Care and Maintenance of my 258 Straight 6 Engine

Alright so finally I have the time to screw around with my 1974 Cj5 Jeep I just bought a few weeks ago. Now I tried not to drive it as much as I could until I had a chance to change the oil and various other fluids associated with the Engine and Trans.

The PO told me he just changed the oil and trans fluid in April (its marked in sharpe on the filter when it was changed) but its always a good idea to change the fluids yourself just to be on the safe side.

I used the search function but to no avail. Now honestly I have no idea what viscosity of oil to use or if I should use natural or synthetic oil. I didnt get any manual with the Jeep so I dont have that information.

Also what size/ brand of oil filter should I put on?

Also anything else you guys think is good to know in terms of how to maintain this engine would be much appreciated.

Here is a pic of my engine, for good measure





Thanks!!

 

If its running fine, 10w-30 in what ever brand you like. As far as filters, there is some really good info here: http://minimopar.knizefamily.net/oilfilters/

 

Awesome site for filters, I think Im deffinatly gonna spend the night sifting through that pile of information!

Another question, how many quarts of oil do I put in the engine??

 

Go to this site and review the Factory Service Manual (Technical Service Manual)...it will tell you everything you need to know.

http://oljeep.com/edge_74_tsm.html

 

should be 6 quarts.

The old sayin for jeeps: 6 in a 6, 5 in a 8

 

I noticed in your other pics that you have what appears to be a Howell TBI conversion, which is a lot less maintenance than a carburetor. If you search for Howell TBI you'll find a lot of info on this setup and you will need to familiarize yourself with the basics of it in order to troubleshoot any issues. It uses a basic GM fuel injection system, so parts are common and cheap. You also have an HEI distributor, which is not stock, but is an upgrade. The FSM won't be much help for these systems since they are not stock, but will be useful for other information.

 

THe howell TBI still uses the stock cam driven fuel pump?

 

That part confuses me, too. I would assume TBI would need a high volume electric pump, but if you look at his other pics here:

http://i94.photobucket.com/albums/l116/TommyGunner_2006/1974 Cj5 Jeep/engine6.jpg

http://i94.photobucket.com/albums/l116/TommyGunner_2006/1974 Cj5 Jeep/engine5.jpg

You can see the wiring and sensors (see the O2 sensor in the exhaust?), and just barely see the throttle body and adapter place. So I'm not really sure what he's got, there, but it looks like TBI.

 

WOW that site with the techincal manual is amazing. After looking at it I proceeded to print out everything I could related to the 74 CJ5.

Thanks guys!!!!

 

I cant see the pics at work, I'll have to check when I get home. But I do remember it looking like it was TBI. Interesting. Maybe hte PO left the fuel pump inline between an electric pmp and the throttle body for some reason, or maybe the lines we see on the pump go nowhere?

 

I'd expect the TBI pump would have to be downstream of the mechanical pump, if that's what's happening here. The connections and clamps on the mechanical pump won't take the pressure of the TBI pump - the TBI pump has to make enough pressure (ca 30 psi? something) to squirt gas into the intake. The mechanical pump only has to pool gas at atmospheric pressure in the float bowl.

 

So the question is do I have a mechanical fuel pump or an electric fuel pump? Also do I have a TBI or stock Carborator?

Honestly based on the work he has done on upgrading the entire electical system and updating other major components so the vehicle is practicle to drive every day I would say that there probably is an electric fuel pump installed and a TBI conversion.

However here are all the pictures I have taken of the engine, maybe one of them will help.



























I hope there is something in one of these pics that will help, and thanks alot guys this forum and its members are amazing!

 

water pump. fuel filter, distributor, alternator,wires...all look new

 

Where does the hose from the mechanical fuel pump go before it goes back to the top of the engine? Show us the "carburetor" with the air cleaner removed too.

 

Alright, Ill have some pics of those areas posted on Saturday evening then.

 

Well I bought the jeep and fixed a few things and she runs amazingly!!!!!

Now today I changed the oil and replaced the oil filter. The previous owner had 20W50 oil in the engine and the constant pressure when driving or at idle was about 40psi.

I just put in the 10W30 oil that was recommended here and my pressure at idle is about 5 psi and 35psi when driving. Is this normal? should the pressure always be constant? Or is it normal for it to fluctuate that much between idle and driving?

 

Sounds about like low/normal.

How bout some new pics now that you HAVE it.

 

Defiantly has a tbi setup on there.
Trace the hoses from the tbi (were the carb should be) to were ever they are going.

 

Ill post some pics tonight when I get home. I took the Jeep to my girlfriends house to show her family.

 

Well here she is in my own driveway at my house! I have the Bikini top on right now but she does have a brand new rag top and door set. Also I have a rear seat but its not installed yet.