Ok guys im having a bit of a problem here with my LT1. It is a 355 LT1 with about 1300 miles on it since rebuild. When rebuilt everything was replaced, including oil pump (melling).

Onto my problem.
Ok, I was driving my car home last night, la de da no problems going as normal as ever. I pull in my driveway and i hear a tick. My header flange came loose the day before so im thinking, bah not again with this exhaust leak, ill have to retighten that tomorrow.
Fast Foward to tomorrow (today).
I go out to move my car real quick, and this tick has gotten ALOT louder. I crawl up under the car to fix my exhaust leak, and i find myself thinking, "this isn't an exhaust leak, this is something else." The noise is just enough different to where is sounds mechanical. I pop the hood, and my initial impression is that it is coming from the valve covers on either side.
So i go get someone else to listen to it to tell me what they think, and his initial impression is the same, and then he asks me if i have oil pressure. I didn't.. Keep in mind, this is not a knock. Ive heard a knock before and this isnt even close.

Now, when driving the car the night before, i KNOW i had oil pressure at least for most of the drive. I didnt pay any attention the last few minutes. Keep in mind i was out hot rodding around also.

My thoughts are, obviously im fearing the worst, but, im thinking becaues of the lack of oil pressure, the valve train is making noise, wether it be lifters not being pumped up or whatever. The problem is, why do i not have oil pressure? The car idles normally, just with this noise. I pulled a valve cover to check some things out, and everything apeared normal, a few of the rockers were loose and i could depress the plunger on the lifter with my hand. I also pull the fuel pump fuse and ICM plug, and cranked it. No odd noises. Can new oil pumps just suddenly...die? I dont think it would be my pickup since i should still have pressure at idle.

I do have oil in the pan, i checked that already.

Anybody have any ideas? I have to have it towed to my dads house before i can start pulling stuff and looking deeper.

Thanks

 

Did you leave something out of your story???? New pump? Why? Was the pickup welded in??????

Why do you think you would have pressure at idle if the pickup fell off?????
Once you spin a bearing your pressure could go south.

Drain the oil and either tap the pan with a mallet to hear the pickup bouncing around or use a coat hanger to see if you can snag it.

 

New pump for the rebuild. I thought the oil level was high enough to still. Get sucked in by a pickupless pump. I sure hope it's not a bearing.

 

Wait, I'm confused......something doesn't make sense here.

So, you have oil pressure sometimes, at idle, and not other times when driving. That does sound exactly like the pickup has fallen out of the pump. That happened to my first 4th gen. It would have good pressure at idle but any movement would slosh the oil away from the pump inlet hole and the pressure would drop to zero.

Here's the bad news. The oil pump feeds the cam bearings first and the main/rod bearings last. You hear a tapping sound at idle because the bearings aren't under any load so only the valve train is complaining. Unfortunately, your engine is probably toast at this point.

Try this to see if the rod bearings are affected:

Add oil to the full mark. Add another quart. Start the engine and let it idle. You should have oil pressure at approximately 10 psi per 1000 rpm. Specifications on oil pressure are lower than that but just about every healthy LT1 I've seen has that oil pressure. If you have zero oil pressure at this point, stop here. Anyway, after warm up, rev the engine to about 4K in neutral. Don't hold it there for more than a second or two and listen. I suspect you'll hear a heavy 'thunking' from the rod bearings.

If you don't hear any heavy bearing knock you might be ok. Drain the oil and pul the pan..yes you can do it in the car. Pull the pump and have the pickup welded in. Replace the bearings in all rods and mains. Yep, the mains are tough but you can do it...I made a tool from a cotter pin that slid the mains right out.

Good luck!

 

If you replace the oil pump did you check the half shaft you could have a strip the gear on the half shaft. I did the same thing pull the pan and check rods and mains every thing was ok . It`s the oil pickup or half shaft I`ll bet!

 

No. Right now I don't have oil pressure at all. At least at idle, I haven't driven it since I realized no pressure. I just thought I would still have pressure if the pickup was the problem. The car has only ran a few minutes to the best of my knowleadge, without pressure. I'm going to drain the oil and see what I can find out. If there are no metal shavings wouldn't the bearings be ok? I hope it's the pickup and I caught the problem before any major damage was done.

 

No if you lost oil pressure while running you wiped out the main bearings at least.

And I noticed you didn't answer the question of welding in the pickup so I assume it was tapped in and fell out.

 

Do you mean the oil pump drive shaft? You're right that could have fallen out and caused theoil pressure to fall to zero. There's only a nylon sleeve holding it in place.

 

The pickup was pressed in. The sleeve on the driveshaft is metal. We will see what happens I guess. If I have to replace bearings I'm going to pull the motor. Gives me an excuse to get a new cam. Maybe 383. I'm hoping I can salvage this however. I will do the 6 qt test as well.

 

No, I don't your engine is OK if you don't find metal shavings in the oil. You'll have to pull a cap and see....

 

Well, I drained the oil pan and from what I can tell the pickup is still on. I'm going to buy some cheap oil and a filter to rule out clogged filter. Prob a mechanical oil press guage also. If that doesn't fix it I will pull the pan and see what I can find. Prob going to be replacing bearings on this one. And a bigger cam

 

This has happened to me many times. Just recently the last time, my engine ran for approx 10 seconds at idle without oil pressure, between the startups and shutdowns. I floored it and watched the oil pressure go to 0 as soon as I shift 2nd.

If you let the car sit about an hour or so, the pressure will come right back up...at least on mine it does, every time. My pickup fell off ages ago. You can't fishtail the car sideways while giving it gas, or you will lose oil pressure. You also cant dump the clutch from high rpm. Just take it easy and you should be alright. I seriously have no idea how my engine has made it this long. This has been happening for about 15k miles now and about once a week i lose oil pressure. lol. I just shut the car off, go into a store and come back out 30 min later and fire it up..and its back to 40 lbs at idle. I don't care though, I am waiting for my new heads to come and i will put the new shortblock in. It is still cool to see it last so long though.

 

Teeth on the stub shaft gear could be gone, too. I had that happen to my LT1.

Jake

West Point ROCKS!

 

Little bit of an update. I changed filter, put some cheap oil in, and cranked the engine a few times. The filter was bone dry....so im in the prosess of pulling my pan. Ill keep you guys updated!

I will pull the intake and check that gear also, i didn't think about that. If thats the case though, wouldnt the cam gear itself be trashed?

 

In my past experience, normally, the cam gear will be fine, that is unless some type of metal had lodged between the cam and stub shaft gears.

You can use a flashlight to visually check the cam gear for excessive wear.

Jake

West Point ROCKS!