cracked block

[Jim89]

I have a 89 3.0 OMC Cobra. The block has a long crack just below the manifold.The crack is only on the outside. I did seal it with a rubber silicone type sealant. I have used the boat most of the summer without problems. However I do have a small leak. Does anyone know of something to seal the crack with. (Other than JB Weld)

 

[Wellcraft 89]

Re: cracked block

Have you chk the oil lately?usaully it finds its way to the oil and will leave you stranded. <br />Fix it right and feel better about it.<br />Just my $.02<br />Rich

 

[The Marine Doctor]

Re: cracked block

Yep...pull the block and take it to a machine shop and get it welded up. I have seen some fantastic work lately. <br /><br />Generally if you get a crack on the outside.. you would also have had stress on the inside...its just a matter of time.<br /><br />TMD

 

[pecothern]

Re: cracked block

What you got against JB Weld.? I drove a triumph Spitfire for 6 years with a cracked block fixed with JB Weld. Still fine when I sold it. Fixed a hole in the gas tank too. I've heard Marinetex is good for that kind of repair too.

 

[Jim89]

Re: cracked block

One of Three, I don't have a problem with JB Weld but I have tried it and same as now. I had a small leak.

 

[Jim89]

Re: cracked block

Thanks Doctor,<br />I knew I could have it welded but just don't want to pull and dissemble the engine. A lot of cost in the end and the boat runs just fine as it is. Just a little water leak. Just thought someone might have know of something that might seal it.<br />Thanks, Jim

 

[Jim89]

Re: cracked block

Hi Wellcraft,<br />Water isn't getting to the oil. I have been running the boat for most of the summer. Just a pesky little water leak! As long as the bilge pump holds up I will be ok. Ha!

 

[crazy charlie]

Re: cracked block

If you are going for the cheap fix,I would try marine tex.The prep of the surface and the crack itself is critical to the end result of the repair.It must be as clean as possible,sanded,wire brushed,wiped with acetone etc. when you are at that point mix the 2 parts as perfectly as possible.too much hardner is worse not better.Force what you can into the crack before you cover the whole area.Temperature is important.If it is going to be cold use a lamp to keep it warm until cured.Dont start with a cold surface.Good luck Charlie

 

[flashback]

Re: cracked block

take a small drill bit, say 1/8 inch and drill a hole at each end of the crack, then using a dremel, grind the crack and drilled holes to form a chamfer or V shape. then clean the heck out of the repair area and fill it with JBWELD.. If you sell the boat at some time then tell the buyer what you have done.....its only fair.......

 

[Jim89]

Re: cracked block

Hi Crazy Charlie,<br />What is Marine tex and where do I get it? Can I get it at a auto store or a boat place. What do I ask for since I don't know what it is.<br />Thanks<br />Jim

 

[Jim89]

Re: cracked block

Flashback,<br />I did stop drill the crack and "V" ground it the best I could. Used a grinding wheel to clean it. Then cleaned it with lacqure thinner. The JB Weld still leaked. Not much,but some.<br />Thanks<br />Jim