502procharger

ok i am having an issue with my new motor, i was kind of putting off finding out what was up because i thought it was just a bad sender. here is the deal. blown 548 done by a reputable local shop. on the dyno the motor made 65lbs of oil pressure pretty much the whole time. after i put it into the boat same thing for the first few hrs 60-65lbs about 3 hrs into it it started to be lower cold then go to like 45 hot. sometimes when i shut it off for a few min and start it back up it would be at 40lbs even though it was at 45 just before i shut it down. well i figured i had fuel contaminated oil of a filter that was collapsing or something so i drained the oil and put a new purilator racing filter on. same thing. the more hrs i put on it the lower it goes hot and lower it starts out cold. it is to the point where hot at idle it is at like 20lbs and at 3000rpm's it is only like 35lbs. i have a eddie marine oil thermostat that keeps my oil at 215deg all the time and i have a oil temp gauge that backs that temp up. really the only other thing i changed in the oil system was i went from stock -6 lines to braided -8 oil lines from the motor to the filter, filter to the thermostat, thermostat to the cooler and cooler back to the motor. i put a mech. gauge on it today and same thing, but i started cold with about 45lbs went down to like 36lbs hot and to like 19lbs at idle. needless to say something is wrong. the motor runs great. purrs along perfect but there is obviously an issue some place. i have to yank the motor this weekend anyways because in the beginning of the season i broke a tooth on the flywheel and after going through 3 starters because of that my ring gear on the flywheel is shot. any ideas what to check? i figured if it was a bearing i would see material in the filter but i don't. i also figured if the thermostat or any of the lines were blocked it would show more pressure because it was backing up. what do i check when i have it out? thanks in advance.

articfriends

do you know how much main brg/rod brg clearence your motor had when it went together?Ive seen after market cranks that were new out of box std/std that had .004-.005 clearence with std brgs,i had to use .oo1 undersize to get .003-.0035 on my 540. It had 100 psi on the dyno (with fairly cold oil) but has 60-80 in the boat.Are you sure you went from -6 to -8 hose? -8 hose (in my opinion is way too small for a big block),i'm running -12,i had lousy oil pressure on my 502 and got rid of every restriction in the flow path,upgraded everything to -12 w/full flow fittings and went from 45 psi w/o to 65 w/o,the bigger fittings didn't make oil pressure but the smaller ones sure held it back. So my guess is you have clearences on the high side and slightly restrictive hoses. Also,when i had 502 w/similar problem the more times i ran it the worse it got(the clearences must have opened up slightly) but it was fine for 2 yrs after re-plumbing it,Smitty
P.M. me with a phone # and i'll call you if you want to discuss it

CMS Racing

I have seen it happen before run great on dyno but put the motor in the boat and some one forget to clean the oilcooler and lines real good and it takes the bearings righjt out. and your oil line should be at least -10 and the oil thermostat is not a must unless the motor dosent make any real oil temp when your just cruisein around.if you have a pro charger lock at that it runs off of the engines oil system

articfriends

Not all prochargers use engine oil,most people choose the self contained option (i did)

Reed Jensen

I love oiling system problems... my starboard had so much oil pressure it would peg the gauge just off idle....hmmmmmm then this happened....

Reed Jensen

Turns out the genius that built and installed the motors plumbed the oil filter and cooler backwards on the starboard engine.... nice guy... I'll post his picture... He claims to be the undisputed authority on offshore engines... maybe you'll all recognize him.... Oh... by the way... he didn't stand behind them either....

502procharger

here is what i have -10 out of the motor into a -10 to -8 reducer because that is what goes in and comes out of my remote filter. -8 to a 10 fitting back out of the filter, -10 line to my oil thermostat, -10 to my cooler, -10- out of my cooler back to my thermostat, then -10 back to the motor. i needed a oil thermostat because i would only get my oil to about 150 because my cooler is so large but i wanted a large cooler for when i run hard. with the eddie marine thermostat my oil bypasses the cooler until it reaches 215 the maintains that temp no matter how hard i run. the oil pressure never dropped like it does not and has gotten worse with time. i figure if the oil lines were being restricted by the 2 -8 reducers into and out of the remote filter it would have always been low and not progressivly gotten worse right? like i said the motor needs to come out anyways for the ring gear replacement so i will pull the pan, prob replace the pump anyways and check all the bearing clearance. what should the main and rod bearing clearances be? thanks.

502procharger

ok here is what i have, please dont mind the half ass oil temp gauge i have there. when i took the picture my gaffrig had not come in and i did not want to run it for the first time without something to make sure it was not getting to hot

articfriends

I prefer .0025-.003on the mains,and .0028-.0035 on the rods. if you have more than this but the cranks not damaged you could put .001 or .002 under bearings in with crank still in block carefully.I would ditch the oil filter adapter your running and put a full flow one in,the line size probably isn't your problem though(it sounded like it though when you were talking about -6 to -8 fittings). But like i also said,4 years ago when i rebuilt my original 502 and installed the blower i ended up with some stock merc hoses and various -8 and 7/16 hose on my setup that the shop that did my r/r on motor installed. It had 58-65 lbs oil pressure but the more hours i put on it the worse it would get and after 15 hours or so i could only get 45 psi hot, i ripped all that stuff off and completely re-did everything with full flow -12 fittings and billet adapters and i had 65 psi again for another 130 or so hours. You also want to avoid excessive bends,90's and adapters,they all restrict flow. Another question,have you tried different weights of oil? If your motor has no restriction in the lines or adapters and lets say you do have .004 clearence just for the sake of discusion then if you were to go up a weight or two in oil you would immediatley see a increase in oil pressure. I had a pontiac 400 i built once w/aluminum rods for a drag jetboat,it ended up having .004 on the mains and .005 on the rods (hot) ,(aluminum rods gain rod clearence the hotter they get). it would carry 60 psi cold,35 psi hot and had 5 psi hot idling with 50 wt oil,i ran one of the 70 wt oils in it (a band aid approach) and it had good oil pressure. If your motor has excessive clearence and you go from 40to 50 wt or 50 to 60 wt you should see a increase in pressure. If you were to actually see a further drop with thicker oil it would pinpoint restrictions in oil system.This would be easier to explain to you on the phone but one more way to look at it,a stock 502 only has .0015-.002 main clearence and around .002 rod brg clearence,they run a bunch of oil lines and fittings that are almost as small as 3/8's inch on the smallest adapters id,they tell you to run 10/30 or 10/40 oil(flows real well),lets as a wild ass guess say the cam,mains,lifters,rods flow(or leak off) 5 gallons per minute at 5000 rpm's,your lines can flow and pump can put out lets say(remember this is w.a.g method),7 gallons per minute,the extra 2 gallons per minute backing up give you your 60 psi oil pressure stock,lets say you build a hi performance engine with .003/.0035 main and rod clearence,you put a high volume pump on that flows 9 gallons per minute and with the additional clearence your combo is flowing(or leaking off) 7 galllons per minute and you go up a little in line size (to -10),you end up with same kinda oil pressure, BUT keep in mind,your oil lines and fittings will only flow as much as the smallest restriction (your -8 adapters). If you tear motor apart and tighten up clearences ,the flow requirements to sustain oil pressure will be less and you'll most likely get your pressure back. I have went as far as measuring every fitting and boring out adapters on oil sytems before where there were fittings that were too small in i/d that were a necessary evil on something.So,if it were me before i pulled the motor and cracked the pan open,i would try heavier oil,if it didn't help,i wouldn't blame clearenecs,i'd look at the id off your smallest fittings,Smitty

Strip Poker 388

Hey Reed the pictures kinda looks like Bob teague