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-   -   To Rebuild or Not To Rebuild (That is the Question) (https://www.moyermarineforum.com/forums/showthread.php?t=604)

jkenan 01-05-2006 04:09 PM

To Rebuild or Not To Rebuild (That is the Question)
 
I'm deciding whether or not to rebuild my engine completely, or just down to the valves.

Facts:

Late model engine, serial number 199700's.

1. Cold, in-shop compression check prior to tear down was excellent, 115psi in #1, and 118psi in #2, 3 & 4.

2. Engine made strong pinging sound, with loss of power/RPM after running for a length of time. Probably due to leak in either head or manifold gasket, or head or manifold studs, or both. Noticed VERY slow reduction in antifreeze level in plastic overflow container.

3. I will count on this engine for the next 10 years at least.


With the engine out of the boat to resolve the pinging issue, I have taken the engine down to the point of removing all valves and tappets and scraping all gasket material off the block and head. Findings so far are:

1. Valves, valve chamber between block and head, and piston tops are all pretty heavily caked in carbon. Although compression was good, valve seats look pretty rough.

2. Cooling jackets have lots of debris build-up (but engine ran at 140 degrees consistently). Have only had a couple of 200+ degree overheatings since I bought the boat, and that was due to scaling clogging the manifold exit port.

3. There seems to be a leak in the accessory drive oil seal (will implement oil level fix) or water pump seal because lots of oil residue on engine underneath those housings.

4. I will have to replace some castings (water jacket side plate, maybe the manifold).

I'm at that crossroads where I have to decide whether to tear down the engine completely, or just down to the valves. My delimna is based primarily in my (conservative) concern over the condition of my crank and bearings. There is no reason to suspect they are ready to fail, but I know pinging is hard on bearings and this engine has pinged for at least a year of regular use. Since the engine is on the floor of my shop and it is already torn down to the valves, I see this as an opportunity to go ahead and insure it will be in as reliable condition as possible for the long term, and learn a thing or two if I ever have to do this again. To my knowledge, this engine has never been rebuilt.

I would check the crankshaft for any cracks and have it rejournaled, have head, block and manifold serviced and machine the valve seats. I'll let a machine shop tell me if pistons, valves, and bearings should be replaced and whether the cylinders should be rebored/resleeved.

What can I expect costs to be for machining and other 'service' costs I may incur? Are there any compelling reasons NOT to rebuild, or other compelling reasons TO rebuild?

Thanks for any feedback.

John

Simon 01-05-2006 08:27 PM

Rebuild-Is the answer!
 
John,
By the sounds of it, I think you have already decided. Go for it! Whatever the costs, factor them over the 10 year period you anticipate sailing and it works out to only what...$300-350 per year. Pretty cheap for peace of mind. I myself am in the early stages of rebuilding after lots of deep thinking and much consultation with Don and his staff. My machine shop is also consulting with the A4 staff for guidance etc...You only live once; once you're dead, you are dead for a long long time. Good luck! :)
Simon
MAYREAU
ALBERG30 1967

rivergypsie 01-06-2011 11:33 AM

If you already have the engine out, you may as well do a rebuild,
you would be sorry if you had probllems later and had to do it all over again
Good Luck

lat 64 01-06-2011 12:38 PM

If you have such good compression then don't get talked into boring the cylinders for oversize pistons. At most just new standard-sized rings.
The bearings are your mystery, and if you have good oil pressure, then you probably have serviceable bearings. This means that the oil clearance is still small enough to keep the oil pressure up to spec.

All the said, I would take it all apart anyway if it is out and getting a valve touch up. The crank bearings are very expensive and should be handled with care if you think you might reuse them. If your machinists says they are worn, then chuck them out.
This "overhaul" is a good time to clean the sludge from the oil pan too.

Remember to take pictures all through the teardown. Very handy for memory loss types like me.

Some of the generic auto-engine rules don't apply here. In particular the orientation of the pistons. It is confusing because some of our engines are installed backwards and some are not. Go with the rules set out by the Moyer team. The manual will clear up this issue.

Cheers,
Russ

Marian Claire 01-06-2011 12:43 PM

I only post this because I have missed it before. Check the date of the post. Dan S/V Marian Claire

lat 64 01-06-2011 12:46 PM

Quote:

Originally Posted by Marian Claire (Post 30978)
I only post this because I have missed it before. Check the date of the post. Dan S/V Marian Claire

Ha!

Thanks dan.:o
Oh well, back to work I guess:D

r

sastanley 01-06-2011 09:02 PM

Must be cold up there, eh Russ? :p

jpian0923 02-07-2011 12:36 AM

I wonder if he rebuilt the engine. I'm dying to know!Anybody got his number???

hanleyclifford 02-07-2011 08:17 AM

Just as a post script to this thread, note that he was experiencing a slow loss of antifreeze AND pinging. The pinging could have been caused by water getting into the combustion chamber. The water loss could also have been a result of a compromised exchanger. If you ever experience a steady albeit slow loss of antifreeze the first thing to do is to pressure test the exchanger.

tenders 02-07-2011 11:00 AM

John Kenan is around on the Ericsonyachts.com site. I'm not sure what he did with his engine but I'm sure it was a major improvement...he completely gutted his E29 and turned it into a masterpiece.

Rustysteel 02-07-2011 11:29 AM

I'm deciding whether or not to rebuild my engine completely, or just down to the valves.

Thanks for any feedback.

John

Hello John,

I probably have the best little old to new Atomic on the planet but it comes at a price. I had a 2 QM Yanmar rebuild available for $3,500 I could have put in my 1967 Islander 29 but the beds would have had to have been rebuilt plus a lot of other changes and even then the little diesel would have shaken the islander to its core.

My early model Atomic 4 has undergone a complete re-build with all latest upgrades available from Moyer, $2,000 in new parts alone. Its lifetime was spent in fresh water which made it a good candidate for a rebuild. Castings and housing gone through by machine shop, $560 with chemical oven cleaning, magnaflux testing, head shaved, crank polished, and cylinders bored out 10thousandth over.

Starter rebuilt, $250 and new 50 amp alternator installed, $250.

The engine has been completely disassembled, cleaned, and examined for wear and breakage. Worn out, missing or non-functioning components have been replaced with new or rebuilt components. It is the functional equivalent of a new part and is virtually indistinguishable from a new part. This engine was new in 1965 and has now been given another 45 years of life!

Transmission taken apart and new adjusting collar with smaller teeth installed to allow fine tuning of transmission.

Old cast iron carburetor replaced with new carburetor for late model Atomic 4 installed using Moyer’s Carburetor flange kit for installing scavenge tube on early model engines with late model carburetors.

All disassembly and reassembly done by certified mechanic, $2,745 labor with all new bolts, studs, bearings, and gaskets. Oberdorfer raw water pump rebuilt, $46.

2 cans Universal engine paint, $60.

$5, 911 spent for all parts, machine shop and mechanic.


Parts list from Moyer Marine.

Pertronix distributor (new) with Ignitor electronic ignition module.

Hold-down bracket for mounting a late model distributor (or new Pertronix Distributor) on early model engine

Thermostat - early model (140 degree) (includes thermostat gasket)

Complete gasket set - late/early model

Exhaust flange. This exhaust flange is drilled and tapped with an 1/8" pipe-threaded hole to facilitate installation of a pressure gauge to be used to check exhaust back pressure.

Pistons - .010 over (aftermarket, set of 4) includes wrist pin and wrist pin clips.

Rings - .010 over (set of 4)

Wrist pin bushing

Exhaust valves

Intake valves

Main bearings - standard size (complete set)

Rod bearings - standard size (complete set)

Rear thrust bearing

Rear oil seal - for direct drive coupling

Carburetor flange kit

1/8 inch scavenge tube for late model carburetor

Engine-mounted electric fuel pump kit

Valve springs (new,longer,stronger)

Aft housing shifting lever oil seal (each, 2 required)

Improved forward adjusting collar

Taking a rebuild down to its smallest parts and back up with all new parts comes in at around $6,000 if you don't do the work yourself.

No Worries, Scott

http://i1194.photobucket.com/albums/...1/a4before.jpg

http://i1194.photobucket.com/albums/.../a4rebuilt.jpg

jpian0923 02-07-2011 03:18 PM

Moyer rebuild
 
http://www.moyermarine.com/exchange.htm

jpian0923 02-07-2011 03:27 PM

This thread had me rolling on the floor laughing for 20 minutes when I saw that post #3 was 6 years and a day late in replying. You guys crack me up! Thanks for the laughter. :D I love this place.

ILikeRust 02-07-2011 03:29 PM

Hey, better late than never, right?

At least we can say we don't leave anyone's question unanswered ... forever.... :D


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