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Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Gas > Atomic 4 > Seattle (Bellevue/Renton) Atomic 4 rebuilding
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Thread: Seattle (Bellevue/Renton) Atomic 4 rebuilding Reply to Thread
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Topic Review (Newest First)
08-12-2010 01:16 AM
contagous Hi Ian

I read your other post, and was wondering between the 3 you have if you may have a spare exhaust Ubend pipe (lol not sure on its name) But its where the water exhaust come from the manifold up in a U shape. Mine just recently blew out and i've been looking for a replacement to save some $ in getting a machine shop it make a brand new one.

So figured I'd post and see, Good luck with your rebuilds.
08-09-2010 02:12 PM
cardiacpaul no, actually, its having had to rebuild an engine with 20.00 in my pocket and making it work.

A-4's are not a mystery engine. They are incredibly simple to keep running and take more abuse that should be possible.

Just put your thinking cap on, diagnose the problem, and they should start and run for decades (oh, wait, they have been running for decades)
Oh, additional machining type things...

On cranks, your goal is to not have oil leak excessively past the bearings, the way this happens is with "scoring" of the journals, meaning there is a clear "path" for excessive oil to fill the grooves, causing low oil pressure.
Pits on the crank aren't so bad, they'll actually "hold" a bit of lube, so its ok. Not as nice as a clean crank, but, take a look, it might make the cost differential work out in your favor..

Pits on the camshaft, are bad. Not so much for the bearing journals, as they are on the cam lobes. Pits on the cam lobes will wear out a set of tappets (things that raise and lower your valves) very fast.

Block "rust"
any machine shop is going to boil your block. That will clean out any internal passageways. Don't take it to a shop that is NOT going to boil the block.

Oil pressure.
as long as you can maintain 15 lbs, you're good.
Under 15 lbs?
instead of 30 weight, get some castrol 20/50. I'm not kiddin'.
Or,if that doesn't bring it up to 15 at warm idle, remove the pressure spring (I think its alone one side of the block and stretch it a little, or put some shims under it. don't arnold on it, you don't want 50 lbs of oil pressure, you'll blow the crank main seals.

transmission...
remember, there isn't an oil filter and your tranny shares its oil supply with the motor, so keep your oil clean. Try to keep it clean anyway.

I think there a total of 2 bearings in the transmission. If its been under salt water for a length of time, then, they're going to be shot.

The only other item that could trip you up is the reversing "gear" assy. This thing IS a mystery to me. I don't know why it works, but it does. Make sure it moves freely (if you even attempt the tranny) and it'll be ok.
08-09-2010 01:09 PM
CalebD I'd say that reply was well worth the wait. Someone actually knows his spit when it comes to A4 engines (among others).
08-09-2010 11:43 AM
cardiacpaul alrighty...

block welding is a good prospect...
UNLESS there are places that internally that they can't get to. Reading your description of the one block (first?) that may be the case. They'll have to pressure test it before and after each weld, and that may be cost prohibitive.

Frozen pistons.
fill the cylinders with PBlaster... FILL them.
wait a week. then, using a wood block on the piston top... Whack the piston with a heavy hammer (a couple of pounds or more)like you're mad at your mother in law. repeatedly. If it looses just a little and then stops again repeat the soaking procedure.

you MAY crack/break a piston, but at this point, whats it going to hurt, eh?
Most likely, with any of the blocks, you're going to need to have it bored. I think .030. is the limit for oversize pistons. Have the machine shop bore ONE hole, the worst one. If that one is under .030 oversize, then you're good to go.

Don't be too concerned about surface rust. A good shot peen blasting will take care of the worst of it.
The cranks are cast and not hardened, so, they start to "rust up" on a humid day.
DO NOT order any bearings or pistons and rings until the machine shop calls and tells you what size to get.
A good thing to do is get the specs, and what size bearings are available. That way the machine shop knows how far to go.

If theres a part that a little "iffy" like, say the crank is @ .030 and theres little black marks on one of the journals, I'd say run with it. You're looking for "smooth" not to have holes filled in. The machine shop may hem and haw, but its your crank.

Cylinder boring is another issue, they've got to be spot on, and really nice. otherwise, the rings will "catch" and tear a line up and down your cylinder and you'll spew oil out the exhaust. lots of oil. This is ONLY true of the distance of piston travel. I've seen shops try to tell a client that they need a new block because the lower part of the bore is as rough as a teenager with acne, but the piston doesn't go there, so who cares.

Heads. they're a "flathead" meaning no valves in them, basically, they're a flat plate with some holes. Have it milled and that should be that (get the copper head gaskets)

Startes are easy. Wander into your auto parts store and buy one for a 1964 chevy nova with the 4 cyl. engine...
If you're worried about it being "marine-ized" take off the back plate from yours, remove the plastic insulator, and put it on the new one before you return the core.
There are no other differences in that starter.

Less than expensive repair alternatives...
Check with the local junior/community colleges in the area. Talk to the auto shop instructor, Chances are, they may have a machine shop on prem, or know of one that does good work. Also try the local "automotive tech" schools, down here, they've got names like ATI, Lincoln tech. The instructors there are always looking for "dead bodies" to bring back to life.
08-08-2010 09:11 PM
CalebD Paging CardiacPaul, aisle 3 clean up! He knows his A4's and visits here sometimes.

I would never have thought of posting your thread as a poll. It would be nice if there were a best choice of engine to start with but you have plenty of parts or so it seems you should be able to build 1 working engine from what you have.
I suggest that you post this question over at the Moyer Marine forums as well. The motor heads over there will want pictures of all 3 engines and while the advice may not come so fast it should be good as those guys know their A4's and many have done re-builds.
The description of the 3 engines is helpful but pictures would be even better.
Good luck.
08-08-2010 06:07 PM
SeattleIanReilly
Seattle (Bellevue/Renton) Atomic 4 rebuilding

Hi everyone -

I am in the process of trying to get 1-2 good Atomic 4s from 3 bad ones. They are all late model (oil fill over tranny) - 2 "latest" model (flat flywheel cover). Don Moyer has been helping me on this & already owe him lots of gratitude & an order.

I am looking for ppl who may be interested in working or advising on this in any capacity. I will likely have left over A4 stuff, happy to barter work or parts or even a loaner on the boat - hope to have it in the San Juans in 2 weeks (27 ft Newport). Looking to do this quickly and on a budget for at least for one of the motors. The other may be a good candidate for a higher quality rebuild.

IF U KNOW people with machine shops / motor rebuilders in the area, pls. let me know. I have the motors currently in our shop by 405 in N. Renton / S. Bellevue. I am looking for most of the following (tbd): Block welding, shaft balance, journal bearings, honing, oversized rings, magnaflux, hot tank - ON A budget - i.e. Renton/Auburn, not Yacht club rates.

Total are 3 motors - except 1 missing head, missing heat exchanger. Most parts are great, others horribly corroded,


1 fresh cooled but submerged, pistons frozen & immovable even w/out crankshaft. (#3)

Basics of the motors:

1. Cracked block/raw cooled (#1)
removed from boat-
Newer model (flat flywheel cover)
raw water cooled
Rebuilt water pump, new fuel tank/filters/hoses/wires, etc.
Start easily & ran well, good compression (90+ on all), generally well maintained, but not properly winterized - has freeze cracks. Got water in oil, but ran only v. little after that & internals look all good so far.
Carb looks clean & seems to run well but lots of vibration - good power, easy starting, no stalling. Lots of steam coming from oil fill when under power.

*******
Current GUESS at a plan - suggestions appreciated - check to see if block can be welded - internal & external cracks visible (oil pan off). If so, possibly just weld (hopefully entire block w/ trans & pistons etc. can be heated in an oven to get a high quality weld?) -
then:
light valve work
wire brush water passages,
new gaskets
? pull mainshaft & check for balance, polish
? pull camshaft & do heavier valve work
? new journal bearings (very lightly scored)
Put back in boat

2. Dissasembled motor - down to block, cylinders out of round but seems good/raw cooled (#2),
former owner was going to have rebored /honed
Rebuilt starter
Older new model - cast iron flywheel cover
Parts mostly covered in surface rust, including crankshaft - probably not usable

3. Motor on dolly - block bare except valves & cam still there, pistons frozen, mainshaft out
Fresh water cooled - probably a good block
Was submerged - gearbox looks v. bad, but mainshaft looks fairly good as do the journal bearings. lots of surface rust around valves, oil was the worst i've seen in my life, like a very thick cold milkshake, but it probably wasn't run w/ this oil as this was submerged.
Flat plate over flywheel

A plan MAY be to take the block & head & pistons from motor 3 & combine with with the rebuilt starter and the rest of the components from the motor that was on the boat.

Given that we are trying to do this somewhat quickly, I think I should order the gasket set now, but wonder if there are any other components I should order at this time so as to avoid delays. I am thinking a set of motor mounts would be good also.

Ian
__________________
1978 Newport 27 in Bellevue / Seattle - Atomic 4 next door to 'house' boat

 
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