To Weld or not to Weld

[merkaba]

Hey, I recently got a boat for free from a family member. When i got the boat it was left over the winter without being winterized and the block got cracked. My wife's father used to weld for a living, and knows what he's doing, but he's not too sure if welding it would hold up through the vibration etc. We don't really want to weld it and put the boat back together and have it not work shortly after. Has anyone had success welding something similar to this? There is no water getting into the oil, so I think that is a good sign. Any suggestions/input would be greatly appreciated. There are a total of 3 spots that would need welding, and you should be able to see them all in the pictures. Thanks!

 

[wifisher]

Re: To Weld or not to Weld

The welds would hold up fine to vibrations. Whether or not to try it is up to you. For the manifold, I would just replace it. The block, if you want to try welding it, go ahead. It would obviously be better to replace it and not worry about it again, as there could be a lot of damage that you can't see right now. (such as internal leaks/cracks) If you do not have the money to spend on a motor rebuild, try welding it and pressure test it before you install the motor into the boat.

 

[RogersJetboat454]

Re: To Weld or not to Weld

If you're going to try this, I suggest setting up some kind of motor stand that you can run the engine on rather than putting it back into the boat only to find out its worse than you thought.

Those cracks are ugly for sure. Being so close to the engine mounts and the deck surface you may have issues.

Good luck, and welcome to Iboats!

 

[jeffnick]

Re: To Weld or not to Weld

I worked for an ex-Navy welder. He said you needed to heat cast iron in an oven for a successful weld. Personally, I'd clean them up, grind them a little and lay some Marine Tex in the crack.

 

[HT32BSX115]

Re: To Weld or not to Weld

Howdy,


1. You're in the wrong forum. You have a stern drive engine.....maybe a MOD will move it for you! post the engine type model, year etc.....

2. Welding a cast iron engine block is problematic because you cannot heat the entire casting as it should be unless you have an oven to heat it in (and keep it hot while welding)

3. Engine blocks FREQUENTLY crack internally when they break from freeze damage. When this happens you'll get water in the oil the first time you run it in the lake and get it fully warmed up. You don't always see it running it on a water hose....... CROSS YOUR FINGERS!

4. Don't even try to weld the manifold. You're wasting your time if you do....

5. Some people have had limited success using JB Weld or other epoxies with non-structural area in engine blocks (but yours doesn't look like it would be worth trying...)

6. What engine is it? Your best bet might be to find another good used engine and just swap it out.


Craigslist, etc is a good place to find another engine. (but a LOT of them are cracked as well and it's not obvious!!)


Good luck!


Welcome Aboard!

Rick

 

[merkaba]

Re: To Weld or not to Weld

Sorry for posting in the wrong thread, i don't know a heck of a lot about engines so i'm not surprised. Thanks everyone for all the information. Someone local here also recommended that i use Marine Tex. I got a quote from a shop to replace the whole thing, and they wanted $1800 to do it. I believe it's a Chevy motor. My boat which it came out of is a 1988 (i think) Checkmate. The specs are below. What do you think i should be paying for a replacement? Are the motors the same in cars as they are in boats, or do i specifically need a marine engine? Sorry for all the newb questions

Small Block
Serial: B625122
Model: MCM 260
Displacement: 350-CID
Horsepower: 260
Rotation: CCW
Max RPM: 4200-4600

 

[wifisher]

Re: To Weld or not to Weld

Howdy,


1. You're in the wrong forum. You have a stern drive engine.....

C'mon cut him some slack. It is outboard for at least a few weeks by the looks of it.

 

[Art Bernard]

Re: To Weld or not to Weld

No, do not try to weld it, it wont hold worth crap. I'm an ex-navy welder (qualled up to 4956 nuc welding) and weld repairs on cast metal don't work out. Evan with pre-heating and stress relieving the metal it's a very iffy thing. In the service, the only time we would evan try to do it was for an emergency repair and than it was ripped out and replaced with a new part once we hit the pier. Sorry.

Art

 

[merkaba]

Re: To Weld or not to Weld

i'm not sure if this helps, but this is a picture i found on the internet that is exactly what my boat looks like.

 

[81 Checkmate]

Re: To Weld or not to Weld

Looks like you already have the motor out? I have been a welding instructor/ welder/ pipe welder for the past 25 yrs and have seen alot of different metal's welded. Cast Iron is one of the hardest metal's to weld and it does not weld very good. Not saying it cant be done, but on a engine block were your cracks are it would be hard to do. Like others have said you would want to heat it up and maintain the heat while welding and also do a post weld heat treatment. Otherwise let it cool slowly to keep it from cracking. Another tid bit is to drill holes at the ends of the crack to keep it from further cracking before welding.
For it to hold presure you would need to groove out the crack to get some penetration into the crack.

1. Buy a new short block and rebuild your motor !!!!! ( This is what i would do)
2. JB Weld / Epoxy it and put back in and run it till she blows. ( If you have easy acess)
3. Try and weld it ???????????? That would be the risk you have to take

P.S. Nice looking Boat for free

 

[merkaba]

Re: To Weld or not to Weld

The engine is already out and on an engine stand for nice an easy access. My father in law bought some thick welding rod which is supposedly made for cast iron. I don't know the specifics, but it has a minimum amount of nickle in the rod. I guess if there is a lot of nickle it has a better chance of cracking after the fact. Again this is all just what he's heard, as he isn't 100% sure. As far as the short block goes, how much do you think I can get one for? Do you have any suggestions as to where i should look? Is a short block for a car the same as one for a marine engine? Thanks a lot for the suggestions!

 

[mrcrabs]

Re: To Weld or not to Weld

an automotive shortblock will work just fine, your really wasting your time and money trying to weld that, But if it were me and I had no big $$ I would use some sort of epoxy like...this http://www.alvinproducts.com/Products/Products.asp?id=2#Suggested uses

I see this stuff on used boats all the time...many have lots of hours on them

 

[Monte1961]

Re: To Weld or not to Weld

This a question I have always pondered. If there is any doubt weather it will work or not? with the obvious that it wont! why take a chance on ruining a good time at the lake? Be smart and do it correctly and move forward. You will be glad you did!

 

[HT32BSX115]

Re: To Weld or not to Weld

C'mon cut him some slack. It is outboard for at least a few weeks by the looks of it.

Um.....yeah.......sort of!! Although I would have thought it would go in Mercruiser I/O & Inboard Engines & Outdrives instead of the Non-repair forum.....








That is a SERIOUSLY COOL BOAT!!

Since you have an SBC, you won't have a huge problem finding a good used engine. Any good (5.7L) truck engine will work.

You'll need to replace the core plugs with brass (don't call them "freeze" plugs! They obviously don't protect against freezing do they?) Use your existing starter, ALT, dist, etc....you'll probably need a new circulating pump.....

Get new risers and exhaust manifolds.


If it were mine I would just get a rebuilt/reman longblock.

Here's a company near me that may be building me a 454HO for my 87 Liberator.....
http://usengine.us/mercruiser.html

There's probably a place near you that will offer a similar deal....

The place above ships nationwide but I would want someone local to help if there was a problem.....


Since your boat was "Free" (THEY"RE NEVER FREE!!!!) It's worth it to put a good engine in it.

While you're at it, drain and refill the outdrive and replace the raw water pump.

Check the power steering and oil coolers (if installed ) for debris.

Check/replace the exhaust shutters in the exhaust y-pipe (if it's NOT thru-hull exhaust), check the U-joints and gimbal bearing.

I would also carefully check the lower shift cable.


Get yourself an OEM Mercruiser service manual, an alignment tool and other tools needed to do the job.

The mod here should post a link to the correct service manual when he sees this thread. But if you want to do your own work a paper copy is sure nice. Don't waste your time on a Seloc or Clymer manual.....(they're pretty good for starting your wood stove though!!)


Cool boat!!



Rick

 

[Don S]

Re: To Weld or not to Weld

As bad as that engine is cracked, I couldn't imagine the inside is not cracked also. Pull the intake manifold and check the lifter valley just above the lifters for cracks. You can't fix the inside.

 

[merkaba]

Re: To Weld or not to Weld

Thank you all very much for all the input/help!

 

[Fordiesel69]

Re: To Weld or not to Weld

I am a cheapskate and not even I would consider having that welded.

Replace the engine. Should be able to get an automotive one and swap your marine parts over.

 

[merkaba]

Re: To Weld or not to Weld

How would i go about finding the proper automotive motor to replace it with? I thought it was a chevy 350, but i'm not 100% sure. I also don't know what year motor i should be looking for. The specs for the motor that is currently in it are below. I found a chevy 350 out of a 93 conversion van with 69k miles on it for $450. Supposedly it runs perfectly and it's from a used car parts shop.

Small Block
Serial: B625122
Model: MCM-260
Displacement: 350-CID
Horsepower: 260
Rotation: CCW
MaxRPM: 4200-4600
Drive Unit Serial: OB752301

 

[mrcrabs]

Re: To Weld or not to Weld

you will need to change the cam.

 

[lcmains1]

Re: To Weld or not to Weld

I had a similar issue several years ago on my first boat however the crack was not nearly as big. I took it to a blacksmith that hadbeen welding for years to have welded. He cleaned it up, welded it and and said "good as new" I put it back together, ran it and the damn thing still leaked. I would replace the parts if I were you!

I see why the boat was free!!!