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Marine 383s

mike20016

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Hi everyone,

I'm getting my new (to me) Road Runner revived, and the engine is seized. I'm pulling the engine later this week to take a look inside to see if it's salvagable, but if it's not I'm seeing a few marine 383's available locally. Were these spec'd any differently than the passenger car 383's? I know some are reverse rotation, so I'm only looking at standard rotation motors.

Definitely not committed to a marine 383 - just trying to figure out my options, and they're cheap-ish for a running motor.
 
I would be very leery of a marine engine. Lots of corrosion and just not my choice for a starting point. If free maybe worth the time to tear it down for inspection. About all that can be possibly used is the short block. Heads and intake most likely HD industrial application.
 
Hi everyone,

I'm getting my new (to me) Road Runner revived, and the engine is seized. I'm pulling the engine later this week to take a look inside to see if it's salvagable, but if it's not I'm seeing a few marine 383's available locally. Were these spec'd any differently than the passenger car 383's? I know some are reverse rotation, so I'm only looking at standard rotation motors.

Definitely not committed to a marine 383 - just trying to figure out my options, and they're cheap-ish for a running motor.
You have to be careful with marine engines because some spin in the opposite direction.
 
Thanks y'all! Looks like I'll be better served keeping my eyes out for a junkyard find if it turns out this engine is toast.
 
I'm getting my new (to me) Road Runner revived, and the engine is seized......
What year RR? Original engine?

Corrosion can differ depending on the cooling system used and where used. I wouldn't use any salt water engine.
Appears 383's were in the 8.2 - 8.5 compression range.
If the hours in service are known, that can be a plus.

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Find an engine that will turn over by hand and move on from there. Marine engines are called "marine engines" for a reason. Unless it's an early (1st Gen) leave it alone.
 
What was the reason for the seizure? Loss of oil, bent crank or other?

Not sure yet -- just started tearing the engine apart last week, but this arctic weather is preventing me from getting much farther until it's at least above 15 degrees in my garage. I have a feeling it's rust since the engine is super dirty and appears to have been sitting for a long time, but I'll keep y'all updated.
 
You have to be careful with marine engines because some spin in the opposite direction.
The problem with reverse rotation engines is that they have some specific components that make it unsuitable for use in a vehicle. The cam is ground backwards, the distributor is backwards and the crank is often different. The rear main bearing surface on some engines had serrations in the crank to pull oil in away from the seal. If that crank is spun the other way, it pushes oil toward the seal and increases the risk of a leak.
 
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As stated above I have a marine RR in my car and the crank rear seal area had to be polished or it will just spit the oil out.
 
What was the reason for the seizure? Loss of oil, bent crank or other?

I actually don't know -- I bought the car after it had been sitting for a long time, and the previous owner bought it when the engine was seized. The owner before him may be the only person who knows, so my impression is that it's an answer lost to time.

What year RR? Original engine?

Corrosion can differ depending on the cooling system used and where used. I wouldn't use any salt water engine.
Appears 383's were in the 8.2 - 8.5 compression range.
If the hours in service are known, that can be a plus.

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View attachment 1068947

It's a 1969 RR, and unfortunately it is a numbers-matching engine (I know it's possible to fake these, so I won't go as far as to say it's the original engine, but it's certainly possible).

So, as an update, I pulled the heads, and the bores look really rough (pictures below). It has big ridges at the tops of the bores, and it hasn't loosened up any after nearly two weeks of applying penetrating oil. There was sediment in the bores when I opened it up, too. I'm really thinking the engine requires extensive machining, which is out of my budget. Based on the pictures and what I've described, does this look salvageable? (edited for picture formatting)

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People put bare blocks out in the weather to season.
Find someone with an oven and bake it.
 
It's a 1969 RR, and unfortunately it is a numbers-matching engine....

What does the pad under the distributor read? I myself, would try to free it up to determine the deck height if it's still at 4.25" bore.
That wouldn't stop me from pursuing another though.
 
just turn it upside down and take the easiest rod loose and drive the piston out with a hammer and a board, repeat
 
all you really want is the block and maybe the crank then you take them down to your machine shop and he'll check the worst hole and see where you go from there
 
Block will have to be cleaned anyway. That is why I suggested baking it. That rust and caked on oil will be gone when it comes out.
 
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