What do you think

[thiswontbetooexpensive]

This picture is of the oil pump on the AMC 258 i6 / 4.2l I6 once I got the oil pan off.
View attachment 12618

This is of the head with valves still intact:
View attachment 12619

I'm pretty sure that the outlook won't be good after I get it to the local engine shop on Wednesday of this week for vatting and inspection.

Also, the cam looks pretty rough. See below picture:
View attachment 12620

Those off colored patches are not oil or staining, I believe the finish has been removed by 32 years of use/non-maintainance! I know this will need to be replaced.

Question is this: I want to keep the motor that I have because it is original. I have done minor engine work, but I don't know how bad this is looking at it dirty. I would like to do the overhaul myself, I think it would be pretty satisfactory to know I did that. What should I look for in terms of dollars and cents here. The cylinder walls look great and there is no buildup on the pistons or rings that I can see. There is an awful lot of buildup on the heads and valves. I'm pretty sure all of that will need be be changed as well.

It just amazes me that this engine was running and driving when I started dismantle on it the week after Thanksgiving. I drove the thing 25 miles that last day without an issue!

Let me have some food for thought with prior experience on engine rebuilds. Types/brands of parts to either utilize or avoid, where more money might be well spent, things of that nature. I am hoping to stay under about $1,200.00 for this rebuild if I do the assembly, I will farm out the machine work and probably source parts through them as well. I like to deal locally when I can.

Also, would it be easier to take all of the stuff off and just take block, head, and crank over for the machine work? Do I need to take all parts over for cleaning an inspection to see what can be salvaged? (This is all new to me)

Thanks in advance.


This won't be too expensive Dear! That's what I keep saying. Over and over again.

 

[coldair]

For the block i would have them boil it, magnuflux it also do the head, have them check the valve guide, grind the valves and redo the seats, turn the crank, line bore the block, Timing chain I would go with a cloyes true roller. Oil pump I would go with a melling pump don't get a high volume pump. I would also go with new cam bearings, and crank/connecting rod bearings. I would have the shop bore the cylinders and new pistons matched.

 

[coldair]

I forgot new cam/lifters. With all this I beleve you can be around $1000 if you assemble it your self.

 

[thiswontbetooexpensive]

For the block i would have them boil it, magnuflux it also do the head, have them check the valve guide, grind the valves and redo the seats, turn the crank, line bore the block, Timing chain I would go with a cloyes true roller. Oil pump I would go with a melling pump don't get a high volume pump. I would also go with new cam bearings, and crank/connecting rod bearings. I would have the shop bore the cylinders and new pistons matched.

I will take your word on that. I will also print that off and take it with me on Wednesday when I take the engine in!

The last time I drove it, I paid special attention to the the Oil pressure gauge. It responded to engine RPM's like I thought it should. It might be good, but how does one check it? There is mention of how to rebuild it in my Chilton manual using a feeling gauge and what-not. Is it just better to replace it?

Pistons. Can these be re-used or just start over with everything? They look great BTW.

Cam. Why use an RV Cam? What is an RV Cam? Pros, Cons? I don't plan on doing any performance mods to the engine, the stock power is plenty good for me but I have heard a lot of folks putting in an RV Cam. Has to do with more lower end something or another.

Do I need to take it all apart before taking it to the engine shop, or just leave it like it is? I have rolling cart to keep it all in order when it comes out just in case.....

 

[coldair]

You might be able to reuse the pistons but if it was me and in it for the long haul I would buy new pistons. The RV cam can change the power curve and also net you more power. If your happy with the power a stock motor I would go with a stock replacement. I will try to address all your other question when I'm around my computer.

 

[mtnwhlr]

When I did mine it had a spun bearing on #6 so I took it all apart and took the block, crank, pistons, and the head to the machine shop. They bored the block 30 over resized the crank and rods checked the rods to make sure they were straight and installed the new pistons on them. Installed new cam bearings and freeze plugs and did a valve job on the head. I got the rebuild kit from them so the bearing would match what they did to the crank and rods it came with everything but the cam and lifters. And I just got a stock replacement for them. And put it back together myself and I spent about $1400. But that was like 10 years ago. But I say get every thing from the shop that does the work because they did the michine work and know what size everything is. I have almost 100,000 on that motor with no problems. Hope this helps

 

[alpha6]

On the bright side, I bet it won't be too expensive. . Well...not really.

 

[thiswontbetooexpensive]

This information helps a lot. Thanks for the help. Really.

Anyone up for giving a little engine rebuilding school in Texas in a month or so? Lol!


This won't be too expensive Dear! That's what I keep saying. Over and over again.

 

[coldair]

The more you tear the motor down the least amount of money you will spend. I sent my motor off just the block the pistons that where labeled per whole. With all that machine work done to my block it cost me $800 ( line bored, crank turned, pistons installed, cam bearings,block boiled, magnfluxed, block 0 decked, cylinders bored 0.030 )

 

[thiswontbetooexpensive]

If I take them all the connecting rods and what not, they will boil all that too and check it out I guess and let me know what to replace?


This won't be too expensive Dear! That's what I keep saying. Over and over again.

 

[coldair]

You can ask them to see if the pistons are in spec. If they are all you will have to do is replace the rings and they will have to hone the cylinders so the rings will break in. If its a good shop ( trust worthy ) they will check them.

 

[thiswontbetooexpensive]

I got it all apart this afternoon. Is it normal to see some groves on the wear surfaces of the bearings? I had to work to get the bearings loose from their respective places and all the connecting rods were tight. Does this mean no real damage? The machine shop will verify it all for me, they have been over in Bryan, Texas for a long time now and are very reputable.

All of the places that I took the bearings off of still had the writing and symbols imprinted on the rods/bearing caps. I thought this pretty impressive as well considering what looks to me like WAY TOO MUCH build up in the engine.

On a side note, I worked in a Walmart changing oil and tires for two years while in college. Some oils, even when changed on regular PM scheduling, just leave deposits. I will get chastised from someone here, but I wouldn't put Penzoil in my lawn mower. Don't even use their 2 cycle mix in the weed eater or leaf blower or boat. I know the oil comes to the refineries from the same pipeline/oil tanker, but from there the differences occur. Penzoil just leaves gunk and that is what the PO of my jeep swears by I found out today.

Side-side note, Castrol has always been the cleanest oil I have ever taken out of an engine. Just my personal experience from changing oil in over 100 cars and trucks a day for two years. Also what I will be replacing all fluids with in the CJ as they get done and what I have ran in my personal and work vehicles for years now without incident.

Engine tear down was pretty cool btw, haven't done that in quite a while! I definitely plan on doing the rebuild myself now. After I get a new pulley for the crank that is!


This won't be too expensive Dear! That's what I keep saying. Over and over again.

 

[alpha6]

Lol...man did you jump into it!!

 

[BrockGrimes]

I'd skip the stock heads and swap on a set of 4.0 heads.
http://offroad-review.com/new/index.php?page=68

See in here also:
http://www.jeep-cj.com/forums/f99/useful-info-thought-id-share-665/

A stroker kit is only 1800 food for thought:
Pro rock Jeep 258 stroker kits and performance parts

Another food for thought:
Moses Ludel's 4WD Mechanix Magazine - Jeep CJ Inline Six Stroker Rebuild

Consider the chevy tbi swap can be done for around 300 to 500 if you do the work yourself and buy some parts.

 

[S76]

Just 2 things.

1. I also had an engine that was prematurely ruined by Penzoil.

2. I hate to rain on your parade but in the long run you would be better off to have the machine shop assemble the motor. If you assemble it yourself you basically have no guarantee for the work they did. If something goes wrong they are going to say you screwed up the assembly process. I see it all the time.

Let them assemble the block and head, oil pan and valve cover. You can dress all the outside stuff. That way they are responsible for everything between the pan and the valve cover, which is all the expensive stuff if it goes bad.

$.02

 

[CJ]

Just 2 things.

1. I also had an engine that was prematurely ruined by Penzoil.

2. I hate to rain on your parade but in the long run you would be better off to have the machine shop assemble the motor. If you assemble it yourself you basically have no guarantee for the work they did. If something goes wrong they are going to say you screwed up the assembly process. I see it all the time.

Let them assemble the block and head, oil pan and valve cover. You can dress all the outside stuff. That way they are responsible for everything between the pan and the valve cover, which is all the expensive stuff if it goes bad.

$.02

In my neck of the woods our machine shops machine metal, if you want an assembled engine they would just smile and point you to an engine builder... I always assemble my parts as I can then verify cleanliness, specs, tolerances and more. Call me old fashioned but I only trust my work on a rebuild. I also only trust my part selections and I don't want to leave the choices to anyone else but myself...

 

[thiswontbetooexpensive]

First off, Thanks to BrockGrimes for bringing this thread back to life.

Secondly, it is a few days past the 2nd of January and this block is still on the stand and the rest of the parts are still on top of the cart in the barn.

The shop this engine will go to, (one day ), does do complete assembly with warranty. While I agree with CJ's comments about knowing it was done right, I'm pretty sure I can't do it right. I don't want my engine to be the one I try to read a book and watch videos while putting it together.

I consider myself mechanically inclined, but $ would go better for skilled labor than tools I may never use again or know how to properly use in the first place!

Again, thanks for bringing this back up!

 

[S76]

In my neck of the woods our machine shops machine metal, if you want an assembled engine they would just smile and point you to an engine builder... I always assemble my parts as I can then verify cleanliness, specs, tolerances and more. Call me old fashioned but I only trust my work on a rebuild. I also only trust my part selections and I don't want to leave the choices to anyone else but myself...

Actually CJ I do the same exact thing as you do. I double check everything they did to make sure it is right and usually supply them with exactly what I want done. Like how much to deck the block and head to establish correct "squish" tolerances etc. But I have a bunch of tools to do this and have built many engines as I am sure you have.

The point though, is that method may not be for everyone. Dependig on expertise and a willingness to invest in tooling the money may be better spent having them assemble it to keep some type of warranty.

Just a thought, not a mandate.

 

[thiswontbetooexpensive]

So...I have read all the way through the AMC 258 i6 / 4.2l 4.0 head swap post linked to here: http://www.jeep-cj.com/forums/f2/258-4-0-head-swap-results-8500/

I think this is going to be the way to go for me. Barring bad news when I get the block to the shop finally, . I found the links included for the #7120 head and have looked up the '95 exhaust manifold/header and they still have those too!

I called the machine shop today and they are pretty busy. Most of their work is oilfield related and a man dropped off 11 Ford 6 cylinder motors to be rebuilt last week. (This is the motor of choice for oil pumping units) Even with all of that; he said they can get the vatting, inspection, and machining done on my engine in 2-3 weeks. If I have them do assembly, it will be 13-16 weeks completion! I almost fell over when he said that!

So, it looks like I will be re-building an engine soon. I'm sure more questions will come. I have made an excel spreadsheet with all the recommended parts so I don't forget more than the usuall stuff. Parts will likely be sourced through my friend that owns the local parts store in town. I would rather give him my money if he can get what I need!

Wish me luck I reckon, I will need it!

 

[thiswontbetooexpensive]

Took it in today. Should have an answer and a project on the engine stand instead of a hoop net weight soon!