Took the ole Taylor out yesterday for a couple of hours. After about 20 minutes of riding I was at idle and starting to get on plain when a hard knocking sound came from in the engine. Oil pressure was at about 10. At idle it would not make the noise. When you hit about 1500 rpms you could hear it. I turned it off and cranked it a couple of time and it idled fine but when i would accelerate it would start knocking. Looks like a rebuild. I will be asking plenty of 455 questions during this rebuild since I want to do it myself and have never done so. My dad has rebuilt plenty of engines but I will still asd jet boat specific questions. Just call me the rookie engine builder. Its the only part of my boat that I have not taken apart and worked on. The furthest I have gone into the engine is removing the heads to paint them.
[ March 23, 2003, 12:14 PM: Message edited by: Taylorman ]
Taylorman, I feel your pain bro. I have one question though, isn't this the boat that you took out the Berk A impeller and put in a B or C? What rpms were you getting out of thing? You must have at some point hit a sustained high rev. Was this your first trip out for the season? I'm curious as to what bearings spun. Mine were the #7 ane #8 rod bearings that were fused together.
I did put a smaller impeller in it. I ran it one time that day and made about 5 or 6 passes at just under 5000 rpms for just about 20 seconds each. I can't say if that did it. It really sucks that summer is about to begin and I have to rebuild. It not my first trip out, I have been out about 4 times so far. I will let you know what I find. What all did you have to do when you rebilt yours and did you do it yourself?
I don't want to be the guy that says "I told you so", but going to a smaller impeller on an Olds is not only asking for trouble, but its like putting an ad in the paper and begging on a street corner. Go back to the A, and bump up the HP as much as you can. Is this a budget build or can you work with the thing? How many hours are on it since the last rebuild? At the very least, you will need new bearings throughout, maybe a crank polish. New rings? It depends on the amount of damage inside the engine. When you pull the oil pan off, you'll have a pretty good idea. Yes, I rebuilt mine, and I wish I would have gone with the restrictors while I was in it.
Taylorman, sorry to hear about that. If you really spun a bearing you're gonna need another crank. We'll be all ears when you get the pan off.
the b-cut impeller is fine and 5,000 rpm is not what killed your olds. Running 5,000 rpm for 20 seconds is probably what killed it. When you rebuild the motor, make sure to address the oiling system and make the necessary upgrades (ie head drain back lines to the pan, oil restricted, main bearings, cam bearings, lifter bores or all of the above.) Once you've made the oiling system mods, you'll be able to push your 455 to 5,500 rpms for extended periods of time (i wouldnt go more than 15 seconds) without turning the bottom end into spaghetti.
Sorry to hear what happened.
Simple question; I heard when you spin a bearing, the oil pressure a lot times goes up? How true is this?
You will be doing yourself a grave dis-service if you don't get, read and understand this:
It is available here.
If anyone has pictures of there external return oil lines please post them. I need to know where to tap the heads at and where to tap the oil pan. Also what modifications do I make to the stock return holes in the heads/block to improve flow.
This is what happens when you don't hear it eek!
[img]http://free.***boat.net/ubb/Avatars/Avatars/meltdown.JPG[/img]
#3-4 rod bearings melted together
KC
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