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I apologize if this has been answered already, I was not able to find a thread regarding this. I noticed after getting my engine back from a rebuild that the water pump ear is cracked on my front iron (see attached pics). I know best case scenario is to find a welder that is proficient in cast iron work or buy a new iron but I really don't want pull the front iron after it was just rebuilt. My gut is to hondabond (or equivalent) both sides of the gasket and pray it holds...I believe torque value for that bolt is 13-20ft lbs.
What are your thoughts? Run it as is and risk having to pull the engine again or bite the bullet and fix it properly now.
If it was me I wouldn't worry about it at all. Those bolts are over kill as is. Your water pump isn't going to run away.
Worst case it cracks then the other three bolts will hold the pump fast. Not only that but looks like the crack is heading up; use a longer bolt and a nut on the end if it does crack.
Welding would be my last recourse. Not only could it cause more cracks it could warp the iron a little... no bueno.
I'd guess that is shipping damage if you sent your engine out for rebuild. Corners take hell in a box.
I'm leaning towards that as well. I plan on running an electric water pump with an adapter anyway so there won't be much weight pulling on the ear/fastener.
Maybe some JB Weld or similar around the circumference to try and reinforce it. If you do spring a leak from that area you'll know it-- pray no coolant makes its way down to a hot turbine housing.
Another reason to run zero pressure Evans NPG+
Also, note (and this is a positive in your situation) that threaded hole takes a long stud which is tightened by a nut.
My opinion on JB or any other epoxy applied on the outer surface in tension in this situation is that eventually it will crack and fail. Epoxies are great in compression, shear, and tension, but not strong enough in tension to survive where a small cross section of epoxy is trying to prevent a highly loaded crack from opening.
So, IMO, it should be left alone or reinforced mechanically.
Thank you all…I’ll see if I can find anyone local that’s comfortable with cast iron
Originally Posted by Qingdao
....Welding would be my last recourse. Not only could it cause more cracks it could warp the iron a little... no bueno...
My background includes a fair amount of stress and failure analysis, so:
The crack shape and location means to me that it was caused by upward vertical stress inside the hole. So my thought on the reason it cracked in the 1st place is that someone put a large upward bending force on that bolt.
Considering that this just holds the WP on, as long as there is no upward force inside the bolt hole, it is not likely to break off. If I was facing this, the suggestion for a long bolt extending out the back with a hardened washer and a nut (or to make it look professional, a plated flange nut with no washer) pressing on the back of the ear is what I would do. This should prevent the crack from growing, because you are preventing the ear from being bent back.
You could with that solution also (gently) drill out the threads in the ear so that the slope of the threads tightening wouldn't be there to stress the hole/crack upward from the inside, and the nut at the back would provide the clamping force.
^ This is what I would do in this situation. Have tried to have cast iron repaired before, the only time it worked was when the part was heated in an oven and welded with the metal in a warm/hot state. Cost $$ but the part was basically irreplaceable so no choice.
...the only time it worked was when the part was heated in an oven and welded with the metal in a warm/hot state. Cost $$ but the part was basically irreplaceable so no choice.
What you said is what I've always heard is necessary - getting the piece to be repaired very hot so when it cools, everything is cooling at the same time, minimizing the possibility of creating high internal stresses that could compromise the repair. Heating a large C-I ***'y hot enough to get the weld/braze to work properly would be likely to overheat anything non-metal in the ***'y and ruin it (coolant and other seals come to mind here).
Update: Sent the pics to a cast iron guy and he was also concerned about properly getting the filler to wet down properly into the crack without having the front iron off the stack. He recommended pulling the front iron so he can get it to temp in an oven and keep excessive heat away from the seals.
Ultimately, I just laid a thick layer of JB weld over the top of the ear and down the sides to hopefully give it support. Thank you all for the input!
Update: Sent the pics to a cast iron guy and he was also concerned about properly getting the filler to wet down properly into the crack without having the front iron off the stack. He recommended pulling the front iron so he can get it to temp in an oven and keep excessive heat away from the seals.
Ultimately, I just laid a thick layer of JB weld over the top of the ear and down the sides to hopefully give it support. Thank you all for the input!
Good on not trying to weld or braze. IMO, the JB Weld won't really help, but since I didn't think the crack would expand anyway, it won't hurt anything, either.
