My freshly rebuilt 396 (With Total Edelbrock Performer RPM Power Package and .060 over) only has about 18-20 psi oil pressure when idling at 800-900 RPM.

The oil pressure is around 55-60 psi when cold but drops to around 20 psi when fully warmed. It then maintains this oil pressure until the motor is cooled down.

I don't think my gauge is bad because the pressure increases with RPM like it should.

The oil pressure use to be around 30 psi when warm and at idle before I tried to check total timing at 3000 RPM.

Is this oil pressure normal W/ 10W40 oil at idle or is it possible I did something to the main bearings or something else when running it at 3000 RPM. The motor only had approximately 2 1/2 hours of break-in (idle only) before I took it up to 3000 RPM. I hope to god that I didn't ruin something..

I would greatly appreciate any help anyone could offer. Thanks...

[This message has been edited by DS76462 (edited 10-27-99).]

First of all, I hope you ran the engine above 2000 rpm for the first 20-30 minutes, to break in the camshaft. Second, what did you use to lube the bearings and lifters when you put the engine together??

If the pressure jumps up to 40-50 psi when you crack the throttle, I wouldn't worry about it.

10 psi per 1000 eng rpm is all we ask.

I also have a big block with the same condition. It doesn't seem to hurt anything. One thing I suspect is the new MSD distributor I have in it. It comes with 2 "o" rings which fit into machined grooves that seal against the boss that the distributor fits into in the lifter valley. To use the "o" rings you had to have chamfered the top of the boss so you don't tear the rings up during the installation. I did not know this at the time I machined the block so I don't use the o rings. I imagine it could only increase the oil pressure at idle since it is a source of internal leakage. When the oil is cold it is too thick to leak through this area, when hot it leaks. At least it's my theory.

Well, this makes me feel a little better. When my father and I put the engine together, I know we used the moly lube supplied with my cam kit to lube the cam and lifters. I'm not sure about the special lube we used on the crank and rod bearings. I know it was some kind of special lube that he uses on all his bearings when he builds a motor. It was kind of dark white/ light gray color if I remember correclty. I'll have to find out exactly what it is.

When we broke in the engine, we ran the motor at about 2200 RPM's for about 25 minutes. Was this enough RPM's to properly break the motor in?

One more question. What kind of oil and spark plug gap would you guys reccommend for this motor? My father and I have different opinions about these and I would like some more opinions. My father thinks I should run straight 30 weight (which is fine in the summer) but I think that's too thick for the winter months. I thought something like 10W40 or 20W50 would be good for colder weather. It was also recommended that I set the spark plug gap between .040-.045" (From the Edelbrock tech line) and my father thinks I should stick with the GM gap of .035" What do you all think about this?

Thanks.....

Since you have the stock ingition, I'm guessing. I would gap the plugs at the recommended .035 I would run 10W-40 in this engine. Depending on where you live you might want to run 10W-30 in the winter.

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Bryan Shook
Burgettstown, Pa.
1972 El Camino
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Happy to hear you got your engine running, i just got mine running a couple weeks ago and I love it. Your oil pressure sounds alright. I got a high flow oil pump so mine runs about 50psi at idle when warm and 75 psi when cold.

As for the oil, I think you have your weight's mixed up. 20W-50 is THICKER than 10W-40, the first number is the weight of the oil, the higher the number the thicker. I would not go any lower than 5W-30 in the winter. It would probably be a good idea to use 5W-30 because it is thinner and therefor doesn't take as long to get around the engine on startup (i know all about winter, livin in Saskatchewan it is not uncommon to go below -30 celcius.) If you have winters like I do then you don't have super hot summers either so I wouldn't go any thicker than the 10W-40 you have now, that's just right for this climate. Hope everything runs smooth for you.

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Chris Dagenais
Saskatchewan, Canada
CST Kelsey
'71 Malibu soon to be 454!
member.xoom.com/Gandalf80/Chris'sPage (http://member.xoom.com/Gandalf80/Chris'sPage)

Glad to hear you ran the cam in!
Sounds like you used a moly lube on the bearings....this stuff does not break down in oil, and will plug the filter and lower the oil pressure. Change the oil and filter, and see if the pressure comes up.
10w30 for winter, and 10w40 for summer should be fine.

What Dave B. was alluding to, and something i'm still not clear on....was the motor being broken-in the very "FIRST" thing that was that done? If that motor had 2 1/2 hours of idling before it was run through a true break-in...well, that's not a good thing.

i agree with dave if you didn't drop the oil and filter after break in the break in lubes will clog your filter, droping pressure, also have friends that there pressure is low at idle don't seem to hurt any thing, what pump did you put on the motor? new, high volume i hope.

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you guys seem to know about bb's very well think ya can check out my question on my sb? http://www.chevelles.com/forum/Forum5/HTML/000814.html there is one reply that is prob it but all the input i can get is great. thanks people.

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OWNER OF 66 CHEVELLE MALIBU
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Fav Quote: Second place is the first loser...

Thanks for all your responses.

When I started the motor for the 1st time, I took it to around 2300 RPM and let it stay there for about 25 minutes. After the initial break in I changed the oil and filter and let it cool down over night and then I ran it the next day for about 1 hour. The following week I tried to set the base and total timing.

It was after checking total timing (at 3000 RPM) that I noticed the lower oil pressure around 20 psi at hot idle. I also noticed a funny smell while checking total timing. It wasn't the exshaust. It seemed to be coming from the motor?? Prior to setting the total timing, it was around 30 psi at idle when warmed up.

I have a high volume oil pump and the oil pressure maintains around 20 psi at idle when warm.

I changed the oil and filter again yesterday, and it still maintains 20 psi at idle when warm. Idle is around 800 RPM.

Any more suggestions? Thanks...

From my (limited) experience, your idle oil pressure seems low given the circumstances. Smokey Yunick said something to the effect of "10 psi for every 1000 RPM is all you need," and this is probably true. But the stock LS5 454 in my 71 Vette holds 40 psi at idle when fully warmed up on 90 degree day--and that is with 113K miles on it. My friend just built a mild 454 for his 71 SS Chevelle, and it holds over 40 psi at idle as well.

A note about high-volume oil pumps. I don't know the capacity of your oil pan, but I believe (you guys know better than I do) that stock BB Chevelle oil pans were approx. 4-qt. capacity. My friend ran the previous engine at 5500 RPM (fast!) for a couple miles and the HV pump sucked the oil pan dry, trashing the motor. His new engine has a standard pump, which is really all you should need.



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Nick
1971 Corvette LS5
Still searching for that Chevelle...

I fell into the FRAM oil filter hype a while ago. Ended up changing back to the AC filters. Found up to 12 psi hot oil pressure restriction with the Fram over the stock ACs. I now run the AC PF935, double length truck spin-on filters, and they give about 5 psi more than the stock AC PF35 does. All told, 17 psi better than the best Fram.

I tested by removing one filter, adding another, topping off the oil, driving. Same oil used for all tests. Best oil I have ever found is Torco. I always use either 30 or 40 wgt straight oils.

Just what I have found on my own engines.

2300 rpms for a half hour should be ok for a big block for break in, and since you changed the oil and filter, should have been OK. I don't do more than 2500 rpms for the break in on my stuff, I don't have engine problems with doing it that way. People don't remember that BBs have openings in the valley that allows runback oil to get to the top of the cam during operation, not like small block cams that only get oil from rod throw-off.