|03-31-2012 05:22 PM|
In the meantime (since my original post), I've had my 455 marine engine built buy a competent engine builder who knows his way around a 455 Olds (and Buicks and Hemi's etc...) and I couldn't be happier.
No oil restrictors in the mains, only restricted pushrods and good old fashioned attention to detail.
I went for coated bearings as insurance and am using outside grooved cam bearings with aftermarket rods (Olds always seem to spin the rod bearings first because the factory rods are crap for HD marine use).
With a 10 qt oil pan and HV pump, I never pump the sump dry and all he did was some standard clean-up for the oil returns.
It's a solid 400-425HP motor and I can run it all day at 4500 without worry (with an 'A' impeller, it tops out around 5000).
|03-31-2012 01:09 PM|
I'm glad to find this old post still active.
I'm getting into an old 455 boat engine that sounded like it had a little man with a hammer inside. For a long time now I have been hearing about these restrictors. It was killing me to see them in the mains. I just flat wouldn't do that. It's crazy. It sounds like a real half *** fix to me. Just from a logical thinking standpoint. The cam bearings will drop the oil right into the crankcase so that's not a problem. the only thing I would concider would be the pushrods. The thing I would def do is deburr and enlarge oil return passages at this point.
My boat engine teardown revealed main bearings scored like you find brake rotors. I think it's never been machined before and think it will come out. This engine ran at 6000 in our boat for verry extended periods of time. If it were running out of oil, I believe this engine wouldn't have lasted through a whole tank of gas. The engine blew a head gasket and was hydrolocked in the morning. The heads pulled and gaskets replaced and oil changed.... note: you can't get to the drain plug in the oil pan so you have a tapped hole in the side of the oil pan that will let maybe a quarter to half inch of oil remain undrained. In my mind oil floats on water so if there was still water in the pan it would be at the point below this tapped hole and remain in the engine along with the fresh oil. The next outing didn't last long and came back knocking. I don't think it was due to oil starvation. Nothing seems hot or siezed up. My experience so far. We put the original engine back in it along with the "C" heads and crower cam. It dosn't turn 6000 anymore but does go about 5700 and no issues yet.....
|02-15-2012 05:13 PM|
|02-15-2012 04:48 PM|
As a side note, I have GM factory service manuals spanning the 1940s through the 1990s, from Olds, Chevy, and Cadillac, and every one of them calls these passages oil galleries, not galleys. Per Webster, one definition of gallery is a long narrow passage.
|02-15-2012 02:17 PM|
People are still building 'em, ya know?
|02-15-2012 11:53 AM|
|FmrStrtracer||You guys realize this post is almost 3 years old?|
|02-15-2012 11:18 AM|
The Olds flows from the main galley via a drilling to each main bearing. It then taps drillings for the lifter galleys and the cam bearings using the back side of the bearing shell to close the passage.
Most main bearing inserts don't align the that bearing's feed hole to the crank journal depending instead of flow around the shell to the other distribution holes to suffice as a feed to the mains. I always considered this arrangement weak in terms of flow and similar to Cobalt, I align the feed hole in the bearing shell with the feed drilling, I prefer using the Dremel with a stone bit for the fine finish it leaves and minimum disruption to the actual bearing surface adjacent to the new hole. Left to my own devices I don't use restrictors as in my opinion they are a so-so fix aimed at the real problem which is the hole location in the bearing shell doesn't match the feed hole, depending on fluid transfer in that small slot to feed the bearing and the other two holes. The restrictor is an attempt to force more oil into the bearing at the cost of the upper end. These wild theories about drain back get sold to sell these parts, but as you can see with main #3 the feed to the bearing is greatly compromised by the position of the restrictor.
Boat engines always work hard compared to an automotive installation, the high volume oil pump is a good investment with the boat motors.
|02-14-2012 10:04 PM|
|tjet||Another thing you can do is to enlarge the drainback holes in the heads & block (see before & after pics)|
|04-17-2009 08:31 AM|
|04-17-2009 01:34 AM|
Oil-restrictiong push rods
I spun a rod bearing in a 350 Olds engine, I believe, due to oil starvation. This seems to be a theme with Oldsmobiles. I am currently building a 455 and have done a lot of reading and talking to other Olds guys. The general consensus from everyone except the guys who sell them, is that the oil restrictors in the oil galleries between the main bearings and the cam bearings are worthless. Besides, common sense dictates you do not want to restrict oil flow to any bearing. Adding restrictors to the lifter bore will, admittedly, slow the flow of oil to the top of the engine, but I not sure what the sacrifice may be in terms of reduced oil to the lifters, especially if they are hydraulics. In the 455 motor I am currently building, I have opted of oil-restricting pushrods. These will not restrict oil flow to any bottom end component, but will restrict flow to the top end.
This solution was suggested by a well-known old school motor builder who is still at it in Buena Park, CA and has lots of Olds-powered boat experience. He speaks from his experience and he's a straight-shooter. I trust his advice with this solution.
|04-05-2009 07:48 AM|
Thanks for the clarification- I stand corrected.
If the bearings were modified as they were supposed to be, I do not believe any damage was done to the OP's mains because of the restrictors. They might not help much, but they do help some amount, IMO.
Like I said earlier, Don't want em? Then don't use em! lol
|04-05-2009 06:33 AM|
|04-04-2009 09:28 PM|
The holes feed the cam bearings then the top end. By restricting the flow of oil to the upper end, it keeps more oil in the pan.
Mondello uses them on everything from the 307 to the 455.
Don't want em? Then don't use em!
|04-04-2009 09:24 PM|
Cam bearings in my book is still considered 'lower' end.
There is no restriction for the oil to get back to the pan from the cam bearings.
The restriction is from the tiny little oil return holes in the heads keeping the oil up there.
Am I missing something?
|04-04-2009 09:20 PM|
|cobalt327||The idea is to keep the oil at higher revs from getting to the top end of the engine quicker than it can return. In other words, to keep more oil in the pan.|
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