Ongoing 75 CJ Garage Adventure

Bought my CJ a month or so ago because I really wanted to expand my wrenching ability and needed a new hobby. This CJ is not letting me down. My AMC 304 has a few problems, I have a loud lifter (Thanks for the help on my other thread), smokes white on rev-down(Valve seals?) and has low compression, yet it idles and revs well. I dont have it on the road yet, so I cannot test its seat-o-pants meter or really see if it burns oil. My compression results in order of cylinders starting with #1:130-130-118-90-125-125-130-114. I think this means I need a rebuild....Should I buy a reman or rebuild this one myself? If I do tear this one down should I have the cylinders and heads machined? Or can should I take a wait and see approach as I open it up.........

 

White smoke is normally water vapor. Oil is blue, and excess fuel is black.

That 90# cylinder is not good. Usually one low cylinder means a burnt exhaust valve, or it could be a head gasket leak or crack in the head or block (since you might be seeing water vapor). Could be oil smoke and be blue not white; worn rings usually smoke all the time, while valve seals cause smoke on deceleration IIRC.

How much do you want to do yourself? If you want to do some research about rebuilding engines, this book is a good place to start: http://www.amazon.com/gp/product/15...002-2617032-3680840?s=books&v=glance&n=283155

hth!

 

X2. One other thing if its a bad head gasket you can usually smell anti-freeze in the exhaust and you'll either have oil in the coolant or coolant in the oil. From the sounds of it you're pretty much looking at an entire overhaul, not just a rebuild. If you really like wrenching you could start with a reman short block and have your heads reworked, but you'll probably end up spending about the same amount as getting a reman long block. Would also be a good time to check out crate motors, there are plenty to choose from and they're not as expensive as you might think (some come with as much as a 2 year warranty). MOPAR, GM and Ford all have perormance crate motors, as well as, several builders like Sallee Chevrolet (comes to mind), Edelbrock, Summit, Jegs and several others, some probably nearby for you. Whatever you do keep it fun.:v6:

 

Golan has AMC V8s for a decent price.

 

Looks like im in for it....anyone think I should pull the heads and see whats there? Any more info on Golan? Not having much luck with an internet search. Thanks

 

just curious
is the 90# cylinder the one with the lifter noise ?

 

I've not heard of Golan. The Jasper engines are pretty good from what I've read. http://www.jasperengines.com/ Depending on what you want to do, you could have your local FLAPS source a Jasper engine for you. You could also buy an Autozone (or such) engine - usually that works out ok. Whatever you do, it will be a lot less expensive to R&R the engine yourself. That's mostly muscle work, and you'll be more likely to get a quality outcome if you R&R the engine yourself. However, if you do the R&R yourself, the builder likely won't reimburse you for your time if the rebuilt has problems.

My preference is to work with a local shop and have them do the machining and I would assemble the engine. I have some experience building engines, so in your case you might want to have them build your engine, and install it yourself.

If you pull the heads, you lose the opportunity to test a running engine. You may or may not be able to easily identify the problem once the heads are off. Once you pull the heads, you will be pretty much committed - if you're ready to commit to a full rebuild, then you may as well. If your not ready or able to commit to a full rebuild, then I'd try to better localize the problem while the engine still runs.

Here's Golen http://www.golenengineservice.com/

 

Good question, but even if that's the reason for the one low cylinder, the compression seems low and variable. The spec in my '77 manual is 140psi minimum, with a maximum of 20 psi difference between cylinders.

 

Cylinder #1 has the lifter issue, Cylinder 3 has the 90 PSI compression. I had figured even with the 90 PSI all the others were under 140 so I am due. TimGr-I have a shop a few blocks away that I am going to talk with tomorrow, but you answered major question on which way I should go. I wasn't sure if doing it myself was that much cheaper then a rebuilt motor. I am thinking I will just tear it down and have the shop do the machining. I am a obviously a newb when it comes to engine rebuilding but I enjoy mechanical challenges. Am I correct in thinking I would dissassemble the engine, have the shop machine and hone the cylinders and redo the heads? I have an original 75 Jeep Tech Manual, a Haynes book, and am going to get the recommended book from earlier in the thread. Thanks

 

rebuilding isn't that hard, just follow the book CLOSELY

Good call on having the block & heads done, but make sure to have the crank checked/ground/polished as well. don't order/buy ANY bearings or anything until AFTER you have the crank done as that will determine what bearings you'll need.

Also, REPLACE the timing chain and the oil pump......NEVER EVER reuse a used oil pump or timing chain

Planning on starting my 360 rebuild about mid summer.....right about the time the frame & body are just about done R)

 

Yeah, more or less. The main operations are for the cylinders, the bearings and the valves. I presume you want a "full" rebiuld. Typically the shop will hot tank the block and check for cracks. Then they will overbore to a standard oversize and fit the new pistons. They will also check the crank for wear. Usually on an engine with a cast iron crank (like the 304) they'll recommend regrinding the crank to use undersized bearings. They'll install new cam bearings. The heads will have the valves ground and they'll refurbish the guides via their favorite method. Probably rebuild/straighten the rods and balance too.

There's LOTS of room for variability in prices and in what machining operations you want or need. When you get into it, you'll need to make a lot of decisions.

Also, on an AMC V8 the timing cover gets a lot of wear since the oil pump is in it. The FSM discusses measuring the oil pump gears and housing. Be sure to ask about this when you get there.