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258 build-up help

258 build-up help
G

Gaberu71

Jeeper
Posts
12
Thanks
0
Location
Gilbert,AZ
Vehicle(s)
1985 CJ7 258 w/2100 T5 w/Dana 300 Rubicon Express 2.5"
Hey everyone,
Well its been 4 years since my AMC 258 i6 / 4.2l dilemma post and needless to say its been long over do. But as they say when it rains it pours and after getting 2 kids through high school, quite a bit of teenager and family drama and getting all the wife's to-do-list finally done it is now "me" time.

So I ended up taking "Caveman's" advice and went ahead and decided to set aside the block with the cracked cylinder wall and find a donor block. After finding one, I dropped it off at CBA Specialist in Chandler AZ and had them work their magic on the block, the crank and the head.

Picked everything up and now ready to put it all together. Which brings me back full circle to here. Again I have never really put an engine completely back together; though I would love to have it under my belt. I couldn't find much on the internet for a step by step procedure for a AMC 258 i6 / 4.2l other than this link:
1983 CJ7 Rebuild: Engine Rebuild Part I (The Break Down)

Which seems to give a fairly good procedure. Any opinions on his process?
Or am I making a mountain out of a mole hill here. Meaning would it suffice to simply use any step by step procedure in doing this; for certain portions of it at least? Meaning as long as I follow the procedure for installing a crankshaft into a 350 block it would be the same for a AMC 258 i6 / 4.2l and/or for the cam etc. And I say 350 only because there are so many videos and write-ups on them. And my Chiltons and Haynes are somewhat helpful but a little hesitant to base it solely on them.

I guess my biggest fear is putting my block altogether, firing her up and a few days later; total engine failure, because in the link mentioned above or some other individual I decided to mirror in their procedure forgot to put a dime sized drop of oil on this point or that point-if you no what I mean-just one of those super minor details; though a critical one, that any professional engine builder just knows to do. Like I mentioned it would be an amazing accomplishment to put this all back together with my own blood, sweat and tears, and turn that key to hear her running again.
Even got my wife on board to take pictures as I go through each phase of the build in hopes that it might be able to help someone else with their project.

Thanks everyone....
 
Gaberu71 said:
Hey everyone,

Well its been 4 years since my AMC 258 i6 / 4.2l dilemma post and needless to say its been long over do. But as they say when it rains it pours and after getting 2 kids through high school, quite a bit of teenager and family drama and getting all the wife's to-do-list finally done it is now "me" time.



So I ended up taking "Caveman's" advice and went ahead and decided to set aside the block with the cracked cylinder wall and find a donor block. After finding one, I dropped it off at CBA Specialist in Chandler AZ and had them work their magic on the block, the crank and the head.



Picked everything up and now ready to put it all together. Which brings me back full circle to here. Again I have never really put an engine completely back together; though I would love to have it under my belt. I couldn't find much on the internet for a step by step procedure for a AMC 258 i6 / 4.2l other than this link:

1983 CJ7 Rebuild: Engine Rebuild Part I (The Break Down)



Which seems to give a fairly good procedure. Any opinions on his process?

Or am I making a mountain out of a mole hill here. Meaning would it suffice to simply use any step by step procedure in doing this; for certain portions of it at least? Meaning as long as I follow the procedure for installing a crankshaft into a 350 block it would be the same for a AMC 258 i6 / 4.2l and/or for the cam etc. And I say 350 only because there are so many videos and write-ups on them. And my Chiltons and Haynes are somewhat helpful but a little hesitant to base it solely on them.



I guess my biggest fear is putting my block altogether, firing her up and a few days later; total engine failure, because in the link mentioned above or some other individual I decided to mirror in their procedure forgot to put a dime sized drop of oil on this point or that point-if you no what I mean-just one of those super minor details; though a critical one, that any professional engine builder just knows to do. Like I mentioned it would be an amazing accomplishment to put this all back together with my own blood, sweat and tears, and turn that key to hear her running again.

Even got my wife on board to take pictures as I go through each phase of the build in hopes that it might be able to help someone else with their project.



Thanks everyone....
Click to expand...



The biggest thing I can say is make sure to time your engine correctly. I would use a bearing assembly paste more so than oil especially if it will take some time to build. The oil coat will drip from the main and rod bearings not leaving much of an oil film when you first fire it off. Also, it’s not a bad idea, before you start your engine, pull the dist, and pressure the oil galley by turning it off a drill. I have heard of people doing it, but I have never done it. You can also pull the engine oil filter pressure sender and go there as well to pressurize it I believe. In the end, it’s a fun thing to do. Just take your time, make sure it’s timed, make sure it spins freely by hand, and make sure to torque everything!


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Been a while since I built a AMC 258 i6 / 4.2l but the procedure is basically the same. Take your time and keep it clean. Timing is the most critical part. .Be sure it is right before you try to start it. I put a Comp cams 260H cam in the last one I built which helped bring a little more life out of it. Plasti-gage rods and mains to check clearances.
As far as assembly lubes I like Sta-Lube and Lucas assembly lube. When I built my 383 last year I tried a new(to me) lube. Normally I used 30wt on the rings when installing pistons but on this one I used 2 stroke engine oil. It did burn out quicker and didn't smoke as bad.
Good luck and if you get into trouble there is a lot of knowledge roaming around on here.
 
Last edited:
jakeh937 said:
Also, it’s not a bad idea, before you start your engine, pull the dist, and pressure the oil galley by turning it off a drill. In the end, it’s a fun thing to do. Just take your time, make sure it’s timed, make sure it spins freely by hand, and make sure to torque everything!


Sent from my iPhone using Tapatalk
Click to expand...

This ^!!
I always pre pressurize the oil system spin the motor over by hand while doing it, gets oil into all of the galleys, fills the filter (should prefill the filter before hand) and onto the rockers. Pre oiler shafts can be made or purchased, I have done both. Cleanliness, cleanliness can't be stressed more, double wrap it when not working on it. Be sure to use assembly lube on the cam shaft when you install it, also use it on the lifter lobes too. It's quite satisfying to know how the motor was built.
 
Always preoil a new engine before you start it and if you are using a hydraulic flat tappet cam be sure to add a zinc or zddp additive to you break in oil.

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Thanks everyone for all the feedback...I will definitely take my time and methodically go through each step, double checking, and confirming each step as I go.

Question though. Obviously I will me moving like tree sap so I think JackH937 mentioned using grease/paste because of the time frame I will be working in- which does make sense since the oil will eventually run off. Would it be wise to use a grease on everything; bearings, bolts, cam, crank, rods, lifters etc. or stick to using the grease on maybe just the cam lobes, rods and maybe lifters and everything else can get oil. Is the Sta-lube from Napa considered a grease or assembly lube or are they one in the same. And is break oil literally referring to motor oil?
Thanks again for all the replies....
 
" Breakin oil" is just motor oil. Ask 10 people what they use and you will more than likely get 10 different answers. I use straight 30 wt. Stay away from synthetics. Above all follow the cam manufactures reccomendations for break in. It will usually be something like 2000+ rpm for 15-30 minutes. It varies from manufacture.

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The assembly lube from Sta-Lube is a light grease with Graphite and Moly.
Use it on all bearings and timing gear, cam lobes etc.
It also works very well as a gun lube on slide rails and such. ;)
Use thread sealer on the ALL bolts that go into the water jacket.
Keep a log book of all PN's
Stay the hell away from anything marked Omix/Ada!
Again and with all respect---
I would have the shop do the rebuild and bench run.
LG
 
Don't use normal axle grease, it doesn't dissolve into the motor oil. If the build lube isn't sticky enough to hold something in place, use chilled Vaseline (same procedure for transmissions and transfer cases).

I did the drill thing with the oil pump, worked great on a motor that had been sitting a year. I used a 1/2" spade bit that I cut flat with a cutoff wheel. Run the pump, leave the plugs out and crank with a wrench a few turns.
 
I have built dozens of engines. Mostly hi performance sbc's - never a AMC 258 i6 / 4.2l , but other 6 cylinders. An engine is an engine as far as the steps to take and what to look out for. I don't have the time to take you through all the many aspects of doing a project like this, but if you have never built an engine, I would take Lumpy's advice and at least have a shop put the short block together for you. They have all the right tools to do it right. Plastigage is for shade tree mechanics. There are several good 'assembly' lubes out there. They will not "drip" off. Again, LG mentioned one good one. If you insist on doing it yourself, at least do the necessary research and talk to smart people. A set of 'quality' micrometers (and the know how to use them) will also get you one step ahead...
 
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Well after some serious thinking, I think I am going to have CBA do as Lumpy and lowcountry suggest and have them do the block and I will take it from there. At least I will have peace of mind that it will be done correctly, and I will be hitting the trails that much quicker. And I've done my fair share of timing chains, water pumps, clutch rebuilds, head gaskets and a few other jobs so Im pretty confident I can take it from there.
Again thanks everyone and will post pics as soon as i can.
 
If you are going have the shop do it, let them do a long block, that way you just have to put the accessories on and drop it in.
 
Gaberu71 said:
Well after some serious thinking, I think I am going to have CBA do as Lumpy and lowcountry suggest and have them do the block and I will take it from there. At least I will have peace of mind that it will be done correctly, and I will be hitting the trails that much quicker. And I've done my fair share of timing chains, water pumps, clutch rebuilds, head gaskets and a few other jobs so Im pretty confident I can take it from there.
Again thanks everyone and will post pics as soon as i can.
Click to expand...

Ask if you can watch-So you can learn..........;)
I would have them do the entire engine-along with a test run. Then, IF there's any issue. It's clearly on them.
Good luck :chug:
LG
 
It surely hasn’t taken this long. Who’s engine rebuild kit did you use? Make sure you break in the cam properly and use a Break In Oil with high zinc content!
 
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