C6vettegfw

Ok guys so we finished up the ls2 408 ysi build yesterday and got the first start up last night. Noticed the oil pressure was slightly lower than my heads and cam install. We were sitting around 50 psi to begin with and down to around 25 when she warmed up. So we brought the car to the Dyno shop last night and left it outdoors for 13 hours. Went to fire it up this morning and got no Oil pressure showing. After about 5 seconds or so the oil pressure began to rise after revving it to about 2500 rpm. Shortly after this while trying to tune it we shut it off and started it only to hear the sound of valve noise ticking. This only happened immediately after starting it and it only lasts for a few seconds then goes away. However now the oil pressure is down to 10 to 15 psi at idle when warmed up. She's idling between 650 to 900 rpm. I'm at a lost. I'm at my wits end with this build. I've been trying to get this build put together since February. It's just two steps forward and one step back. Anyways here's the clearances that my builder told me he has done with the engine.

2006 LS2
4.00 inch crank
4.030 bore

Clearances
Rods (2 thousandths)
Mains ( 1.5 thousandths)
oil pickup is stock and a bit less than a quarter inch off the pan floor.
We made our own catch can and its constantly blowing smoke out the filter.

ajrothm

Something is wrong...you may as well pull it. The fact that the pressure gets lower and lower the more it runs, tells me its a bearing. .0015" sounds a little tight to me on the mains...

Maybe the o ring got cut on the oil pick up tube, but odds are, the damage is done.

I'd start with pulling the oil filter, cutting it open and look inside the pleats and the shell for bearing material...

C6vettegfw

Ok well wouldn't having a tight clearance raise the oil pressure not lower it

irok

damaged o-ring on oil pickup tube will cause these exact issues.hopefully that's all it is. 1.5 thousandths is definitely not tight on the mains.the new o-ring has to be lubricated with engine oil when installed and seated completely.do not pull up with bolt before hand.as stated above cut filter and check.

C6vettegfw

I hope that's all it is too man. Just waiting to hear back from my builder now. He's mins away from taking apart the oil filter...

schpenxel

It would unless damage was done...

Pull the filter and go from there. Not much anyone can say beyond that honestly

C6vettegfw

Ok great news.. The filter and and ill look fine no debris at all.

schpenxel

That certainly isn't a bad sign!

C6vettegfw

It sure ain't thank god

realcanuk

That's good news. Now they have to find the reason for the pressure issue. Checking that Oring isn't fun, but gotta be done I guess.

inspector12

Don't know where your getting your data from, but for a stock motor those clearances are totally possible. But I don't know of anyone that sets them up that tight on any performance motor at all. JMO. The AL blocks do grow a lot when hot so the pressure will vary from cold to hot quite a bit, and you don't want to go beating on them at all till up to temp. Most do anyways, but wanted to mention it again for your benefit. Glad you checked the filter looking good for you. A few things to verify is pick up tube O-ring as everyone has suggested as its common, but also the pick up tube distance from the bottom of the pan. To close can cause similar issues and won't show a problem until you get some miles on it Third is the oil pump bypass seen them stick open and do the same thing and then free up etc... GL!

C6vettegfw

Why isn't checking the o ring fun? Is it hard to get at or what?

SquatchMachining

As long as it maintains above 10 psi at hot idle you are perfectly fine. If it bothers you run a heavier oil like 15/40 rotella or 20/50 VR1. High oil pressure is just as bad as low oil pressure, it can cause hydraulic lifters to stay pumped up and act like a solid lifter taking your preload out of the equation and hanging valves open.

As mentioned above, it's worth giving the pump a look since it can be done in the car. Pull the pump off, disassemble it, look the housing and rotors over and reassemble it using assembly lube.. Reinstall with a new o-ring.

inspector12

Yeah on the vettes the steering rack is right in front of the balancer so it adds another level of PITA lol. But your going to have to do it to look at the pump and the O-ring. GL!

C6vettegfw

Ok so the pump is apart and put back together. He said it's fine. So now he's lowering the cradle so he can check the pick up and relief valve. How far off the pan floor should the pick up tube be. He said it's less than 1/4 inch..

old motorhead

Are you sure your gauge is reading correctly? On the older GM motors, that's the first (and easiest and cheapest) thing to cross off your list of possibilities.

irok

if you are using the factory pickup tube, oil pump, crank bearing cap and oil pan your spacing cant be wrong

SquatchMachining

Agreed


and even if the spacing was off, unless the pan was empty or oil level was low, this wouldn't effect pressure. If the pump was cavitating due to low oil level, you would see that...

C6vettegfw

After tearing apart the oil filter and finding nothing wrong we moved onto the oil pump. Again after no trouble we took the oil pan off and the oil looks fine... After review of the oil pickup o ring the conclusion was...... It's $&@&ed!!!! it was in terrible shape and even blowing a bit of air on it it was moving all over the place and very sloppy in its place. I'm thinking we have found the culprit!!!! Fingers crossed guys. It's going back together tomorrow and hopefully started before lunch.

schpenxel

I sure hope that's it