Low oil pressure... Cam specs on a 305?

Sadder still I found my way to this thread because I am having the same issue in a 305 in a truck that I just purchased.. Seller said "crate motor has less then 10k miles on it". The truck is an 86.. with 43k miles.. excellent shape.. block stamp traces the engine to a 1977 C10. Looks like a Jasper long block rebuild to me.

I looked at the truck.. started and drove fine.. no smoke.. no knock.. faint valve train noise but just sounds like lash to me.. no clack like a stuck lifter or anything have to have your head outside or under the hood to hear it.

Get it home and do some tinkering and come to find out its got low oil pressure. Not DANGEROUSLY low.. but a little lower then I would like it to be. Cold idle 30 - 31psi, cold 2500 - 3000rpm 45 - 50psi, hot idle 11psi out of gear, 8 - 9psi in gear, 25 - 27psi hot mid RPM.

Thought I had this problem licked last night when I found the fitting for the pressure gauge was cracked and leaking oil but it was apparently just a tease.. swapped out the mechanical gauge for an electronic and it displays the same.. UGH.

There is a decent size dent in the oil pan but its only caved maybe 1/2" no more then 3/4" so I don't think its oil starvation but it could be.

I will be pulling the pan this weekend to see what I can see. From the fact that I found there was only about 2 quarts of oil in the engine the first time I changed it I have a hunch the previous owner ran it dry. Though i chopped the old filter and there were no shavings what-so-ever in it.. small amount of sludge in the bottom but no shiny bits that I could see.

Not trying to hijack a thread.. just found it odd to be in the same situation.

Any thoughts would be greatly appriciated.

 

No, that cam is find and wouldn't affect oil pressure any way.

NO

You heard it run, BUT did you see an oil pressure gauge on it then? And was it fully warmed up?

This would make me su****ious of the pick up tube as well. You also could have done some damage to the motor if it wasn't picking up oil before you straightened the pan.

Probably not likely here since the motor hasn't been rebuilt so there were no bearing changes to cause an issue.

Is that a MONEY BACK GUARANTY

Good suggestion -try a mechanical gauge for reference.


Just noticed this was 3 months old. Did you figure it out?

 

Drive the piss out of it. If and when it fails replace it with a 350 Crate motor. 305's are just an under performing motor anyway.

 

If you guys figure yours out, please post the cure.

I have low pressure on a 305 also.

I've put in new main bearings, and oil pump, still lower than I like.

Rich

 

is it smokin any blow by ,this isnt one of them motors with a oil filter changed to lay on its side they cause major problems

 

What kind of oil filter are you running?

 

That sounds like a great idea! Dime a dozen around these parts.

Not what I like to hear. I suspect I am going to pull this pan to find that the mains and rod bearings are fine.. Probably replace the oil pump while I am in there also.. I have a hunch that that will not correct the low pressure but my 'mechanical OCD' isnt going to let me get off that easy.

Filter is in the stock location on my engine.. no smoke and not really any blow by to speak of at all. By sight and ear the engine is in excellent fresh condition. Runs strong, no smoke, knocks, squeeks or over heating. Just... low oil pressure! ugh

For myself
Purolator with Valvoline 10-40

 

Well I pulled the pan.. unfortunately found some shiny bits in there.. Copper color.. very very fine. so then I pulled a main cap but was surprised to find all aluminum bearings.. which of course would not have been dropping those copper shavings. 2 score marks like something went through the main but all in all not scuffed much at all. One of the rods had been replaced and all 8 pistons were new. Cam didn't look washed. Now I cant speak for the composition of the cam bearings, wheat her or not they are leaving the filings, but I have a hunch that this engine was rebuilt and not thoroughly cleaned. I put a new high volume oil pump on and filled it back up with Rotella T 15w40 not too heavy (was 10x40). Also pounded the dent out of the oil pan. Fired it up and oil shot right to 55psi cold idle. 72-75psi 3000rpm cold. Drove it about 15 miles.. hot oil 2800rpm or so (55mph) it was holding 45psi steady.. hot idle is still a tad low at 13 - 14psi at 800rpm. but a world of difference.

Engine runs smoother, about 10 degrees cooler and has noticeable power increase.

Now I cant help but wonder how much damage was done! Engine was "rebuilt" 9k ago.. Hopefully I have prolonged the life several thousand miles.

 

Do Not Use Rotella T in a gas engine. It is designed for diesels. They are all together different, from the ash content to the EGR systems. I would use straight 30w or 20w 50 before Rotella T

 

Really should have checked all the bearings,especially if you were seeing sparklies in the oil.

 

That is a great debate. We use rotella in our entire fleet at work. Gas, diesel, air cooled.. all the same oil.

Well that would have been ideal but I didn't pull the motor.. and it was 100 degrees outside lol. I will run it till it destructs and look for a 5.7. This engine may last for years who knows. It is after all a 305.