1971 Demon with some coolant issues

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71_Demon

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I picked up my first Mopar project yesterday... a 1971 Demon, 318, 55000 original miles, one owner (literally a grandma who only drove it to church on sunday..). It has been sitting covered outside for approximatly 10 years.

The previous owner would start it up once every 3 months or so, let it warm up, then shut it off. He would also change the oil periodically. Last time the oil was changed there was water in it. I towed it over to my garage, pulled to plugs and ran a compression test:

1: 130psi
2: 135psi
3: 130psi
4: 130psi
5: 100psi
6: 130psi
7: 100psi
8: 90psi

As you can see the back cylinders look like they have a problem. It has been suggested to me that I change the oil, refill the coolant, start it up and watch it carefully. Does anyone else have an idea of where to go from here?

I am really hoping it is not a cracked block or a serious problem. Because the 318 only has 55,000 miles I am hoping that there is still quite a bit of life left in it.
 
When you say they found water in the oil at last change, was it water or glycol and approx. how much, a tablespoon or a cup. Either way, pressure test the cooling system with the special hand pump that connects to the rad cap and see if it holds pressure. The low compression test numbers could just be stuck rings and the engine will come around if it's run for a few days.
 
If you can't find or have a hand pressure tester, they have these pills you put in the cooling system that turn the coolant different colors depending if it is leaking from either oil system or combustion chamber. I myself would change the oil and refill the coolant and change the thermostat. Run if for a while to get everything set again. If a motor sits for a while natural condensation from sitting with a valve open let's in a little water. Add that up. Same thing happens from air getting in through the breather, so it collects up in the valve covers also. After running it for a while pull the oil filter and cut it open and check for anything odd. Go from there.
 
If the car was outside but had glycol in the cooling system I would suspect condensation to be the water in the oil problem. Especially starting it only periodically and warming it up. Engines can get quite a bit of condensation in the crankcase when only started occasionally. The suggestion to change the oil and watch it is a good one. Drive the car if you can, just sitting there idling will not warm the oil enough to vaporize the water in the oil.
 
Well I was going to change the oil, refill the coolant and start it up, but.....

Drained the oil, left the pan plug out and started to refill the coolant. I heard a strange noise, looked back under the car and it appears that the coolant (I am just using water) is running straight out of the coolant system into the oil pan. I put a few gallons of water through the system and now clear water is coming out of the oil pan... This is not looking good.
 
sounds like its time to pull the intake and heads, look carefully at all of the gaskets as you take it apart, look for signs of leaking, if nothing is found then you need to have the heads pressure checked for cracks, heres hoping you find it in the top end. good
luck
 
Well gentlemen.. the engine is done. There is a 5-6 inch bulge with cracks on top, bottom and through the center. on the inside of the block under the manifold, right on the inside of cylinder 5.

Anyone know a good place to buy a new engine? :sad2: :cussing:
 
Sorry to hear that. My local pick a part junkyard has yielded several engines for me. The slant 6 currently in my dart cost me all of $75.00. I put a new chain& gears in it, checked the bearings(they were good), adjusted the valves and threw it in. It runs great! If you check all the plugs for any signs of oil, turn it over, check to see that it still has green coolant in the block you can get lucky on mopar engines. This is all if you want to go the cheap route. A crate 360/380 hp would run in your car if you want to spend for it.
 
thats a real bummer, and i bet you will never make the same mistake again. dont feel to bad we all have done something similar ,or even worse... good luck in finding a motor ...

p.s, what city/ state are you in ?
 
I am near Spokane, Washington..

Right now I am leaning towards the 360/380 Magnum. The best price I have found on those so far is Summit Racing (unless someone knows somewhere else). I looked at some remanufactured engines, but by the time I get it to where I want it I might as well just buy the Mopar cate engine.

I am not familiar with the drivettrain on my 71 demon, it has a column shift Auto trans, original engine was a 318.. not sure what rear axle I have. Will my stock drivetrain stand up to a 380hp crate engine?
 
It's a way off, but I have a 318 you can have..unfortunately, I'm on the East Coast..CT...
 
I,m closer, N.D. and have a 318 short block minus heads and intake and cam. Was an excellent engine, had gone through it, new bearings and rings and cam bearings. Had a bud help me put it together and had a rather annoying rattle to it that I thought was a problem with bearings and puked oil out the breather on the right side like a Texas oil well, later found out (after pulling the engine to swap in a difrent one) that same bud had no clue about how the rockers get oiled and had put the rocker rail on upside down and backwards on the right side. So I am quit certain the engine is in excellent condition. Anyway if your interested I would part with it very cheap.
 
I am leaning towards going this route:

http://www.rebuiltautoengines.com/dodge-V8_5.2_318-engines.html

This outfit is local and pickup would be simple. It looks like a 318 is $1,189 plus a $124 core charge. I want to set my self up with a platform that I can build a mild street engine from. Initially I was looking at the Mopar Crate 360, but I think this is more my price range (and speed).

Any thoughts on these engines? It appears they will work with you to customize the engine if wanted, are there any options I should look into? different heads? porting?

I will probably use an edlebrock manifold and 4bbl carb (600 or 750?). Thanks for answering all my questions.. this is my first mopar project.
 
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