head removal/valvejob

well my jeep kept failing on nox. i couldnt figure out why so i broke down and brought it to a mechanic. he did a compression test and took off my valve cover. he said my #2 cylinder, the valve (probably intake im guessing) wasnt working right and since it was driven like this much before i bought it ($200!) i will need a valve job. im pretty handy so i figure with no school and a long weekend i can pull the head myself and save some $$$.

does anybody have any tips for romoving the manafolds, head, and then putting them back on? i just got some pb blaster and a long breaker bar. i have a toarch.

while i have everything apart im gonna clean/paint the block/head/ valve cover. im also gonna replace the leaky raditor while the block is drained.

what will be the cost (ball park) for machining?


thansk in advance

1990 4.0 cherokee .

I just did some work on my head (???) a little while ago for the first time. Tips that I would pass on are.

Look, see what works for you. When you pull the head some people leave the manifolds on, some take them off. Figure out what works best for you. The head and manifolds are bloody heavy if you have to lift them out by hand. With 2 people it is doable, but can still be tricky. I used ratcheting tie down straps hanging from the rafters to slowly lift the head, and reposition it when I was putting it back. If you want to pull the manifolds off, I found it WAY easier to reach up from the under the engine with a wrench to get the lower manifold bolts off. I couldn't manage to reach them with extensions and swivels from the top. I have an aftermarket exhaust manifold if that matters.

Also on my 92 I only needed to remove the top 2 bolts on the AC condenser bracket where they go into the head. And not remove the whole thing and set it asided like my Hanes book said. Same goes with the powersteering bracket, but you do need the take off the power steering pump to get access to one of the bolts that hold the intake manifold on.

Make sure to take time to look at your lifters and such since you have it all open anyway.

well ive got a parts xj and im gonna go to a compression test on it right now. im hoping that head is good b/c that engine was rebuilt. so i may just switch heads. thanks for the help

Some bits of wisdom...

It is almost invariably easier to pull the head and manifolds, and service the manifold gasket on the bench. Get a helper if you have to (I'm a pretty big guy, so I can pull the assembly lone-handed. Don't hurt yourself...)

Replace the nuts on the exhaust studs with brass - you'll be glad you did next time you have to work on the thing. If you have time, go to Fastenal (or someplace similar) and get a batch of non-ferrous bolts for the manifolds, they tend to sieze over time (brass or silicon bronze both work well, I have used both.)

Don't look at your lifters - replace them. You don't know what shape everything else is in, and it's easier to put new lifters in while you're doing this than to keep them sorted and hope they work (lifters MUST got back onto the cam lobes you removed them from. No exceptions. New lifters can go in any hole on your cam the first time.)

Check your pushrods by rolling them flat on a flat piece of glass. If there is any visible "wobble," replace them as well. If they are flat, you are fine (these are easier to replace.) Try to keep them in the same order they came out - but this isn't as critical as it is for lifters.

You shouldn't need the torch. PB Blaster usually does the job.

Check the head bolts for paint marks. If there are marks, get new ones (you can get them from Fel-Pro, the dealer, or other sources.) If you aren't sure, get new ones. The 242 head bolts are a modified "torque to yield" fastener, and can only be reused once.

You'll need (apparently) and 8mm square drive to pull the block drain plug - you can grind out in about two minutes from an 8mm hex wrench - you just knock down two corners. I don't know what the thread size is (yet,) but if it's a standard pipe thread, you'd do well to change it out for a brass plug for next time... It is usually easier to remove the coolant temperature sensor for draining the block.

You may want to consider at least a re-ring while you're about it. Resealing the top end will eventually cause ring leakage - correct it while you're in there.

That's all I can think of for the moment...

5-90