chana1634 Posted May 31, 2020 Share Posted May 31, 2020 I been having problem with my e7 350. I check rockers plugs but i did not see any leaks remove and replace rod bearings main bearing oil pump, i notice that crank was cut ones before main bearings are p10, rod bearings still standard some mains when in tight and some when in kind of easy, install oil pan add oil and oil press when up, from 60. To 70 with new bearings and pump, but when driving truck weather was around 80 degree, oil drop around 15 psi this with no load on truck. Now i was told that cambushing if they never been change can make oil pressure drop while hot. Is this possible or is something that i over look. Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/ Share on other sites More sharing options...
theakerstwo Posted May 31, 2020 Share Posted May 31, 2020 If you pull the pan again then plastic gauge the brgs 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452337 Share on other sites More sharing options...
1965 Posted May 31, 2020 Share Posted May 31, 2020 None of that looks good. Looks like it had something previously go down and wasn’t cleaned good when repaired. I’d say cam bearings need replaced looking at those pictures. Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452339 Share on other sites More sharing options...
chana1634 Posted May 31, 2020 Author Share Posted May 31, 2020 I did used a plastic gauge to check crank let me see if i can upload a picture Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452343 Share on other sites More sharing options...
chana1634 Posted May 31, 2020 Author Share Posted May 31, 2020 Well looks like im going to do cam bearing job maybe this will help oil pressure stay at least 20 . Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452344 Share on other sites More sharing options...
davehummell Posted May 31, 2020 Share Posted May 31, 2020 remember if there is ware on the ends of your gears and ware in the pump housing you will loose pressure as a bypass in the flow of oil and it will show up worse as the oil thins out. Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452347 Share on other sites More sharing options...
Mack Technician Posted May 31, 2020 Share Posted May 31, 2020 Cam bearings are popular on that vintage of engine. Usually you could drive through it, except you lose your engine brake around 1,100-1,000 RPM as you descend. Mack came out with a spec for gauging acceptable loss vs rebuild time. Oil at a certain temp and RPM at a specific rate should create “. “” “”” psi of oil pressure. I don’t remember “” “ “ psi. Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452350 Share on other sites More sharing options...
theakerstwo Posted May 31, 2020 Share Posted May 31, 2020 If you do cam brgs then get the acc drive bushings also.Did you plastic gauge the mains also?Reason i ask is most people grind the mains when the rod throws are done. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452362 Share on other sites More sharing options...
1965 Posted May 31, 2020 Share Posted May 31, 2020 7 minutes ago, theakerstwo said: If you do cam brgs then get the acc drive bushings also.Did you plastic gauge the mains also?Reason i ask is most people grind the mains when the rod throws are done. Original post says mains turned and rods standard Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452365 Share on other sites More sharing options...
Mark T Posted May 31, 2020 Share Posted May 31, 2020 That thing is shot. Something went through it that wasn't supposed to (dirt...filings ???) wrist pins are going to be just as worn too . Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452368 Share on other sites More sharing options...
chana1634 Posted May 31, 2020 Author Share Posted May 31, 2020 No i did not plastic check the mains just rodbearings . I got the truck running but will drive for a while and then do bushings on cam. And now that i was looking at the bearing that we remove I'm more convince that it was not done right and that dirt was all over. The bearings that i posted are from 1 year ago. Pressure is nice while cold but once hot just won't hold up goes to low and when i stop for a while it goes up, Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452380 Share on other sites More sharing options...
chana1634 Posted May 31, 2020 Author Share Posted May 31, 2020 I like to thank all of you for u opinion and help 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452381 Share on other sites More sharing options...
1965 Posted May 31, 2020 Share Posted May 31, 2020 Before I’d go to the trouble & expenses of cam bearings, I’d probably try to shim up regulator & relief valves to try to get more psi. If (I) was going to do cam bearings, I’d pull engine & polish crank & have tolerance checked. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452383 Share on other sites More sharing options...
Truck Shop Posted May 31, 2020 Share Posted May 31, 2020 Looks like it was using coolant at one time, IMO. Quote One ping only Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452389 Share on other sites More sharing options...
1965 Posted May 31, 2020 Share Posted May 31, 2020 Definitely wouldn’t hurt to have oil analysis done 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452395 Share on other sites More sharing options...
alex g Posted May 31, 2020 Share Posted May 31, 2020 I realize there's more to it than this but a bad or plugged oil filter will definitely lower your oil pressure. When I started driving I worked at a place where maintenance was not so good. I remember my oil pressure dropping one day I got back and reported it. They spun a new set of filters on and it was back to normal again. And yes all they did was filters no oil change 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452406 Share on other sites More sharing options...
Mack Technician Posted June 1, 2020 Share Posted June 1, 2020 (edited) 10 hours ago, chana1634 said: No i did not plastic check the mains just rodbearings . I got the truck running but will drive for a while and then do bushings on cam. And now that i was looking at the bearing that we remove I'm more convince that it was not done right and that dirt was all over. The bearings that i posted are from 1 year ago. Pressure is nice while cold but once hot just won't hold up goes to low and when i stop for a while it goes up, You can’t plasti the mains in chassis, you can do rods. If your creative you may load the crank upwards with a porta power to try it. Edited June 1, 2020 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452417 Share on other sites More sharing options...
theakerstwo Posted June 1, 2020 Share Posted June 1, 2020 15 minutes ago, Mack Technician said: You can’t plasti the mains in chassis, you can do rods. If your creative you may load the crank upwards with a porta power to try it. I and many mechanics have did it for years.Two ways to do it and one is to use a jack and jack up the weight of the crank but i always remove front and rear main cap and double up some paper and put on the lower brg and then tighten up the main cap.I was in involved in a deal just like this one but it was a 8.3 cummins in a bus.The mechanic that did the over haul put standard main brgs on a .010 010 crank and got the right rod brgs in but std mains in it.Same deal it had low oil pressure.The lead man at a truck dealer made the call to pull engine and send crank out for more measurements.I was asked that evening for my 2 cents worth.I showed him how to plastic gauge the crank and found the mains were standard after checking it.Come to find out he had check the new rod brgs for size but did not check mains.Some one there sure did like me for a few days. 1 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452420 Share on other sites More sharing options...
Mack Technician Posted June 1, 2020 Share Posted June 1, 2020 Lol, yup, you porta power the crank up you’ll find a 0.010” under mishap!! Heck, you probably can save money and use the same piece of plastigauge for the whole thing! In the dealer world Mack wouldn’t allow us to machine the crank. Only Remack cranks. Machine shops don’t ease the corners of journal cuts and it predisposes the journal to crack. Don’t suppose that matters as much at 350HP, but 12 liter cranks turning 480HP May be a little more critical. On the rare occasion it was needed we used a porta power. Seems like the weight allows for a lot of sag distortion if shimming. We’d generally, 99%, check to make sure crank was std, and if polish was good, it got a shell. In most cases main failures destroyed the block. Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452436 Share on other sites More sharing options...
chana1634 Posted June 2, 2020 Author Share Posted June 2, 2020 i like to know were is the , I’d probably try to shim up regulator & relief valves, in this engine, and i notice that this engine on top of cover, says that is remack engine . now the relives valve and regulator is in the oil pump, well i install a new pump, well today drove and work with truck, got load it and work ok, but weather was not that hot, like 80 degrees, waithing on thursday weather look like is going to be on the 90 degrees, well will let you know if repairs will hold up. Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452494 Share on other sites More sharing options...
chana1634 Posted June 5, 2020 Author Share Posted June 5, 2020 well the main and rod bearings, did the job, truck is running ok psi hot don't drop below 18, maybe in the near future will change cam bushing, that shoul inprove oil psi, Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452727 Share on other sites More sharing options...
JoeH Posted June 5, 2020 Share Posted June 5, 2020 How many hours on the truck? Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452735 Share on other sites More sharing options...
mechohaulic Posted June 6, 2020 Share Posted June 6, 2020 not for nothing; reading all the technical ideas that are on track ., did anyone consider maybe the brand of oil being used isn't holding up . the pictures show a definite problem with foreign matter raising havoc with bearings etc; the oil itself may be breaking down ,, Quote Link to comment https://www.bigmacktrucks.com/topic/62731-low-oil-pressure-at-idle-when-truck-is-hot/#findComment-452743 Share on other sites More sharing options...
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