5-90

Perhaps I'm missing something - but did the broken screw break above the deck surface of the block, or below? Massive difference in difficulty - if it broke off above the deck, you just lift the head off and back the screw out with vice grips. If it's below, you're in for a little more work (and having a good ***** or centre punch and a machinist's centre drill comes in very handy to prevent drill walk.)

To remove a screw broken off below the surface, you have to drill right about in the centre of the screw - don't walk into the threads! I find that using a left-hand twist drill can make things simpler sometimes - if you're luckly, the left-hand twist will grab the screw and back it out while you're drilling. Problem solved.

If it doesn't, you drill out about half of the screw (the screw is threaded 1/2"-13, so the solid part is 1/2" less 1/13" of an inch thick. Drill out 1/4"-5/16" - whatever you can get without hitting the block threads.) Use an easy-out or a left-hand-thread tap (very carefully! If you break the tool off, you're looking at pulling the block to take to an EDM shop, finding someone with a portable EDM, or finding someone who is very good with a mixed-gas torch to burn it out with an oxygen flame. None of these are going to be cheap...) and back the screw out.

Failing that, your best option for a good re-thread is going to be to take the block to a machine shop (or find someone who is very good with a hand drill - I'd be loath to try it...) and overdrill the hole to accept a 1/2"-13 screw thread insert - there are several, with preference for Heli-Coil, Re-Coil, or Keensert. I've used all three in various applications with good results.

However, if you're lucky enough to remove the screw without damaging the threads, you won't need a screw thread insert.

Fritjov

thanks, i flipped out over nothing, the bolt broke above the engine block and my bolts had thread that ran halfway up the shaft and that made me think the cylinder head was threaded, it just came off like you said, I got the head off earlier today, it was stuck pretty good, about 45 minutes of pounding away with a hammer and screwdriver, but it came off. The gasket wasnt as bad as I hoped it would be but there were a couple holes letting antifreeze mix where it shouldnt. I cant tell if the engine block is cracked somewhere down below but everything looks nice, and while cleaning the head i ran hose water into the cooling rings with the head upside down and it ran straight to the thermo housing, no leaks there. so now all I need to do is buy a new Temperatre Sending Unit that I broke, and put everything back together. Before I do that I'd like to check all the lifters, Haynes says i need a special tool to do that, I tried pulling one out with a telescoping magnet but it didnt have enough power on it, are there any easy ways to get this out without buying a special tool or renting it from autozone or something.

5-90

The valve lifter puller is a "specialised" tool (a magnet-on-a-stick won't work - the lifter may not be too heavy for it, but there are deposits and suction to be dealt with...) but it can be had from most auto parts houses for $20 or so. The better ones use a sort of "inside-out-collet" arrangment to grip the lifter from the inside at the top, and have a sliding weight so you can use it as a slide hammer if you need to to break the thing loose. If you're going to build an engine, you should have one (you can also use it to set lifters into place.)

I believe that they're standard, and can be used on pretty much any flat-tapped engine.

NB: DO NOT MIX UP LIFTERS!!! If you remove a lifter, it either goes back on the very same camshaft lobe you removed it from or it goes in the scrap bin. If you're even a little bit unsure, it goes in the scrap bin. Period.

Mixing lifters around will wreck your camshaft in short order. Note the following:

New Cam + New Lifters = OK
Old Cam + New Lifters = OK
Old Cam + Old Lifters = OK if lifters replaced on same lobes!
New Cam + Old Lifters = Wrecked Cam
Old Cam + Mixed Lifters = Wrecked Cam.

Treat this point as important.

Fritjov

All my lifters were in beautiful shape, they looked new, not even any carbon on them, I just got everything back together, even the battery, it's about 1 in the morning. Tomorrow I'm going to flush the system with cheap store brand oil and cleaner twice, then take off the oil pan and clean the screen and everything under there, I already got a gasket for the pan, then change the oil filter and fill up the oil with good stuff, and then we'll see if I still get less miles per gallon on antifreeze than i do for gas.

5-90

As long as you've kept them sorted and they go back in the exact same hole, you'll be alright. If you even think they may be mixed up, scrap them and buy new.

I'm serious. The only think that wrecks cams faster than mixed used lifters is running it with no oil!

Fritjov

To be extra careful, I took my lifters out one at a time, and put the one i had out back in before i took out the next one, oh and I did get them out with a magnet on a stick, I couldnt find the lifting tool anywhere around here, autozone didnt even know what i was talking about, and oreily's could order it for me for 38 bucks, so i just got 6 dollar magnet on a stick at advance when i went to pick up the temperature sending unit i ordered, what does a temperature sending unit do anyways. that little eletronic plug on a brass screw that goes in the head near the back of the valve cover

smtippin

That gives the reading to your gauge cluster. When you get a new one, make sure to call it a "sending unit" as there is another temp sensor and you don't want that. Also, you will want to specify whether you have gauges or a light in your gauge cluster when you get the sending unit.

s

jeepfreak82

they also call it a temperature switch, depending on what store you go to... I have dealt with that one before

Fritjov

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Fritjov

Well I've got everything back together, I ran this GUNK oil cleaner with 6 quarts of cheap motor oil through my car twice, changing the oil with fresh stuff and changing the oil filter each time, and I tried to take off the oil pan to clean that all out but couldn't get it out from between the transmission and front axle so just stuck it back up there without replacing the gasket, It's not leaking any oil or anything so i just took back the oil pan gasket and got my money back. It took about 10-15 minutes to start up after i put the engine back together, I figured so, to get the gas up in there, before i put the valve cover back on i poured some fresh oil in each of the rocker arms, and before i put the head back on i smeared a little bit with a rag and then my finger around the pistons.

The good news is I'm not leaking antifreeze into my oil, or anywhere now, which was the point of me changing the head gasket, but there are a few pretty concerning things, in order from not to bad to pretty sketchy, and they are all good ones that baffle everyone I've talked too. first off, my check engine light is on, and I can't find the diagnostic box, at autozone the guy looked it up in a cherokee haynes manual, and came out where i was parked and was looking near my air filter housing, and there is just an electrical plug there with like 4 or 5 prong sockets that look like my fuse box and doesnt plug into anything, the plug is near my brain box or whatever that electronic thing is right by my air filter. anyways luckily the dealership printed on the back of my cherokee is still around and is in the next town over, the one i used to live in. So I'm heading up there tomorrow to ask them where the heck my diagnostic box is, or where it should be if i even have one anymore.

Another problem started actually a day or 2 before took her apart. When I'm driving theres a high pitched constant humming noise, it sounds like someones mowing the lawn 2 houses down, but its more high pitched, not so much that its a squeal, almost like an electric motor, and it sounds like its coming from behind me, like from the gas tank, or my drivers side back door, or possibly even exhaust, but it doesnt make noise out of the muffler. When I turn the key to the on position before I start the engine the humm will happen for about 1 full second maybe less, and sometimes when I start her up it wont start humming until i've been driving for 2 or 3 minutes, even weirder is sometimes, very rarely, but sometimes it will stop completely for up to half an hour and then start again. sometimes when i start up the engine, when i put it from park to reverse with my ligths on the humm will change frequency slightly, it will also change frequency more so then shifting when i turn the headlights on and off.

There is only high-milage 10w-30 and a little bit of Lucas oil stabilizer in the oil, i drained all the cleaner out and replaced the oil filter with a new bosch, and my transmission fluid is actually a little high, I drove my jeep around for about 4 or 5 hours today, trying to work out any kinks, and get the oil and gas running right, i filled her up twice and each time i put some fuel injector cleaner and octane booster because when i first got it running the exhaust was pretty noisy.

My last and worst problem, which scares the crap out of my girlfriend, is very violent shaking, so violent my toolbox will jump up and down like i was driving 25mph down a backwoods dirt road. I dont feel it in the steering wheel at all, I'm pretty sure it's the engine shaking my whole vehicle but not I'm not positive. It only shakes when I apply gas when I give it a little more gas it wont shake, but this prevents me from driving at a constant speed, I either need to deal with the shaking, or accelerate, then let off the gas completely, then floor it, then let off, then floor it.... I was watching my gauges so I could better describe it, and it seems to depend on how fast im going/how much forward momentum, whether im going uphill or not, but the RPM will be around 1500-2000, and then I apply the gas, and the more i apply the gas the more violent the shaking gets, until it hits a certain point and it will stop shaking completely and my RPM will jump up to 3000 or 3500, and skip the points in between. I really have absolutely no idea why it would do this, because as I may have mentioned in another post, the very first time i even got under a car was a few months ago, and everything i have done has been a learn as I go experience, one thing I will check tomorrow is my rear gear box, I backed into a curb a month ago and put a little hole in the gear box, I patched that up with JB weld and refilled it with gear oil, I'm fairly certain it isnt leaking, but it couldnt hurt at all to pop off the seal and stick my finger in there to make sure I still have plenty of gear oil. for all I know the shaking could be anything from a problem with the fuel injectors to the transmission, I've never been around a car with a shot tranny, so i dont know what it sounds like or feels like. the shaking also seems to come and go sometimes but I dont recall if it was in sync with the humming, and I'm fairly certain the two are unrelated.

HockeyFan

The humming noise sounds like your fuel pump. I have no idea about the shaking. Does it idle smooth? Have you checked your motor mounts? If you can make it shake at a standstill have someone check under the hood while you do it.

I'll be doing a head gasket on a '96 or '97 soon so thanks for posting this up. While I have the head off I may clean up the ports a bit. Does anyone know if there is any power to be found in porting these heads? Any tips would be helpful.

Fritjov

well the dealership wanted 85 bucks to just look under the hood, so i left, and went to autozone, and they taught me a little trick, just use my key, on off on off on, and sure enough my check engine light flashed and gave me some codes, 12, 27, 51, and 55, in the haynes manual 27 is fuel injectors and 51 is a PROM problem, i think PROM is the brain box that controls the fuel injectors, which my brain box is all cracked apart, but that doesnt explain why it wasnt doing this BEFORE i took the head off. i think the humming and vibrating might be related but im not sure, as i drove it to the dealership this morning, the car didnt hum OR shake until i had drove it for 10-15 miles. I filled it up again today and put in some STP fuel system cleaner, an octane booster and a STP gas treatment. my antifreeze level still isnt dropping so i fixed it.

89Cherokee

Have you tried changing the fuel filter? may not help but maybe....

Fritjov

are sport parts compatible with a country, more specifically fuel injectors and fuel pumps

Fritjov

ok i am officlialy a moron, I read the codes for an earlier make,, the shaking has stopped after i unplugged and replugged all the injectors and spark plugs, and the code for that is gone, but code 51 is not for the PROM computer it's for an oxygen sensor/vacuum leak, and i got under my jeep and the humming sounds like its coming from my fuel tank. so I'll look into fuel pumps now. and im going down for a pressure guage to check my vacuum.