Oil pressure dropping during camshaft break-in.

Need some advice with a possible oil pressure issue.

I just completed breaking in the camshaft on my new 455 engine. Oil pressure during pump priming was almost 40 psi. Upon engine startup it was a little over 40psi at 2000rpm. 10 minutes into cam break-in it dropped to 30 psi so I shut the engine off and cranked in the oil pump adjusting screw about 2 turns and restarted with no improvement. I continued this back and forth until the adjuster was screwed all the way in. Still just 30 psi at 2000rpm. So my first concern was that maybe there is a bearing issue but there was no knocks,ticks, or rattles and no metal flakes showing on the dipstick when I checked it. I'm wondering if it's possible I accidently put the wrong spring in the pump when I set it up. The pump was set up with .0015" clearance between the gears and booster plate. I did install a new Metric style cover and I'm pretty sure I used an orange spring as T/A suggested in their instructions. I'm going to recheck tomorrow if I get a chance before running it again. I was kinda suspicious of my oil pressure gauge but it was showing a little over 40 psi at startup. I did Rev the engine to 4000rpm and the oil pressure showed 50 psi so I know it's oiling but still am a little worried. My engine bearing clearance is .0015-.002 and the oil I'm using is Gibbs 5w30 break-in. I am pretty sure the oil pressure should be higher. Any advice or suggestions would be greatly appreciated.

Jim

 

Can’t remember if the metric cover takes the long or short springs,
See my pictures below
,

 

[QUOTE I think it would take around 10 mins for the oil to reach temperature , cut the filter open check for torn paper , no doubt there will be some metal in the filter , should only be fine grey iron ="68Buick-Jim, post: 3476939, member: 133326"]Need some advice with a possible oil pressure issue.

I just completed breaking in the camshaft on my new 455 engine. Oil pressure during pump priming was almost 40 psi. Upon engine startup it was a little over 40psi at 2000rpm. 10 minutes into cam break-in it dropped to 30 psi so I shut the engine off and cranked in the oil pump adjusting screw about 2 turns and restarted with no improvement. I continued this back and forth until the adjuster was screwed all the way in. Still just 30 psi at 2000rpm. So my first concern was that maybe there is a bearing issue but there was no knocks,ticks, or rattles and no metal flakes showing on the dipstick when I checked it. I'm wondering if it's possible I accidently put the wrong spring in the pump when I set it up. The pump was set up with .0015" clearance between the gears and booster plate. I did install a new Metric style cover and I'm pretty sure I used an orange spring as T/A suggested in their instructions. I'm going to recheck tomorrow if I get a chance before running it again. I was kinda suspicious of my oil pressure gauge but it was showing a little over 40 psi at startup. I did Rev the engine to 4000rpm and the oil pressure showed 50 psi so I know it's oiling but still am a little worried. My engine bearing clearance is .0015-.002 and the oil I'm using is Gibbs 5w30 break-in. I am pretty sure the oil pressure should be higher. Any advice or suggestions would be greatly appreciated.

Jim[/QUOTE]

 

I appreciate the suggestions and will report back tomorrow my findings. I did go purchase a test gauge kit to verify oil pressure reading is accurate. I plan on checking the bypass valve and relief spring tomorrow and might as well check the contents of the oil filter too while I'm at it. My suspicions are the spring or bypass. With the drill priming the oil pump for several minutes cold I was showing about 38-39 psi with the adjuster screw at base setting as received. Upon startup and at 2000 rpm I had 41-42 psi cold. It dropped to 30 psi after 10 minutes and fully warmed up. The engine stayed between 170-200 degrees water temp the entire time with a 180 thermostat so I know things are cooling properly.

 

One thing to consider is the RPM of the drill.. if its spinning 950 rpm, you gotta double that number in terms of engine rpm since the cam spins at half speed. So it tracks your getting 40 psi both ways with cold oil.

If you blip the throttle will the pressure go higher than 40 psi?

Also it takes forever for oil temps to peak when idling..

 

Correct!
The engine needs to be under load to get the oil hot.

 

That’s pretty thin oil.
Try 10/40

 

Oil won't be an issue here.. Gibbs BR30 is what we use in every iron engine here on break in. It is 5w30. It is very thermally stable.

I see oil pressure at 65-70psi typically at initial start up, and it will drop 5-15 psi at cam break in speed, depending on bearing and lifter bore clearance in a particular engine. Not unusual to see oil temps in the 180 to 200* range during a cam break in on a new engine.

I agree.. check the oil pump relief valve for free movement.

JW

 

I would have used Gibbs BR40 10W-40 break in oil not 5W-30. The 5W-30 isn't even meant for flat tappet cam breakin.

 

OK I was able to spend a little time out in the shop today to do some investigating. The first thing I did was remove the pressure adjuster, spring, and relief valve. It did come out with a magnet and upon inspection I did not see any scoring or other blems. The spring was orange which is what T/A said to use with the metric cover. So I had another orange spring and relief valve piston from my oil pump kit and installed those. I backed the pressure adjuster to about midway and locked it in place. I went ahead and pulled the distributor after bringing #1cyl back to TDC so I could prime the oiling system to see what pressure I was getting. Keep in mind I'm using a cordless drill on low speed setting which is 400 rpm. The pressure gauge read about 50 psi on the test stand. I then installed an oil pressure test gauge I purchased last night and repeated the priming. The new test gauge read 62 psi at 400rpm drill speed. My suspicions were correct with the gauge being inaccurate as a 12 psi difference is a lot to me.
Next I went ahead and drained about half the oil out of the pan and noticed a little dark grey material on the magnetic drain plug. Reminded me of clutch material you find in an Automatic Trans pan. Mind you it was just a little. I then took my finger and stirred the oil up some and noticed a very slight grey sheen. No metal pieces.
My question is how much grey is acceptable? I realize there may be a little from first startup and cam break-in but what's OK? I've had a cam failure before and there was a lot of fine metal particles in the oil. This was not like that.
When I was building this engine I specifically told my Machinist I wanted .002 Main and Rod bearing clearance. Upon checking everything most had .0015 and a few were .002. So I believe my clearances were OK. The thrust clearance was a little tight and after centering the bearing was .0015 which after checking specs was the minimum.
Another piece of info that may help is I remembered last night that when I first originally primed the engine it didn't matter what drill speed I was running. The oil pressure would only read about 40 on the test stand gauge. Where as now when you put the drill on high which is 1500 rpm it is 70+ psi. I want to cut open the filter but do not have a large tubing cutter or similar tool. I'll figure out something to get inside it.
Here are some pics and I really appreciate the help!

 

Pressure seems fine but that oil.....if not magnetic must be aluminum. Or...maybe excess zinc from break in oil?

 

ZDDP is clear light amber colored, similar to oil. You cannot see any zinc particles.
Some assembly lubes with moly-b can cause that.

 

Yeah...moly lube likely...I say put fresh oil in and hope for the best. Some will put break in oil in again but that may be over doing it...but other than cost can't hurt....then change that out at 1000 miles. Might want to cut filter open and take a look....

 

I lubed the s!#@ out of it during assembly. I used moly lube on some parts and permatex ultra slick assembly lube primarily on the bearings and sides of lifters. I used the Lucas cam break-in lube that came with the camshaft. I did finish the camshaft break-in so the engine has a little over 20 minutes of run time on it at 2000 rpm. My engine temps were all good too staying between 170 and 200 degrees. Even with a stock waterpump. I guess the two row aluminum radiator is doing its job well. I have a waterpump on backorder with T/A since November....
I still would like to open up the filter and see what's inside. Maybe if I get some spare time this week after work I'll do it.

Jim

 

That would do it...I once used a 16 oz can of Isky cam lube to pour over cam before putting intake on. I freaked when I drained oil but turned out all good.....better to have a bit much than not enough. Change that filter....mine was almost plugged with moly lube. It's good stuff but need to be gone once it has done it's job.....

 

I have used a pair of diagonal cutters on the lip of the filter, cut it down about 1/2 inch and then use needle nose like the old "ham can" opener.

(wear heavy gloves)

 

That's a great idea! I'll give it a try this week. I'm anxious to see what's in the filter.

 

My oil looked exactly like yours after run in ( roller cam, really no break in)
At first I thought WTF, but attributed it to the fresh bore/ hone, new rings scuffing up the walls getting seated.
I changed oil/filter and have been beating on it for two years so far, oil comes out normal looking.

 

Of course the oil pressure drops as the oil warms-up and the viscosity thins.

Whether this is acceptable oil pressure, and acceptable change with temperature is debatable.

950 RPM? Unlikely.

Yup. When the oil is the same temp as it was, the pressure should be the same at the same oil pump RPM.

Fully-hot? Likely even longer, depending on how hard the engine is being used. Hot enough to drop the oil pressure at idle? Probably significantly less than ten minutes.

Most--nearly all--of my experience with engine oiling system "priming" has been on engines with submerged, cast-iron oil pumps. This does not exactly transfer to Buicks.

I have used a "2000 rpm" direct-drive 3/8" air drill. I cannot get anywhere near 2000 rpm out of an oil pump that's pushing room-temp oil.

I generally use a "500 rpm" gear-reduction 1/2" air drill. I get 500 rpm, or close to it until the oil pump quits churning in air and actually starts pumping room-temp oil. At that point the RPM noticeably drops.

I don't believe it's possible to crank an oil pump at 950 rpm with room-temperature oil, unless you've got some sort of monster drill motor. The drill may be rated for 950 rpm free-speed, but it's not turning that fast under load.

An engine achieves adequate (cold) oil pressure on the starter motor. The starter turns the engine at something like 150 rpm; more-or-less. Therefore, if the oil pump is spinning at half that--about 75 RPM--that's PLENTY to "prime" the engine, and depending on the relief valve spring, maybe even open the relief valve with room-temperature oil.

I could accept that the Buick pump may have additional leakage due to loose clearances against the aluminum housing, and of course it has to "suck" through two feet of pickup tube, block, and timing-cover passages. Still, I don't think it's so different from what I'm used to that my experience should be negated.

But we don't care about "peak" temp; and we don't care about "hot". We care about warm-enough to drop idle (or priming) oil pressure.

You are very likely to burn-up a typical cordless drill, especially on a low-speed setting unless that low-speed is achieved with gear reduction. If the drill motor armature isn't spinning it's lil' heart out, the fan on the end of the armature isn't moving enough air to keep it cool at the same time that the amperage draw of the motor is going to be pretty high.

This is why I insist on using a gear-reduction, 1/2" AIR drill. No armature to get hot, and a steady supply of air pressure so that the longer I use the drill, the colder it gets.

Again, are those "rated" speeds, or are they actual speeds?

You've got more than one gauge, and they're not reading the same. You need to verify which gauge is accurate--and it's possible that neither one is.

You've also played with the pressure relief valve setting. So it's no surprise that you're getting different pressures now vs. before.

As for your grey matter in the oil--this is why I install a bypass asswipe oil filter on a fresh engine, in addition to the normal full-flow filter. The bypass filter may or may not be a "permanent" installation, but it'll be in use at least during the entire engine "break-in" process. MAYBE you want to send off a sample of that oil for analysis. I probably would not. I'd get clean oil and a fresh full-flow filter in the engine, and see what happens now that the assembly lube has been flushed-out. The bypass oil filter is still a good idea, though.

I get mine from eBay, prices vary but ~$80 to $100 should do it, shipped to your door. My preference is the SKY-manufactured Frantz filters; but there's several brands, multiple models, and Amsoil and others sell new ones if that would be important to you.

There's at least six listings for Frantz asswipe filters on eBay right now, using search terms "Frantz filter -Ferro -Magnetic" and with the "US Only" filter. There's also several associated listings for oil filter caps/adapters, fender covers, asswipe filter elements, etc.