Here is the head off of a .50 over bored 2.5L.
See any problems????

Good luck on a .60 over bore.

 

Hey Dusty, I'll play... I tried to blow up the pic and didn't get it much bigger but... The first thing that jumped out was the end intake valve looks like it has a piece missing... Might be the pic.. And the second issue looks to be a head gasket sealing problem...My guess is : Boring the engine takes away valuable real estate needed to seal up the head gasket...
Pineapple, that's a rebuilders tag... It's the date of the rebuild not the date of the block casting...Looking at your pics it appears the builder put a heat tab on the head's rear core plug.. That's to tell if the engine was overheated or not for a warranty claim... Does that engine already have oversized pistons ??? It'll be interesting to see when it gets torn down.. You might have an undersize crank as well only the tear down will tell...

 

As you can see, nothing out of the ordinary it looks like. I might be wrong, as I don’t pull off enough heads to know what looks out of the ordinary

You can see where the lobe has is actually flatter. I haven’t measured lift yet, but I’m pretty sure this cam is done

The distributor drive gear is really worn down. My boss said that was the source of my noise, and my slight misfire

Nothing remarkable here. The pistons must be standard sized, because there’s no markings indicating any kind of over-sized pistons being used. (Side note, I thought there would be more area between the cylinders, so I’m probably only going to go 0.0010 over, if even that.)
Well, got a good bit of work done today.

I got the harmonic balancer that was broken kind of off, enough to remove the front cover. I found that there was a lot of slop on the timing chain, probably because it was the original chain.

I got the gear off for the camshaft and removed it, and found that the distributor drive gear was worn down, and that all of my lobes had a good bit of wear on them. It’s probably the original camshaft, judging by the wear on it.

I also took the head off and found, well, nothing really. I mean the pistons look fine, as well as the bores. The valves look normal, there’s no abnormal wear on them, and the head gasket was completely fine. I haven’t torn off the oil pan just yet, so we’ll see what that holds.

I had been chasing this rattle sound that I could not for the life of me fix, and I’m pretty sure that noise i was hearing was both the timing chain and the distributor drive gear.

 

Well, I haven’t done much of anything to my motor because I’ve been swamped with tearing apart other ones.

I did however get around to getting the rest of the broken balancer off without damaging the end of the crank, which was awesome. All it took was some PB blaster, an acetylene torch, and about an hour of air hammering. It was really really stuck on the crank, so it’s no wonder it broke off.

But I figured I’d at least update my plans with my Jeep and the engine.

As of this moment, I’m going to try and keep the pistons standard sized. If the machinist tells me I need to go a certain amount over, I’ll do it, but that’s all I’m going to do. I realized that it’s not as simple as it seems, and not really worth the extra headache. As far as internals go, it’s mostly going to be stock. Stock rods, crank, bearings, and pistons (hopefully). What’s not going to be stock is the roller rockers, the camshaft, which is coming from 505 Performance, and it includes the springs, keepers, retainers, pushrods, timing set and the bolt for the cam gear. The intake is already “ported”, and it has the 4.0 TB on it with the opening bored out to match. I’m keeping my long tube header as well, along with the 19LB 4 hole injectors. I’m hoping to get some gain from the cam, but the one I selected is best used for low to midrange.

Im wanting to use my Jeep for towing/hauling, so I want to add in a high flow water pump, heavier duty clutch fan, and a little bit cooler thermostat. I also plan to upgrade the brakes to the Liberty brakes in the front and rear, or maybe the ZJ conversion. Whatever has the better brakes is what I’ll do.

As far as the rest of the drivetrain goes, I’m going to put in an AX15 with the Dodge Dakota bellhousing, mated to an NP231. I’m not going to swap in a front axle just yet, because I’m not wanting to rebuild the entire Jeep just yet. The reason I say that is that when I pull the front axle in mine, everything is going to get replaced. Anything that has to come out is getting brand new parts, and that’s adding a lot of extra time and a lot of extra money that I don’t want to spend just yet. I’ll probably end up rebuilding the NP231 that goes in mine, just for peace of mind.

I also want to paint my engine, but I’m not sure what should be done to make it look good. I want to paint the pan, block, head, and all brackets black, the valve cover blue, as in the same color as my Jeep, and the intake white, as well as painting the lines on the top of the valve cover white to help contrast the blue.

That’s all I can think of for now. If anyone thinks of anything else I might need to address, please tell me so I can add it to my growing list.

 

Well, I finally got it torn down the rest of the way. I kind of had to because I need the stand for another engine job.

Anyway, all of the bearings showed signs of wear, and dirty oil with a lot of dirt in it. None of the scratches were deep, but it clearly looked like there was really dirty oil that was run through this engine. There was however, no sludge anywhere, which was nice.

Regarding the bores, there was a really bad ridge at the very bottom of the bore, and there was damage to sides of the number 2 bore from a piston skirt. I think that damage was from this knock I was getting that was only at idle. It would knock louder and then go away after 1k rpms. So it’s looking like I’m going to have to get it bored over at least 10 thou. We’ll see.

I took some pictures, but I didn’t notice the bore damage until after I put it in the parts washer.



These are the main bearing caps. They all show the same groove wear that you’d find from dirty oil. I did see some slight “bent crank wear” on the middle bearings, so I’ll more than likely get a crank with the bearings included

Rod bearings show the same type of wear, but thankfully I don’t see any signs of a bent rod on any of them



This engine looks so small when it’s completely stripped down to just the block

 

Well, got some bad-ish news from the machine shop on the block.

The machinist had to deck the block by 5 thousandths, because it was very slightly warped. I’m pretty sure the head is probably warped the same amount, and it shouldn’t be an issue. All I’ll have to do is put 10 thousandths rocker arm shims if it totals out to be 10 thou in total.

But the story gets a little worse when it comes to the bore. It turned out that the block was already bored out by 10 thou than stock, and he attempted to go 20 over to clean up the bore, but he said it only cleaned up half of the cylinder. He said there was pretty bad damage from the piston skirt in number 2, and the bore was severely out of round. He tried to do 40 over, but it still needed a total of 60 over from stock. It’s funny how I was wanting to do 60 over regardless, but there was so much damage that I had to go 60 over. I chose this path because a new block would be pretty pricey, and if I went the route of getting a used block, I might run into the same problems.

Anyway, it didn’t need a line bore. The crank was razor straight, so I don’t think I’ll end up getting a new crank. I might just because I can get a crank, rod and main bearings for about 300 shipped. Idk though.

I did order the cam bearings for him to install, as well as the stage 2 cam kit from 505performance. Once the block gets back, I’ll go ahead and order the bearings, pistons, rings, and oil pump. I’ve also got a gasket set on the way, and I’ll slowly start to put it all together. I do have to track down an AX15 and a NP231, as well as the linkage.

Once the camshaft gets here, I’ll send the head to my guy and he’ll install the springs and retainers, as well as deck it if it needs it, and hopefully I won’t need any valves. He’s got the tools and skills to fix seats and guides, so as long as I don’t have a cracked head or valve, I’ll be in the clear.

 

I finally got the block back from the machinist, and I set it in a box far away from everything else. I soaked it in oil and some WD-40 to prevent rust, since everything was freshly cut.

I also got the camshaft and the rest of the springs and retainers, so I’ll send my head off and see if it’s still usable and go from there ordering parts.

My next step after the head is to get a new crank, rods, pistons, and rings and get the bottom end assembled with the new cam, timing set, and all of that stuff. Once I get the head bolted back up, then I’ll have to play around with what pushrod length I need for this new cam, and I also have to account for the material that was already taken off of the block as well as what is probably going to be taken off of the head as well.

It’s finally happening!

 

I don’t think I’m gonna do a 4wd conversion. I’m not scared of doing it, I just don’t think it’s practical for me at least. I love the idea of having a 4wd XJ that I swapped, but the biggest thing for me is I feel like once I add 4wd, I’m gonna want to do a bigger lift, bigger tires, bumper, long arms, you name it. I just don’t think it’s logistical enough for me to swap this XJ. I feel like I’m better off getting a 4wd XJ that’s a beater of some sort.

It also boils down to the fact that I can’t find a Dodge Dakota bellhousing. The two listings I found on car-part were dead ends, as both bellhousings were in working transmissions. That means I would either have to wait for one to show up in the junkyard, pull that one, take the bellhousing off, and then get an AX15 for 4wd, or buy a “junk” one and steal the bellhousing off of it.

I think for what I have in mind for my XJ is more suited as a 2wd. I really do want to swap it, but knowing me and how my brain works, it’ll be an even bigger money pit.

Enough about that.

I got a call from my guy who’s machining my head, and he called me with mostly great news. He said the head had been previously machined, but not very well. There were certain marks on the head that showed that they just cut it, and with some tool that he said was commonly found in someone’s garage, just to “resurface it”. He also said that someone bored out the valve guides, and he didn’t have the correct pilot to correct them. He said he tested just lapping the valves and grinding the valve seats on the middle valves, and he said it held a great vacuum. He did say that I could either get the correct pilot or get new valves and guides, but he recommended that I don’t do either because it still held a great vacuum.

He hadn’t cut the head yet or cleaned it, but he did check it for cracks and it wasn’t cracked. He said he’ll finish it up tomorrow and install the new valve springs that came with the cam kit along with cutting it and cleaning it. Once I get it back from him, I’ll order a new crank and new rods with the new piston heads. I’m sure the crank I have is okay, it’s just that the main bearings on 2-3 showed more inside wear than the outside bearings on 1-4-5, which means my crank is probably slightly bent. My rods on the other hand, some of them showed signs of being bent, which might explain the piston skirt damage I saw.

Once I get the bottom end assembled and the head put on, I’ll have to figure out what pushrod length I need. I thought my cam kit came with pushrods, but it didn’t, which I guess is a good thing. It means I don’t have to shim my rocker arms and I can just get the correct length pushrods to account for the new cam and whatever material was shaved off the head and block.

 

Finally got around to assembling the bottom end, somewhat. I ordered the wrong sized bearings and didn’t check the numbers on the back, and I put the crank together and went to plastigauge it, and it didn’t even squish the wax. I had ordered standard bearings instead of the 20 over bearings I had originally.

I finally got the right bearings in today, and measured my clearance and got just shy of what the service manual wants, right at 0.06mm (I’m not bothering to convert into standard.) and the service manual wants to see 0.051mm. I’d buy that for a dollar.

I also got the camshaft installed, with lots and lots of break-in lube. I also timed the engine, and the new cam I got came with a thicker chain that looks beefy as hell. It also came with a new cam bolt, crank sprocket and cam sprocket. My next step is to get a machinist to install my new rods and pistons because I don’t trust myself to do it the old fashioned way of heating the rod and sliding it all together. Once I get that done, I’ll install the rings and put the new bearings in, measure the clearance, and put together the rest of the oil pan.

 

Thank you for taking the time of updating this thread, I really enjoy watching it.

 

I’m glad someone’s enjoying this

But today, I cleaned up and spray painted some parts, which would be the timing cover, valve cover, and oil pan. I primed it with high heat primer, sprayed them with black engine paint, and then coated it with a clear enamel. I think they turned out awesome, and I’m still planning on painting the brackets black as well. I still have to paint the white lines on the valve cover, but this has to be my favorite part of engine building

 

I used to install those Bower/BCA cabinets in shops, lol. I worked for TRW, then Federal-Mogul for 13 years calling on shops in behalf of local parts stores.

 

So clean and organized. Must be a diseased mind

 

I’m going to be 100% honest here. I never noticed that cabinet until you pointed it out. I have no idea what’s in there and I’m gonna take a look on Monday

 

Im trying to be more organized in my life. I’ve gone far too long being disorganized and loosing everything I touch, and I’m trying to be better organized because it’s less stressful if that makes sense