90hp block is damaged and I need some advice

[mikesea]

Re: 90hp block is damaged and I need some advice

I worked for 2 rebuild shops and many times had cases like this from corrosion and repaired with success by welding,then using an 80 grit paper on a marble block to deck it level.I tried many epoxies and sooner or later found it failed.There is a permanent fix ,but costly.The make a "flanged sleeve"the old sleeve comes out ,the new on has a shoulder that is equal to to total widith of mating surface,that is the thichness of the metal flange and the alum .cast you need repaired.That process requires total disassembly ,not worth it

 

[jonesg]

Re: 90hp block is damaged and I need some advice

The easy way to disassemble something that was glued or glassed with epoxy is just hit it with a heat gun.

 

[fire7882]

Re: 90hp block is damaged and I need some advice

I got the rods in but the MAPP gas won't get the block hot enough. The mass of aluminum is to large and it dissipates the heat to fast. Would putting the block in the oven and heating it up to 450 degrees help? Could this damage the block? I figered getting the temperature from 450 to 750 would be a lot easier than 85 to 750.

 

[crxess]

Re: 90hp block is damaged and I need some advice

Any seals in the block would be toast. Otherwise that is exactly how a cast iron exhaust is repaired. First heat up / repair / SLOW COOL

 

[fire7882]

Re: 90hp block is damaged and I need some advice

Thanks, the block is now bare. No pistons, seals, crank exc. I'll give it a try this afternoon.

 

[fishrdan]

Re: 90hp block is damaged and I need some advice

A word of caution, the aluminum repair rods melt close to the melting point of aluminum. I was working with a 1/2" thick piece of aluminum and could see areas where it was melting, SS brushed the aluminum and it was taking off melted aluminum, not the rod material.

Just saying, by the time you get the bottom (or lower section) of the block heated sufficiently so the rod flows, the top edge could melt off.

Try practicing on something other than the block, I think you will find it's harder than it looks in the video's.

 

[fire7882]

Re: 90hp block is damaged and I need some advice

Thanks fishrdan, I aided on the side of caution while heating. Could be the reason the brazing rods didn't work out. I practiced on a few smaller pieces of metal and had some success but couldn't get the rod to melt on the block, even after putting it in the oven at 450 degrees and then adding heat with a mapp torch. I decide to go ahead and try the JB Weld repair and hope for the best.

This is a picture of the port side(the good side) after a little resurfacing. I cover the entire gasket surface area with JB Weld and let it harden for about 4 hours. Since it was warm here today, that was long enough for it to get hard enough to sand. I placed a piece of 220 grit sand paper on a marble tile and sanded in a figure 8 pattern untill the inner steel sleeve was exposed. The remaining material(dark areas) filled the low areas.

This is a picture of the second application on the starbord side(bad side). I was still a little low in a few places after the initial try but this side should be done tomorrow. As you cab see, the missing pieces from the outer cylinder sleaves filled in nicely.

 

[HybridMX6]

Re: 90hp block is damaged and I need some advice

Looks like good work, hope it works out well when it's all done and back together. Definitely keep us posted on how the final repair goes and also how it runs once done, could help someone in the future to know of your success or failure, hopefully it's the better of the two.

 

[And-Con]

Re: 90hp block is damaged and I need some advice

i hate to do this, but i will never use it so here goes i have a spare block (you'll find out why shortly) in the pictures it looks like you're running an omc crossflow v4-if not than feel free to disregard this but if you'd be willing to pay shipping from ft myers, fl 33901, you can have it, its out of a 1994 turbojet(same engine as ob's) now i happen to have this block because the po broke off 5 head bolts(i think all on one side but cant recall which) and i got a really good deal of the replacement, (did i mention a really good deal) if you're interested, ill put up some pictures of its current condition, and just apologizing in advance-getting pictures for me takes forever-sorry

 

[fire7882]

Re: 90hp block is damaged and I need some advice

That would be awesome. I'll even pay $20 plus shipping cost for your trouble. I'm still going to get this one running but an extra block would allow me to start a proper rebuild w/ new pistons, exc.... I'll send you a PM

 

[iwombat]

Re: 90hp block is damaged and I need some advice

You'll also want to take a piece of steel roof flashing, or the like and bend it in place around the outside of the cylinder. Then, clamp it in place. Without any backside support the aluminum rods will simply run off.

 

[fire7882]

Re: 90hp block is damaged and I need some advice

You'll also want to take a piece of steel roof flashing, or the like and bend it in place around the outside of the cylinder. Then, clamp it in place. Without any backside support the aluminum rods will simply run off.

I did that but was never able to get the rod to melt. I most likely needed an oxy acetylene torch but went ahead and used JB Weld. Hopefully I will be able to get another block from And-Con and have a fresh start.

 

[aclmvh]

Re: 90hp block is damaged and I need some advice

Hope the JB Weld works. I used it to repair some salt water pitting on the mating deck of my v4 head (outside the cylinder sleeve) and it's worked very well so far. You can seen in the picture the severity of the pitting. Keep us posted.

 

[Cofe]

Re: 90hp block is damaged and I need some advice

If you don't bring it to a professional, Then click on this link, it is the only thing I would recommend other than Cronatron welding rods. http://www.maintenance-welding.com/welding_supplies/?page_id=13

 

[fire7882]

Re: 90hp block is damaged and I need some advice

Hope the JB Weld works. I used it to repair some salt water pitting on the mating deck of my v4 head (outside the cylinder sleeve) and it's worked very well so far. You can seen in the picture the severity of the pitting. Keep us posted.

I think it should work fairly well. Longevity issues may arise but I plan to fully rebuild another motor in the near future.

If you don't bring it to a professional, Then click on this link, it is the only thing I would recommend other than Cronatron welding rods. http://www.maintenance-welding.com/welding_supplies/?page_id=13

Although that looks like a great solution, I already went with with the JB Weld method. It should hold up fine but I'll post here with the results either way.

Thanks again for everyone's help.

 

[fire7882]

Re: 90hp block is damaged and I need some advice

Just a quick update. The power-head gasket kit i bought was missing a head gasket but they sent me one Friday and I should have it sometime this week. I went ahead and assembled the block and just used some gasket material to make a temporary head gasket to protect the mating surfaces. While it was together and before I painted it, I installed the starter and flywheel and ran a compression test. I got 107 on two cylinders (good side w/ proper head gasket) and 110 on the other two (bad side with home made gasket). The small difference could be attributed to the thinner home made head gasket but regardless, I'm super happy with the numbers considering it hasn't even been started, much less properly broken in. If the JB weld repair holds like I hope it will, this should be a strong motor.

I'll be sure to update this thread once I get the outboard back together and finish up my project boat. Now a few pictures.

I painted it gray because I've never been a fan of black engine blocks. Black tends to make leaks and other problems less noticeable.