Crack in head

hunterdan

hunterdan

Well-Known Member
Joined
Apr 13, 2009
Location
Morganton,NC
Got a 87 Jeep YJ a few weeks ago in a trade with a local guy in Drexel
Everything seemed fine with engine. Good oil pressure, bright green anti-freeze....New radiator, new manifold and valve cover gasket. Been working at some steering issues but just recently noticed a coolant leak on head.
After cleaning area up I see "someone" welded the head in 2-3 spots and repainted it. I was thinking I did pretty good on this deal. It all makes sense now....New manifold and valve cover gasket, new radiator and water pump...should have knownšŸ˜¬

I'll be looking for a good 258 head in the wanted section....I think it's an 83 engine and head.
 
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Will PM You.
To justify being in tech. Two leaks are tiny ...like 1/8" outside of weld. Should I just take it to Powell's ( great welding shop) and see if he can nickel rod them a tad or get another head now?
 
hunterdan said:
Will PM You.
To justify being in tech. Two leaks are tiny ...like 1/8" outside of weld. Should I just take it to Powell's ( great welding shop) and see if he can nickel rod them a tad or get another head now?
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clean it very well with brake cleaner and make sure no coolant and JB weld it.
 
willness33 said:
Got ya. Hit me up In PM. Got an 83 258 on the stand in my garage.
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orange150 said:
I've got a 4.0 head and wiring harness if you want to go that route. It's all in Raleigh.
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Haven't given that much thought. Might do a 4.0 head swap but not sure if it would work with my headers and offenhauser intake.... Don't really want to go Fi.
Jeff B said:
clean it very well with brake cleaner and make sure no coolant and JB weld it.
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That would be great if Jb weld worked. I've heard some people drill a small hole at ends of crack and then use tapered pins with Jb weld. Anyone here ever tried anything like that successfully?




welding?
 
Iā€™ve use JB weld on the side of the block on a Chevy 350 that had water put in it and it froze and cracked. Whole tube of JB weld and still hold to this day and that was bout 12ish years ago. Wasnā€™t a daily driver just a weekend toy, but I still never thought it would have lasted this long.
 
Chased a similar style crack on a inline motor. Block not the head but still. Tried welding and kept chasing a small weep. If you have the chance and a known good head Iā€™d bite the bullet and do a weekend head swap. If itā€™s cracked outside no telling what else is going on.
My thought is head swap or risk something you canā€™t see and put a motor in it down the road.
 
skyhighZJ said:
Chased a similar style crack on a inline motor. Block not the head but still. Tried welding and kept chasing a small weep. If you have the chance and a known good head Iā€™d bite the bullet and do a weekend head swap. If itā€™s cracked outside no telling what else is going on.
My thought is head swap or risk something you canā€™t see and put a motor in it down the road.
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One day really. 258 might be the easiest tractor engine to ever work on.
 
I helped do a head swap on a 85 S-10 blazer back in 96. That's my extent of knowledge. This engine has an exhaust leak on the middle of header. I guess I should swap the head since I need to remove all the intake/exhaust anyway. I can read and follow directions so a few videos and I'll probably be able to do it.
 
hunterdan said:
I helped do a head swap on a 85 S-10 blazer back in 96. That's my extent of knowledge. This engine has an exhaust leak on the middle of header. I guess I should swap the head since I need to remove all the intake/exhaust anyway. I can read and follow directions so a few videos and I'll probably be able to do it.
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No bullshit it's super easy to do. Did my head gasket in about 4 hours and it was literally the first time I'd ever been that deep in an engine. If you can take apart a Briggs and Stratton you can do this.
 
willness33 said:
No bullshit it's super easy to do. Did my head gasket in about 4 hours and it was literally the first time I'd ever been that deep in an engine. If you can take apart a Briggs and Stratton you can do this.
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Thanks for the vote of confidence. I have always been a DIY'er when it makes sense.
 
it worked for me on an old willys L head block that cracked. I had to preheat and weld the block with Nickle rods. the weld would be wet all the time, so I cleaned it really well with brake cleaned and coated it with JB weld. Worked really well for me.
 
Decided to take the leap and R&R the head. As mentioned it already needed a new manifold gasket whether I could fix the crack in head or not. After removing intake and header I could see that the rear portion of intake had been leaking on the block.
In the pics you can see where tip of screwdriver is pointing and just below small socket. That's where PO welded 3 cracks. I expected to see more emulsion/mayonnaise under the valve cover. There is some due to sitting and short drives all winter.
Lots of oil pooled on top of rockers and pretty clean. Oil pressure is about 55psi cold and 40-42 warm at idle.
I got everything done down to pulling head bolts and removing items connected to it. I broke bolts free in reverse of mounting procedure that I found. I'm going to install a rebuilt head since I don't want to do it again. I won't break head free until new one arrives. I don't know if that matters.
 

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It won't matter either way but good on ya for tackling it. It's really stupid simple. Follow the torque sequence with the new head and head gasket and all will be good. Same goes for the rocker bolts. I was right where you are not 2 months ago and all is still good DDing mine.
 
Ordered the head. Seller didn't know company that did the rebuild. It is same casting # as mine with a tag A258-3H.
Anyway I believe head company's shave the head a couple thousandths. I believe I'll use caliper to see difference in my head and new one..then order pushrods to fit based on length of original pushrods. Any better ideas?
Should I get new rockers,bridges...or just rods?
 
hunterdan said:
Ordered the head. Seller didn't know company that did the rebuild. It is same casting # as mine with a tag A258-3H.
Anyway I believe head company's shave the head a couple thousandths. I believe I'll use caliper to see difference in my head and new one..then order pushrods to fit based on length of original pushrods. Any better ideas?
Should I get new rockers,bridges...or just rods?
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Personally I'd just swap rockers and bridges. If you haven't taken your rockers off yet don't be freaked out when the bridges bend. Just straighten them back out. You'll see oil grooves in the under the bridges. Make sure they line up on every rocker. Itll make sense when you see it. As for the pushrods, I could be totally wrong, a few thou wouldn't make a lot of difference on this engine. I would probably be wrong to do so but I'd clean them and run them. These engines are just sloppy with tolerances.
 
willness33 said:
Personally I'd just swap rockers and bridges. If you haven't taken your rockers off yet don't be freaked out when the bridges bend. Just straighten them back out. You'll see oil grooves in the under the bridges. Make sure they line up on every rocker. Itll make sense when you see it. As for the pushrods, I could be totally wrong, a few thou wouldn't make a lot of difference on this engine. I would probably be wrong to do so but I'd clean them and run them. These engines are just sloppy with tolerances.
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Thanks for the info. I've been reading almost too much. LoL
Some say oem valves can adjust for .02 but any longer and bend rods and mess up a lifter. Too short and valves don't open long enough and rattle.. I believe mine are supposed to be 9.7" or 9.65. Will pick up my first caliper tomorrow and be sure. Haven't removed rockers yet...thanks for the warning.
So, my list is head gasket(OEM?)
rockers, bridges, things under rockers and pushrods if needed? Anything else?
 
I worked at a machine shop years ago. Headwork was what I did the most of. All engines have a cut off as to how much can be machined off of them. Before I ever surfaced one, I used a dial indicator to check it to see how much would have to machined off to square and clear up the surface. This was for heads that were being gone through and or owner wanted it checked due to a blown head gasket. Race engines were a whole other story. "If" the reman person of your head did as I did, then there should be no problem with just replacing the head with a quality head gasket. If the cut till it cleared, tat may be an issue. Not sure about the AMC 258, but some engines you can get thicker head gaskets to compensate for more being cut off that should have been. About the only way to check to see if too much has been cut off, is to cc the heads combustion chamber.
 
I used a felpro stock style head gasket. It's still working so I guess it's a good one. Most important thing is to follow that torque sequence and put liquid ptfe on the front drivers side head bolt threads.
 
willness33 said:
I used a felpro stock style head gasket. It's still working so I guess it's a good one. Most important thing is to follow that torque sequence and put liquid ptfe on the front drivers side head bolt threads.
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Oh and use the good felpro gasket for the intake and exhaust with a good coat of copper spray on the paper side.
 
use a push rod length checking tool to verify.

I would also be sure to drain the lifters in case any are stuck, simple to take apart and drain. Be sure to rotate the engine assembly when you prime the oil pump to get all the air out.
 
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