Just did a rebuilt 283, first start, and had it up to about 2000 to bed the cam in, and noticed that the oil presure was at 60 PSI. I will stick another gauge on , although I was reading it on a new Smith's capillary type gauge which i would normally trust. I used a standard Mellings high volume pump, but I'm kinda stumped as to what is going on. I have always had these sit around 45 PSI. Any clues ?
60psi at 2000 rpm? That's a good, tight rebuild. Nothing wrong with that pressure on a sbc. FYI, my 65 yr old flathead runs over 50 at 2000.
Hey 36, when you use a high volume pump the oil pressure will run at the higher setting, no problem, I use High volume pumps in all of my go fast engine. If you want the pressure back down at 45 lbs., you will have to change out the pump to a low volume pump.
Used a Mellings Hi-Vol pump in 383 stroker SBC & had similiar high oil pressure @ 75+ lbs pressure......started to push engine gaskets out before long, so off came oil pan and in went a normal SBC oil pump......happy motor now !!
Ask any reputable engine builder and they will tell you a high volume pump is only for race engines with big clerances. A normal pump is all a street engine needs. You will get mysterious oil leaks after running the high volume pump for awhile.
I would like you to list which gaskts. / seals have hold against direct oil pressure ..... think about it .. dave
Looks like no answer so here it is ...the seal on the oil filter ,period..Given a properly operating engine w/ good ring seal & a functiong pcv , there's actually negative pressure in the crankcase/valley...... therefore NO pressure applied to any gaskets or seals ... dave
Melling has several versions of the high volume pump. Most come set up for higher pressure byp*** and some include a byp*** spring to lower the pressure. You need to know which pump you have. I'd call Melling. http://www.melling.com/Aftermarket/High-Performance/Cast-Iron-Aluminum-Oil-Pumps
I agree about the relief spring. The last two Mellings pump I bought came with the high-pressure spring installed, and a medium pressure spring as an extra in a plastic bag. For a stock engine, you need the standard 45 lb spring. (I think it is green.) A quick call to Mellings will get an explanation and the proper spring on it's way to you.
I agree with the others that all you really need is a standard volume, standard pressure pump to keep things as they should be. The Melling is a high-quality unit, so you're on the right track. But on initial start-up the oil pressure is naturally going to be high because the oil is going to thin a bit as it reaches operating temperature. Have you run the engine long enough to get it all fully up to temperature? If so, what is your oil pressure like then? Also, what oil are you running in it? I wouldn't be concerned at all with 60 psi cold startup pressure, in fact, I'd be pretty excited about it.
In my time I have put about 17 or 18 engines. Most were small blocks, 283,301327 and 350s. All had high volume standard pressure pumps and never a problem. When I mention this I here about how some guys use 0-30 oil in their engines. Man, that oil is for when you are RACING and need ALL the horsepower you can get. Unlike sitting in traffic possibly with air or crawling slowly along when you engine needs a little extra pressure. My present is a350 that has been together since 1997 with 60 cold and 25 to 30 at idle cold. I also have a1947 straight 8 Pontiac that gets 40 to 45 running at 2700 rpms. 15/40 weight always. Steve
i hope you used a heavy duty oil pump drive shaft the 283 in my `36 has about 60 PSI cold. it has the Melling high volume oil pump. been 7 years and just under 8,000 miles with no problems
Thanks for the input everyone. I will push ahead with what I have and be happy! The last engine I did was a stovebolt Chevy, and I was excited when I got 15PSI out of it!
Actually, a race engine has less of a need for a high volume pump than a street engine. Race engines normally run at high rpm to create maximum horsepower so the pump is putting out much more oil. Double the speed of the pump, double the volume. Street engines can spend lots of time at idle in hot conditions. The high volume pump will keep the oil pressure up in these conditions. As the engine wears, the clearances increase and the pump wears pumping less volume. The high volume pump will offset this. Racing engines are usually rebuilt before they get much wear.
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