Pontiac G8 Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
4,305 Posts
Discussion Starter #1
Almost ALL LS engine failures are traced to leaks and low oil pressure. Start with the big one, DOD lifters. The only real problem with them is the limited internal travel limiting them to .500” valve lift. The pins getting jammed and the lifter collapsing is caused by low oil pressure. That’s it. It’s not metal fatigue, it’s not advanced wear. It’s all from internal oil pressure leaks. The pick up truck crowd sees it better because they have oil pressure gauges.
There are plenty You tube vids that show the before and after of replacing the pick up Oring, porting the oil pump and adding a couple little washers to raise the base pressure. If you find your hot idle oil pressure dropping to 20 psi or less. You are in Big Friggin Danger. Turn you AFM off if you can. GM made a big mistake on our AFM system. They gave us a good high volume oil pump. But made the oil pressure so low to protect the LVOM solenoids.
Now add in the pick up O ring leak and oil pressure drops too low. This is the #1 cause of DOD failures. Easy to do during a cam swap, but every LS motor needs this. And the cure is simple. Again it’s GM fault. The pick up tube has only one bolt, but the oil pump can take 2 bolts. Adding a bracket so the pick up tube is held on both sides will extend the life of the O ring. With it held with one bolt a fresh O ring seals but as it gets old and flattened
it leaks. You can buy a bracket for the other side of the pump and a 2 bolt bracket. Either work and can be bought for $15 to $30 plus an O ring. Add 20 to 30 cents for the washers to shim the oil pressure spring and that it for the parts. Gaskets a balancer bolt and rent or buy a puller. This will fix the biggest weakness any LS engine has. Then there is the pump itself.
I have seen new pumps that now have a sealing ring between the pump and the block to prevent leaks. The bar bell or dog bone in the oil gallery at the back of the block. Also a good idea if you have the trans out or engine.
All are good if you have taken care of the main fault.
 

·
Registered
Joined
·
763 Posts
Add to it the fact that we got the split on the #2 cam journal for VVT, even though we don't have VVT. That split causes excess wear on that bearing, and no doubt leads to another point of lost oil pressure.
 

·
Registered
Joined
·
4,305 Posts
Discussion Starter #3
Absolutely true, that is another source of oil pressure loss in our system. GM did start producing a wider # 2 bearing to help with it on later models. This wear start from having low pressure in the first place. Its the cascading effect from low pressure to start with. This next fault one is the easiest to fix. The oil filter. Even the best quality ones, the stock size is too small. Now if you change your oil every 3000 miles or less and never go over. Then your OK. The PF48 is just too small and can't hold enough dirt. When the filter goes into bypass, look where the oil goes first. Straight to the oil pressure sensor and the little filter below it. So if you ever loose oil pressure and set the code. It is likely from the dirty bypass oil from your filter, clogging the little filter and sensor. Changing them fixes the problem, but does not address the cause.
 

·
Registered
Joined
·
763 Posts
Yep, although, even with the small oil filter, mileage is going to get the best of that #2 cam bearing. Also, anyone who says don't look at the cam bearings on one of these engines (with higher mileage) is destined to have problems. My #2 was delaminated and crumbling at 155k miles. I understand that not everyone has the means of pulling an engine out, but doing a DOD-delete is much simpler with it out, and my machine shop did new cam bearings for $120 (less than the price of the install tool). And that was done with the short block fully assembled.
 

·
Registered
Joined
·
1,701 Posts
My mechanic decided to swap my stock pan on the LS3. So I had him address all the oil pressure issues while he was in there.
 

·
Registered
Joined
·
4,305 Posts
Discussion Starter #6
The stock pan is just fine. Unless you needed more room. Just replace the relief valve with a plug and they are equal. Good that the other items were done.
 

·
Registered
Joined
·
1,701 Posts
Well we made the decesion to eliminate the camaro stock oil cooler (or heater) and swapping to the stock pan seemed to be easier. He plugged all that needed to be plugged. I'm only 50% on this because it seems the stock oil cooler connections could be used for an aftermarket oil cooler.
But after data logging my runs for 30 min, my oil temps were just fine. And the tranny temps were fine too
 

·
Registered
Joined
·
4,305 Posts
Discussion Starter #8
The Camaro cooler attaches with 2 bolts to the pan. Plug the coolant lines and this cover bolts to the pan. Under $20
 

Attachments

·
Registered
Joined
·
445 Posts
For what its worth


GTDrew, you speak of shimming the pump relief.
Explain your reasoning as that would not affect pressure at lower engine speeds and pressures below the set point.
Thanks


Jeff92SE , if you have the heat exchanger set up unused from your replacement LS3, and are thinking of selling it, drop me a PM.
 

·
Registered
Joined
·
4,305 Posts
Discussion Starter #11
Our stock pump uses a very weak spring inside the pump. It starts bypassing oil back into the pump at just over 30 psi. They are also noted for being very leak prone. Just a little speck of crap can allow the bypass to leak. The AFM system is designed to operate between 27 to 65 psi. The relief valve in the pan is the 65 psi limiter. Better would be to replace the stock spring for a stronger one like from a non-afm pump. A couple small washers at .070” to .120” (two or 3 washers) will bring it up to 30 to 40 psi on the low end. The washers increase the tension so it will seal better and reduce the chance of oil pressure getting too low. GM Truck forums have 100 time more member, with AFM problems. They have seen more failures and more solutions than we ever will. I’m also going to test my relief valve in my oil pan. See that it reaches the full 65 psi.
 
1 - 11 of 11 Posts
Top