258 oil pressure

[Kman]

My sons 1989 YJ has low oil pressure(first line on gauge)The manual only calls for 13 lbs at idle which seems low.There is a lot of lifter rattle also.What are you guys carrying for oil pressure?I'm thinking about putting in a new cam and lifter but thougtht I'd see waht you guys are getting for oil pressure.

[rick]

I run 10-15 at idle based on the gauge. What is "a lot of lifter rattle"? Do the lifters make less noise when you increase the rpms? If so, you may have a worn out oil pump, or maybe an oil pickup issue. You definitely do not want to run it long at idle if you have a lot of rocker noise. Can you remove the valve cover and start the engine to see if sufficient oil is getting to the rockers? If not, try using a stethoscope through the oil fill opening in the valve cover and listening to a rocker. Put the stethoscope probe on the rocker bridge. I'm assuming you have a stock set of hydraulic lifters. If so and you hear something that sounds like a ball peen hammer smacking the ever loving heck out of something really hard, you probably have a wasted cam and/or lifters and need a rebuild. If you run it with high valve train tolerances like this, you will possibly wipe out the cam, which often scraps the rest of the engine bearings in the process (it did in my case ). How many miles are on it?

[Kman]

We just installed a new oil pump to see if it would help,but to no avail.The Jeep has 134,000 miles on it,however I think the engine is a 1982 model.I'll have to check the casting numbers with the site you put in my other post.I think I'll rebuild my "spare" 258 to put in it then rebuild this one.Is there a "high pressure" oil pump available for these 258's?I see high volume ones listed.

[rick]

I opted for the stock oil pump when I did my rebuild because I had heard of issues with high volume pumps failing prematurely on several AMC engine sites. I'm not sure how reliable that info was, but the idea was that if you are using a high volume pump, you may not develop as much pressure as a stock pump (like any pump there is a pressure/volume relationship or curve).

If you are doing a complete rebuild, it's worth the money to have the rotating assembly balanced. I believe this was the single best improvement to my engine. I'm running a Comp X4-254 cam and love it. Even with the stock Carter carb, my engine is waaay stronger than it was stock.

If you have a 258 laying around and want to build a stronger engine, find a fuel injected 4.0 and build a stroker with the 258 crank .