Any New 575sc Mercury motors out there??
07-07-2009, 11:20 PM
#21
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They ( merc) put the PCV valve in the intake manifold,
right between the supercharger and the distributor,
unlike automotive applications where they put it in a
valve cover, that also is usually baffled.
If the baffle isn't there, the PCV valve is directly exposed
to the lifter valley area, and all the oil splash that goes
on there.
right between the supercharger and the distributor,
unlike automotive applications where they put it in a
valve cover, that also is usually baffled.
If the baffle isn't there, the PCV valve is directly exposed
to the lifter valley area, and all the oil splash that goes
on there.
I would think there wouldn't be much splash as it would be aerated oil heavy fog. I still think its weird that 4 quarts blew out in 30min before it shut itself down, When he tried re cranking it the next day to put it on the trailer he said he had to go wfo just to get it to crank......."bad vacuum leak?"
Can PVC valve suck out 4 quarts in 30min?
He also said on the trip over he was at 4lbs and no blower whine.
its got me stumped,but I don't have any experience in hurting/weird marine blown engine problems,
So he's got the hippie coming back Friday with felpro intake gaskets and putting the tray back in and going to be running again Sat am
07-08-2009, 12:08 AM
#22
Rob-I'll be the first to admit that I'm never too old to learn,but this thread has me perplexed. Are we talking about the black, stamped steel tray that snaps in the lifter valley under the intake? If it is, GM started using those on the L-88's about 1969. I remember buying one of those trays back then . It's sole purpose then was to keep hot oil from hitting the underside of the intake manifold. Blown or unblown, I can't imagine how it would affect oil consumption. I had a street driven 435 427 Corvette then without that plate and it didn't use as much oil as gas! I did use that tray on my SCCA Corvette. As I said, I'm always willing to learn about these things. Rob, do me a favor and PM me a status on your boat. Thanks!
}. I was told the factory head gaskets were not the best, I assume the intake were cut out for the pan?guessing.Maybe the intake gasket push into a intake runner and sucked the oil out?I'm sure the pan helps the intake charge, like my cars they have the air gap under the intake runners so the heat doesn't hit the runner heating up the charge,I guess thats why the old Buick 455's had that intake belly tray.
My thinking is how can a pan/tray cause 4 quarts to burn out, it would have to smell bad
I know it has hot oil splashing against it,maybe 300degrees max? But when I tear mine down it doesn't have any burnt oil residue running 8psi for 4 years,or when it was stock..... I know the 575sc is cooking the intake charge because of no innercooler, I assume Merc tuned it safe/fat for that fact.IC has to be high when running for long time in boost!!maybe the pvc is stuck open,running boost and pushing the oil mist,splash thru the PVC into the throttle body?
Anybody with experience/suggestions please chime in.
Id like to learn more as to why.
Rob
07-08-2009, 03:29 AM
#23
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Rob- 4 quarts of oil in 30 minutes is a LOT of oil! Where did it go? Had to go out the exhaust or in the bilge. Either way, you'd think you'd notice it. Way back in prehistoric days,the GM intake set had reliefs where the tray tabs locked on the heads. You're right on, sealing the intake gaskets was typically a nightmare as soon as you decked the block or milled the heads. I can't tell you how many times I cut the intake surfaces to get a good(?) match. Then when I found a gasket manufacturer whose gaskets matched the machineing,I'd buy a bunch for future use.If you were lucky, you'd weep a little oil, but I've had vacuum leaks that were frustrating when you were racing. WOT would be fine,but part throttle power was pathetic. As you said,the corners are a b***h! Maybe JC or one of the builders will chime in??
07-08-2009, 03:34 AM
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Yeah check the baffle plate. I bought a pair of 575 SCI motors from Derberry a couple of years ago and had them rebuild them before they shipped them out to me and they left out the baffle in one motor(acually they said it never had it). It burned a quart of oil per hour before Absolute Marine in Havasu found the problem. $34k for 2 used motors (including rebuilding) and they couldn't spring for a $40 baffle plate. Sh*t, I would have paid for it if I knew it was "missing". I cost me $2k to fix it after the fact...
07-16-2009, 12:04 PM
#25
Well a few of ya were right
the mechanic put the tray in, replaced the PVC valve,and put the FelPro intake gaskets on,so far he said its running fine.
if so it was sucking out so much oil and dumping it into the throttle body's,it fouled out the plugs makeing it down on power and then killing the motor.
I would of never thought that much oil could be sucked out the PVC in that short time to do what it did.Oh-well I learned something from it.
Rob
the mechanic put the tray in, replaced the PVC valve,and put the FelPro intake gaskets on,so far he said its running fine.if so it was sucking out so much oil and dumping it into the throttle body's,it fouled out the plugs makeing it down on power and then killing the motor.
I would of never thought that much oil could be sucked out the PVC in that short time to do what it did.Oh-well I learned something from it.
Rob
