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-   -   Cost to freshen up a 502 MPI (https://www.offshoreonly.com/forums/general-q/363837-cost-freshen-up-502-mpi.html)

flashgordon 11-12-2019 02:16 PM


Originally Posted by articfriends (Post 4714661)
Yep, I get asked prices all the time to "freshen up" bbc marine engines, price can be hard to nail down , huge price difference between re-ringing a motor VS replacing heads, pistons, valve train, cam, boring, decking, balancing, upgrades , dynoing, tuning in boat, exhaust upgrades,etc, etc. And since most 502 mpis are 18 to 25 years old, no telling how rotted heads or what you will find and other stuff is until its apart. Ive seen countless threads on here where guy says he got "ripped off" by some marina or engine builder, I think the majority of the time the guy who gave them initial estimate didn't make it clear enough upfront of what might be involved and then as they dig deeper they find more and more stuff thats not re-usable. I'm sealing up some oil leaks on a pair of blown 502s out of a 30 ft eliminator that were "rebuilt/freshened" 5 hours ago by someone who post here OFTEN, or at least used to. Not sure WTF he was paid to do or told customer he did but its clear the rear cam plug was NOT out recently on either motor so how did he possibly "rebuild" these, hone cylinders with cam bearings in motor? If so, thats some backyard ****,Im not digging any deeper as this customer ONLY wants oil leaks fixed. MASSIVE amounts of blue rtv over top of 1 piece oil pan gaskets, timing cover sealing surface (gen 6 motors), why??? Things looked like a oil explosion, leaking everywhere, oil lines leaking too. These were dynoed too, I cant believe that no one saw all this oil leaking on dyno, tells me, YOU GET WHAT YOU PAY FOR (and sometimes you don't even get that), Smitty


ahhhh,,,yea rebuilt a motor, boil it out, hone it , and dont take off rear plug for cam shaft....
hmmm,,, i want him rebuilt my next motor ,,,NOT
i dont think alot of people really understand what goes into putting a motor together and time it takes.
people just look at the dollar amount.

F-2 Speedy 11-12-2019 02:26 PM

The old saying, Double the amount you're thinking of spending is pretty accurate, the bleeding has finally stopped on my 2 500 EFI rebuilds,

Baja Rooster 11-12-2019 03:59 PM


Originally Posted by F-2 Speedy (Post 4714704)
The old saying, Double the amount you're thinking of spending is pretty accurate, the bleeding has finally stopped on my 2 500 EFI rebuilds,

Well, you just jinxed that. :p

Tractionless 01-12-2020 12:58 PM


Originally Posted by 92nsx (Post 4714646)
On a single complete rebuild I has estimates form $6000 all the way up to $14000 on 502 mpi . All depends what is preformed. To freshen up top end and if you can turn a wrench. $1000-$1500. Again depends on what you have replaced in the heads.

Receipts on my PQ for both of them to be rebuilt / freshened up was $22k.

Damn!!! Might as well just buy rebuilt long blocks for $6k then plug and play.

sailtexas186548 01-12-2020 11:56 PM


Originally Posted by Tractionless (Post 4721536)
Damn!!! Might as well just buy rebuilt long blocks for $6k then plug and play.

Bargain remains are just as scary as a cheap rebuild. You pay with your money or your time, or u get **** work.

And 6 to 14,000 is a pretty accurate range if you’re doing it right

thirdchildhood 01-13-2020 05:59 AM

As a retired heavy automobile mechanic who has rebuilt hundreds of engines I honestly cannot see how a 502 rebuild could cost in excess of $10,000. If the engine is in that poor of condition then maybe it should just be replaced entirely. A "refresh" or rebuild to me typically involves boring the block and replacing pistons and rings and bearings. The crank may need to be turned down .010, any more risks removing the case hardening. Heads can be rebuilt with a quality valve job, springs, seals, etc. Lifters should be replaced and possibly the camshaft. All clearances carefully checked on assembly. $14,000? You can buy a low hour 525 take out for less than that now.

Steve H 01-13-2020 12:24 PM

If you had rebuilt "hundreds" of high output marine engines, you would understand.

Tractionless 01-15-2020 07:07 AM


Originally Posted by sailtexas186548 (Post 4721620)
Bargain remains are just as scary as a cheap rebuild. You pay with your money or your time, or u get **** work.

And 6 to 14,000 is a pretty accurate range if you’re doing it right

$6k from a highly reputable west coast florida rebuilder. While a bargain not a cheap quality rebuild by any stretch. Seen a multitude of rebuilds running for year from them without issue.


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