4.3L Vortec mercruiser cracked block - swap with automotive engine block?

Discussion in 'DIY Marinizing' started by mmanning63, Jun 19, 2010.

  1. broke_not
    Joined: Jun 2008
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    broke_not Junior Member

    I'd have to see specs on different bearing clearances to believe it. Lower viscosity oils are typically called for in automotive and light truck applications because their operating environment varies much more widely than a marine application does. When was the last time your boat was fired up at -10F?

    Additionally, "thinner" oils have been spec'd for automotive engines to help them meet fuel economy goals. That's where the whole "energy conserving" label and starburst symbol come from on oil containers.

    Having bearing clearance "A" for a marine engine and bearing clearance "B" for the automotive equivalent would lead to disasters aplenty. People would put in whatever oil they had available, and if the oil was "too thick" for that engine's bearing clearances, failures would result almost immediately.

    ;)
     
  2. Frosty

    Frosty Previous Member

    A lot to do with water cooled oil coolers and that a boat engine generally runs at 90% all the time. A car can have little cool down at the lights and when changing gear.

    If I was an engine I would rather be in car.

    Short motors do both, cams will be torque related usually for 4 wheel drive applications and definately do not have a late intake closure or too much overlap or reversion will pull in cooling water.

    Main bearing tolerances are not something you change its set at that for the application of the operation of white metal bearings and journal diameter.
     
  3. gonzo
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    gonzo Senior Member

    The thread starte by someone giving him the advice to get an engine "from some old Blazer". I think that getting a tired worn engine is not a good idea. A rebuilt engine is a much better option and won't cost any more.
     
  4. Frosty

    Frosty Previous Member

    An old worn out and tired engine would not be a good idea, but he said he had the opportunity for a working motor from a 96.

    Mileage would be a good indication, if your really strapped for cash he has no choice.

    Forget the freeze plug swap, if its a fresh water cooling then the engine does'nt know where it is,- car or boat.

    Sea water does'nt touch the engine apart from the exhaust cooling jacket.
     
  5. CDK
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    CDK retired engineer

    Interesting, the OP never responded.
    We have been talking to ourselves again!
     
  6. broke_not
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    broke_not Junior Member

    That's a pretty silly statement. I'm not saying that buying a used engine is the best option in every case, but if a used engine "cost the same" as a rebuilt one, businesses selling used engines would have kind of a tough time selling them...wouldn't they?

    I've bought, (many times), entire running vehicles for less than the cost of a rebuilt engine. I've pulled what I needed off of the vehicle, and turned around and sold the rest. Making my net cost for the "tired, worn-out" engine, (which is neither tired nor worn out or I wouldn't have bought it), essentially zero.

    Additionally, many places that quote you a price for a rebuilt engine are making that quote based upon you turning in a good core. That means you need to have a good core, and in this poster's situation...he doesn't. Also, while many rebuilders tout their inspection/rebuild processes, I've seen plenty of details on rebuilds fall through the cracks. Despite what some rebuilders say, every engine they see does not get completely re-machined. If a core in good condition comes in, it's freshened up with whatever it needs and sent back out the door.

    Anyone that frequents boating, car, or light truck forums has seen posts about a rebuilt engine, (or starter/alternator/transmission/whatever), that lasted for half as long or less than the original one did. If the rebuilders were doing everything they say they're doing each and every time a core comes in, the longevity of the rebuilt stuff would fare better. "Good as new" is rarely, (if ever), the case.

    Yes, you do get a warranty for a rebuilt component. But that warranty is no guarantee.
     
  7. gonzo
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    gonzo Senior Member

    The rebuilt engines I sell, by Jasper, have an 18 month warranty on parts and labor. By the time you marinize a truck engine, the price will be the same or quite close. Whatever people do at swap meets, it doesn't usually have to do with price. Mostly they are looking for a hobby. Your opinion on rebuilt parts is based on anecdotal stories by people that had problems. Many of those are owner inflicted. The industry records shows that remanufactured parts last as long as new. I don't understand your statement that a warranty is not a guarantee. Also, you are putting zero value on your labor. That only counts if you want to kill time. Otherwise, you can spend that time on a profitable occupation and buy something much better.
    Your statement the cores are "freshened up and sent out the back door" is only true for disreputable and dishonest shops.
     
  8. Frosty

    Frosty Previous Member

    But-- he has a marine engine complete with starter etc all he has to do is swap it all over.

    If he can get another for 500 dollars his labour (reward) for a days work would be more that getting a temporary job in a country with 12% unemployment. If he spent a bit on a good manifiold and a cam he will have a better motor at still less than 1000 dollars much lees than 1/2 the price of new.

    As far as guarantee for an engine did'nt you say previously that the engine failure would be blamed on not looking at the guages and stopping it in time.
     
  9. broke_not
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    broke_not Junior Member

    If my only "experience" with rebuilt parts were through stories I've heard from others, you may have a point. That's hardly the case though...I've been turning wrenches full-time since 1983.

    Really? Post a link to these "industry records", and then after you do....explain this....from your same post:

    Are not the less-than-reputable shops considered a part of the rebuild industry as a whole? Or are the "industry records" you referred to a cherry-picked sampling of only positive data?

    Think of it this way if you're having trouble wrapping your head around the concept: If you operate a marine repair shop, then you're a part of the marine repair industry. If a reman or rebuild company produces less-than-stellar components to sell....it doesn't matter much if their products are sub-par. They're still a part of the industry.

    Good grief dude, when a used part is rebuilt or remanufactured, it's disassembled for inspection first. Engines, transmissions, starters, alternators, etc., etc. all have individual components inside that have specifications. A service manual will state, (for example), what an original dimension was, and what a serviceable wear limit may be. If an individual component is within an allowable spec, it's cleared as okay to re-use. It may be halfway towards requiring replacement or meeting a service limit spec, but it's cleaned up re-installed as is. Now add up several such individual components and consider them as whole. A rebuilt or remanufactured assembly is never "good as new". It's only as good as the opinions and skills of the rebuilder have allowed it to be. When I refer to "opinions" it's important to remember that not only is the opinion/decision about whether to re-use or replace a part is being made, but also....if the part is going to be replaced...what it's going to be replaced WITH. I can go to a parts store right now and be offered two or three "lines" of replacement parts to choose from. Something as simple as a bearing, or a starter drive inquiry is met with a follow-up question from the guy behind the counter such as , "Do you want the good, better, or best one"? Is there any set of rules or regulations about the quality level of replacement parts a rebuilder must use when they re-man an assembly? If not, then where does that leave your assertion that rebuilt stuff is as good as/reliable as....new?


    Lastly, I'd like to echo the sentiments of another post above and point out that every time a thread comes up here about someone wanting to swap in a car or light truck engine, you point out the allegedly astronomical costs of doing so....because the engine will need to be marinized. The OP in this thread, (as well as many of the other threads on the topic), already HAS a boat. The boat he HAS, happens to have a cracked block. Most of what he'll need to do the mysterious marinizing is ALREADY in his possession. If that STILL fails to register with you, then dig out the last invoice you issued a customer for an engine you dropped into their boat. Do you tack on the cost of the parts an engine needs for a marine application to every job you do....even if the boat comes into the shop WITH those parts already?

    ;)
     
  10. gonzo
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    gonzo Senior Member

    There are parts, like the camshaft that are different. You can piece together something, but if you want reliability, a remanufactured engine by a reputable company can't be beat. Yes I "cherry pick" the companies I refer to as reputable. For a list of what gets done and the written warranty check this link: http://www.jasperengines.com/index.php
     
  11. Frosty

    Frosty Previous Member

    Taken from Jasper engines.

    USED ENGINES, TRANSMISSIONS AND DIFFERENTIALS
    Used components are pulled directly from a vehicle – typically a junkyard vehicle – and generally not even so much as surface cleaned. There are no provisions for disassembly, internal cleaning or inspection with a used component. Used or junkyard components may have high mileage and a poor maintenance history – a failure waiting to happen. Many used or junkyard components come from a vehicle that was involved in an accident and may have unseen damage.
    REBUILT ENGINES, TRANSMISSIONS AND DIFFERENTIALS
    To rebuild is to recondition by cleaning, inspecting and replacing severely worn or broken parts. Serviceable parts are reused within the manufacturer's acceptable wear limits. The quality of rebuilt components varies widely and many come with only a limited warranty.
     
  12. broke_not
    Joined: Jun 2008
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    broke_not Junior Member

    Read my post again. I didn't ask if you cherry-picked companies, I asked if the "industry records" you referred to did any cherry-picking to obtain the results you claim they've reported.

    Oh, and thanks for the Jasper link....didn't need it though. I'm pretty familiar with them already. What I asked for, is a link or source for the information regarding your claims that <cough> "industry records" <cough> have shown that reman stuff "lasts as long as new".

    Here's what you posted:

    ;)
     
  13. lilrobobx
    Joined: Aug 2011
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    Location: Hope Mills, NC

    lilrobobx Junior Member

    Well, i have been reading threads for months concerning auto vs. marine, and it appears that everyone has THEIR opinion, but not proof, i have heard and believe cams ARE different grinds, that makes sense, i have heard of valves, valve seats, and valve guides being of a different material than their automotive counterparts, oil pumps being a high volume, standard pressure( makes sense) ring gap being larger on the marine engine due to the colder block theory (kinda makes sense) freeze plugs being brass( makes sense, HOWEVER...not sure when GM started it but the 2006 Vortec i have, removed from a 2006 Silverado, 5 spd also has brass) and several engine builders personally told me the engines (marine) are built looser (bearing clearances and ring gap alike) and they want like 1 to 2 grand MORE than the auto engines they sell...WHY?
    So far, i have removed heads from both engines, and i cannot verify valve seat and valve guide material, i DO KNOW, that a magnet sticks to the intake valve on BOTH, and it DOES NOT stick to the exhaust valve on EITHER engine.
    Also, i do not know why, but the head gaskets both appear very similar, almost identical other than P/N and a magnet will stick to both.
    I am more anxious to check clearances, but i am willing to bet they are the same which will conclude that most likely, the cam and oil pump(other than the Mercury Marine tag) are the ONLY differences.
    While i do not know why, it appears the marine engine has been disassembled at some point and this may explain the head gasket...probably re-assembled using Auto Zone gaskets...not sure, i will run the P/N and see what comes up.
    Stay tuned,
    Rob
     
  14. lilrobobx
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    lilrobobx Junior Member

    Well, i cannot find out what the head gasket is, though it appears original as it has black paint on it where it protrudes beneath the head, the only number stamped on it is 5924, where the auto engine has GM12550024...not sure but they both have steel core.
     

  15. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    just tell the GM parts guy you have a marine engine and see what part no. he pulls up
     
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