Engine Rebuild

[sawyerSX4]

Hey everyone, I'm thinking about possibly doing some sort of engine rebuild on my 1983 SX/4.  It's got the 258 inline 6 and an automatic trans.  There's not really anything wrong with it, it does burn some oil and sometimes I'll hear a ticking sound, but other than that there's nothing wrong and it hasn't had any engine work done to it.  I just thought it would be a fun project to do and I've always wanted to do it.  I have been looking at some engine rebuild kits that range from about $300 to $400.  Just wondering if these kits are even worth it or is more of a hassle than anything? If they really are worth it, does anyone know a good place to get one?  I think this would be a fun project, just want to make sure it's worth the money.

[doc65]

Sadly you get what you pay for in those kits, a good/complete kit will usually run about double that.  If you are going to do it there are a LOT of factors in what you could or should do depending on the engines condition.  While doing it I would usea  4.0 HO cam & get a 4.0 head to have a valve job done on instead of the 258, either a 7120 or 0630 casting, they are usually only about $40-$50 from a u-pull yard or the local classifieds, new bearings goes without saying, and if I was in it that far I'd bore & hone the cylinders & put new pistons& rings in(unless the cylinders are in spec and will hone clean, then you "might" be able to get away with just new rings).  At a guess you should be able to do a good budget rebuild for around $1000 if you do some shopping & don't get too carried away on additional upgrades.

All that pre-supposes that you just WANT to rebuild, otherwise a good low mileage 4.0 from a Cherokee/Grand Cherokee/Wrangler would be an expediant option, then get an electric fuel pump(4.0 block has no provision for mechanical pump), and use your existing intake/carb and a 4.0 exhaust,

OR bite the bullet and go all the way to a 4.0 HO with multi port fuel injection

OR combine a couple of the options & build a Stroker

OR.... 

[sawyerSX4]

Sounds like a lot to consider but good and important info.  Thanks doc65

[eaglebeek]

While I was typing doc65 typed just about everything I was going to say. I think your question was if the rebuild kit was worth the money. The answer is maybe. The kit doesn't have anything beyond rings, bearings and gaskets. If your 258 is in any way beyond the scope of these parts you're in for additional expense. You won't know that until you tear it down and start looking and measuring.

The 4.0 is in so many ways better than the 258. Unless you want to keep your Eagle all-original I would not put the money in the 258.

[doc65]

Casper, it's a little more complicated than that, you need to be careful using stock 4.0 pistons, it can work, depending on the specific year & parts, but it can also wind up with high compression & ping something fierce. 

In the scenario of buying parts before measuring then finding that you need to bore the cylinders will not mean you have to buy rings, it will mean you need to buy PISTONS and RINGS.  Even a very small overbore of .010" (which likely wouldn't clean the bores anyway) would have serious blow by, and RATTLE like a worn out diesel

Most of the 4.0's can be made to work, I think my preference would be a 96-98 because it will be the NVH block, that block is marginally stiffer, it will have the main bearing girdle, the block will have the alignment pins for the head, and the head will be a 0630 that also has the dowel pin holes, and optimally I would go 97-98 as they have all those plus the later dual pattern cam.  With all that said I would have no issue using any of the 91-99 HO blocks if the price was right, just avoig the 0330 head as they are very crack prone unless they are the very late version with TUPY also cast  into the head near the 0330 casting number   

[A-A EAGLE]

SawyerSX4, why would you do a rebuild with so less complaints about the engine? When it still has its power, not consuming more than 1 litre oil to 1000 miles, pretty good compression and nice looking sparkplugs I would say no, unless you want to tune the engine a little. In that case I would advise a nice rebuild with a torquier camshaft and 4.0 head and things like that and choose for quality.
Oil use is often caused by hardened or cracked valve stem seals which you can replace with the engine in the car.

Anjo
Holland

[A-A EAGLE]

Oh, and give it a good oil change with quality 20W50.....

Anjo
Holland

[sawyerSX4]

Thanks for all your input everyone! It looks like i'll probably just leave the engine as it is and fix it up as need be.  A lot of good info to keep in mind for the future.  Thanks again everyone!