I'm not sure where to post this but I know a lot of forced induction guys have built their engines so I figure this topic will be seen here by people with experience on it. What would you expect the oil pressure to be on the first cold start up and how much would you expect it to drop as the oil heats up and everything wears in. I figure it would be a considerable amount just from the difference in a cold start to it being at operating timp but I'm not sure what is acceptable as far as engine wear goes.

My concern with my engine was that the first startup it had great oil pressure. 65-70 psi at idle on the first cold start. I have a wideband o2 sensor and efi live. I purchased the shortblock and assembled everything and installed it in my car over the weekend at the shop I was working at. Of course I'm watching everything closely and monitoring everything the first startup. Anyway, as the engine came up to timp. The oil pressure dropped down to around 30psi at idle, still responsive to changes in RPM, and acceptable to me. I just don't like the fact that it dropped of so much so fast. I can attribute some of it being the difference in a cold start and being at operating timp and some of it from the clearances opening up a bit but I don't know what is normal. I had estimated the tune fairly close I'm guessing as it fired right up and idled fine with around 13.5-1 afr. I don't remember where the timing was but I know I pulled a lot out of it and didn't have the supercharger on the car yet as I wanted to do the initial brake in and tune without it and keep everything completely safe before installing the supercharger on it and taking it to a shop with a good tuner to either tune it or assist me in making sure everything I did was correct with the tune. I let it come up to timp that night while keeping an eye on everything then shut it down, checked over everything, and closed up shop then took the car out to put some load on it to seat the rings. I probably drove it 30 minutes loading it up, varying the rpms, keeping any eye on the tune and shut it down. Over the next couple weeks I put 600-700 miles on it logging the afr, doing a bit of fine tuning then parked it as I was ready to put the supercharger on it and everything seems fine with it. The only concern I still have is with the oil pressure. After putting 600-700 miles on it, the oil pressure starts off 40-45 psi on a cold start, and drops to 20psi when up to timp. It increases with rpm but still never gets where I would like to see it maybe 50-55 psi at 6k. That might be acceptable but I don't like seeing it at 17-23 psi at idle. I don't know if its an issue but I don't feel comfortable with it and would rather see 40-45 psi at idle and have it increase from there. The cam that I had in the car was to big so I swapped the cam, and put a new high volume/pressure pump in it when I had it apart doing the cam swap. I drained the oil and it looked fine. Cut the filter open and I'm not real sure what to think, it wasn't clean like I would like for it to be but I'm not sure how much is normal as far as the matalic shimmer the filter itself had to it. No big chunks, or shavings or anything but that's the first oil filter I've cut open on a new engine so I didn't know what to expect. I know you don't want flakes of copper but should it have been completely clean with no more than 700 miles on it?

The car has been on jack stands for almost 4 years now put back together with an F1A Procharger on it. It's pretty much been ready to start up this whole time but I hit a huge financial road block and basically put the car together but couldn't even afford new spark plug wires or a belt to put on it so I could fire it up and see what the oil pressure is with the new high pressure pump. If that tells you anything, needless to say I didn't have the money to have it tuned like I wanted or fix anything if anything needed attention. I've been flat broke and the car has sat in the garage on jack stands. It's a fully forged 402 ls2 block. AFR heads, Procharger pullied with a target HP range of 800-850rwhp. 18ish psi I expect but its never been run with the blower.

Hopefully this has been a bunch of paranoid pointless rambling, but the oil pressure thing has bothered me for almost 4 years and I'm just now getting to the point where I have money to mess with this project again. I'm just wondering what the community thinks as far as it being an issue so I know what to expect before I start putting money into it again. I can afford to get it running but I can't afford an engine issue. I hate even looking at the car though. I've done nothing but dump time and money into it and never got to finish it. Not sure how long some of you have had to wait for a project to be completed but I'm sure many of you have gotten disgusted with problems and unfinished projects before.

 

I just torn down my d1 making 525 on a 155k mile stock bottom end. I lost oil pressure too, went to drain the oil but no oil was in the pan, i had a oil pan of gas lol

 

Yeah, mine never completely lost pressure or oil or have anything mix. I'm just concerned in the difference in pressure from the very first cold start to where it now idled when at operating timp after putting some miles on it. Seems like a huge difference. I would like to know what is normal.

 

What type of oil? Thickness?

 

Been years ago but good question. It was what the thickness and brand the shop recommended that I got the shortblock from with a high anti wear agent that most oils don't have nowadays due to emissions. They also sent a bottle of an oil additive that Chevy recommends for engine break-in. I researched both the oil and the additive and bought a case of both. Can't remember the names. Like I said, its been years since I looked at the car due to financial reasons. I can assure you I did my homework on it and next time I go back to where everything is stored I can look as I'm sure that is something people will question but I highly doubt its an issue.

 

Pretty sure it was Valvoline Racing 10w-30 or 5w-30 and GM (EOS) as that is one of the few oils that still have a decent amount of ZDDP and the engine oil supplement from GM just adds more and helps with wear during break-in.

 

No one around here carried it so I researched it and ordered a case of both. I had more time and money to spare back then...

 

I'm very curious too because the same thing is happening to me. First few start ups I had around 45 psi now at operating temp it idles around 20-30 psi. Scares the **** out of me! If it makes a difference I have gmpp's high flow oil pump.

 

I was using 5w-30 but after the break in I switched to 15-40 due to a lower(still good but my piece of mind) pressure and the thicker oil cured the problem.

 

When we first finished my build last year with my 347 I had mobil 1 5w30 in it and that turbo would turn that oil to water practically. I'd lose 20-25lbs of oil pressure from it then it would come back after it had time to cool down. I switched to mobil 1 15w-50 and it kept really good pressure when it was hot. I kept using it untill I got my 408 built and i'm running valvoline VR1 20w-50...now that's some good stuff!

 

Valvoline VR1 is the oil not Valvoline racing. I knew it was some Valvoline oil but that sparked my memory. As far as the weight, I don't remember because the vender that put the shortblock together recommended it and I just trusted them as far as that goes. I don't like the idea of having to run a real thick oil. In a non racing engine that usually means you and covering up a clearance issue from wear or abuse. The clearances might just be a that loose though considering the vender built this shortblock with somewhat high boost and high HP in mind. The bar seems to he a little higher now but when I started the project 850rwhp was considered on up there lol. I was a Ford tech so I've delt with a lot of engines but they aren't assembled with racing in mind. As a tech we never put together a bottom end or had parts machined. If it had a bent rod, cracked piston, dropped a valve into the combustion chamber it got a new short block or crate engine so I don't claim to know a Hell of a lot about what the actual clearances should be when putting the bottom end together. If it needed a new bottom end it got a new shortblock from Ford with a warranty to cover my *** and the shops if anything was wrong with that area. The fact that others are reporting that their oil pressure is lower than what is normal for a factory engine gives me hope that all is well. I will see what it is with the new pump installed and maybe run a thicker oil and see if it gets closer to my comfort zone. Pressure as explained to me in school means you still have resistance to the volume of oil the pump is putting out and in theory if you have pressure and it increases with engine rpm its fine. That's what they taught. I still don't like to see low pressure on my engine personally. I would feel much better with the old 10-15psi per 1000 rpm increase with a good base pressure of 30-40psi at idle. Basically I would be happy with 65-70psi at 6k but I don't like 55 psi. It may not be a problem but I feel more comfortable with it higher. Maybe I'm just worrying to much and need to finish this sucker and be happy. At this point if I dump another 10-15k into it like I want and have a bearing failure on the dyno I would just want to walk away and let them keep the ****. To much time and money and no enjoyment out of it so far. The car has had about 1500 miles put on it since 03 partly because of problems and partly because I always want to upgrade something and end up running out of money or having to save for 6 months before I have enough to really put what I want in it. It could have been done years ago if I would have settled for anything less than what I though it should have. I've tried to build it with the intentions of everything holding up and its been a long costly project that finally drained me dry. That and I went back to college so I went from making good money as a tech to being flat broke. Gotten married and divorced in that time frame too so the car has just had to sit.