Ditto what Grum.man said about flatness! If the head (or block) has the least bit of warpage, no head gasket will seal it!

 

I checked the head for flatness using my granite counter top and a feeler gauge. I couldn’t get a 0.005” feeler under it anywhere so I think it’s pretty damn flat. I don’t want to wait until Tuesday for a machine shop because alll the parts are in now. Everything seems to look good now. I’ve been cleaning with diesel fuel and a scotch brite pad.

 

Well, when torquing the driver head down I was following the 25-50-70 sequence since that was the lowest set of values I could find. All went smoothly until I went to take #1 to 70, and I felt the threads let go. First thought is okay, lets pull it apart and helicoil it, but i have seen some horror stories on here regarding that. I am also afraid that when I put it all back together in 2020, I over-torqued the crap out of everything and that a lot more threads are going to do the same thing. It could be a fluke, and this could be the only one with issues, but given it was the first nut, I'm worried. I don't remember what torque specs I used back then, but I do think I remember using more than 70 ft-lbs. I didn't find the 25-50-70 until I went directly to ARPs website, but Atlantic British has an indecital PDF on ARP letterhead that says to go to 100 ft-lbs and I think that's what I used back then.

I'm not sure what the best course of action from here is because, if my memory serves, then every nut was likely over-torqued. If that's the case, this will likely not be the only one to fail. I am heavily considering picking up a parts truck and spending my summer when all of my roommates are gone fully refreshing another engine in my living room (no garage, but I have concrete floors in the house so I wouldn't be worried about doing it indoors). If I get a whole parts truck (like one nearby for $800 with a bad transmission), then I could at least recoup some value out of it, which is the only reason why I am considering just rebuilding a whole other motor.

I want to still get this truck up and running long enough to make it through the semester so I can wheel with my friends before they graduate, but I will not have time to go through and rebuild a motor or helicoil half my block until summer. The nut that I torqued and let go hasn't been pulled out yet, but I am fully confident the threads are fked because I was able to make a full 360 with the torque wrench. There is a part of me that wants to say f it and leave it how it is, torque the rest to maybe 55 or 60 ft-lbs, then drive until summer when I can put a new engine in it so I can at least go to a few trips with friends. If it's going to be undrivable, that would be silly. If it just blows the HG again and misfires and burns oil who cares, it would last long enough and Im replacing it anyway. If the threads are trashed in the block then its unusable. What would yall do if you were in my shoes? Reminder, I'm in college and a bartender, so I am working on a budget (yes, i should've just bough an XJ lol).

 

I'd guess the head gasket let go again because the threads were already weak from the last head gasket job. Are you sure the stud is fully threaded into the block. That's a lot of threads to pull out and I doubt even 100 lbft would do that. There are also different length bolts/studs so be sure you have the long ones in the proper place though I don't see how that could be wrong and still look reasonable to the eye.

If the block is truly stripped then I'd either find a used engine, or parts car. I have a bare block located near Raleigh NC I'd sell for $100.00. When I rebuilt my engine I bought a block that already had top hat liners installed so my old block is just sitting here. It was fine other than the faint sleeve knock they all get around 180k miles. There is also a guy in Durham NC that has a freshly machined top hat bare block he is asking $2,500 for but he might be a little flexible.

 

I agree, defiently plausible that bad threads could've caused this head gasket failure. The studs are in the right place, they never came out of the block. 2 of the exhaust side studs came out with the nut (guessing the exposure to heat locked the nut on extra tight). I chased the threads out with a same thread/pitch bolt I cut slits into, then blew the holes out with compressed air and reinstalled handtight (as per ARPs sheet) with blue loctite. After that, I went back through and checked each stud to make sure they were tight before I reinstalled the head.

I'm looking for a whole engine or parts truck so I can have a second complete motor to work with and not have to strip mine to build a new one, but I will keep you in mind if I can't find what I want. A top hatted block would be great, but $2500 for a bare block is way out of budget for me.

Do you think the motor could go another few thousand miles if I just put it back together as is? I know that the correct answer is no, don't do that, but it only needs to survive a handful of trips. I am the VP of the offroad club here at my college so I have to go on all the trips anyway, and I am tired of catching rides with people every time and want my own rig back. I don't have a truck and trailer but plenty of the guys do and could get me back on theirs if it did decide to fully let go on me.

 

sounds like the only way to find out is to go for it. likely to blow again quickly but depending on how or where it fails this time would decide on how big of a deal.

 

That's why I want to send it, but I wanted to hear others opinions on it. BTW, I read your vehicle description; how much hp and tq do you pick up with the cam? When I build a new motor I plan on keeping it all stock and reusing whatever I can, with my only exception being maybe a cam.

 

it's not super noticeable but one truck is super heavy so figured every little bit helps (in CO at elevation it doesn't matter much these things are dogs) and the other was 165K miles or so figured a refresh was worth the coin and extra work. I'd probably do it again if I dug into another motor if I had the time.

 

FWIW, I would never dive that deeply into an engine without installing the optimal cam. If she'll be a mall crawling garage queen, then leaving the stock cam might be fine; if you care about how she drives and want to realize a simple increase in performance, then install a better suited cam while the engine is apart. Now, should you open up the engine solely to install a cam? That's a different choice.

 

Gotcha. I'd like to do a cam, but that will be budget dependent. If I get a parts truck and can make enough selling parts off of it then I will definitely do a cam.