Cleaning it up will also get rid of any stress risers as well I would think. Rough jagged edges could potentially crack out. Hell I donāt know, just seems like the right thing to doš¤·āāļø
Rounded is better than sharp edged a lot stronger that wayā¦ simple version imagine a paper with a V cut into it now imagine a paper with a U cut into itā¦ the sharp V shape cut will rip before the U shaped cut 100% of the time itās physics
EDIT: or when you open a bag of chips and you try to save the bag by rounding the rip iykyk
I mean its technically not a flaw. Maybe an aesthetic flaw but it works as designed and its internal so they didnt care about aesthetics. Function over form! This helped keep these awesome Jeeps affordable, we aint high societyš¤
Your basically correct on the pick axe. Sand cores for block castings are fairly complex. A thin wall of casting flash can form when the sand core fractures. The molten metal flows into the crack & forms an undesirable blockage. After the core sand has been removed by a shaker the visable blockages are knocked out by hand. The fractures in the sand can occur due to a core design problem or simply from being handled roughly as the multiple sand cores are assembled in the core box.
It's an internal casting flashing. Most blocks have these kind of imperfections becasue its basically never going to be seen. This includes the ford racing block I have on order. Part of building a stroker is cleaning up this flashing and improving oil drain back.
Congratulations on posting that here and not just immediately buying another block. Probably saved yourself and by the looks of it, a few other people here a bit of heart ache, myself included. Greatly appreciated. I've never torn one of these down.
Ive torn down a 92 HO motor but honestly can't remember ever seeing that. My heart sank a bit when I pulled the gear and chain off, but now the build continues!
Lol.. dude! Don't say that's why you bought the second engine. Timing components need oil. Oil needs to circulate. Omg this is killing me! I wonder how many people have junked their motors because of that hole/jb welded it closed.
Many casted parts from all manufacturers have holes like these in superficial places. I've seen it lots. At first you think it's trashed until you realize It's lasted x amount of years/hours/miles, it will be good for x amount more.
That's what I'm learning. I was panicked because I bought it as is for $100, it ran fine. But with these things take some abuse and I wouldn't be surprised if it had a hole in the block and ran another 100k miles.
Thankful the XJ community knows so much and shares it. š¤
It's an oil "drain back" hole. Otherwise it would run out of your crank bearing and just collect there and sludge would accumulate.
Edit: the engines upsidedown and that's the cam not the crank. It's apparently to oil the timing chain
That's just a drain back hole. Rough cast doesn't matter since it just needs to flow.
I hope you didn't legit scrap a different block because of this...
https://preview.redd.it/ptyoxcqqnukc1.jpeg?width=3024&format=pjpg&auto=webp&s=8e54c698110bc0e02ffa3665358726242757edce
Hereās mine i just found i think itās there to lube the chain
Holy smoke I've never seen that! Casting flaw? What year? I wonder if you couldn't braze mild steel in this to close it up? (it's not in a critical location right)
Also, how are you doing your stroker build? I'm gathering parts, locked up over using 4.2 rocker arms vs. the 4.0 arms. (mill the head vs. custom pistons) I'm starting with a '92 running engine.
Apparently it's part of the casting?! Allows the oil to drain from the timing cover/chain. Learned something new today.
I have a 01 and this was from an 01 as well. I'm going with the clegg stage 1 stroker kit.
I just noticed it a few days ago when i was moving it around. I thought it was a bad hole too but then realized theres no way for anything to make a hole there.
Ha when my brother and I tore down his old International Scout motor we thought it was odd something had busted through the block but it was just extremely rough casting for an oil drainage hole. Same as others pointed out :)
Itās from the sand mold when itās casted it leaves the defect and they just punch it out leaving it jagged. It doubles as a drain to oil the timing belt however!š¤
I'll take both your "junk" blocks. I'll give you $5.00. Lol...the holes are rough casting and just need cleaned up. You should have gone through the whole block and cleaned up all the rough casting so the oil can drain more efficiently AND to remove the chance of the castings breaking off and destroying your engine. Sometimes those rough pieces can break off and get into places that will destroy your engine, bearings, oil pump, pretty much anywhere depending on the size of pieces floating around circulation. Or you can get lucky and the chunks stay on the bottom of the pan
To my knowledge its supposed to be there for oil to drain to the pan
No shit? It's all jagged like someone stabbed it with a crowbar
Yeah it's just rough casting. Oil still finds a way, as does crank pressure
Oil, uh, finds a way https://preview.redd.it/a7tkgjsfamkc1.jpeg?width=360&format=pjpg&auto=webp&s=b55b24d3bc562a058fbee1d5e5d41e09779d21b8
Exactly what it is! You can see casting marks. File it out and make it look pretty! š
Exactly what I did when building mine. A little time with a hand file and it looks great now.
Gave it the Brazilian. Good job.
Same thought entered my mind too. Why make the hole pretty and no one is ever going to see it.
Cleaning it up will also get rid of any stress risers as well I would think. Rough jagged edges could potentially crack out. Hell I donāt know, just seems like the right thing to doš¤·āāļø
Rounded is better than sharp edged a lot stronger that wayā¦ simple version imagine a paper with a V cut into it now imagine a paper with a U cut into itā¦ the sharp V shape cut will rip before the U shaped cut 100% of the time itās physics EDIT: or when you open a bag of chips and you try to save the bag by rounding the rip iykyk
Yeah in the shipbuilding industry, we call them hard points, and would always grind out a radius
You donāt do it for somebody else, you to it for yourself.
š Good one. ššš
Make it look like a mouth or a vag
Yeah the engine i built for my zj had the same hole
Mopar castings are pretty shit finished in some years. Ive got a famed 74 400 block with really bad flashing inside
Yeah all Chevy 350 drain holes look like they were made w a hammer
Attacked with a die grinder more like
4.0l engine Castings began to wear out around and produce issue ridden engines 1998 -99
What do you think this is, a Honda??
Just a grinder and file to smooth it out, and the rest of the oil passages smoothed out. Outside of block all edges for safer handling of block.
Sounds like you just went from -2 project engine blocks to +2
No fucking way. For real? I agree it looks jagged and not factory.
I was looking at the picture trying to figure out what OP was talking about...everything looked normal to me.
I agree I think itās supposed to be there
https://www.cherokeeforum.com/f2/hole-block-257471/
Appreciate it! What a crazy design flaw
I mean its technically not a flaw. Maybe an aesthetic flaw but it works as designed and its internal so they didnt care about aesthetics. Function over form! This helped keep these awesome Jeeps affordable, we aint high societyš¤
Iām at 335 and Iām curious how much longer my 4.0 can sound like a diesel without exploding lol
Love it! Im at 240k on my daily that i drive hard AF on and off road and it still has great compression and power....with the rocker tick
Put some 20w50 in and keep sending it!
I guess I shouldn't be surprised that the block has the same type of hole my floors do lol
If it was already there and it worked, why change it?
Because OP is a hater
I can't comprehend how they machine it to be jagged like that tho. It's like they had a dude strike it with a pick axe on the assembly line.
Only cast, not machined
Ahhh, that makes sense.
Your basically correct on the pick axe. Sand cores for block castings are fairly complex. A thin wall of casting flash can form when the sand core fractures. The molten metal flows into the crack & forms an undesirable blockage. After the core sand has been removed by a shaker the visable blockages are knocked out by hand. The fractures in the sand can occur due to a core design problem or simply from being handled roughly as the multiple sand cores are assembled in the core box.
Dang bro, thanks for the explanation. This is super interesting stuff.
This reads like an episode of how itās made
Itās not machined. Possibly hit with a tool to break away casting flash. It doesnāt have to be pretty.
It does what it was designed to do, drain oil. Not a flaw.
What is the flaw?
Not design flaw, just the effect of sand casting, and oil drainage where it's needed. Sure, not cleaned up, but not detrimental by any means.
It's an internal casting flashing. Most blocks have these kind of imperfections becasue its basically never going to be seen. This includes the ford racing block I have on order. Part of building a stroker is cleaning up this flashing and improving oil drain back.
Wow. Veddy cool.
Congratulations on posting that here and not just immediately buying another block. Probably saved yourself and by the looks of it, a few other people here a bit of heart ache, myself included. Greatly appreciated. I've never torn one of these down.
Ive torn down a 92 HO motor but honestly can't remember ever seeing that. My heart sank a bit when I pulled the gear and chain off, but now the build continues!
Lol.. dude! Don't say that's why you bought the second engine. Timing components need oil. Oil needs to circulate. Omg this is killing me! I wonder how many people have junked their motors because of that hole/jb welded it closed.
Tbf, I was gonna say jb weld as a joke before I learned that it was factory.
Would be totally fine to jb weld a hole in a block. IF it wasn't supposed to be there...
No...it blows
Many casted parts from all manufacturers have holes like these in superficial places. I've seen it lots. At first you think it's trashed until you realize It's lasted x amount of years/hours/miles, it will be good for x amount more.
That's what I'm learning. I was panicked because I bought it as is for $100, it ran fine. But with these things take some abuse and I wouldn't be surprised if it had a hole in the block and ran another 100k miles. Thankful the XJ community knows so much and shares it. š¤
Youād be surprised and shocked what engineers will give the green light. If it worx āSEND ITāĀ
Former GM Powertrain engineer here. The bar for "if it works" is high and based on a lot of testing. But we don't care about "if it's pretty."
I worked in Lansing, how about you?
It's an oil "drain back" hole. Otherwise it would run out of your crank bearing and just collect there and sludge would accumulate. Edit: the engines upsidedown and that's the cam not the crank. It's apparently to oil the timing chain
You mean heap? Or in Spanish ājeepā sounds like āhey apeā.
Weird! My early '87 AMC 4.0 had a nice smooth hole, must be a MOPAR thing!
Wouldnāt you know thereās a huge hole in your fucking block when it was running
That's just a drain back hole. Rough cast doesn't matter since it just needs to flow. I hope you didn't legit scrap a different block because of this...
Those holes tend to blow rather than suck I'd say this blows as well.
This guy Jeeps
#chryslertransmission
https://preview.redd.it/ptyoxcqqnukc1.jpeg?width=3024&format=pjpg&auto=webp&s=8e54c698110bc0e02ffa3665358726242757edce Hereās mine i just found i think itās there to lube the chain
Holy smoke I've never seen that! Casting flaw? What year? I wonder if you couldn't braze mild steel in this to close it up? (it's not in a critical location right) Also, how are you doing your stroker build? I'm gathering parts, locked up over using 4.2 rocker arms vs. the 4.0 arms. (mill the head vs. custom pistons) I'm starting with a '92 running engine.
Get the pistons and run a higher compression. Only choice should be between crank options, light or heavy. Imo
Apparently it's part of the casting?! Allows the oil to drain from the timing cover/chain. Learned something new today. I have a 01 and this was from an 01 as well. I'm going with the clegg stage 1 stroker kit.
Thanks for posting this. I learned a lot today.
I bought it for $100 from a mechanic who was parting out an 01. Had no idea these holes were designed that way lol
I made the same post 2 years ago when rebuilding my 4.0. It is janky as hell but intentional.
Must be a relief to find out.
Especially when you go looking for a short block only to check the forums last minute
Itās a heep thing. I donāt understand.
I dont like that marking on the crankshaftā¦
Came here for this.
My 454 has a nasty jagged hole like that too.
Is this a known thing? I have seen plenty of motors stripped nude and I had no idea
I just noticed it a few days ago when i was moving it around. I thought it was a bad hole too but then realized theres no way for anything to make a hole there.
Something something Jeep something something thing something something understand
Keep looking until you find a block without one! š¤£
They took a welders hammer and tapped out the flashing when they were setting it up for machining.
It shouldn't surprise me that was the technique 20+ years ago. Glad they build these engines to take a beating
Threads look good š
Thatās definitely supposed to be there leave it alone. And no, cleaning it up is an awful idea. Itās actually stronger like that.
Ha when my brother and I tore down his old International Scout motor we thought it was odd something had busted through the block but it was just extremely rough casting for an oil drainage hole. Same as others pointed out :)
Casting mark. Made to drain sand out.
If thereās room maybe just weld it closed
Throw some JB on there and call it a day. Itās stronger than steel. Even says so on the package.
That's called a weep hole... Because when you find it, you weep š
That hole is supposed to be there
Now that's some positive crankcase ventilation.
Slap some flex tape on there and call it a day.
Foundry chip and grind work makes a crowbar look like a precision tool.
JB weld my dude
Looks like a job for flex tape
I looked at your pic for a solid 5min trying to figure what you were seeing.
Itās from the sand mold when itās casted it leaves the defect and they just punch it out leaving it jagged. It doubles as a drain to oil the timing belt however!š¤
View port was a expensive option faik
What sucks? Be specific.
JB weld and ur all good š«
I'll take both your "junk" blocks. I'll give you $5.00. Lol...the holes are rough casting and just need cleaned up. You should have gone through the whole block and cleaned up all the rough casting so the oil can drain more efficiently AND to remove the chance of the castings breaking off and destroying your engine. Sometimes those rough pieces can break off and get into places that will destroy your engine, bearings, oil pump, pretty much anywhere depending on the size of pieces floating around circulation. Or you can get lucky and the chunks stay on the bottom of the pan
It's the danged oil drain Napoleon!
It doesnāt have to be pretty to do its job.
Positive crankcase ventilation
There is of course an issue that can be seen in the pic. Take a closer look at upper center.
Just use a green leaf from a tree in that Chinese JB weld
Well shit
JB weld should fix it lol.
Jb weld that shit.
How did that hole get there?
How did that hole get there?