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Decided to test drive the 46 before we replace the engine (cracked block). Only noise was the throw out bearing. Shifted good and the motor ran great. Shame we have to replace it. Only other problem was the charger guage showed discharging. Next step is to replace the engine.

If it runs good, why not repair the crack?

Before you replace the engine confirm what serial number is used on your title...many States back in the day used the engine serial, not the chassis...

Mike B

Thank you for the info. I don't believe N.H. requires the engine number but will check.

NH does not require engine numbers. The previous owner had a rebuilt that he had bought and he offered it to me.

If the 46 is running the original cooling system, it's a "zero-pressure" system. As long as the cracked area of the block is cleaned thoroughly, a coat of "Marine Tex" over the crack and an inch or so beyond it in all directions, it should contain any leaks. If you press a piece of 40 grit sandpaper over the repair as it's curing, the texture of the patch will be almost exactly like the surrounding cast iron.
Jerry

My comment above has nothing to do with current law and whether NH requires the engine number on the title. It has to do with what serial number (engine or chassis) the first State that titled the truck way back when used...prier to the mid 50's may States used the engine serial number when processing titles. Just confirm your paper title serial number matched something on the truck other than the engine number before you scrap the engine, it will save you a lot of heart burn when you go to sell it.

Mike B

Not to old yet I'd take a shot at that crack,as was suggested,don't know about marine tex but you could "sew it up" with iron plugs or use epoxy,can use cast iron 1/8 inch pipe plugs,probably best to use those smaller tapered plugs but they take a special tap. Fixed a cracked head with epoxy 15 years ago still fine,think it was really a sand hole.

Depending on where the crack is, it can be fixed. I had a cracked cast exhaust manifold in a bolt hole location and tried a few welding solutions. The fancy nickel .030 MIG wire did not work (did not stick to parent iron). Ended up using regular mild steel .024 without pre heating. Grind the crack, hit a dot of MIG, let cool, grind. Repeat until crack is filled I was able to torque it down without any cracking, but have not tried a heat cycle yet. Just my .02

Kevin, did you preheat the manifold before using the nickel wire? I just bought a spool of .035" nickel wire, but I haven't tried to weld anything with it yet. I've been stick welding cast iron with nickel rod for 40-something years.
Jerry

KevinW Had good manifold repair using 309 3/32 stick stainless,welded heat riser holes shut.309 is a little pink rod that runs real smooth.

I don't have a stick welder, just MIG. I used a propane torch and temp gun to get area up to 350-400 deg as the instructions show. Nickel wire still did not stick to parent metal From what I read the preheat is to do a slow cool down which helps to prevent cracks. I figured not allowing the manifold to heat up a lot (usually from continuous welding) would also help with crack prevent. Seemed to work, but I have not installed on a running engine. Bunch of projects in the wings

Did you grind a V groove along the crack, and take all the surface rust down to bright metal for at least 1/2" or so on both sides? Rusty cast iron is almost impossible to weld (or braze). Getting a good bond on the initial pass is essential. Once that is done, plain old 6011 all purpose steel rod can actually be used to build up secondary passes. Weld a 1/2" long bead, peen for 5 minutes for stress relief, preheat- - - -weld- - - -peen- - - -"rinse and repeat". Then bury the part in a pile of sand overnight for a slow cool-down.
Jerry

Kevin W In another life I learned to cut exhaust manifolds into 2 pieces grind for a good fit weld with 309 stainless. This was to fit my first 53 3100 v-8 truck,ran a long time. Now it wouldn't work on just cracks,had to be 2 pieces.

Not to old yet Did you get your cracked block fixed,never did hear yet ??? They seem to suffer down on the left by oil pressure fitting,I think radiator sludge might hold the anti-freeze back then it can freeze in powerful cold,specially if it's had water in it like for summer !You know you often have to help the block drain get open so it can drain.

Decided. To put this one to one side for now. Found a person in Milford, Mass, Frank Cassy, that I am told is excellent. If the engine I just got doesn't work I will try him. Thank you for your imput.