cmartin2112

Hey guys,
So I just test fired my 89 4.0 rebuilt motor for oil pressure and other issues... Well unfortunatly a few came up...

1) My oil pressure seems to be a little on the low side. The gauge is reading probably about 25 to 30 psi at idle. Is this ok?
-I replaced the sending unit
-I primed the motor with a drill in the oil pump drive shaft and verified oil coming out of the rocker arms.
-Also cranked it with no spark and no fuel to check for readings on the oil gauge (Sat around 19 to 20 psi).

2) Long cranking time and rough idle. I have to sit on the starter (probably about 5 to 10 sec) and pump the gas pedal to get it to fire... Once it does start its got a rough vibration to it. I pulled off the oil fill cap and I got a small amount of smoke coming out of the valve cover when the motor is off.
-New motor mounts.
-I repalced distrubuter and timed it correctly.
-I am pretty sure that crank and cam timing is correct.
*Now i dont know if this is a reliable tool to check ignition timing... But I hooked up my timing light and checked the timing on the balencer and it was sitting at the number 12 notch... Is my timing off since it is suppose to be sitting at the 0 mark? Or is this just useless info?

3) I have a tranny cooler line leak... Can I use a high pressure high heat hose to fix it? Or should I order the steel lines?


***Also wanted to throw this out there but I can not keep my motor running for longer then 15-30 sec's due to the line pissing out tranny fluid.



Thanks for the help guys!

Chris

bigbadon

Forget about the oil pressure for right now.... you do have oil pressure. Correct the other problems first.

EVILXJ

at idle as long as it is 13psi or higher u are fine

also did u index the distributor properly?

cmartin2112

13 psi?? Hmmm I would assume that it would sit at 40 psi since its rebuilt... Oh well... But to answer the indexing question, yes, I belive I did it right... Tomorrow I am going to play around with it more after I repair the tranny line.

cruiser54

12* timing is correct. But the dizzy can still be indexed incorrectly.






Remove the distributor cap and cut a "window" into the side of the distributor cap at the #1 spark plug wire post . The "window" should be large enough to allow easy visual inspection of the position of the distributor rotor at the #1 spark plug wire post. Reinstall the distributor cap.

Install a ¾" wrench or socket onto the vibration damper retaining bolt. Rotate the engine in a clockwise direction until the #1 cylinder is at top dead center. Align the timing mark on the vibration damper with the "0" degree mark on the front cover timing scale. The tip of the distributor rotor should be near the #1 spark plug wire post.

Disconnect the distributor electrical connection. Remove the distributor holddown clamp, holddown bolt and distributor. Remove the distributor cap and rotor.

Place the distributor housing upside down in a soft jaw vise. Scribe a line 1/2 inch from the end of the distributor locating tab. Cut the distributor locating tab at the scribed line with a saw.

Remove any burrs and metal filings from the distributor. Reinstall rotor.

If necessary, using a flat blade screwdriver, turn the oil pump gear drive shaft until the slot is slightly past the 11 o'clock position. The oil pump gear drive shaft is accessible through the distributor mounting bore in the engine block.

Visually align the modified locating tab area of the distributor housing with the holddown clamp bolt hole.

Turn the rotor to the 4 o'clock position.
Lower the distributor into the engine block until it seats. The rotor should now be very close to the 5 o'clock position.

Reinstall the distributor cap with the cutout "window". Rotate the distributor housing until the trailing edge of the distributor rotor tip is just departing from the #1 spark plug wire post terminal .

Reinstall the distributor holddown clamp and bolt.. Reinspect the position of the rotor to the #1 spark plug wire post to insure that it has not moved.

Install the new distributor cap, reconnect the distributor electrical connections.
Revised 07/03/2012

cruiser54

And this shows where # 1 should be looking into the engine bay from the passenger fender.

EVILXJ

i just rebuilt my motor over the summer, at idle it is below 20

xKHANx

Same here, after rebuild mine sits at about 13-15 when idling after driving on the interstate for 15min. Around town at temp it stays at around 20.
That is with Mobile 1 5W-30 Full Synth and 090 filter.

V8XJDavid

I am guessing you installed a new oil pump when you did the rebuild? And used a gasket between the pump base and the mating surface? And a new pickup tube/screen? And a mechanical gauge?

As for the trans lines, you can use rubber hoses. Fuel line works great.

I would not use synthetic oil in a freshly rebuilt engine. Your rings may not seat properly if at all. Run regular oil for the first 1500 or so miles, change oil and filter, run another 3000 then change to synthetic. Just my personal experience.

bigbadon

Oil pressure is the indicator of engine clearances. Increasing pressure (if possible) does absolutely nothing to compensate for wear or loose clearances and will add no benefit to reliability. So my recommendation is learn to live with it unless you want to go back into the engine. You have pressure,be happy.

cmartin2112

Crusier thanks for the pics... It looks like my rotor is sitting in the 6 oclock postion at #1 TDC so indexing is probably off... I will re index and go from there.

Yes new pump, pickup tube, and gasket.

I heard that fuel lines were a no no for tranny lines because the rubber will swell... I guess it is just a temp fix for right now so I'll give it a shot.

I'm not using syn oil. Its standerd 10/30

Trumpster

I haven't bothered to read the rest of this thread yet but my 2000 XJ with nearly 160k miles on it runs at about 23-ish pounds of oil pressure at idle when warm (running 10w30 full synthetic - Amsoil). 13lbs is the bear minimum, anything around that is about when I would look at rebuilding personally but technically that's within spec for the motor.

cmartin2112

Alright so just to throw out an update I got the dizzy all straight and timed correctly. So I am pretty sure my rough idle issue is due to a vacuum leak on the MAP sensor... I tried to tinker with it and then the lower cooling line popped off and pissed coolent all over the place... So tomorrow I will refill it and tinker with it again.

But is it possible to get that black vacuum connector that sits on the back of the throttle body off? It's the piece that the map sensor line connects to.

I also got the tranny line issue straight! Just used some fuel line and a connector to jerry rig to the radatior.

cmartin2112

Right. I understand how oil pressure is created. My question was is it ok that a rebuilt motor only creates 20 PSI on idle. But that question was answered when a few people on here told me that their motors were rebuilt and only emmiting 20 psi at idle. So with that being said I guess I am HAPPY.

cruiser54

Here's how the throttle body vacuum line to the MAP is supposed to connect.