Cost to freshen up a 502 MPI
11-12-2019 | 02:16 PM
#11
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Joined: Sep 2012
Posts: 523
Likes: 38
From: new baltimore mi
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.
11-12-2019 | 03:59 PM
#13
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Joined: Oct 2013
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From: SF Bay Area
01-12-2020 | 12:58 PM
#14
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Joined: Jul 2015
Posts: 1,201
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From: Atlantic Southeast
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.
Receipts on my PQ for both of them to be rebuilt / freshened up was $22k.
01-12-2020 | 11:56 PM
#15
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Joined: Aug 2013
Posts: 397
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From: Kemah, Tx
And 6 to 14,000 is a pretty accurate range if you’re doing it right
Last edited by sailtexas186548; 01-13-2020 at 12:08 AM.
01-13-2020 | 05:59 AM
#16
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Joined: Oct 2005
Posts: 5,825
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From: Clarkston, Michigan
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.
01-15-2020 | 07:07 AM
#18
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Joined: Jul 2015
Posts: 1,201
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From: Atlantic Southeast
$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.
