Smoked 502 mag
08-16-2012 | 01:50 PM
#11
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From: sint maarten
To the OP - I had a piston go south on my 454 a couple of summers ago and started hunting around for a replacement long block. A buddy of mine had decent luck with 1-800-runs-new, and bought a complete new GM 502 mag from them with a 1-year warranty for less than $6k. However, that was ten years ago, and since then it seems the price on these engines has gone up considerably. When I priced them two years ago they were over $7k for a GM base engine, and some were saying that they were no longer warrantying the mag engines in marine applications (which I find ludicrous - never did verify that.) If you buy one straight from Merc, you are likely to be well over $10K for a 502 Mag. I think GM still has the crate 502's available from many of the dealers, but most of them explicitly state not for marine use, and once again you may have warranty issues. It might be worth it to try to find a competent MARINE engine rebuilder and have them tear it down and inspect it. If you are lucky it might be an easy and relatively inexpensive rebuild, but as with anything, get any warranty agreement in writing. If it was an oil pump failure and it was run at speed when it let go, you may very well be looking at considerable damage, not only to the reciprocating assembly, but also the block and heads.
that would be my thinking if i were standing where he is.
08-16-2012 | 02:10 PM
#12
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for sure this is correct but what i am thinking would be take outs ( if any ) i bought my pair with 60 hours on them complete and turn key for 4400 each plus shipping but don't the guys at ateco sell 502 shortblocks for about 3000 or so ? thats what im talking about. if you assume that the bottom end is burned but not blown up, then there is precious little money to be saved rebuilding that vs replacing the shortblock and one is a hell of a lot quicker and easier than the other.
that would be my thinking if i were standing where he is.
that would be my thinking if i were standing where he is.
Have not heard of them, but from other posts it sounds like they have a good rep. $3K for a new 502 shortblock sounds awfully cheap - wish I had found that deal before I built mine. BTW, I tried their website, and it appears that the server is down.
To the OP: Do you know for a fact that the other engine is stock? That might have some bearing in your decision.
08-16-2012 | 03:11 PM
#13
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From: Delaware
08-16-2012 | 04:57 PM
#14
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From: Ankeny, IA
I just had my 502 mpi rebuilt after seats fell out of number 4 valves... had to put new gm head on,a good used piston, and just honed cylinders.. polished crank, new rings, bearings, etc etc.. complete rebuild.. I ended up right around the $5000 mark total out of boat machined and back in boat.. little over $2000 of that was labor...
08-16-2012 | 05:42 PM
#15
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From: Omaha Ne
I think Ateco sells the short blocks on a with acceptable core basis. I have heard good things about them. As far as the oil pump failure the mechanic in question could have been generalizing as there are many factors involved, dist roll pin, dist gear, oil pump shaft, pickup cracked or fell off. Almost impossible to tell until disassembly my bet would be the pickup cracked or fell off. Not trying to start anything just saying. Randy
08-16-2012 | 08:12 PM
#16
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Thanks for everyone's input. I don't have any marine engine backround, but I do rebuild very large semi hermetic compressors and worked on rotory wing aircraft for the military. Not saying that I can fix my engine, but I am willing to give it a try. I tried to find ateco in Illinois, but their website host has been offline. Any other reputable engine companies? I am looking at doing a long block.
Thanks
Thanks
08-16-2012 | 08:28 PM
#17
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From: Between A Womans Leggs in IL
fixx
Thanks for everyone's input. I don't have any marine engine backround, but I do rebuild very large semi hermetic compressors and worked on rotory wing aircraft for the military. Not saying that I can fix my engine, but I am willing to give it a try. I tried to find ateco in Illinois, but their website host has been offline. Any other reputable engine companies? I am looking at doing a long block.
Thanks
Thanks
08-16-2012 | 10:04 PM
#19
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From: On a Boat
Thanks for everyone's input. I don't have any marine engine backround, but I do rebuild very large semi hermetic compressors and worked on rotory wing aircraft for the military. Not saying that I can fix my engine, but I am willing to give it a try. I tried to find ateco in Illinois, but their website host has been offline. Any other reputable engine companies? I am looking at doing a long block.
Thanks
Thanks
