Mercruiser 470
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Category: General Correct Craft Discussion
Forum Name: Off Topic
Forum Discription: Anything non-Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=13665
Printed Date: January-08-2025 at 12:22pm
Topic: Mercruiser 470
Posted By: Luchog
Subject: Mercruiser 470
Date Posted: May-13-2009 at 11:55pm
Some guy stepped into the shop with one of this burning oil.
Mercruiser designed, aluminium block, Ford 460 head, cooling issues, disimilar metals etc, my mech told the guy to dump it, but he wants to rebuild it anyway.
We dont have any manuals for these around here, and we need to know std crank jorunal diameters to know if it's already been worked on and therefore order the new bearings.
Does anyone has this info?
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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Replies:
Posted By: eric lavine
Date Posted: May-14-2009 at 10:21am
got it.
look at the bearings and they will be stamped std, or .020 or .030 they will tell the story, if so thats undersize
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"the things you own will start to own you"
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Posted By: Luchog
Date Posted: May-14-2009 at 2:20pm
I need some practise on my technical english, remember the other thread where I said that bigger bearings was oversize? now it's clear for me.
The 470 is a Mercruiser engine by design, inline 4, block is casted aluminiun, Ford 460 Cobra heads, goes between 170-190hp depending on the carb. they came with closed cooling system, wich was one of the issues on the earlier models because the heat exchanger was too small.
Another issue was the charging system (dinastat??) was mounted on the crank pulley under the circulating pump, wich if leaked would make a mess. Conversion kits are available for this fixes. The circulation pump has it issues on itself, circulating water was separated from the block with a set of retainers, wich in case of failure would allow water into the block. It has a draining path between the 2 retainers so you could notice if service was equired by seeing water dropping through this hole
There's also the disimilar metals issue, sometimes when running too hot the piston would get stuck and you had to wait for the block to cool off to restart.
The general consensus is trash them, but some people actually claims to have gotten good service from them.
They were made from the the ending 70 to the ending 80's.
Anyway, we'll take a look at the bearings this afternoon and report back. it's sitting next to my engine parts at the shop.
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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Posted By: eric lavine
Date Posted: May-14-2009 at 10:50pm
ah yes, the crank mounted altenator blows up on them, the magnets let loose and its a 600.00 fix unless you get the conversion kit. i thought they were labeled the 170. seen a few and threw out a few.
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"the things you own will start to own you"
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Posted By: Luchog
Date Posted: July-16-2009 at 4:46am
anybody have a service or shop manual for these?
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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Posted By: eric lavine
Date Posted: July-16-2009 at 9:14am
I looked and i do not have one, i was talking to a guy yesterday and has twin 470's in his wellcraft, 70mph he claims and he cant blow them up. rare boat with that twin option
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"the things you own will start to own you"
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Posted By: Luchog
Date Posted: July-16-2009 at 1:27pm
Thanks for taking the time for looking in the first place
Some people actually state than they are quite nice and reliable engines... go guess.
I've made several searchs on the web, I found a forum where they say the engine was a joint Mercury/Ford project, the blocks were even offered in a Ford Racing brochure once, since the deal between them broke up for they both wanted to own the rights on the design.
Some people are actually looking for these blocks to put aluminium upgraded aluminium heads and are using them on race cars, go guess again.
We have this guy at the shop with one of these tore apart in pieces, he took the crank to the machinist and he told this guy to go 0.10 in all bearings, but I'm pretty sure mains were already undersize, now he doesnt remember where he left the can with the old bearings for us to look again and we suspect the machinist didnt check either since he very unlikely has the 470s crank measures.
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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Posted By: eric lavine
Date Posted: July-16-2009 at 6:18pm
im in a good mood
endplay.006-.010
crankpin diameter 2.4979-2.4989
clearance on bearings .0003-.0031
out round .0002
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"the things you own will start to own you"
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Posted By: Luchog
Date Posted: July-17-2009 at 12:02pm
that deserves a big THANK YOU
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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Posted By: Luchog
Date Posted: July-17-2009 at 9:12pm
Eric, sorry, lost in technical translation...
Is that the measure for the connecting rod bearings? or the "crank to block bearings"?
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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Posted By: eric lavine
Date Posted: July-20-2009 at 11:40pm
it was an old manual and this is word for word, i would say if you measured the main journals and they were in this spec then yes, it is for the mains. then check for egg shaped journals for the rods, idf within .0002 then you sre good to go and would assume the crank hasnt been touched. it would be unusual to just grind the mains and not the rod journals
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"the things you own will start to own you"
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Posted By: Luchog
Date Posted: August-19-2009 at 2:32pm
well, we havent been able to convince this guy from dumping this thing...
I'm a bit confused, the main journals size you gave me is almost dead on his rod journal size. Maybe the machinist confused journals?
Do you happen to have rod journal diameter also?
Machinist "standar" sizes:
Mains: 2.7445
Rod: 2.4968
He would turn it and told to go .10 on all bearings.
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http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique
Commander 351W
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