New to Forum - Rough Estimate for Engine Machine Work

[RQCinLHT]

I'm new to the forum. I recently bought a CJ5 with the AMC 258 i6 / 4.2l motor. It burns oil pretty badly, and the plugs are very oil fouled. I'm getting ready to pull the motor to rebuild it, and just wondering what you guys have been in for on getting the machine work done. I won't know for sure till I get it apart, but pretty sure the block will need to be bored and crankshaft reground. Not looking to make a race engine out of it, just want to make it reliable again, put it back to stock spec.

 

[Hedgehog]

If your bottom end isn't knocking it is likely that the crank is alright. Maybe a new set of bearings at most. It is likely that the majority of your troubles are top end related. More than likely valve guides, reseat the valves or replace, new rings and a good honing of the cylinders and your good to go. But, that is just guess work. Cleaning up the crank is pricey specialty work, lets hope your crank is in good shape. oh yeah, and hope there isn't any cracks.

 

[Belizean]

I have an 84 7 with 4 cyl with 235 K miles and still running great but know it will not last forever. The short-long term project is I bought a AMC 258 i6 / 4.2l this summer and and just got it back from a local machine shop that was recommended to me. I was told by the guy I got the engine from that he thought the engine was ok but really had know idea because he had bought the jeep and removed the engine to put a V8 in. Engine was disassembled and looked ok but I decided I would go for the rebuild. With all machining done crankshaft turned,head reconditioned new springs,valves, guides, cam kit for fuel injection and engine kit with pistons and all seals and gaskets. I have around $ 1,800 in that

 

[tarry99]

By the time you pull the motor , boil the block & heads , measure it , bore the block, buy a set of pistons , wrist pins & rings, recondition the rods, grind the crank, buy a new bearing and gasket set, grind the valves, recondition the valve train, buy a new cam , lifters , cam bearings , timing set and oil pump. rebuild the carburetor & ignition and reassemble you'll be in it $2200-$2500.

There are rebuilt motors out there on the internet that are cheaper......the problem is you never know what exact parts or procedures have been done............

If your going to keep the vehicle having someone that is both qualified and has a good reputation in your area I believe is a better option for quality control.

Pay me Now or Pay me Later!

 

[RQCinLHT]

Thanks for the thoughts and ideas, I appreciate it. Sorry it took me a while to reply. The bottom end sounds smooth to me, I can just hear a definite misfire in the exhaust, probably just due to how bad it's burning oil. I'm going to go ahead and pull the motor. I'm a cnc machinist, have a shop at home, so I've got the micrometers and dial bore gauge and other tools to check it out good. I've always wanted to get a project vehicle to rebuild an engine on. Guess I got one now.