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How can you tell what scored your cylinders?

Old 04-29-2015, 09:17 PM
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Originally Posted by Tinkerer
I don't know why anyone uses a flat tappet cam anymore. Its a crap shoot these days with those cams. I lost one years ago and it didn't do anything to the engine. ( except for the VERY fine metal in the oil ) the metal was so fine that it didn't even mark the bearings.
I flushed it out with diesel fuel , changed the oil filter a few times and flushed the oil cooler. ran it for the rest of the summer and then pulled it apart in the fall. NO damage at all. ( and yes I did break it in properly ) Pissed off the neighbor at the old house. So when I broke in the other engine I dragged the boat over to a local ramp in a commercial area. BOY did get some looks.
spend the $ for a roller cam and no need for break in.
Why would you bastardizes set up that's proven and it works. Take to stock mercury 575 engines. Spend hours of dino tuning. Hours of prop testing. And make something that goes 100 miles an hour in the boat dated 2000. It's a beautiful thing. There's no need to bastardize it by changing cams and both engines remapping re-propping (granted you could probably get a couple more hours miles per hour out of it.) However more powers going to start blowing the drives. It's a perfectly set up boat. So why not just fix what broke and keep driving. I don't know why people can't figure out how to make a flat tap at camshaft work. I should've built the engine myself. I've done dozens of them and never had this problem.
you could put another 10 grand into it and redo it with roller camshaft. Then do another 20 hours of set up and testing on top of that. I like the way it is. And i just wanted it fixed. Thats all i was askin

Last edited by mcprodesign; 04-29-2015 at 09:20 PM.
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Old 04-29-2015, 09:39 PM
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mcpro,i understand what you are saying but not even mercury uses a flat tappet cam anymore.there is a reason for that.if you went with a hyd roller with the same specs as the flat tappet there would be no need for ecm reprograming.

Last edited by mike tkach; 04-29-2015 at 09:42 PM.
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Old 04-29-2015, 11:05 PM
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Originally Posted by mike tkach
mcpro,i understand what you are saying but not even mercury uses a flat tappet cam anymore.there is a reason for that.if you went with a hyd roller with the same specs as the flat tappet there would be no need for ecm reprograming.
Thanks Mike, i did see some wear on the cam and lifters and I know roller is better. No one I know said i could go roller without remaping . Or i would have , you and i know how important set up is . It's like 10-30 mph ! I got lots of time and money in taking it to the lake , testing , blueprinting etc. I finially got it perfect and dont want to start over. I would glady dump 1200 on cams and lifters if i did not have to go through all the set up and prop test bs. I could try roller but i dont want to spend $1500 dynoing both motors. Dynos are hard on stuff too imo. I just dont want to burn one down on a hot day you know
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Old 04-30-2015, 02:56 PM
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I came late to this thread but just wanted to throw out there, I had a solid roller lifter break in my Chevelle. I heard a slight tick and it sounded like a header gasket so I headed to the house. When I got a mile or so from the house it was painfully obvious it wasn't a gasket. (loud car) The lifter and cam peppered the cylinder and piston with metal so bad there were chunks in the piston. BBC 670 lift roller #7 cylinder. Was a sad day!
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Old 04-30-2015, 04:17 PM
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I might be able to help you out here. I still have the original cam and lifters, heads and pistons and rods out of my 575. 100hrs on the cam and heads, 140hrs on the pistons and rods. Let me know if you are interested in any of it and I am sure we can work something out.

http://www.offshoreonly.com/forums/s...r-pistons.html

http://www.offshoreonly.com/forums/s...ort-heads.html

Last edited by snapmorgan; 04-30-2015 at 04:23 PM.
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Old 05-01-2015, 09:13 AM
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Originally Posted by snapmorgan
I might be able to help you out here. I still have the original cam and lifters, heads and pistons and rods out of my 575. 100hrs on the cam and heads, 140hrs on the pistons and rods. Let me know if you are interested in any of it and I am sure we can work something out.

http://www.offshoreonly.com/forums/s...r-pistons.html

http://www.offshoreonly.com/forums/s...ort-heads.html
Thanks but 575's come with
hypereutectic pistons ( not forged). The one good thing I got from Pfaff was their piston supplier copied a stock piston and now I get cnc forged pistons for my boat. What year was you motors. 01 -2 are a different motor than 03 04. Mine are 04. Remember that you can not separate the rods without wrecking something ( in most cases). 100 hour cam will have wear if the operator did not use the right oil. And I would bet the lifters have some wear too. Are the heads fresh water or salt water
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Old 05-01-2015, 09:47 AM
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i find it hard to believe that merc put a non forged piston in a supercharged engine,even the old 365 mag had forged pistons.
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Old 05-01-2015, 09:52 AM
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just did some research,the sc 575 [550 hp] came from merc with a 7.5-1 forged piston.
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Old 05-01-2015, 01:57 PM
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Originally Posted by mike tkach
just did some research,the sc 575 [550 hp] came from merc with a 7.5-1 forged piston.
Yea me too , i was shocked but they looked like cast pistons , i will find a pic
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Old 05-01-2015, 03:24 PM
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Who can't separate rods from pistons without wrecking something? I have done it hundreds of times. My parts are 05 model and fresh water only. I remember my cam looking pretty damn good when I removed it. I think I would rather have a good proven used one that the new soft junk they are making now. I have put new lifters on a used cam many times and have never had one fail.
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