My motor is a 455 OLDS. I took off from the no wake zone and punched it and I was doing 15mph. So I said it needs a pump rebuild or something clogging the jet. So I pulled back in and I took off the hand hole and I'll be damn. I had about 6 feet of ski rope wrapped around my pump shaft. So I took the rope out and said I'll try again. I nailed the gas and VVVVRRROOOOOOMMM I was off and running. I drove around for about 15 minutes at 1/2 throttle to check oil and temp. Everything looked good so I floored it. The motor got louder and speed grew faster. I was like damn I like this. So I kept it at WOT for about 10 seconds. Everything sounded good so I hit WOT again and I started to hear a soft knock so I backed way off and it went away. I hit WOT again and I heard the knocking again. So I then let off the a little bit (3\4 of full throttle) and the knocking went away. So I decited everything looked and sounded ok except the knock so I went back to shore. On the way back I was cruising at half throttle and I punched it to full and I didnt hear a knock untill about 7 seconds after holding full throttle.My oil is a little milky.Oil pressure is good at idle and while driving. I dont know my rpm's yet because the tach doesnt work.My question is did I throw a rod or spin a bearing?????What do I need to do to make sure everything is ok?
The boat runs great and idles clean. Could someone please help me?
eek!
You said you checked your oil? Last time I spun a main bearing I had lots of pretty shinny glitter in my oil. Found it up in the valve covers, the oil filter, everywhere. Just glad I cought it before I went back out on the water. I still had to rebuild the engine, but it would have been more expensive had I run it any further. I hope this is not the case with you. Good luck.
If it still idles, or runs for that matter, you can bet you have not thrown a rod. A spun bearing is a possibility, but it sounds more like a tune up is needed, your motor may be getting into some detonation. Are you running premium fuel? What kind of set up do you have? Make sure you check your timing. I have worked on the olds motors before, and found that they like 12-14 degrees BTDC, with all of the timing (35 degrees BTDC) in by 3000 rpm. Of course the set up may change these #s, but I think these are pretty conservative. Anyone else have any ideas?
396 you need to see why you have water in the oil
may just be a intake gasket or could be a head gasket. Do you have thermostat with a bypass?
If the outlet side of the cooling system is not flowing well (sand,rock,rust out of block) the water preasure may be high in the block and blowing by the gasket.
Hope that helps
Two things... one of which is pretty Junior-Varsity, but the other is good...
One way to get all of the milk out of the oil from sitting is to cut off the water almost completely. Let the oil temp come up until steam comes out of the breathers, and then slowly bring more water on until it is normal. I have heard of more than one person doing this with great success. When my first picklefork sunk (before I owned it) I got to de-water the engine and the very last of 50 or so steps was to do this. It worked out great!
The second little kernel of advice, is to examine your gas. Did you put it all in? The new gas with MTBE as an octane agent supposedly loses a ton of octane really quickly in vented (boat) tanks. Something like from 91 to 85 in two weeks, and 91 to upper 70's in two months. I don't know if this is true, it seems pretty aggressive for degradation, but the fact is a lot of motor builders tell you about this when the motor delivers to prevent you from running your new motor on gas that has sat in the car for the length of the motor build.
Squirts up!
Well, it turns out those olds motors dont like spining at high rpms. Keep that thing around 3500 as often as possible, depending on your pump and hull, you probably couldnt get anymore than 4700-5000 rpms out of that motor, maybe less, but unless you do some oil modifications, I would keep your foot off that thing period, no WOT blasts, nothing, if you want that thing to last, go easy!! Or move up to a BBC or BBF, I can run mine (BBF)at WOT all day long and pull 4700 rpms with 60+ psi of oil press and about 280 degrees of oil temp. Another thing you need is an oil temp guage, they are a necessity for jets boats and can keep you out of trouble when it comes to oil temp, either too warm or too cold and you can kiss your motor good bye.
Another thing you need is an oil temp guage, they are a necessity for jets boats and can keep you out of trouble when it comes to oil temp, either too warm or too cold and you can kiss your motor good bye.[/QB][/QUOTE]
I'm running an old BBF jet w/o an oil cooler. Any suggestions as to how I can retrofit an oil temp gauge into my system, thanks.
gotdamp:
Another thing you need is an oil temp guage, they are a necessity for jets boats and can keep you out of trouble when it comes to oil temp, either too warm or too cold and you can kiss your motor good bye.I'm running an old BBF jet w/o an oil cooler. Any suggestions as to how I can retrofit an oil temp gauge into my system, thanks.[/QB][/QUOTE]
I think you can tap the oil pan for a sending unit. If you dont have a welder, you will need to have somebody weld a bung to the oil pan to hold the sending unit. There may be an easier way to check oil temp, but that is the only way that I know.
that is the only way that I know.[/QB][/QUOTE]
Thanks for the input. I wasn't sure if the oil pan was an appropriate place to sense temp or if an oil cooler was required.
396....What are your cam specs? If exhaust duration is more than 238 degrees at .050 and you are running wet headers, you are experiencing reversion. Been there, done that!
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