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New issue, low to no oil pressure!

So far things look good with no loss of coolant and no gains in the oil level. I may have won this battle, now back to the original question of how much bearing damage was done. At this point it's going to get driven till something else happens.
 
RCP Phx said:
Believe me I've considered it but, that's a bandaid! But it could buy me time till winter! I thought about a HV pump, but since I'm pulling the pan,

if I'm pulling the pan, I might as well replace all the bearings,

if I'm doing all that I might as well go thru the heads,

Get where I'm going with this !!!!!
Click to expand...


LOL we replaced the oil pump with a HV, pan gasket that was leaking, the crank bearings since we were there, and I switched to 20W50 dyno oil 12 years ago and 70,000 miles ago on my 87 Renix and it is still one of my DDs.

I get 55 psi cold, and 22 psi hot at idle after a hard high rpm run in 100 F heat waves.

Only other problem I had was a slow gasoline dilution in the oil dropping the pressure over time as the leaking valve seal on #1 and #2 fouled the spark plugs slowly....New valve seals fixed that for a while, now 12 years later I am going to get new valve stem guides...or swap the head with my spare. Have you considered checking for gas build up in the oil? Oil analysis?
 
Green Mesa XJ said:
I was curious if the old head was so bad it helped improve the flow.
/QUOTE]

There are no oil gallery's in the 4.0 head, only oil returns for the oil pumped up by the lifters and that's not a lot. The entire motor was scrubbed and cleaned inside when I started this project with the removal of the vc gasket and the oil pan.
Click to expand...
 
Ecomike said:
LOL we replaced the oil pump with a HV, pan gasket that was leaking, the crank bearings since we were there, and I switched to 20W50 dyno oil 12 years ago and 70,000 miles ago on my 87 Renix and it is still one of my DDs.

I get 55 psi cold, and 22 psi hot at idle after a hard high rpm run in 100 F heat waves.

Only other problem I had was a slow gasoline dilution in the oil dropping the pressure over time as the leaking valve seal on #1 and #2 fouled the spark plugs slowly....New valve seals fixed that for a while, now 12 years later I am going to get new valve stem guides...or swap the head with my spare. Have you considered checking for gas build up in the oil? Oil analysis?
Click to expand...
Are you sure the gas dilution isn't from a leaky injector? That is a lot more common.
 
RCP Phx said:
Green Mesa XJ said:
I was curious if the old head was so bad it helped improve the flow.

/QUOTE]



There are no oil gallery's in the 4.0 head, only oil returns for the oil pumped up by the lifters and that's not a lot. The entire motor was scrubbed and cleaned inside when I started this project with the removal of the vc gasket and the oil pan.
Click to expand...


I was curious if you saw any improvement, i didn't really expect you would. But with gases escaping and viscosity affected you might have a sight improvement. If the head was seeping at a crack then it I guess it probably wouldn't show much improvement.



Sent from my iPhone using Tapatalk
Click to expand...
 
old_man said:
Are you sure the gas dilution isn't from a leaky injector? That is a lot more common.
Click to expand...

Yes I had installed 6 brand new 4 hole injectors.....

The #1 and #2 cyls on mine have sideways wallowed out valve guides. That movement slowly wipes out the new valve seals in 1000-2000 miles now. The oil fouling took 30,000 miles in 2005, got worse over the years, 70,000 miles since I bought it would foul and bridge a plug in 300 miles and miss fire and stall. New seals bought me about 2000 more miles. New seals stop the oil pressure drop till the plugs foul and the miss fires hit. y that time the oil pressure had dropped from 30 to 19 psi. New plugs and new oil the problem is gone till the new plug foul with oil. Been studying this one for 12 years. In slow motion. I thought at first the high sheer polymers multi viscosity oil were going bad. But if I install new seals and plugs, but keep the old oil, the pressure returns in a few hundred miles or less.

I am known for never having COMMON problems LMAO.
 
Since I got the coolant leak fixed and a brand new head, I ordered new lifters and a set of roller rockers to help eliminate wear as much as possible!

I should add that when I was doing the head, I noticed some galling of the rockers and pivots so I knew I wanted/needed to do some thing!
 
Last edited:
RCP Phx said:
I finally got a return call from Basko Engines. Ray has been doing my machining/balancing work for me for over 40yrs. He said the 4.0 is notorious for eating cam bearings. That's the type of info I was trying to find out!
Click to expand...

Tore the motor down last night(building a stroker), the cam bearings were indeed wasted! The crank journals didn't look as bad as I would have thought and the main/rod bearings were definitely not that bad.
 
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