Lose oil pressure as 345 warms up.

C

crazygunnison

New member
Okay, so I have a 1980 345 with about 100k on it. Fresh re-build heads with all new gaskets on the motor except the rear main which leaks a little. Starts great, runs smooth. Oil pressure is at about half way on the gauge while she's warming up.(do I trust the gauge?!) then when it reaches operating temp. The needle falls quickly to below the lowest line on the gauge. Sounds like the top end starts to lose oil and the valves and rockers start clacking a little. I am running fresh 10w-30. Also I should add that my Scout has been running on the hot side and I am working on a cooling problem momentarily, but I don't let her overheat. Worn oil pump? Rings? Help! Thanks guys. (just realized I should have posted this under engine tech most likely, but can't figure out how to move it, sorry)
 
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I moved this thread to a more appropriate forum for ya.

There are two particular stickys at the top of this sub-forum ya need to familiarize yourself with, then ya can diagnose your issue yourself!

And if you thumb through all the threads in this sub-forum, you will see that juju cam bearing stuff popping up over and over.

You must have a fully functional and accurate oil pressure gauge to determine any issue. The oem oil pressure indicator is not a diagnostic tool in any regard, though by running it in conjunction with a true oil pressure gauge, you can draw some conclusions about what the needle position might mean in various points on the indicator face for your system.

In my experience, a fully functional IH oil pressure indicator in either a Scout II or a pickall will indicate 50psi when the needle is dead in the middle of the horizontal indicator bar. And that is with an engine lubrication system that has no issues (cam bearings) and a wix, hastings, napa gold, or purolator pure one oil filter freshly installed.

Typical hot idle oil pressure onna I-4/sv engine with 20w-40 oil will be 10>12psi, which appears on an oem oil pressure indicator as nearly nothing!

If you are hearing valve train noise at hot idle, you do have a lubrication system problem that needs to be investigated and diagnaosed.
 
Just a few words from the swepco guy....

Michael,

when I saw this post, I knew you would get into it and move it since it seems to be a mechanical problem, one that has been covered in quite a few threads before.

However, as far as the choice of oil is concerned, in my estimation the 10w30 oil that mr crazygunnison is using might also be a little light. My first recommendation would be to use a good 15w40 with the more robust additive package which is pre 2007 specs of sm/cj-4; in other words oils which meet the "sl" and earlier for gasoline service rating and "ci-4" in the diesel api rating. This has also been covered in great detail in the oil tech section.

Suggest that when the overheating and mechanical issues are resolved, to put the older, "higher quality" oil into that puppy.
Of course, I recommend the swepco 306 - 15w40, which has a higher zinc and phosphorous additive package along with the more robust base stock they use. Since it is a high quality, high performance product, you will notice that it helps maintain a tighter oil pressure from cold to hot as well (lower when cold, higher when hot), another fine product from the only lubricant company in america to achieve the energy star partner rating! (just had to get that plug in!)

dick floryanowich
 
For my 345 I use straight 30 in mine. Oil pressure for me in idke warm is 15 in drive about25, cold is 50. Hope this hekps
 
New to me '74 345 in a Scout II. I've read a fair amount about the low oil pressure causes on this and other forums. I think mine is 'normal' but figured I'd pull the oil pan on the first oil change to look for cam shavings. It needed a gasket anyway. I found some thin shaving-like pieces of metal that measure up to about a third of an inch in greatest dimension (most were smaller) and cover an area a bit larger than a quarter when spread out. There was one oblong piece that reminded me of a drug capsule and was about as thick as the quarter (see pic). There was also some grey thick sludge around the drain plug holes that reminded me of anti-seize compound. I recall a picture somewhere that seemed to indicate cam damage leaves more and bigger metal pieces. Is what I have concerning for cam damage or not?

Since I am there, how do I check the condition of the oil pump and whether it needs a rebuild? Thanks
 

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Unfortunately, that material is cam bearing kibble. The grey sludge is another sign that the bearings have delaminated. At the least, your engine needs new cam bearings installed. The cam and lifters will need to be examined for wear and replaced if necessary.
 
Ok, well that's bad news. I'm not a mechanic. My obvious options are to drive it until it craps out, or fix it. Given the damage already present, any estimate on remaining engine life? I take it a fix will require pulling the engine. At that point will it be cheaper to rip it apart and fix, or just get a new long (or short) block?
 
Its hard to say, partially because its impossible to know how many hours have already been logged in that condition. You push it long enough and the engine will need a full blown overhaul if it doesn't already. Run 15w40 diesel/gas dual rated oil. Always keep it 1 quart above the full Mark on the dipstick. Get an oil pressure gauge hooked up so you can see a needle pointing at numbers rather than just a nondescript line. Limit long duration upper rpm driving as much as possible. Monitor the gauge while driving looking for a minimum of 10psi per every 1000 rpms when hot. When that baseline can't be maintained, or the pressure drops off randomly while you're driving and has trouble recovering after you slow down accompanied by valvetrain/lifter noise, you know you're about at the end of your rope.
The cheapest and quickest solution is to source a used runner that you can hear run before you buy. Then swaperoo and get on with life. Be wary of any engine that's been sitting dormant for more than a year. Hibernating engines can be just fine, but they need to be revived very slowly and carefully. You don't just hit a sleepy head engine with fresh gas and a battery right off the bat. Everything is dry inside. The trouble with used engines is it can be difficult to honestly assess what condition they're in internally. But for the cost of a crate engine or of having yours rebuilt, you can go through several used runners. Its not a fun situation to be in. I've been there.
 
So just to add to sb74. We know you will need a minimum of
1) a cam and lifters
2) cam bearings
3) a bottom end gasket kit

if it runs well other wise, meaning no knocking, smoke or bad blow by, you are probably safe to just do the above.

I would roll in new rod and main bearings while you are at it.

You'd be in it $500-600 (est) and know what you have if you did the work.

Now the bad news. :icon_gonk:
1) when a cam bearing spins to the point that it is in pieces, the bearing bore in the block will/can be over sized and out of round. That means a scrap block unless oversized cam bearing are available.
2) when a bearing gets ground up it spreads fine bits of metal throughout the engine. This usually plugs up the oil filter and it bypasses the metal throughout the bearings of the engine. That can destroy the crank and pistons.


You have nothing to loose, pull one main bearing cap from the center of the crank and have a look. Post a photo if you want and we can give you our opinion.
 
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