HitmanLSX

Ok need to get some ideas as to what might be wrong. Oil level is good, but at WOT in first oil pressure drops from 40-20 and you can feel a noticable loss in power then like a variable timing system the power kicks back in as pressure goes up to 60.

here's a video I took with my phone if this helps... unfortunately quicktime didn't wanna export it with audio

http://www.sccow.com/joshs/oilpressure.avi

Need to change my oil though so maybe the 0w40 will help?

Rokko

iTrader: (2)

it doesn't sound good at all. no more WOT until you get this figured out. If I was a guessing man, you probably came awful close to seizing it or seriously breaking something.

General rule of thumb for a small block chevy is 10psi per 1K rpm's.

Bad oil pump, o-ring gone, plugged or clogged oil pump pickup. Any of these could be the culprit.

Rokko

iTrader: (2)

Change the oil pronto, keep it and the filter. Cut the filter apart and inspect the media for metal shavings. Have the oil analyzed for wear metals.

The only real way to remedy this is to drop the pan and check the oil pump and all associated oil system parts.

HitmanLSX

hmmm it only does it in first gear though no other gears?

and I'll keep off the throttle until it gets figured out... I can't afford a motor

Rokko

iTrader: (2)

it might only do it in 1st cause it winds up so quick in 1st gear. What does it do if you rev it in neutral to 3-4 rpm's?

what would scare me is the way you described losing power as the pressure dropped.

change the oil asap no matter what, specially if it's due. if you can, drain it into a large glass something or other, so when it's been sitting for a while you might be able to see the shavings settled out on the bottom through the underside of the glass.

WAHUSKER

iTrader: (4)

I agree TOTALLY with Rick...no more WOT until yo figure this out!!! COuld be any of those things, or something worse. Check them first. If it was a spun bearing, you should have low oil pressure all the time. But if you continue to drive it, you might hurt it bad.....

Tranzor

Mark and Rick are on top of this with the suggestions... it may be your oil pump getting ready to take a dump on you, at least that's the best case scenario. Check the oil, make sure there's no foreign matter in there... if it looks good, change it out, and honestly I'd go for an oil pump swap at this point just to be sure.

For comparison, when I hit WOT in first gear, my oil pressure spikes hard... jumps up over 70 psi. It definitely in no way should EVER go down when you hit WOT. Should always go up...

WAHUSKER

iTrader: (4)

Oh, and the loss of power is likely due to the lifters collapsing when the oil pressure tubes. Restricted valve movemnet is going to act like the gas getting shut off. So, in this order - drain the oil & replace the filter. INSPECT them! If you find nothing wrong, as everyone is saying, these oil pumps are known to fail, so replace it. I have my stock one sitting here if you can't afford a new LS6 pump (which is the BEST fix, but if the $ aint there....) so all you'd need is the time....gasket is re-usable.

Rokko

iTrader: (2)

Good call!! I didn't think about that.

Doesn't the oil pressure register off the cam bearings? If so, a crank bearing that was spun wouldn't show up as a loss of pressure? Unless of course it was spun to the point of taking out the crank, and then you'd hear it knockin first?

Josh, Do you hear any abnormal sounds while the motors running?

HitmanLSX

Ok... just got done changing the oil. with 0w40 Mobil1 this time instead of the 5w30 Mobil1 I was using. Also it'd been about 7k which I know is a long time but Mobil 1 "should" be able to go that long. Anyways this is what I found... I hadn't checked this before doing the oil change so I didn't drain it into a glass, but on the magnetic end of the oil drain plug was this:



after cleaning


This looks like some metal particles but it wasn't a visible amount just like microscopic amounts in the oil, it was fluid to the touch.

Anyways after changing the oil:
Idle (hot): Before: ~20psi After: ~40psi
1st gear WOT: Before: Flucuated from 20-60 After: Spikes to 60

The only way I was able to get it to go below 40 was to have it in gear and slow down enough to where it was at less than 500rpms.

Could this be because the oil was too broken down after so long between oil changes? or maybe the filter was plugged and not flowing as well?



Oh and for noises save for piston slap at start up when cold nothing out of the ordinary I don't think. It's not like my mustang where you can hear the lifters when the oil gets low.

WAHUSKER

iTrader: (4)

Looking at the mag plug, I'd guess your filter was plugged. And you need to change oil more often / use a different brand. That is a LOT of metal Josh.....I would NEVER use 5W30 in a V8! I don't give a tinkers damn what the manual says. Use 10W30 or 20W50. You drive your car too hard for that 4 cyl oil.....but stay away from 10W40, it crystalizes when it gets hot.

Racehead

The way you describe it only happening in 1st gear sounds like a classic example of LOW oil level. Acceleration is highest in 1st gear so you might have been uncovering the pick up tube ? Just a guess of course. At what level do you run it ? LS1's LOVE 1/2 quart over full and that's where I run mine 24/7.

Tranzor

I agree there... but I don't think it is entirely the Mobil 1 5w30s fault, I think you were running that filter in bypass mode. Any oil is gonna fill quick with contaminents if the filter gets plugged. What filter was that, btw?

Also just FYI... Mobil 1 5w30 is on the thin side of the 30 weight spectrum. After running it for 7k+ miles, I wouldn't be surprised if it tested out to be a 20 weight. And that's WAY too thin for our cars. Oils like Amsoil and Redline actually tend to get a little thicker as the interval goes on, protecting better for longer drain intervals.

I think I know someone who sells Amsoil oil and filters if you'd like to make the switch...

Rokko

iTrader: (2)

Did you cut the filter apart yet? What kind of filter was it? Those spikey looking shards on the tip of the fine powder was what caught my eye. 7K is a lot, specially if your hard on it. I've been running that 0/40 since I got my car. I don't think I've ever let it go past 4K, usually around 3500 is where I end up doing it.

I'm totally **** about my oil level and changes. I fill my oil filter with oil before I put it on and then use the rest of the quart to pour down the fill tube till it drains out into the pan clean. Then I button it up and fill it up with 6 quarts. After I fire it up that puts the level on my dipstick about a third of an inch above the full to a quart low hash mark lines. If I was a shop teacher I could count on one hand the amount of times I've let it go much below the full mark.

Hey Jason, I'll shoot you a pm about some oil and a filters. How does the amsoil filter compare to the k&n?

Tranzor

Amsoil's filter is actually solidly between the K&N and the Mobil 1 filter for flow and filtration. The K&N flows the best out of all the filters, Mobil 1 seems to filter the best. The Amsoil filter has had independent tests on bobistheoilguy.com that shows it flowing almost as well as the K&N, and filtering just as well as the Mobil 1... just without the flow restriction the Mobil filter has.

Price is also comparable to a K&N filter, just a little bit more... retail usually around $11.50-$12.50 or so. But we don't talk about retail around here between friends.

Tranzor

Oh, and the filter is a completely synthetic media... also it is packed with more media than most filters, so it collects a lot more dirt before going into bypass mode. For instance, Rookie probably wouldn't have had all that metal flakes in his oil with an Amsoil filter, since at 7k it should still have plenty of media to trap dirt.

The Amsoil filters are rated up to 12.5k miles... personally, I would always change my oil and filter at 6 months, regardless of how few miles I put on my car.

I change mine once before racing season, and once after... but I also only put about 5k miles on my car a year.

HitmanLSX

I always use K&N filters. and the spikey parts were only spikey because of the magnetization, you could move them around like puddy kinda but more fluid. And I haven't cut it apart yet... not quite sure how to without adding possibly any more metal particles to it?!

WAHUSKER

iTrader: (4)

Bill makes a good (& obvious....duh) point. What was the oil level? Being 1 qt low could under hard accel expose the pickup tube. The low oil level indicator comes on at 1.5 qts low. But I'd still cut that filter open & see what it looks like. If you were using a Fram-type filter, it might have just fallen apart. They are paper & are known to fail that way....

HitmanLSX

it was about midway in the hash marks

TwoFast4Lv

iTrader: (8)

WI am going with the low oil thing. I have scene it way to many times. When I am racing I run a 1QT over. You get over a QT in the valve covers!

5W-30 has worked on Stephs car for over 135,000 miles and when we cracked it she looked good. I have ran it and 0W-30 in the blue car with good luck also. Always Royal Purple or Mobil 1. Oils have changed ALOT over the past few years as Tranzer will atest

More then any thing I would say low oil level.