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Post by Crikey on Nov 8, 2007 8:04:33 GMT -5
My buddy Dave bought a Shamrock last year was having problems with the motor running rough. After doing a compression test found that the last cylinder on the right side was dead. Turned out to be that he intake valve was burned out from heat and it shrunk then when he had the head work done all the intake valves on that side where some what burned. Now I know that prop was a little to much for the boat but other than maybe the fuel pressure is not right what else might do that. Timing was good, new tune up everything else checked out fine before we put the boat in the water. It is a 2004 351 Ford GT40 MPI 340 HP with 250 hours on it just strange that only one side was messed up any ideas to check.
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Post by sideburns on Nov 8, 2007 18:28:51 GMT -5
did he have both heads done?seems strange if only one side had burnt valves,I would see if there are any tech bulletins etc from ford it may be an issue with that particular motor,poss valve guides machined too small causing the valves to stick
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Post by Crikey on Nov 8, 2007 19:49:32 GMT -5
Yea its crazy both heads were done port side fine starb messed up. I looked up many searches on the motor etc and it seems that those heads are good heads and no problems so far. Seen something with SS valves and aluminum heads but his are steel. Well we are going to do as much as we can to double check everything and go from there
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Post by sideburns on Nov 8, 2007 23:34:34 GMT -5
well if the heads are good... the basics... air ,fuel ,spark ....somethings not right...injectors may be bad on that side of the motor,or an engine wire harness,causing a lean condition...vacume leak...check plug wires and plugs...were the tops of the pistons white?lean?what rotation does the motor spin?...valves burn due to too much heat or being open during combustion...too long of push rod ,or sticking from carbon build up on stems,but the motor is pretty much new,so it may be something set wrong.... timing ,check the timing marks may have one tooth off?too advanced?its a tuff one, hopefully you find something
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Post by noobie on Nov 9, 2007 6:52:54 GMT -5
Check exhaust risers etc for water reversion, it will rust the backsides of the valves near the seat, and then gives a perfect place for the valve to burn as it wont close on the seat properly.
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joc
New Member
Posts: 41 
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Post by joc on Nov 9, 2007 10:42:24 GMT -5
I'm not familiar with that engine, but my first thought is it's running lean on that side. Maybe a vacuum leak on the intake. Is it throttle body or tuned port injection? Maybe look for a common element that's restricting fuel on that side. But my first guess is a vacuum leak. Do you still have the old gaskets to inspect? You did say the valves on the other side checked out ok?
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Post by Crikey on Nov 10, 2007 19:25:17 GMT -5
Yea all the valves were ok on that one side. Its Multi port fuel inj so each cylinder has an injector will look at the gaskets and do a vacume check when we get it back together. All these points are helping so keep em coming thanks guys dont want to go through this again. Going to have the injectors checked as well.
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