Jump to content

Engine block internal rust


Recommended Posts

So I decided to tear into my spare '36 Pontiac flathead 6 this weekend to see what kind of condition it was in. Lots of good news in terms of wear, but the water distribution tube that runs the length of the block is broken off behind the water pump and the remains are very rusty and very attached to the block itself. There is very little room to work with - it's a ±1" x 2" slot – although you can get at both ends. Apparently the days of immersing a block in toxic solutions that could do the job are over, so I'm wondering what some other remedies might be. Anyone have any good ideas how to rescue and otherwise very solid engine? I've thought of spraying PB Blaster in there and constructing a scraper shaped to fit, but I wonder if there is an easier way?

Any advice much appreciated!

Link to post
Share on other sites

Look at the threads on electrolysis rust removal as well as molasses rust removal.

Electrolysis works quite well and uses a chemical reduction process on the iron oxide. This should change the rust to either iron or iron magnetite, both of which can be brushed off with a wire brush.

Molasses mixed 1:9 with water will work to remove rust as the molasses contains phosphoric acid which in turn will the iron oxide into iron phosphate which is easy to brush off leaving a nice surface below.

You can also buy Phosphoric acid at your local home improvement store. My Home Depot has a product called 'Phosphoric Prep and Etch' by Kleen Strip. You can spray this on (wear a good respirator), let it soak a bit, clean and repeat until you like it.

For all procedures, don't be fooled by the rust turning black quickly. You have to get that stuff off and there is usually rust underneath it. You will have to repeat a couple of times. That said, I've done the above procedures multiple times and they work. I prefer the electrolysis method as once you have the system built it is easier and quicker. It will also get rust out of areas that you can't reach.

Link to post
Share on other sites

The water tube on my Renault was like that. Driving it moved it a bit but the pieces would then jam up at each of the openings along the way. So I cut those away with pliers and a torch, depending on how bit, solid, etc.

The hard thing is making a new tube the right diameter, thickness, and holes in the right places. I found two drawings on line, but they were different. So i figured out which was right by the dimensions I had, and asked on line to find which end goes at the pump.

There wasn't really a way to dissolve a steel tube in an iron block.

Link to post
Share on other sites

If you stand the engine on its back end you should be able to fill the water jackets with your favorite rust eating solution (if the head is on tight).

Once you get it cleaned out put in your water tube, wonder if you could find a NOS one from one of the old car specialists?

Don't forget to take out the core plugs, clean the water jacket, and replace the core plugs before putting in the new tube.

Link to post
Share on other sites

That is going to depend on what is sealed and not. You don;t want those solutions getting into cylinders, water pumps, ail pump, etc. And I presume it is like mine, where there are various holes along the tube.

post-56369-143139081484_thumb.jpg

Link to post
Share on other sites

[ATTACH=CONFIG]144063[/ATTACH]I built this puller to extract the water distribution tubes from Auburn (Lycoming) engines. A nut is welded on the end to accept a slide hammer.

If you can borrow a good water distribution tube from a friend to get the hole spacing just right, it will save a bit of agrivation.

Link to post
Share on other sites

IMO if you are going to have to oil pan off might as well do oil pump gears and bearings. and if you are going to do that might at well have the block hot tanked and the crank cleaned and checked for balance. and since you are doing stem seals might as well have the head hot tanked too. i know it sounds over the top, but a clean engine is a happy engine, and having it all apart will break loose deposits that can clog up the strainer like happened to me. i took the short cut and just threw it together, painted and drove and lost oil pressure from dirt buildup on the strainer not even a month later. short cuts = short life. as for the rust, 2 words. bead blast. :cool:

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...