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Can I use a automotive motor in my houseboat?

D

David Osborne

New member
I have a 1971 Gibson Houseboat with a single 1971 Chrysler 318 225 hp motor. Is this a marine motor or is this the same motor used in cars and trucks? Since the clutch is slipping and the oil looks like a chocolate milshake I was just hoping to swich the motor out for one I have found in a junk yard. I know I will have to do some part swapping like manifolds, power steering pump etc. But are these the same motors?

Thansk for any help,
David
 
I have raw water cooled system. I thought Chrysler only made a car and heavy duty (truck) version of the 318 back in 1971. So there is a marine version? What are the differences?
 
In a raw water motor, use have to replace the head gaskets with marine (stainless) gaskets and brass freeze out plugs. If not, you'll soon blow a head gasket. Not hard to do with the motor out. Be sure to replace the freeze out plug located behind the flywheel.

Jeff
 
Thanks for the info Jeff. I did look up the Head Gasket ( part 18-3860) on this website and it does not appear to be stainless steel. Whats up with that?
 
David, the cam profile will also be somewhat different. You may be able to squeak by, depending on the exhaust system.
IOW, if the design poses a lessor issue with regard to water reversion, it may work for you. "May" being the key word here.

If the savings from using the Auto Engine is great enough, consider adding a Closed Cooling system to the engine.
Now the cylinder head gaskets, Engine "Circ" pump, and core plugs do not pose the same issues.
 
Rick - I dont know about going with a closed cooling system. Are you talking about using the radiator and fan? Wouldnt I have to change the exhaust manifolds. Those are crazy expensive. The automotive motor I have found has a model number of 5M318. I am heading to the boat tonight to see if the model number on the bad motor is the same (exact match) or if it is a marine motor like LM318. Maybe I can just take the automotive motor and put a stainless steel head gasket, use brass freeze plugs, move the intake, power steering pump and maybe the adaptor for the oil filter and be good to go. I will know alot more Saturday afternoon. Because we are pulling the bad motor out and then we will see what matches up. Then make a decision on rebuilding or swaping. Thanks for all the information I will keep this thread updated on what happens.
 
Bad News - Like there is any other kind of news reguarding a houseboat. I just spoke with a "mopar expert" at a local marine shop. He said I could not use an automotive enging in the houseboat. The cams are different. He said the cam in the marine enging is designd for higher RPM's than an automotive engine. He said I should be able to run the houseboat up and down the lake all day long at 4000 RMP's with the marine engine. I have never had the thing over 2800 RPM's. Oh well, I guess I am rebuilding my marine engine.
 
The car engine--unless it's one of the higher performance motors--would still work fine. Lots of people have tossed them in successfully, for the standard car motors were fairly mild.

That said, a new long block is the best way for you to go. Don't mess with rebuilding yours, for the block is well rusted by now. Futhermore, it's not worth it since rebuilt long block Chrysler 318s are cheaper than Chevies.

Jeff

PS: You need to verify the rotation of that motor. Single screws are often reverse rotation motors (which cancels out using an auto motor).
 
Thanks for the reply Jeff. However, I am really in a cost savings mode now. I think I am getting more money in this boat than I will ever get back out. I still have interior upgrades to do this winter. I am now thinking we (my brother and I) will just try to put a new clutch and head gasket on the existing motor and see if we can get it going again. I dont think we will have to pull the motor out of the boat for these repairs. The motor starts and sounds good. The clutch is just slipping (new clutch plates) and the oil is mixing with water somewhere (new head gasket).
 
"He said I could not use an automotive enging in the houseboat. The cams are different."

So, swap the cams and lifters.

"will just try to put a new clutch and head gasket on the existing motor"

What are your compression numbers?
 
"So swap cams and lifters"

I would think just rebuilding the existing engine would be more cost effective than tearing two motors down and swaping cams and lifters depending on what the existing motor looks like when we get into it. I am hoping to just replace clutch and head gasket and get it going again. I want to check the model number on the existing enging this afternoon and see if the thing is actually a marine enging. If its a not, then I am just doing an enging swap. I may not post again until Monday but thanks for all the input. Maybe I should just bolt an outboard to the thing and live happily ever after. Ha ha.
 
"I would think just rebuilding the existing engine would be more cost effective "

Depends on where / why you are milkshaking the crankcase oil. Where is the leak?
 
David Osborne said:
Thanks for the reply Jeff. However, I am really in a cost savings mode now. I think I am getting more money in this boat than I will ever get back out. I still have interior upgrades to do this winter. I am now thinking we (my brother and I) will just try to put a new clutch and head gasket on the existing motor and see if we can get it going again. I dont think we will have to pull the motor out of the boat for these repairs. The motor starts and sounds good. The clutch is just slipping (new clutch plates) and the oil is mixing with water somewhere (new head gasket).
Click to expand...
Your engine probably has a cracked block and is no good. A compression and leak down test will tell you whether it is a head gasket or not. Likely the engine froze and cracked. Since you are in fresh water you can get away with using a truck 318 from a pick up. Car engines will have the wrong cam. I would just swap over the marine parts from the current engine to your replacement.
 
I'd strongly advise against over-hauling any previously Raw Water cooled marine engine, especially one this age.
You're only a few dollars away from an automotive core that has never seen river/lake/salt water before.
A no brainer, IMO.

David Osborne said:
Rick - I dont know about going with a closed cooling system. Are you talking about using the radiator and fan? Wouldnt I have to change the exhaust manifolds. Those are crazy expensive.
Click to expand...
David, here is an imgae of a Heat Exchanger that provides Closed System Cooling. Sea Water acts as air does with a radiator..... but much more efficiently.
The E/G (ethylene glycol mixture) surounds a bronze tube bundle, and remains captive within the engine's cooling jackets.
The sea water passes through the tube bundle, and removes the heat.... much like the air does with a radiator.
images

The reason that I mentioned this is multi-fold.
  • Minus the cam profile (of which the exhaust must be considered), you will not need to change out the casting core plugs, nor the head gaskets, nor the "Circ" pump, saving you $$$$$.
  • Your winterizing becomes more simple, and the risk of freeze damage is greatly reduced to that of manifolds ONLY, unless you do a Full System.
  • All in all.... it may represent an actual savings to you, given the over-all scope of things.
fastjeff said:
The car engine--unless it's one of the higher performance motors--would still work fine.
Click to expand...
Normally I would never recommend this, but ditto Jeff if you are typically running at low speed.

However, don't under-estimate water reversion issue due to the camshaft lobe separation that the Marine Profile cam offers.
Again...... look closely at your exhaust system, and let this be part of the equation.

.



 
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Just bolt your cooling system on the junkyard engine and throw it in there, it will run fine. Keep your core for when you can afford to rebuild it. You should be able to several years out of it with no problems. You said you wanted to do it cheap but I see a lot of people suggesting expensive ideas.

Dan
 
Unless I missed it, David has not mentioned the water that the boat is kept in.
Whether River/Lake water, do not under-estimate the out-of-balance PH level, and the effects it may have on head gaskets, Circ pump impeller, casting core plugs, etc.
If brackish or full salt water.... forget it!

I'm not completely disagreeing with you, Dan..... but this is something to factor in.

Perhaps we need to define doing this on the "cheap".

  • Do we install a cheap engine, only to have head gaskets fail, and then the following year or two, install another cheap engine?
  • Or, do we install a cheap engine, and fit it with a Heat Exchanger that can find it's way onto future engines, should that ever occur?
 
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Thanks for all the recent post. We did not get the motor pulled out as we were greatly slowed down over the weekend by the 92 degree heat and even more by the cold drinks we were having to beat the heat. But we should get it pulled this week and go from there. I like the idea of checking the compression and first determining where the oil and water are mixing. I do like the idea of a closed cooling system but not sure if I will get into that or not. My sytem pulls lake water and then back out the exahust manifolds over the exhaust. So I dont want to buy new manifolds.
 
If the manifolds are okay there's no neeed to replace them. I pressure tested mine a while back to see if they were leaking. (Use a 1/4 " steel plate to block off the ends. Put water in it and pressurize to 15 psi.)

Jeff
 
Ok guys. The motor is out. It was a bitch, but its out. The model number on the 1971 Chrysler is LM318XYLX-378. So I am guessing this is in fact the origional motor and from my research its a marine motor (LM). So my brother (the mechanic) and I will rebuild it. He was asking me to do some research on the cluth. He said it looks different than the ones he as seen in automotive applications. Does anyone have a parts book for this model?
 
David.... all due respect to you and your brother.........., but when you are only a few dollars away from an automotive core (one that's seen ONLY E/G in it's cooling system it's entire life), why would you be willing to spend the money and labor over-hauling an engine that has been raw water cooled it's entire life?

Internal engine block corrosion has no set path that it is supposed to take and remain on.
This stuff takes a completely random path......, and any dang path that it wants to.
When the block has been cleaned free from the rust scale........ whether baked or chemically cleaned......, how much material is no longer there?
What areas have been compromised?

Just food for thought!

.
 
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Thanks for the reply Rick. The motor had to come out because it was mixing oil and water. The clutch was also slipping. Pulling the motor and tearing it down will cost me nothing....(Brother). If it looks bad after tear down, I will have no choice but to go with an automotive core. We actually do not know the differences between an automotive enging and the marine enging. I cant get clear advice on this. I have heard everything from an automotive motor has a different rotation to different cam, marine accessories will not hang on the automotive motor, etc. I have even heard that if I used an automotive motor I would have to tear it down and replace the head gasket with a stainless steel one. So we were just thinking we would use the marine motor if we could.
Please advise.
 
David, I know of no method to determine how severely corrosion has affected the inside of a raw water cooled engine block and cylinder heads. If you and your brother have some magical method, please share.

Yes..... some sarcasm.... but all in fun with you. No offense please! :D

I just hate to see you toss good money after bad!

Most all of our V-8 Marine gassers began their life as automotive engines.
True..... there may be some castings that offer better material for Marine use.
Perhaps similarly to that of the GM SBC, there may be light castings that DO NOT belong in a Marine application.
You can likely search for this info and find it.
Can't help you much..... I'm more into the SBC.

Std Marine Engine is LH Rotation.... same as Car/Truck engine.

Rev Marine Engine is RH Rotation.... opposite Car/Truck engine.
Piston wrist pin orienation is changed, camshaft phasing rotates opposite, firing order is reversed, etc.

Otherwise, these are nothing more than automotive 318's (minus cam profile, casting core plug material, C/R, etc.)


Either rotation (LH/RH) is viewed as though looking at the flywheel end!
 
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Thanks Rick. As you can tell I am no mechanic. But I get what your saying about water sitting in the origional engine for the last 40 years. Not good, and your right my money may very well be spent on looking at another engine.
 
RicardoMarine said:
David, I know of no method to determine how severely corrosion has affected the inside of a raw water cooled engine block and cylinder heads. If you and your brother have some magical method, please share.

Yes..... some sarcasm.... but all in fun with you. No offense please! :D

I just hate to see you toss good money after bad!

Most all of our V-8 Marine gassers began their life as automotive engines.
True..... there may be some castings that offer better material for Marine use.
Perhaps similarly to that of the GM SBC, there may be light castings that DO NOT belong in a Marine application.
You can likely search for this info and find it.
Can't help you much..... I'm more into the SBC.

Std Marine Engine is LH Rotation.... same as Car/Truck engine.

Rev Marine Engine is RH Rotation.... opposite Car/Truck engine.
Piston wrist pin orienation is changed, camshaft phasing rotates opposite, firing order is reversed, etc.

Otherwise, these are nothing more than automotive 318's (minus cam profile, casting core plug material, C/R, etc.)


Either rotation (LH/RH) is viewed as though looking at the flywheel end!
Click to expand...

I think you may be confusing him by comparing GM maring engines with Mopar? I have rebuilt both of my engines and have a set of spares and all the part numbers for the blocks, heads, intakes, cranks etc are standard automotive parts except the reverse crank, reverse cam and reverse dist. drive gear. The pistons in my 440s are not reversed like some GMs, anybody know about the 318s?

Dan
 
Rick - you might find this interesting. I was on the phone earlier with the people from marineenginesforsale.com. I was trying to price a remanufactured LM318. They said they did not have one in stock but I could ship them my engine ($400) and they would rebuild for ($1,800). So I asked about the block sitting in fresh water for the last 40 years and they said it should be just fine. Once again, no matter who you talk to, no one is on the same page on these motors. Very confusing.
 
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Rebuilt Long Block $1300 with warranty.........still have a whole lot of parts to take off,inspect,clean,repaint,repair

or go get the junkyard motor get your drive plate and flywheel housing,starter..... bolt it up
 
David, I think that is bad information to be passing on.
Years ago, I thought the same thing. I thought that I'd over-haul a 302 Ford that had been raw water cooled.
The shop cleaned the block, placed the block in the boring machine, bored several cylinders successfully until they came to one cylinder.
Corrosion had taken it's course...... (remember the randem path that I mentioned earlier?????)
Well, the boring bit went right through the cylinder wall.
Mind you....... a first over bore of .030" is only .015" off the wall!

All that prep work for nothing.
I later learned that this is not uncommon!
I'll never do that again, nor could I ever recommend to anyone that they do this when a good automotive core is so dang cheap (cylinder block and heads only as we'll have all of the other items).

Warrantee or no warrantee..... I would not want to pull an engine later on due to this type of failure.

Your call!


Dan, I was being pretty careful to be clear when it came to the GM vs the Chrysler.
It was more of a caution for David than anything.
Perhaps similarly to that of the GM SBC, there may be light castings that DO NOT belong in a Marine application.
You can likely search for this info and find it.
Can't help you much..... I'm more into the SBC.
Click to expand...
 
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