[MarineOpLaw]

258 engine \'Mid-Life enhancements\'

Just bought WebJeep's used motor from his '78 CJ-5 (running 258 w/ ~70k mi) for my Scrambler.

(Thanks Web! You're a 'Great American' ! Looking forward to spending more time w/ you.)

While motor is out of vehicle, I figured I ought to 'fix' what is NOT broken, and thereby avoid unnecessary labor costs later and perhaps extend its life somewhat. I am looking for suggestions from those smarter than me (everyone?) on what should be addressed.

So far, I intend to replace the valve cover, timing cover and oil pan gaskets; and replace oil pump, rear main seal, and ring gear (flywheel).

When I have timing cover off, I will check play in chain for potential replacement.

What else do ya'll suggest? Any recommendations (type/brand)on replacement parts (especially oil pump)?

Thanks aforehand!

R/S

 

[880]

Re: 258 engine \'Mid-Life enhancements\'

You might want to find a 4.0 head and do that quick swap over. I never did it on my 258 because of all the emission crap on the intake was hitting my manifold.

 

[Tippy]

Re: 258 engine \'Mid-Life enhancements\'

You may want to change the timing chain - (When I get mine out I'm going to put a double roller one on). May want to look at a little more agressive cam, and the 4.0 head swap is still cool. Fuel Injection is also a great add on!

 

[517]

Re: 258 engine \'Mid-Life enhancements\'

New bearings would help the oil pressure as much as the new pump.

 

[Dirt Dog]

Re: 258 engine \'Mid-Life enhancements\'

Sounds to me like you have all the bases covered. (although at 70k the 258 just broke in

)

My "personal taste" in pumps are melling. Good name and never let me down.

 

[1830]

Re: 258 engine \'Mid-Life enhancements\'

Absolutely do the 4.0 head swap. Seriously. It's 30-40 horses for free, and basically almost doubled my gas mileage. Just keep your eyes open for a head.

 

[jdoggmoney]

Re: 258 engine \'Mid-Life enhancements\'

Until you find a 4.0 head, I suggest a Motorcraft 2100, and HEI distributor. These two mods along with a set of dual outlet headman headers gave my 258 tons of newfound get up and go. Very affordable and you cure known problems at the same time.

 

[Jim_Lou]

Re: 258 engine \'Mid-Life enhancements\'

In 78K miles on my '78 I've replaced the oil pump which probably was unnecessary, timing chain and sprocket, ditto, and now the rear main is starting to weep a little. Also the oil pan was rusted thin and I replaced it.

The timing set is much easier to change with the engine on a stand, so I'd replace that now. If the engine was holding proper oil pressure I wouldn't fool with the oil pump and bearings. They're not that bad to do with the engine in the Jeep if they need attention later.

Valve cover gasket, many many carb rebuilds, water pump and typical tune-up parts are all else it's ever needed.

 

[MarineOpLaw]

Re: 258 engine \'Mid-Life enhancements\'

Thanks gents for all the good advice. I guy couldn't ask for a better group of advisers.

However, the head swap will have to wait... for now. My 'tired' 258 puked out on the way in to work this morning

. Looks like I'll be taking leave for the next couple of days so I can get my 'new' engine up to snuff/into Jeep (my DD).

If I can get ahold of Web, I'll find out what the oil pressure was doing when he was running the engine. Based on what he tells me, I may look at replacing the bearings. Absent any revelations from him however, I think I will just replace the pump since that will be cheap & easy peace of mind/insurance, and I am no longer prepping this engine at my leisure.

IF I replace the timing chain, should I go standard chain, etc., or to a roller (double roller?)-type chain? Any suggestions? Worth the difference in price? Product preferences?

I'll be putting an MC2100 on it, motor already has the Motorcraft HEI cap on it. (And, I've got a spare GM HEI distributor sitting on a shelf in the garage.)

Current oil pan has no skidplate, so I intend to take a spare I have (w/ skidplate), and replace that since it'll already be off.

Again, thanks to all for your sage advice/recommendations. Keep it coming if anything occurs to you (timing chain?)!

R/

 

[webjeep]

Re: 258 engine \'Mid-Life enhancements\'

col,

sent you an email. and if you decide to do the double rollor clifford has a nice one

-web