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cameron henderson (aka vegalover2005) [ View ] [ Email ] [ Car Ads ] [ Blogs ] lodi, California

im having problems with my sbc 400.when its cold it pumps 60psi. but when it warms up my psi drops to 10psi.ive been told that im running too thin of oil???? any suggestions?

Comments

Posted by ronhotrod  -  03/27/2008 08:59 PM several more questions - what oil weight are you using? what oil pump? how many miles an engine? mechanical or electric gauge? what temperature is normal for your engine? ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001   Posted by vegalover2005  -  03/27/2008 09:08 PM 5-30,its a standard pump from summit, the motor when pulled had 100,xxx miles on it, i rolled all new bearings main and rod.i replaces every gasket on the motor, put a new cam in it and had the heads done. it has a mechanical gauge and it runs at about 170 vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by REBORN55  -  03/27/2008 09:26 PM Did you check bearing clearance. May have dropped a galley plug. Ken [ View ] [ Email ] [ Blogs ] [ Car Ads ] De soto, Illinois   Posted by vegalover2005  -  03/27/2008 09:29 PM i plastigauged it and even got the micrometer out and everything was good vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by ronhotrod  -  03/27/2008 09:30 PM If you didn't replace the cam bearings you're getting all you are going to get (I think) If I were you I would run straight 30w detergent oil, perhaps an oil cooler and just drive it. All you need for a small block is about 7lbs unless you're taking the rpms way up there ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001   Posted by vegalover2005  -  03/27/2008 09:48 PM those are the only things i didnt replace.when i rev it it pumps 40 psi, and when i drive it it puhes 25 psi vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by dixie  -  03/27/2008 10:12 PM man you live in CL YOU NEED TO B RUNNING AT LEAST 10/40 ARE 20/50 SAY WHAT YOU WANT BUT THAT STUFF YOUR RUNNING IS AS THIN AS WATER. I ALSO RUN A BOTTLE OF LUCAS OIL COND. ALSO ,DON'T THINK STRAIGHT 30 WILL HELP MUCH.I HAVE A 400 SBC IN MY 32 AN I RUN SHELL ROTELLA 15/40 WITH A BOTTLE OF LUCAS OIL IS 50 COLD 40 HOT TEMP IS 170 YO 180 jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006   Posted by Streetrodder007  -  03/27/2008 10:21 PM I would run 10/40 or 20/50 oil, also oil pumps do go bad, I had a brand new Melling HV55 go bad right out of the box, new motor for a guy- no pressure. Another thought to keep in the back of your mind, you might have a partially spun bearing. I personally like about .002 - .0025 clearance on my rods and mains. But even if you have good clearance when its sittin still and being built, a used egg shaped rod can move a bearing out of its tang. It pays to recondition rods from a good shop, and always have the crank looked at to be turned. Streetrodder007 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Port Huron, Michigan Charter Member since April 2006   Posted by JAWS  -  03/27/2008 11:44 PM I am curious and maybe some of you already asked, but what rpm are you checking oil pressures at. If it's 10psi at 750rpm when hot and you have a high volume not high pressure pump, I would say everything is probably fine. Especially since you are running such light weight oil. If you are talking 1500 rpms or higher and the pressure is still only 10 or so, then you do have a bearing clearance issue. It only takes about a tablespoon of oil for a pump to make pressure. I've seen pickup tubes too close to the pan, and under high rpms, there is an air pocket around the screen. Due to more suction than oil in the pickup area, because it's too close to the pan. This scenario would have higher pressures at idle and lower at higher rpms. That's one of the reasons I asked what rpms you are checking pressures -Brant An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by vegalover2005  -  03/27/2008 11:52 PM its 10psi at idle 750rpm, and when i rev it to 2,000 it pushes about 35 -40 psi vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by tlp1968  -  03/28/2008 10:14 AM I always heard that you only need 10 psi at idle but it does make a person nervous to see that number. I would suggest looking into a good synthetic (heavier weight) like the Amsoil stuff. I had a cousin that ran synthetic with low pressures like that for over 175,000 miles. Matter of fact I think the car ran out before the engine. StreetRodding.com Marketing Director [ View ] [ Email ] [ Blogs ] [ Car Ads ] Springfield,, Illinois   Posted by Crazyhorse Rod Shop  -  03/28/2008 10:51 AM normal with a high volume pump. run synthetic and it will drop further. it's not about the pressure, it's about moving the oil. high pressure means restiction. dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003   Posted by JAWS  -  03/28/2008 11:24 AM My coupe has the same pressures and that's with a stock pump. That poor thing has lots of miles on it. I did switch to 20w-50, and that did bring the pressures up a little. If it ain't smokin' or rattlin' it's working. Check your oil for glitter, if there isn't any, I'd say it's probably fine. Shine is right on the oil moving thing. I find that the synthetic oil finds easier ways to get out, at least in the old motors I have run it in. -Brant An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by Tweety37  -  03/28/2008 11:39 AM The relatively fresh rebuilt 350 in my '37 Chevy shows about 10 psi at 750 idle and 45 - 48 at highway speed. Thats with Rotella T 15w-40. The race shop that built the motor put in a standard pump. They said that in their experience a high volume pump will run the pan out of oil at high rpm, if you have a standard 5-quart pan. Tweety37 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Bismarck, North Dakota   Posted by vegalover2005  -  03/28/2008 12:27 PM i just whent outside thismornin and started it and guess what. 60psi cold, im getting redy to drain the oil and put in 20- 50 vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by ol bear  -  03/28/2008 12:34 PM GOOD MOVE VEGA ,, I REALLY DONT SEE A NEED TO WORRY AT THIS POINT ,, I MIGHT TRY ANOTHER GAUGE ,B4 I DID ANYTHING ELSE,,,,,,,,,,,,,JUST MY OPINION ,OL BEAR OL BEAR [ View ] [ Email ] [ Blogs ] [ Car Ads ] crown point, Indiana   Posted by vegalover2005  -  03/28/2008 01:30 PM i just got done putting in the oil and i ran up to the parts store and got some stp. i now have a soild 15psi when warm at idle. when i cruze on down the street it pumps 30-35 psi. cold it was pumping a good 50-60 psi. man does that 20-50 take forever to get in the engine lol. now all thats left is to clean up my mess and polish up the truck and get ready for the goodguys event tomorrow. I did manage to spot my rearmain leaks a little vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by ol bear  -  03/28/2008 02:14 PM I THINK YOULL BE OK JUST KEEP AN EYE ON IT ,,,, LES AKA OLBEAR OL BEAR [ View ] [ Email ] [ Blogs ] [ Car Ads ] crown point, Indiana   Posted by JoeP  -  03/28/2008 04:31 PM Rear main leaks don't heal on their own. When you get some time change it, or you will be parking on cardboard and kitty litter. Joe [ View ] [ Email ] [ Blogs ] [ Car Ads ] Somerset, New Jersey   Posted by dixie  -  03/28/2008 05:16 PM DON'T USE STP USE LUCAS MUCH BETTER jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006   Posted by gman0046  -  03/28/2008 05:59 PM STP????? Didn't know they still sold that stuff. Don't understand the rationale of of posters using high viscosity oil to boost oil pressure. I remember they used to sell Motor Honey that you could hardly pour but it sure inreased oil pressure. There's no cure for increased bearing tolorances other then a rebuild. gman0046 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Anchorage, Kentucky   Posted by JAWS  -  03/28/2008 07:42 PM You are correct there gman, but I have also seen new motors having this same issue and the builders recommended a higher weight oil from the start. Newer design engines have tighter clearances everywhere and the thicker oils have a hard time effectivey lubricating. The newer, tighter engines must run thinner oils for this reason. An old smallblock chev, whose design was long ago, will never, no matter how fresh it is, have close enough tolerances to require thin oil, hence the reason they designed the other oil pumps, higher volume and high pressure. All trying to find a solution to the lubrication issues. Still the stock one seems to be the best when it comes to stock or mild engines. Racing engines and lubrication and tolerances.......that's a different subject for a different time.. -Brant An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by Tweety37  -  03/28/2008 07:49 PM Seen lots of SBC's run for years with 10-12 psi idle pressure. It's the pressure at higher rpm that's important. Tweety37 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Bismarck, North Dakota   Posted by artie  -  03/28/2008 08:26 PM Just went with a wix filter and castrol10-30 pressure stays at about 60 at highway speed (65mph ya I drive slow). I had used quick lube filters what ever there house brand is and castrol 10-40 and pressure would run down to 50 or less at my highway speed sometimes go to zero and cause's a heart attack. I have replaced oil sending unit four times. It works for about 20,000 miles and then goes bad. I finaly(sp) put in along with stock guage a real pressure guage . This is my work truck 2000 dodge dakota with 4.7 v-8. I have read about a lot of problems with oil pressure on this motor. I only have 200,000 miles on it. About 50/50 highway and stop and go. What is everyones opinion on brand of filter and oil. I also change oil +/- 3,000 miles. artie [ View ] [ Email ] [ Blogs ] [ Car Ads ] ozark, Missouri   Posted by dixie  -  03/28/2008 11:36 PM HEY GMAN 10/40 IS NOT HIGH V CHECK IT OUT. jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006   Posted by JAWS  -  03/29/2008 01:15 AM Artie, for your 4.7 dodge, you need to run exactly what the manufacturer suggests and nothing different. I know it's not the cheap way out, but if you think about the alternative of changing engines, it is cheap. Call your dealer and ask the service guys what they use -Brant An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by rat fink  -  03/29/2008 03:35 AM An interesting discussion.....spun bearing.....most times you will hear some "sound indication"from this. I too have known guys to loose a new engine because of a bad brand new oil pump!.....it pays to take them apart and check them over before installation.As far as oil goes.....the thicker the better.....to a point !......in your situation......20w-50 sounds like the ticket.....but NOT synthetic....in 30+ years with small blocks.....have seen a fair bit of camshaft failures because of it.......super with roller cams!.....but tends to break down under the "nose"roll-over which is the point of the highest pressure.....in my years of experience......you cant beat Kendall oils.....been in the performance game along time!...worn cam bearings could be a factor......for the cost.....you should have done it any way!.....whenever you do a partial build like this.....you leave your self room for guessing about problems like this. As with any rebuild......it is normal that the oil-press will be higher than when the engine has "broken in"and started to loosen up. Also, its a high volume pump....not high pressure......too much pressure....not good either.With older style small blocks, I have seen alot of "pressure-flexing" from idle ....to high-revs.Engine operating temp. can be a big factor too.....you will get a different reading say in July....compared with lets say...Nov. KEN COPE [ View ] [ Email ] [ Blogs ] [ Car Ads ] RIGA, LATVIA, Other Charter Member since March 2008   Posted by vegalover2005  -  03/29/2008 08:09 PM its not a spun bearing, i found out that i have a exahust leak. im taking the truck in to have it fixed.She ran beautifully to plesington. Water temp stayed right at 160, oil ppressure was 27- 30 psi at 65mph.Im still taking the engine out to fix the rear main and im going to put the stock pan and a new oil pump in and ill prob spend the money on new bearings again if needed.Fun Fun time i got lots of looks, but i forgot to take a picture of my truck being at its first car show vegalover2005 [ View ] [ Email ] [ Blogs ] [ Car Ads ] lodi, California   Posted by robymarks  -  03/29/2008 08:21 PM Artie Wix or Napa Filter is what I really like. Really like Quaker State Oil 10-30, 30 straight weight, whichever. Don't scrimp on those filters!!!! Had that one years ago. Learned my lesson. robymarks [ View ] [ Email ] [ Blogs ] [ Car Ads ] Houston, Texas Charter Member since October 2005   Posted by koolstuff0099  -  03/30/2008 11:56 AM Years ago, And I mean YEARS ago, I had a L88 big block that ran in the 11's right off the street. The oil pressure was quite low (scary) at an idle. One Sunday at NewEngland Dragway there was a tour of Pro-Stocks putting on a SHOW. While in the pits one of the drivers named Dave Strickler was running a "Jenkins" car and I notoiced at Idle there was prctically NO oil pressure. When I asked about it he said "no problem" it's what pressure is at just off idle. My BB L88 would make 30+ lbs immediately off idle....never had a problem for years with that car. LOW OIL PRESSURE at idle...."forget about it" B-Dog [ View ] [ Email ] [ Blogs ] [ Car Ads ] Newburyport, Massachusetts

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