Mercruiser 5.0 1(b3) - MPFI Rebuild Teardown

hello welcome to another video by lsx engines tuning marine in this video i'm documenting the uh part three of the tear down of a mercruiser 5.0 mpfi engine multi-port fuel injection engine um at this stage we've got the intake off the uh all the valve training has been removed bagged and tagged uh each all the tr like for example this is one e one exhaust and all the components for one exhaust the push rod the rock arm the the uh the ball and the nut are all bagged up in one bag for one e so each uh each component valve train is back and then we're now ready to the uh the head bolts have been removed from the holes in the head and we're now ready to remove this head when you remove head bolts you go in the opposite order of the firing order but not the firing or the opposite or the tightening sequence so example tightening one bolt is in the middle so the last one is 17 on this end so you start with 17 you can look up the tightening sequence on the internet but you start with 17 and go backwards so it's 17 16 15 14 13 so so you're just going opposite direction the tightening sequence when you loosen and you loosen each bolt just crack a little time and then go go through the series and then come back and loose a little more i generally take about four stages i'm loosening so that um so that it doesn't warp the head that's the purpose of doing that so um at this time we're going to pull off this this this cylinder head this is the uh uh reconsider the driver side in this case would be the port side of the engine from the boat's perspective and we're going to move this head and see what condition is underneath if there's anything unique or interesting about the underside of this head i'll show it in the video all right continuing with the mercruiser 5.0 mpfi teardown part three um looks like there was a little bit of a head gasket blown between cylinders three and five than the middle two on this bank this is on the starboard side um excuse me this is on the port side um it's not real bad blowing head gasket but there's definitely some traversing between the two cylinders based on the black looking stuff this side is clear nothing wrong there again between seven and five nothing wrong there except water in the cylinder which did not come from a bonehead gasket and uh but this one had a little bit of a bonehead guys it wasn't i don't know if it was fully blown but it was definitely leaking from one side to the other so we get the other head off we'll view that and show what it looks like all right continue with the mercurizer 5.0 mpfi engine teardown we now have the starboard engine off and um it is showing um well let me say i call this the pasture side um it's showing the possible blown head gasket on this side too it's between cylinders uh four and six you see how that's clear that's clear and there's some black smudging going on between these two so i don't know if it's a fully blown head gasket but there was i think it was definitely some leakage between the two not to mention the water and the cylinders but that's a different issue so this time we're going to continue working on tearing this thing down and uh next i'm on the roof going to remove the starter the front harmonic balancer and then i will uh remove the oil pan and flip it off flip flip it upside down so the next video will show this engine uh probably in a state with oil pan off and it flipped upside down continuing with the mercruiser 5.0 mp if i tear down i'm about to well i've already removed the harmonic balancer off from the engine and i removed the oil the oil remote oil filter adapter and i'm about to remove the oil pump and the windage tray and the oil dipstick and then i will take off the front timing cover and uh work on the valve train so stay tuned for that continue with the uh mercruiser 5.0 mpfi teardown just want to make a note quick note on how these piston rods are oriented there's a tang on the outside edge of the rod that always faces away from the other rod so this tank here the tank there tang tang the tangs are as far apart from each other as you can get on the rod just wanted to show that because that's that's critical so about i'm about to remove the piston and rod for cylinder number three looks like and then i'll do four so i'll pick it up after i get these two out one of the tricks i like to do is um you can either put rubber sleeves around these bolts to keep them from contacting the crankshaft journal but what i like to do is use the old bearing and rotate it around and that keeps this bearing between the crankshaft journal and that the threads on this bolt and if i tap on this bolt on the top side and always push down and keep this bearing between it this bolt won't hit and it'll just push it right on out without touching the crank so i use the old bearing as kind of a protector for the crank so the bolt doesn't contact with it it's a little bit faster than having to put the rubber sleeves on each time okay continuing with the teardown of the mercruiser 5.0 mpfi engine i went a little long between videos this time but i'll basically describe what i did so we've removed each piston one at a time and uh the way i did it and identify the pistons took them outside i'll show you that later but anyway um remove each piston one time and they'll remove the bearing caps and we're at a problem we or we have a issue where the rear main seal won't come off back the back because the engine stands in the way and there's this stud right here in the back of the engine that won't let this ruined seal lift out so as a going forward not only do you need to take out the the bolts that hold this rear main seal you also need to take out that stud if you want to be able to get this out easily so in order to get this crank out we're going to have to take the entire engine this engine and the stand bracket outside set it on the bed of a or on the tailgate of a pickup truck and uh pull this piece off the back before we can get this out before we get the crank out but in the meantime i was going to pull out and crank the cam shaft to make this thing lighter and what i've discovered is that this thing just been rebuilt before the owner told me it was rebuilt and they did not do a good job because they took a roller block and converted it into a flat tappet cam and what they've done is when they put this cam in they didn't put a retaining plate back in i got i don't know if that's because the they just relied on the timing gear to walk out and hit the back of the timing cover i don't know i'll check the timer cover in a minute if it has any marks from the from the time of gear that means i did not put it's called a cam button uh if you don't put a retaining plate here you're supposed to put a if you convert an older block to a roller cam you have to use what's called a cam button on the inside of the timing cover so that when this camshaft tries to walk out it hits a stop and you want it wearing on one spot but um in this particular case i don't know that they did that i'll check in a minute but um i'm about to remove the cam to make this a lot lighter and um to do that i put a five six five sixteenths by uh 18 bolt in the hole and use that as kind of a tool to help me work this cam out which is what i'm about to do now so this blocks almost torn down the next stage after we get this cam out and by the way the lifters are still in there too they haven't fallen out which is a sign that may have been the wrong lifter but um well obviously the wrong lifter because they're not roller lifters in the rotor block but there was nothing sticking up even when the cam is it even when the lifter is at its highest lift point the roller the lifter still doesn't stick out up past the block so i'm going to try to shake those out or by gravity or wrap on the block with a hammer and see if they fall out by gravity all right continue with the uh mercruiser 5.0 mpfi engine teardown i'll now have the crankshaft out and expose the main bearings and i want to show you what i found um this is number one main bearing it's got some uh significant scoring in it but it's still functional um it's definitely neat replacing but it wasn't gone yet that's number one bearing and obviously your your lower halves the halves that are in the caps show the water square because that's where the load is pushed as the pushing pushes down making power this is number two different story number two is starting to go starting to uh melt this is a lo these are aluminum bearings by the way they're not tri-metal they're called bi-metal and to me they're not as good as the tri-metals i don't know has anything to do with this bearing here but um this bearing is about to go it's starting to show welding of heat damage from the bearing melting and welding spots on itself if you look in here this is the top half and you can see the there's one spot where it's melted but it's also got spots where aluminum from the lower bearing has welded itself to the upper bearing so um this engine wasn't going to last much longer because of this bearing um the reason i have this engine the reason i'm rebuilding it is that the owner um i'm not exactly sure how it happened he was probably on a business trip and the cover was leaking and some somehow the the drain plug got left in the boat and the boat filled with water and the engine got submerged so the lesson learned is um even though you got a cover on your boat you probably want to take your drain plug out when you're along away for long periods of time i'm just assuming speculating i'm not sure exactly what happened anyway um so this engine was submerged and that's why i'm rebuilding it and um the fact it was not this in order what i'm getting at is this damage was not caused by running it after it had been submerged uh the owner did not run this motor from the point it was submerged he just cleaned it up and then sent it to me to get rebuilt so this damage was not caused by the fact that i'm rebuilding it this was this was damaged due to the the poor rebuild it was done before and i don't know how many hours this had on it but it wasn't going to last much longer so this is another example of a quad a shoddy rebuild in the boat industry then you've got this this bearing here again not some scoring not too bad but it's it does need replacing and that scoring if you see scoring like that what you can do also there's two marks on that bearing i didn't do that that was in here so somebody it's great marred up this bearing before i was even when i was rebuilding the motor um the uh let me go into number four here's some more scoring there was about to say if you see scoring like this you can take your fingernail and scrape the crankshaft or run your fingernail across the crankshaft like this and if you feel uh if you're if the fingernail catches on ridges the crankshaft needs to be turned to smooth it out and uh so this is gonna have to this crankshaft is gonna have to be turned and smaller bearings put in i don't think these are oversized bearings they might be let me see it says gm yeah they say it says gm aluminum it is oversized bearing hold on let me see if i can get a good picture of that stable shot of it oh it's undersized by .0006 so it's pretty much a standard bearing that was a just a slight undersize but this the fact that says al that's aluminum bearing you know because i like to use tri-metal bearings they don't have a they have some copper in them or something but anyway um there's there's your number four bearing again there's a two mark on the side of that bearing and uh more scoring on number four and then last number number five there's your uh this is your lower bearing half some deep scoring there and spots where the bearing is starting to come pieces of it's breaking off and welding into the grooves again number five on the upper half so even though these bearings are not absolute terrible it's that number two it would still run for a little longer but this engine was uh was on borrowed time so that's all for the bearings i want to show the main bearings and the conditions main bearings oh and the rod bearings all consistently show a pattern of this is the upper half bearing on a rod bearing one of the rod bearings and you can see the pattern it it wears a spot right there because that's where the load when the piston is pushing down it puts that load on it so these are all aluminum bearings too they all show a similar type pattern like that i didn't save them in their work but they all show something similar that right there you see some scoring on that too there's another rod bearing it's got some scoring in it so again uh just not the best rebuild when i rebuild engines i rebuild them using the tri-metal bearings the best i mean obviously not i don't buy the brace bearings the 150 dollar bearings but i buy the tri-metal bearings which are better they're they're best quality for uh stock use so one other thing i want to show is my son taught me this trick this is the rear main bearing cap and when it's seated down like this with the crank in the way it's kind of hard to get out you can't wobble it side to side because these two sides here here and here are thrust thrust flanges so you can see the thrust flange on that bearing right there and right there so you can't walk it side to side so what i was doing was putting the wall put take one of these bolts and move it to the oil pump bolt putting in the hole and just taking my uh either my palm or a hammer and right lightly tapping on the side of this to break the to kind of make the bearing pop the cap pop up like this but my son uh i was showing him how to do it and he drove this bolt in too far with a socket set and as he was tightening it just it just pushed the bearing cap right up off the bearing and like okay that's cool how'd you do that so as it turns out if you look up under here the hole for the oil pump bolt is drilled through and tapped through so as you're threading this in it's pushing further and further so it just lifts this bearing cap right off the off the crankshaft now obviously this this bolt is is uh pushing against the back of the old bearing so you might be damaging your old bearing but who cares you're gonna replace that one anyway do not i would not do this with a new bearing to remove this cap because you might do some obviously you might do some uh dinning or warping or whatever but on an old bearing i wouldn't worry about it so if you're you're doing plastic gauge and you gotta torque this down and get it back off don't do not do this to get it back off on our knee bearing just want to point that out one other thing i found that's kind of that i'll do another video on i found kind of a little issue mystery um this front cover it was one of the plastic vortec covers it has a crankshaft position sensor in it so it's what they use the plastic covers what they use in the vortex from 96 up and i noticed that this gasket on the vortec cover was not completely it was not completely sealing against the surface of block you can see how this curve this this line right here is made by the factory seal in the cover and it goes off the surface of the block and comes back so it wasn't sealing right against this block so like i said i just want to point that out but i'm gonna do another video on on the analysis of that and see if this see if this box even functional this customer has npfi so it has to have the crankshaft sensor to function so if i can't find the proper cover that seals against this block this block may not be reusable uh like say the previous builder this block to me is not the fact it's not the original block it's got some underlying paint on it red paint so they took a 305 maybe a truck engine or something and made it to a boat engine which is fine but the fact that it's got this red paint underneath the black paint tells me and there's some over you see how the black was overspray and it didn't get into all the red but uh this engine to me is obviously not the original mercruiser engine so they took a possibly the wrong block to to make this mpf engine i'll dig into that more in a separate video though so i just want to point that out all right so this block is done i'm about to take it out put it in truck and i'm going to measure i'm going to check the bore conditions see if these boards need to be reborn or just honed i'm going to check them with a diabolical see how much clearance i got and see if it's possible just bore them out i mean excuse me to just hone it without boring but um i'm gonna have to buy new pistons anyway so might as well just go ahead and board and it's only an extra like 150 to get it bored that's it i hope you enjoyed watching this part three or phase three of the tear down and if you have any questions put them in the comments thanks for watching

Channel: Moccasin Marine LLC

Views: 1,620

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Id: f6giS7QRa0w

Length: 18min 11sec (1091 seconds)

Published: Sun Mar 14 2021