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Milky oil again...
brianflhrci
Member Posts: 62 ✭✭
I am at my wits end...I recently saw oil pressure creeping up on our port 2003 mercuiser 5.0, I checked the oil and it was very milky. Three weeks later and too much money with a boat mechanic he comes up with too much water in the gas and the leak down has cause the slow frothing of the oil. He pumps out the gas, cleans the engine up and sends me on my way. Cut to two weeks later, oil pressure starts to rise a bit, check the oil and bam!..Milky again. He tested the manifolds and risers and said they were good to go..Any advice?
Thanks in advance,
Brian
Thanks in advance,
Brian
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PC BYC, Holland, MI
Thanks,
Brian
x
ruhroh... sorry to hear that....
I gotta say, that is a strange place for a crack due to improper winterizing if it is visible on the surface of the block..... how close is the nearest water passage?
it sounds to me like something else........... which points to your builder.
a crack high in the block not directly adjacent to a passage indicates it got hot. Or, and more likely: it indicates improper torquing of either the heads or the intake manifold, again depending on where the crack is...
different metals expand at different rates.. if the decks are clamped down with the right torque and with proper bolts, the movement is isolated between the two surfaces via gasket- which takes the brunt of the blow. it's at that time, though, when temperature hasn't uniformed and all movement stopped, that you're at highest risk of blowing out a gasket (especially a head gasket)...
problem: some folks don't use the right bolts- and opt for stuff like grade five or grade eight... I used to hate torque to yield bolts (tty), but have since learned to love them.. they stretch into the threads and lock, can't be seriously over torqued, but do this at a disadvantage of not being able to be used but once. where grade five or eights are used is on intake manifolds more often than they should- and in the past was common practice... grade fives have good sheer strength, grade eights good resistance against stretch.... grade eights used on a modern engine that relies on the mating surface floating are a bad idea, as the clamping force is tremendous and the seating not likely to give much room no matter the temperature- which can result in cracking a block. grade eights have little raised lines at each point of the hex's face and are easily identifiable because of that.. grade fives have five raised lines on the face of the bolt.
a cracked high block, though, speaks of high temperature or improper torquing and use of improper bolts.
it's always the seemingly little things that nail ya, huh?
Good comment about the right grade fastener for the application. Far too often people up the grade assuming more must be better and even fewer torque them correctly on top of that. Even fewer know high tensile fasteners are a one and done deal, used properly.
PC BYC, Holland, MI
you would be correct while speaking of Ford 302's... they don't appreciate it much....
Ford defied GM's innovation of modular design, and still produced Windsors and Clevelands, as an example, both in 351cid, but totally different engines...
however, the Merc 5.0 is actually a GM build which is the modular designed 'small block', which is used from 283cid all the way to 400cid engines, which the only exchange being bore dimensions, pistons, and crank (stroke) on the rotating assembly (short block)...
the famed Chevy Bowtie 302 was placed in '67-'70.5 Z28's only, and were in response to hotrodder's playing with the notion prior to them- it was a 283cid block with a 327cid crank in most cases, but could also be accomplished with a 327cid block and a 283cid crank... the compression, as you can imagine, on the 283cid fitted with the 327cid crank was high, and allowed for one powerful naturally aspirated engine (somewhere just above 400hp at the crank, though they were degraded from the factory, rated at a different RPM, and advertised as 290hp, and done so because of the IROC series and insurance purposes)...
the 327cid block retrofitted with the 283cid crank was no slouch, though, and was a heckuva platform for boost due to it's squishy low compression.. they were fitted with hood defying high rise super chargers, and atop tunnel ram duel four barrel carbs of HUGE venturi's for silly high RPM powerbands (such as needed for drag racing)....
meanwhile, Ford didn't have anything near so exciting for rodders to play with...
the whole concept of 'stroking' came from bowtie rodders interchanging parts and pieces between the line up of small block engines... Mopar did the same as Chevy, offering the small block mopar in 318/340/360, which allowed for interchangeable parts, too...
anyway... cool story I thought I'd share if anyone else finds it as interesting as me.
Oh, and Ford did make the 289 which was fun (my father had it in a t-bird with 3 speed...fun little toy). But I agree Chevy made the easier to play with blocks! (the Ford guys used to tell me no way, the distributor was in the front making Ford much easier...I'd just say once I had it set, no reason to mess with it). :
Dream 'Inn III -- 2008 400 Express