[Bobalong]

Put a quart of synthetic oil in your freezer.
Put a quart of same viscosity regular motor oil next to it.
Next day uncap both and pour one and then the other.
Synthetic oil will flow much easier.
I use it in everything in the winter.
Had an old 6.2 GM diesel in a Chevy suburban awhile back, synthetic oil eliminated the need to plug it in on cold winter nights. Almost 300,000 miles on it when I sold it. Still ran fine.
I don't drive rusty vehicles.

[AdamIsAdam]

Originally Posted by Sirrotica

The reason for the dipstick rising up is usually due to excessive crankcase pressure and it pushes the stick up as the pressure rises internally in the engine. Ring seal when you run the RPMs up can cause this as well as a faulty PCV system not allowing enough pressure back to the intake manifold.

When you open the throttle all the way the manifold vacuum decreases, and there is very little draw on the PCV system until the throttle plates are partially closed again causing a restriction and restoring manifold vacuum. By this time the dipstick is unseated and the pressure has found the path of least resistance to equalize the crankcase pressure to atmospheric pressure.

I have had Pontiacs when using synthetic oil that sealed the rings better than regular oil that actually caused detonation in a marginal situation, and actually cracked the top ring, causing blow by and excessive crankcase pressure. Unless you have an engine that is really close to maximum compression and detonation prone this probably isn't your problem. It may just be the synthetic isn't allowing as good of a ring seal as your regular oil did,or the engine is becoming tired and in need of a refresh.

Synthetic oil in an engine that is fresh, will definitely slow the ring seating process compared to regular oils. I have no idea what state your engine is in as far as fresh rings and being overhauled recently, another variable.

A leakdown test would be a good indicator of the condition of the condition of the engine valves and ring seal. A less scientific test is to disconnect the PCV system and remove the oil fill cap and observe the amount of blowby gases coming from the oil fill opening as you rev the engine, not as accurate, but if the amount of blowby is excessive it is at least and indicator of ring seal failing.

The oil pressure may just be to thinner oil when hot causing lower pressure. You don't state how much lower the pressure is. As long as you have 10 lbs. for every 1000 RPM you should be sufficient, I.E. 30 lbs at 3000 RPMs. If your not meeting that criteria, it may be time to do some investigating. Or if you've had a large drop in oil pressure, say 20 lbs. I'd be running some tests, maybe pulling the engine to look for problems.

These are things I've run into before, I'm sure others will add more to this.

My engine was built about 3 years ago with modest seasonal use only. It's 10.4:1 Butler 469 stroker on a 400 block. I have no detonation at all, even on pump gas.

I changed the oil filter from STP to K&N with this oil change too. I may switch that back in the Spring just to remove that variable and see if the oil PSI changes.

PCV: I am running one PCV from the passenger side valve cover to the carb base, non-ported, and also a Mopar type Moroso PCV/separator from the driver's side to the base of my open element air cleaner with the idea of pulling pressure out of the engine during WOT. When I bought the car last Spring, it had a bad leak at the rear main seal that a new seal didn't cure. The engine was using two open element breathers in both valve covers; no PCV. Changing to this new PCV setup eliminated that leak by about 95% or more. (The rear main seal was replaced by a friend just before I took delivery of the car.) Now I get a few drips of oil on the floor whereas before it was a small puddle.

[AdamIsAdam]

Remember this thread? I just remembered that I wanted to put back an STP oil filter to see if my oil pressure goes back up to where it was. I was smart enough to take as picture of it before removing, but not smart enough to take a CLEAR picture.

Can anyone make this number out? I don't think this was a Pontiac number filter.

[AdamIsAdam]

Remember this thread? I just remembered that I wanted to put back an STP oil filter to see if my oil pressure goes back up to where it was. I was smart enough to take as picture of it before removing, but not smart enough to take a CLEAR picture.

Can anyone make this number out? I don't think this was a Pontiac number filter.Attachment 395598

[HWYSTR455]

Well, just to say, I would never run an STP filter. AC, Wix, or K&N, in that order of preference for me, though some will say Wix first, due to AC changing design/quality.

.

[AdamIsAdam]

Well, in the fall I switched from Dino to Amsoil and a K&N filter. My PSI dropped, especially when warmed up. I talked about it before, I think on this thread. Over the winter while parked there was also some oil leaking from the front of the pan where it didn't leak before. Slippery stuff.

Anyway, I thought I I'd at least swap oil filters back, even if temporarily, to see if the pressure comes back up.

Oh, and my dipstick pushes up now and it didn't before.

[HWYSTR455]

What weight dino did you switch to?

I've noticed K&N filters usually do show a slight drop in psi, because they filter to a smaller micron. They also clog faster, and require changing more frequently.

Still say use a PF24 or Wix.

.

[AdamIsAdam]

You have it backwards. I went from Dino (10x40 & 20x50 mixed) to Amsoil 20x50 zmax when I got the immediate drop in PSI, especially when warmed up.

I actually had anther thread on this subject here:
http://forums.maxperformanceinc.com/...count=48<br />

[HWYSTR455]

Originally Posted by AdamIsAdam

You have it backwards. I went from Dino (10x40 & 20x50 mixed) to Amsoil 20x50 zmax when I got the immediate drop in PSI, especially when warmed up.

I actually had anther thread on this subject here:
http://forums.maxperformanceinc.com/...count=48<br />

That is starting to happen more frequently than I would like to admit, but I swear, has nothing to do with age! (I just don't multi-task as well as I used to!)

.

[AdamIsAdam]

I'm going to pick up a Wix today. Found one at the local parts store. I'll put that in before firing up the car for the first time this year (should be less oil mess that way) and see how the psi flows. so much for the $12 K&N.

As for multi-tasking, well, they say it diminishes IQ. Or something like that. I forget because I was multi-tasking when I read the article ;-)

[HWYSTR455]

Oh dang, if that's the case, I must be down around 30 or something by now!

.

[78w72]

is the pressure excessively low? remember, pressure isnt as important as flow, if you have 15-20 at idle with the synthetic & it jumps up quickly to 50-60 off idle & into the rpm range... the psi is perfectly fine. unless its scary low i would leave it alone, lots of work & $$$ into the amsoil & k&n filter & technically a smaller micron filter is better than a run of the mill stp etc, even if you loose a few psi. personally i would leave it alone & go drive & enjoy the car, you arent hurting anyting with a few less psi.

[AdamIsAdam]

When I put in the Amsoil 20w-50 temp was about 40* out in November. Car started up and gave me nice pressure right away on a cooled down but not cold engine. Over 50psi at around 2500 RPM. Once hot, at 2,500 RPM I'm barely around 40psi (maybe even 35, hard to tell with my gauge) and at idle all the way down to about 12-13 PSI. That's lower than before. At idle before it was around 25psi and I think it easily 45-55 at cruising before.

Old dino oil was a mix of 20w-50 and 10w-40. And yes, level is full - right up to the top mark on the dipstick. (took 5.5 qts)

Take a look for yourself. According to AutoMeter, that hash mark between 25 and 50 = 37.5psi.

[Chris-Austria]

I've tried some oils as well... the best results are with 10w40 and 5w50. I prefer the 5w50 because it gives about 5psi more when hot.. cold both are the same.

At 220°F oil temp I have 20psi (idle) with the 10w40 and 25psi with the 5w50. Hot cruising is more than 40psi starting at about 1500rpm.. all the way up to 80psi at 4000rpm and more.

I also think the engine starts easier with the 5w50 than with the 10w40 and especially with the 20w50. Before I could sometimes hear the starter.. now it turns without any noises. That's why I would say 5w50 or maybe a 5w40 full synthetic is a good oil when using a hyd. roller cam, but it always depends on the condition and the build of the engine.
Butler told me that I can use 20w50 oil for my engine but maybe not in the winter... The pressure is almost the same with the 20w50 and the 5w50 when hot (and cold).. but I think just because of the fact that the 5w50 can supply the cold engine faster and better at startup it's the better choice. (the 5w50 and 20w50 are Valvoline Vr1, the 10w40 I tried was a Mobil oil).

I guess the 5w40 will have about the same pressure readings as the 10w40 and the 0w40 will have a little less when hot. (I don't think 0w40 is necessary until it's very very cold)

[AdamIsAdam]

ok, so yesterday I swapped out the K&N filter for the same size (3" diameter) AC Delco PF61 (I have headers and the wider filters don't fit). They didn't have the Wix 51045 in stock. I topped off the oil level and fired the car up for the first time in 3 months.

Oil pressure old was immediately good, just above the hash mark at about 63+psi. See first video.

Then as I drove and warmed up the car, pressure went down to just above the 37psi hash mark at 3,000 RPM just as it did with K&N filter (so maybe 40psi, see second video).

Hot oil pressure at idle is around the first hash mark, so about 13psi.

I guess this is just a characteristic of the slick flowing Amsoil over the Dino oil with Zinc additive that was in there before.