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Port Engine Oil Pressure Concerns

knuckle47

knuckle47

Advanced Contributor
"The boat is still not in the

"The boat is still not in the water but my spring commissioning sequence will soon be complete. I am thinking a bit in advance here BUT...

After I had re-assembled the port engine top end and cooling system last March, I realized that I did have some coolant fall into the lifter valley and into the pan. Of COURSE..I changed the oil last year several times to be sure but ONE OF THE REASONS I changed things frequently is my concern for contamination in the oil. This one block has a situation where the oil pressure would drop off as the oil got hotter... IF I changed the filter, the pressure was restored for a few weeks until possibly 1 month later the condition would show up again randomly.

Again, change the FILTER and the pressure would restore to 40+. As the season passed it took longer run periods for the pressure to drop back to 20's but changing the filter restore pressure. Is it possible that collant is still turning to gel and clogging oil filter or ??? As for performance, both engines run extremely well and would give no hint of any trouble.

Does this trigger something developing in anyone's mind or am I overly concerned?"
 
"Your filter is becoming clogg

"Your filter is becoming clogged with use, like you suspect. I've seen it happen with engines with quite a bit of blowby, causing carbon (soot) loading of the filter. You could always open up a used filter to be sure. High blowby might not show much loss in performance, especially if its only one bad cylinder."
 
"Al,
I have a few question

"Al,
I have a few questions that come to mind.What weight oil are you running?When you say you are seeing 20's in pressure, is that at idle only or at cruise as well?What did your dirty oil tell you?Did you cut a filter open to see what you find?After a season of running and several oil changes and even more filter changes I am not in belief that you have any coolant issues there.Can always have the oil analyzed.You would need to do a leak-down test to see whats really going on.On a new engine you will get initial wear that finds its way to the filter, but by now you should be clean and green.Let us know....Todd"
 
"Al:

I suspect the oil filt

"Al:

I suspect the oil filter bypass valve is opening prematurely. That lets unfiltered oil slip past the filter, dropping the pressure somewhat.

Racers plug the bypass valve to keep it from blowing a motor, then use a higher pressure capable filter (100 vs 50 psi).


Jeff"
 
"I'll elaborate a bit on t

"I'll elaborate a bit on the carbon plugging. I had one scored cylinder, caused by a broke ring. There was a fair amount of blowby but no apparent power loss. The engine turned up as fast as the other side, within a couple hundred rpm at WOT. I noticed at oil changes, my oil pressure went to the normal, 40psi. After about 15 to 20 hours of use, the pressure started to drop, and would reach about 25 psi, at all rpms over 1500. A new filter would bring back up the pressure. When the engine was bored, the issue went away. No work was done to the oil pump or pressure release, just an inspection."
 
Al:

How often do you cange

Al:

How often do you cange the filter and oil?

What does the inside of your rocker box covers look like?

How many hours are on the bottom end?
 
"WOW ! All great details ...

"WOW ! All great details ... I change oils frequently ( every 3-4 weeks of use is 10-12 hours each weekend) especially last season since I knew I had "some" coolant in the pan. As for the insides of the covers. I can say so far they LOOK clean via mirror inspection however upon removal from the bad valves, that side looked like gloppy slimey mud and paste. Maybe like the remains of a colonoscopy....

The bottom end has about 700 hours +/- 5% or so as I know it. I never did cut open the oil filter but I did latch on to a case of CRUSADER LABELED oil filters. I can't say who makes them but they are white with blue CRUSADER Lettering. I use straight 40wt Pennzoil and USE to add Lucas Oil additive to it but I don't since 2007 since reading that engineers know way more about oil and my indiscriminate additions my screw it up .

I am inclined to get in line with Dave's thoughts as it may appear (from memory) that the pressure drops at about the same time line. Now as I said, LAST year towards the end...it did not do it as frequently which help to enforce my belief that I was GRADUALLY removing the gunk that was so prevalent in the top end.

The low pressure is at cruise speed which for me is no more that 3200-3400 but then at 1000 it would be 10-15. Blackstone's oil analysis in December of 2007 resulted in that engine getting the valve job and cooling system replacement for teh 2008 season. Oil was loaded with coolant even though visually it only looked dirty.

My question might be that if blowby is a problem to any extreme, might it not be visible in any smoke or excess oil film somwhere? This I do not see. When I start up, there is no smoke, no gas (unless I pump it too much prior ) zero delay in ignition. Timing is perfect 11 on both engines. Idle RPM is a smooth 700-720 (laser) I should get a vacuum gauge for mixture but I have been lazy there. I am again SPECULATING that if this continues, I would like to be prepared to solve the mystery by bringing data to this table. It could also just be my "stranded" fears getting the best of me.

You guys are great..... ! Thanks, AL"
 
"You would see blowby if you d

"You would see blowby if you disconnect a valve cover vent or oil filler cap. I forgot to mention also that the high blowby engine also had a high enough crankcase pressure to cause oil leaks from several places.
Al, if your issue is engine gunk, that should self clean after a bunch of oil changes. I've never used an oil flush, but that's another possibility to speed the process."
 
"The blowby is from the cylind

"The blowby is from the cylinder/head chamber usually past the rings into the block. If slight and block gaskets are secure, the only indicator would be from the vent hoses from the rocker boxes to the flame arrestors. Nothing into the exhaust so no 'smoke'. If the blowby is 'extreme' you'll develop a positive pressure inside the block and the gaskets will start letting the oil out.

That 'stuff' you described so well was circulating thru your oil galleys. It works like a sand blaster but on a much smaller scale.

I'd say keep doing what you have been and keep the details in your log book. If the trend keeps getting better, the engine should be okay."
 
"Thanks Gang,

The issue IS

"Thanks Gang,

The issue IS SIMILIAR to the description of TIME that Dave spoke of but thats about it... I literally gaze in the engine compartment( with earmuffs) if I am not at the controls just analyzing stuff and I have not seen any upper end blow by AFTER, I did the valve job. Prior to there would be some out of the rocker cover vents to the flame arrestor and they would make a collection of tan mayonaisse from the water /oil blending. I too am hoping the gunk in the pan is loosening and getting filtered out. HAD I been able to get in there, surely I would have cleaned it out but .... I have had my hands over almost every outside surface on those blocks inthe last 5 -6 weeks and there is no oil leakage or soot anywhere to be found, in fact I was admiring how well the new painted stuff held out last season.

As I remember I did scoop out about 1 coffee cup's worth of thickened emulsified goo out of EACH rocker cover and top of the valve assembly. That would probably be about 3/5 of a quart of material.

At this stage of the game I had to re-do the foredeck balsa rot...DONE! New forward 23"x23" hatch, below gets the new headliner, side wall closets and carpeting. Re-cover the v-berth cushions and add some lighting. Added a new seacock for the generator cooling raw water intake and used the old one for the washdown pump. I never saw the value of the washdown pump until we went fishing...BIG Fishing..what a mess!"
 
"two other things you may want

"two other things you may want to try:

1) go to your favorite parts house and see if they can provide you with an oversized (taller) filter. this will provide you with more filter area which should equal more time between pressure drop events.

2) Try the ATF 'flush' before the oil change. Few variations - basically add some atf to crankcase, run engine, change oil and filter. ATF has a 'cleansing' property...many 'old timers' I know swear by this as their preferred method of de-junking the internals."
 
"Mark, I too have heard that s

"Mark, I too have heard that since the detergents can work better...

I had a friend who had passed 10 years or more ago who was a SUPREME car/bike enthusiast and mechanic. His name was Freddy Lange and he had been a proponent of so many different tricks and simple fixes. His cars won here in NJ at Wall Stadium many times. His collections of Indian motorcycles and stories were terrific.

He told me once about a call he'd gotten from his brother... MAYBE 1935 -36 37?? He told him the bike front end was getting longer and longer as he rode. Fred figured he was drunk and told him to stay put... he was coming to get him

When he arrived, the neck on the bike had cracked and the extension came from the bending metal frame. They took it home to weld and repair...

Somewher in the 1960's he saw a bike at auction with THAT welded gusset on the neck...Knowing it was his brothers' ...he bought the bike and still had it when he had died in the 1990's

SORRY for the chat ! BUt This was interesting to me when I'd heard it! I have a gallon of ATF in the garage here....thanks"
 
"Neat story. As traffic at wor

"Neat story. As traffic at work was all messed up, I did some more reading after punch out time. I came across some interesting independent research that I found enlightening.

http://www.knizefamily.net/minimopar/oilfilters/opinions.html

Some of it may be dated but I think it provides a good reference point.

Also, I noted a lot of my responses duplicated Dave's...guess I'll have to learn to type faster."
 
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