corrosion city under cooling cover, whats the best way to remove busted bolts

[chum1]

Hello all, just got the lower end installed after re sealing everything on this 77' 85hp, works and shifts great!! The next feat is to fix the leaking spark plug hole, I carefully removed cover and found quite a bit of corrosion, is there anything that can be done to the cover to stop the corrosion?

Also only one bolt came out normal, the others just snapped off ( it was the only way), is there an easy way to remove them?, I've heard of wire feed welding a new nut on them but since that equipment is still on my "wish I had list" I will have to find an alternative

Here is a couple pics:

1st) cover just pulled off
2nd) rebuilt lower end and many thanks, especially to Chris from Australia.

 

[ENSIGN]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

Take the power head to a machine shope and have the bolt holes resized,You will end up doing more damage to the casting trying to drill those bolts out than what it's worth.You could prime and paint the cover

 

[Chris1956]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

Heat the bolts with a torch (Mapp or hotter), and remove the flame and spray with penetrating oil like PB Blaster. As tehy cool they will suck the stuff in. Now use a vice grip or pipe wrench on the bolt studs and see if you can turn the out. Repeat the heat+oil treatment, and try to remove them, when still pretty hot. You should get most of them, hopefully all of them

 

[Chris1956]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

Ok another idea. Look on the block and see if you can drill thru the block and use bolts and nuts to reinstall the water jacket cover. I was able to do that on my '77 Merc il6. The '73 IL4 I had used thru bolts, vs tapped bolts, so replacement would have been easy.

 

[chum1]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

Thanks Chris, yes i could put nuts in behind the block if nothing else, there still is a lot of life left in this thing before it turns to dust, Phil

 

[turbinedoctor]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

I agree with Chris but would add that while using the vise grips and heat to work the bolts back and forth as you are removing them, this helps to move some of the penetrating oil into the threads still in the block. I was able to get all of mine out that way.

As to the corrosion, it's not that bad. Just keep flushing it when you come back from salt water running. I have seen alot worse then that.

 

[chum1]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

Here is the fix on water jacket bolts: I only snapped 11 of the 12 bolts, hows that for luck?

It took a whole Sunday to fix this, a lot of effort just went into making the area accessible, had to pull some front accessories off the engine so the engine lower cover would come down enough, 6 of the broken bolts came out on the top side by using heat, pb blaster and vice grips.

1st pic) I carefully ground down what was left of the bolt flush with the case with a die grinder, then started out with a sharp 3/32 drill bit,then step up with a 5/32 and so on. The broken bolt extends in the case about an inch so its a slow and careful process, on this engine only about half are accessible from the back the rest are just holes bored straight into the solid metal case.

2nd pic) Discovered a nice little helicoil kit at shmucks for under $20.00, now there is a bargain, comes with tap, install tool and helicoils.

3rd pic) here is how these little jewels work after the hole is to its final size, careful not to install at an angle which is very easy to do.

4th pic) here is the finished product, I think i installed six helicoils, after this pic I ran a flat file on the surface of the case to smooth out all burrs and pry marks.


Now waiting on parts, found a water jacket cover on ebay for $15.00, ordered new gasket and will probably seal it with a thin coat of aircraft fuel tank sealer called proseal.

 

[sschefer]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

If your still looking to get rid of that corrosion you can remove the stuff in the cylinder tub with a wire brush on a electric drill. The stuff on the cover can be blasted off with 60 grit crushed glass or 70 grit Aluminum Oxide. Once you have all the corrosion off you should follow up with 80 grit glass bead. After that clean it spotless with de-ionized water and Dawn dishwashing detergent then apply Alodine 1201 to convert the aluminum and give it some corrosion resistance. If you object to the gold color of 1201 you can use 1500 instead but it doesn't give as much protection.

Sounds like you got away fairly clean with the bolt problem. If it happens again, consider taking it to a shop with a EDM. I've had it done and the results are amazing.

 

[chum1]

Re: corrosion city under cooling cover, whats the best way to remove busted bolts

Thanks SShaefer for the expert advice ( been reading on your frankinmerk), I will be using this engine on fresh water so not to terribly concerned with the corrosion problem, forgot about the alodine used to use that when i worked at Mcdonnell Douglas back in the 80's.

I figure I can make this into a reliable engine if I can fix the 30+ years of monkey rigging, its been a good project, just hope i can get this boat out on the water soon.