Noob, OMC 3.8 6 cylinder questions

[prinler]

I just purchased a boat. 1982 Sea Swirl. The old owner was a budget owner and towed his boat with a car and didnt cover it or take much care of the motor. I would like to get the motor ready asap for the lake or river here in barstow area but i have never dove into boat motors much. Not sure of the differences right off the bat. Motor starts instantly and sounds good.

Who makes this motor? OMC is the manufacture but is this a GM 3.8? or a ford?

The owner noticed water in the oil so i want to rebuild the motor up to be reliable. Speed is an after thought.

What does a basic rebuild consist of? water pump? gaskets? fluid flush? are there cams? Timing chains? bearings?

When purchasing the parts: How to i know exactly what motor i have? Where do i get them from? pls dont tell me local boat shop

repair manual? Where i get one for this? motor or boat?

Thanks a bunch
Boat Noob
Steve

 

[danond]

Re: Noob, OMC 3.8 6 cylinder questions

Steve - you may want to research OMC on these forums before you spend a bunch of $$ on that engine and drive, especially with a cracked block and poor maintenance. OMC has been out of business for 10+ years and parts are getting hard to come by. Mechanics are almost impossible to find locally. Parts are expensive, etc.

Definitely worth a second look before you get started. In the end you'll have to find someone who doesn't know about OMC in order to sell the thing.

 

[cr2k]

Re: Noob, OMC 3.8 6 cylinder questions

3.8 is a GM engine. Water in oil and running good is most likely cracked block. Since previous owner was not much at care, doubt he winterized it and/or drained the block and manifolds.

And yes it does get down to "hard freeze" temps in the desert

GM V blocks (V-8/V-6) tend to crack inside the valley under the intake. Usually just below the heads.

Manifolds tend to crack along the lower edges on the outside.

If this is the case you might consider a used replacement from a marine salvage yard like ShipWreck or Rancho Marine Salvage. Maybe someone at Havasu may have a line on salvage places.

Basically Marine Engine Differences are:
Stainless steel head gaskets, Marine (spark shielded) Distributor, Starter, Alternator. Internally vented Carbs.
Camshaft, Distributor advance curve and Carb are more performance oriented than car (no smog), higher compression.
Circulation pump (water pump on a car) is either SS or bronze impeller and veins are straight not swept or angled.

If the distributor (V-engines) is closer to the transom it's GM based if it's closer to the bow it's Ford based.

Hope this helps.

 

[prinler]

Re: Noob, OMC 3.8 6 cylinder questions

DING DING DING! We have a winner!

I got my bro and we dismantled the motor. Got to the intake and the freakin valley wall is cracked. *sigh*

Block was not winterized. Called the previous owner and he said whats winterized? He gave me $300 back and we left on good terms.

NOW, it seems everything is ok except the block. When calling around what do i ask for? While googling my brain off i found some info about the motor...
3.8l GM/Buick 1982
Needs to be a RWD with 14 bolts holding the oil pan on?

Can anyone help me figure out what to ask for.... Lots of car junk yards around here. Just need to know what to ask for...
one place said if they got one $175 good or money back//// i pull! So please help!

 

[mbest1312]

Re: Noob, OMC 3.8 6 cylinder questions

DING DING DING! We have a winner!

I got my bro and we dismantled the motor. Got to the intake and the freakin valley wall is cracked. *sigh*

Block was not winterized. Called the previous owner and he said whats winterized? He gave me $300 back and we left on good terms.

NOW, it seems everything is ok except the block. When calling around what do i ask for? While googling my brain off i found some info about the motor...
3.8l GM/Buick 1982
Needs to be a RWD with 14 bolts holding the oil pan on?

Can anyone help me figure out what to ask for.... Lots of car junk yards around here. Just need to know what to ask for...
one place said if they got one $175 good or money back//// i pull! So please help!

gm made 2 differant 3.8 v6 engines, ones based of a small block chevy(229 cu), the other is based off a buick v8(231 cu), easy way to tell the differance is the chevy design has the distributor in the rear, the buick design has the distributor in the front, hope that helps.

 

[Dustin0330]

Re: Noob, OMC 3.8 6 cylinder questions

I would stay away from the buick,olds,and pontiac engines and look for a decent marine engine, I've owned several 3.8 powered gm g-bodies over the years and I only had one that was reliable.