makes for easier assembly. Adjust the lengths of the nipples to get the mixing can aft and inboard (makes room for other stuff in that area).
For lagging, I used McMaster 5556K14 - fits right over the 1 1/4" pipe. They sell similar stuff for Tees and 90 elbows.
Finally, check the hoses downstream of the mixing can - Tartan originally used short pieces of black iron to join those parts. The ones in my system crumbled in my hand, and were replaced with 3" pieces of stainless pipe - also from McMaster.