Rusted block, repairable?
 

Hello.
I just got a B engine I know who need to be sleeved but what about this pitting on the valve seats.

Do I need to worry about this?

Regards.

Re: Rusted block, repairable?
 

I would be concerned about the valves not sealing with that degree of pitting. You can get away with pitting on the head gasket surface because of the crush, low compression, and the spray many use.

Since the block needs to be sleeved, it has probably been decked several times which means it may or may not be a good idea to deck the block again to get rid of the pitting.

Also, B engines are notorious for cracks, so be sure to give it a thorough inspection.

Re: Rusted block, repairable?
 

usually pits like that indicate a crack somewhere in that cylinder. You can install new valve seats to solve the pitting, however I would magnaflux the block to see if there is a crack in that cylinder area.

Re: Rusted block, repairable?
 

I'm not sure how far a person can go when shaving the deck but it would likely need a good skim of the surface to insure good sealing. Valve pockets can be counter bored to install replaceable seats. The more machine work done, the higher the cost.

Re: Rusted block, repairable?
 

get another block..........

Re: Rusted block, repairable?
 

Why do you say it needs sleeves?
with that rust there is a good chance that there is a crack through the valve seat toward the cylinder ---this crack is common with "B" blocks
If not cracked a replaced valve seat will fix the rust , the other pitting in the combustion chamber area won't matter as long as it doesn't go under the gasket surface

Re: Rusted block, repairable?
 

https://i.imgur.com/ASYA73K.jpg?1

this is rusty :).Im actually going to try and save it. B blocks have varying casting thicknesses,they are way more prone to cracking and machining issues than an A block.Some B blocks are thick in the valve seat and pocket area,some are thin.I have one with 21 crack pins in the deck..step into the machine shop lightly,magnaflux and sonic test prior to committing to it

Re: Rusted block, repairable?
 

A/B blocks can be safely bored to 4" (.125" oversize), many were bored to 4.062" by racers back in the day. Your rust indicates water entered from somewhere, maybe just the head gasket?

Re: Rusted block, repairable?
 

Do you know any history of this engine? Was it stored outside or in a leaky shed for years? You should be able to find the blueprint dimension for the distance from the pan rail to the deck surface, which will tell you how much the block has been resurfaced, if any.
How deep are the pits in the cylinder wall? It may clean up without sleeving. B blocks no longer grow on trees so if there are no fatal cracks either you (or the next owner) should save it.

Re: Rusted block, repairable?
 

Drawing A-6015 specifies that the dimension from pan rail to the top of the cylinder block is 11.500/11.505 inches.

Re: Rusted block, repairable?
 

Thanks for all your replies. What's the issue of shaving the deck too much, too little material left or piston clearance. Obviously it stay outside for a long time and the pitting will compromise sealing, two cylinders are pitted too that's why it needed to be sleeved. A crack have been fixed already and the block suppose to have been pressure tested.
I don't think it have been shaved before, you can see a "M" stamped on the surface at the top of the upper cylinder and it's still very clear. I will try to measure the pitting but I will remove the remaining rust with electrolysis before.
Best regards.

Re: Rusted block, repairable?
 

If you decide not to use, I would give it to someone else to try an save.

As mention earlier, there just aren’t a lot around.

Your trash is my treasure.

Enjoy.

Re: Rusted block, repairable?
 

Yes the more shaving you do the more piston ping becomes a problem as they get closer to the head. If it has not been shaved before it is worth doing it.

Re: Rusted block, repairable?
 

If I were in your shoes, I would find the best antique engine rebuilder in your area.

If it were in my shop, I would treat it as a rare or 'one-off' engine where replacement was not an option. Terry is correct on the pan to deck measurement however if we did not have a measurement (-and I would do this anyway on this particular block) I would use a sonic tester and map out the areas that are pitted to know the thickness in all the areas. If I recall correctly, the Ford print called for 0.375" deck thickness, and as long as it measures 0.350" or greater after a surfacing, you are probably OK. If not, then I would use a TIG and something like Muggy Weld 77 to fill the pits. Preheat the block, fill the larger pits, stress-relieve and resurface. Not going to be cheap, but the repair would be solid.

Re: Rusted block, repairable?
 

What size is your bore now? It will likely clean up with another .030", and not need sleeving. If there is no sleeve, it won't cause any problems.

Re: Rusted block, repairable?
 

Model "B" engines can quickly become "money pits" as the more you do to them the more they seem to require.

It is difficult to give an assessment based on only a partial view of two of the 4 cylinders.
I would guess you are showing us the worst area of the block. If you still have close to 11.5" total block height, a light decking of the top, just enough, to provide a good surface for the gasket would be required. Don't try to eliminate all the pitting in the combustion chamber as it is not necessary. The bad pitting in the valve area could be worked around by installing oversize valves and with the light decking you should be good. The increased diameter seat cut would get you to good metal. If it were my block, I would use larger valves, keeping them set high, before risking cutting in hardened seats, or cutting deep for standard size valves.

I used this method on two "B" blocks with bad pitting as you show. They both are not high HP engines and are still in service.

To counter the previous experience, I also had a badly rusted "B" I rebuilt for myself. I decked both the top and manifold surfaces to fully clean it up. I also needed to install three helicoils adjacent to the decked manifold surface. (More lost metal!) It failed at about 15,000 miles. The removed metal from the manifold surface weakened the block, enough so that it cracked at two of the head bolt areas with helicoils into the adjacent water jacket openings. I should have left the manifold surface alone as the gasket would have sealed it. Lesson learned, the hard way about removing too much metal and about money pits!
Good Day!

Re: Rusted block, repairable?
 

I don't have the perfect tool to measure the damage but shaving .030" will remove most of the pitting for a proper gasket seating and I have 11.5 of total block height. My idea was to install a high compression head and the Brumfield 5.2 have extra material to be shaved to 5.9 so no problem for clearance I think. The bore is actually 3.890" but the pitting on one cylinder is deep, probably .050" The engine came with the sleeves and pistons anyway. My main concern is the metal remaining around the exhaust valve and port, approximatively .300" at the thinnest point. The lobes on the camshaft are pitted also.:(

Re: Rusted block, repairable?
 

And this corrosion on the exhaust port. It will leak?

Re: Rusted block, repairable?
 

B block casting variations are common,some decks are thick,others are thin.Sonic testing is very touchy and as a result isnt reliable unless performed correctly which is very time consuming.I have a B block with 21 crack pins in the deck.Most of the pitting in the combustion chamber is ok,your concern is the fire ring area of the headgasket.Way more reliable to pressurize a late 31 A block than to deal with a B block

Re: Rusted block, repairable?
 

At least on Model A engines, pitting is very forgiveable. I was able to spray copper sealant on my head and exhaust gaskets and have never had a problem with pitting there. Of course the pitting was not extreme and I cleaned the surfaces with a sander.