The Stovebolt Site Forums The Shop Area Engine Shop Cracked 235 block! Repairable?

I have a 5 to 6 inch crack running horzital on the lower left side of my block it is pretty much in the center of the block. I do not have any water in my oil.
Is this repairable?

If you are wanting a temporary fix, I patched a very similar crack on a 53 GMC with JBWeld and drove for about five years. It was just starting to dribble when I sold it to a guy who wanted to build a hot rod. drain the block and make sure the surfaces are good and clean.

What kind of driving were you doing? Daily or causual?

I've done the same thing with JB weld, but mine has started dribbling again already after two years. But the truck is driveable, so what the heck. Search the site here for JB weld you will find some good tips. When I did mine, after draining the block I even hooked my shop-vac up to the radiator while applying the JB weld, it sucked right into the crack. Not that it helped in the long run.
Some other guys here will mention different welding patches. Do a search and you'll find both positive and negative opinions.
Whatever you do, drill small holes at the end of your crack before you patch it, to keep the crack from spreading.

Contact http://www.locknstitch.com/ for their do it yourself permanent cast iron repair kit. Comes with a video how to and is a professional quality technique, been in business for many years.

It was mostly casual. weekend hardware and dump runs usually. The truck was too slow to drive to work daily. That was when I did the interstate drive to work.

If you have a cracked block and just want to drive it, a fix will work. Even if it leaks a little, it doesn't hurt anything if you don't get coolant into the oil. However, I would never spend money on doing machine work on a repaired block. There are too many good ones around.

Hey thanks guys. I think i'll JB weld it and start looking for another block. Another quick question what other inline 6's use the same stuff as the 235? i.e. head, exhaust/ intake manifolds and distrubtor.

The 261 is very similar

ryan,

If you are referring to a 54 235 truck engine, most parts are interchangeable with 54-62 235 truck engines and, to a slightly lesser extent, interchangeable with a 53-62 235 car engine. As 38 Canadian says, a 261 engine is very similar but there are some significant differences in comparison to a 235 (also, depending on the year).

If you find an engine, post its casting codes here and people will advise you about the differences.

If you are going the JB Weld route (temporarily, perhaps), clean the outside of the crack very thoroughly with a wire brush. At the ends of the crack, drill an indentation into the block. With a grinding point, groove out the crack. Then, apply the JB weld.

Maybe other people who have tried JB Weld on a small crack in the block will also offer advice (unfortunately, I had to do this about 12 years ago on a 261 block - it is still not leaking - I am lucky on this one).

I've done JB Weld on a cracked 228 block about 15 years ago and I still see that engine regularly. When I did it everybody told me not to, but the darn thing keeps on running.

54Monster

I have exactly the same issue on my 3100 235 block.

Lower left just aft of the manifold

Little pipe comes out the side of the block near this leak.....don't know what the pipe is for.

Seems the leak is a little higher up

Prob 2 inch crack

Looks like is an old crack as the block is rusty below and aft,of the crack.

Some JB weld on order and some K seal radiator/block sealer

The area is a bit hard to get to.....just Gotta do what I can I guess to clean it all off before applying the JB weld

Thought I had nearly finished the refurb.....

But hey, wasn't to be I guess.

Philip

You are on the right track in my opinion. That crack is common and not the end of the world. If fact it shouldn't be a point of much concern at all. These engines come with a radiator pressure cap of between zero and 4 pounds, which isn't much, so you won't have to worry about your patch blowing out.
Carl

Hey all. Im nearly done with my 11 year rebuild of a 1955 1st series 3100. However now my rebuilt engine has shown a crack right below the head gasket behind the manifold. Can this be welded? I can provide pictures of where the coolant/rust is leaking from.

I have had good luck using Marine-Tex. It's an epoxy like JB Weld but geared toward use around water. A bit pricey but very good. This 1940 Pontiac flathead six has been going for eight years with no sign of leakage. First media blasted, small groove along crack, roughed up with 24 grit one inch to each side of crack and then put about a 1/16 layer of the Marine-Tex along two inch wide prepared surface. Didn't take a chance with a drive in freeze plug but used an expandable rubber one which is replaced every couple years. Sorry no finished photo.

[img]https://s31.postimg.cc/gopjyjagn/40_Pontiac_engineand_trans_002.jpg[/img]

Here's a trick for hiding the repair- - - -a piece of 40 grit sandpaper pressed into the patch material just before it cures fully will give it a surface roughness almost identical to cast iron. Once the block is painted, the repair almost disappears.
Jerry

I "repaired" a small crack near that location on a 1960 261 with JB Weld - over 10 years ago.

No leak.

One thing people don't consider (but should) is Harris Stay Brite solder. I like JB Weld and use it all the time, but I can promise you this will repair cast iron if you clean the crack, use their flux and are able to heat the area to about 450 degrees. Most of the time you can do this with a MAPP or Propane torch. I've repaired plenty of cast iron, mild steel, even stainless steel with it. Note: it isn't cheap but I'll bet you'll find uses for it the rest of your life. Also it is lead-free (silver bearing solder) so you can use it for plumbing.
Jon