Corrosion, corroded aluminum block at steel cylinders. How to seal head gasket? Pics.

[dazk14]

Johnson 87 big bore v-4 140 HP. Compression a little lower on one bank (93 vs 109 psi), so I pulled the head.

The pics will show some of the aluminum block has corroded away. The steel liner is perfect.

Has experience shown you that a good properly torqued/re-torqued head gasket will work??

I've had no problems with similar corrosion on smaller motors.

The gasket was NOT leaking at those locations. Please note the second band of brown (right most) is light rust in the cylinder above the top ring.

What is the best system to remove corrosion clean up block?(Short of a machine shop)

I never use sealers on head gaskets, but I'm VERY open to suggestions.

Any help would be appreciated. The owner cannot afford a repower.

 

[Daviet]

Re: Corrosion, corroded aluminum block at steel cylinders. How to seal head gasket? P

When I used to work on salt water engines in south Florida I seen some worse than that. I would install a new head gasket and they seamed to seal up ok. The seal surface is the steel liner anyway. Make sure your head is flat.

 

[dazk14]

Re: Corrosion, corroded aluminum block at steel cylinders. How to seal head gasket? P

Well, that's encouraging. A special solution to removing the salt to get the best seal possible.
I usually just use a scraper.
Thanks

 

[Daviet]

Re: Corrosion, corroded aluminum block at steel cylinders. How to seal head gasket? P

Anything that will remove corrosion, scraper, emery cloth or anything you have. Just make sure the head is flat.

 

[dazk14]

Re: Corrosion, corroded aluminum block at steel cylinders. How to seal head gasket? P

Anything that will remove corrosion, scraper, emery cloth or anything you have. Just make sure the head is flat.

Thanks DavieT, sounds good. I think I'll send the heads out to the machine shop to get them surface planed and clean up the face ~.003".

I'll need to haul out the factory manual and check head machining limits.

 

[wilde1j]

Re: Corrosion, corroded aluminum block at steel cylinders. How to seal head gasket? P

The heads only need to be surfaced, not milled. You can do it yourself with a piece of heavy flat glass or other absolutely flat surface and ~ 200 grit emery paper. Use a spray 3m adhesive to fasten the paper to the glass, move the head slowly in figure 8's. You will be able to easily tell when it's flat by examination. Of course check for flat first ... you may not need to do anything.