Why are Olds 455 that bad?

[mark49]

Just had my 21' Hondo completely rebuilt, as i picked up the engine he said just keep that old Olds under 4000 RPM same from the installer...
ItÂ’s completely rebuilt 1973 Olds 455, what makes the Olds that much inferior to lets say the Chevy 455?
Mark

[Liberator TJ1984]

455 Olds are very reliable , just not at the higher RPM's . not an olds guy but I believe it have alot to do with the oiling system ? other than that lot's of people running them down here trouble free for the most part ....

[Sleek-Jet]

Your best bet would be to ask this down in one of the tech forums...
But the cliff notes version is the Olds doesn't have an optimum oiling system... at high rpms a stock olds will pump all the oil to the heads and starve the lower end... instant spun bearing...
There are a few easy fixes, but even then, the Olds isn't a high rpm screamer, unless you want to spend a little money.
If you want a cruiser, the Olds will do just fine...

[SB]

It's a good engine, but at high rpm it pumps oil to the top and leaves the bottom of the engine without oil. This can be improved with restrictors, drainbacks, etc.
Do a search in Just Jets, it's all there.

[BrendellaJet]

Im pretty sure the olds has monster main and rod bearings compared to the chevy. The motor can be made to run, howeverZ(unfortunately) since its already been rebuilt some of the work will be tough to do without a partial disassembly. If you are willing to take the heads off for a minor machining operation a couple of areas that need work can be addressed.

[Faceaz]

All the above. Basically the Olds has a really wide V in the block & the oil doesn't drain back to the pan very well. I had an old eliminator with the olds, after blowing the engine 3 times I found the following was a good comination:
1) Use a stock oil pump - not a high flow.
2) Use a 12 quart pan.
3) Use restrictors in the push rods, to keep more oil down low.
After I made these changes, the engine ran good till I sold it 2 years later. Good luck.

[RVRKID]

We have been very lucky with our Olds (Knock on Wood). We bought our Kona in 1971 with the Olds and I ski'd behind it Fathers day in Parker (235LBS) with no problem. We have never touched the inside of the motor, new carb, plugs and fuel pump is about all for the power plant, andit is stil running pretty strong. Took it to Lake Almanor last summer and Powell the year before and she still is a turn key boat. Everyone that I have known personally that have done anything to there Olds never had it run the same again. They ended up wrenching on it every or every other trip. So we are afraid to do anything.

['75 Miller]

Pretty much "what they said". If I remember correctly, the holes in the heads for the oil to drain back down to the bottom end are small and aren't positioned particularly well. If possible, pull a valve cover and check 'em out. realoldspower.com is a site dedicated to olds fanatics and has tons of useful info.
You might try sending a pm to "oldguy" here on ***boat. He's modified his olds and had good results.

[TahitiTiger]

I myself run the 455 as well. I have oil retrictors in the main journels, restricted cam bearings, restricted push rods, and an oiling jet for the cam. I run it up to 5k all the time (that is where I have the rev-bisquit). I also have a 12 quarts pan and a high preasure low volume oil pump. This engine is on its 3rd year of reliable operation. I filled it once with water, and that was my own dumb fault. :cry: Emptied the water out, new gaskets, still running like a champ :D Very resiliant engine if you ask me.

[HM]

You guys put a lot of work into making a turd spin 5000 RPM. :D

[Sleek-Jet]

You guys put a lot of work into making a turd spin 5000 RPM. :D
... and there it is... I'm suprized it took 10 posts to get someone to say it...
:idea:

[Keith E. Sayre]

I've had alot of friends with them and have sold a bunch over the years
and the failures that I have seen are regarding pushrods bending when
the valves hit the pistons at high rpm. Most were jet boats and if you
over rev one by flying it, there's a good chance that the valves would hit
and bang. game over. I don't have a mechanical explanation for you,
but I've seen it happen dozens of times.
Keith Sayre

[HM]

... and there is it... I'm suprized it took 10 posts to get someone to say it...
:idea:
I never hit submit on my first post....which would have been the first response. I let the rope out just enough to hate without hating. :D

[hkunz]

While I'm not "the old guy", we've run our 455 (now 461) Olds for years with only a few issues. We get 5,200 RPM out of it regularly, as long as no one screams (that's high 60's). The oil starvation is a well known problem. We fixed it with a number of modifications, and it works great now. I didn't make these mods up, I got them from Joe Mondello's shop in Paso Robles.
Our boat used to pump so much oil into the valve covers that it would blow out the breathers onto the kids - nothing like a hot oil bath during a nice hot day on Mohave. One time, it even cracked the valve cover, which really started it squirting. We were on a boat vacation in Havasu, so I fixed that with epoxy in our room at LBR. The kids were very impressed NOT. something about girls and wierd smells.
In the bottom end, you can put in a Dooley pan, which is a modified stock pan - the depth is the same, but the front kickout wheer the car's suspension went is added on to so the pan goes the whole length of the block. You can get the cryo rod and main bearings, but I'm not sure they are all that necessary. The Mondello boat cam really wakes it up so you can get the RPMs. You drill out the oil return holes in the heads - simple to do, but take them off the engine first, and make sure you clean everything very well afterwards - you don't want those shavings floating around in your oil. Clean up the holes' entrances and exits so the oil will transitionally flow better after you drill. Drill in small increments, and take your time. Don't go super big, just open it up.
Replace the rings with Zero Gap Seconds, available from Mondello as well. These rings are a full set, but the second ring is a two piece ring vice the normal one piece ring, so you install them with the gaps on opposite sides of the piston (not on the thrust face) from each other. They afford a complete seal, reducing blowby, and the crankcase pressure drops, keeping the oil from trying to find its way out the breathers. Then, for the topper, tap two breathers into the valve covers (you probably already have one, just drill a hole in the other one, see pictures) and route the outlets to a "puke tank" with a filter on top. This becomes your breather. If there is any blowby, the oil collects in the tank, where it can be drained out after a hard day of boating. I get about three drops of oil/water mix.
Just one more bit of go-fast lore/info. Tap into those rear water jackets via your intake manifold, "T" the lines, and put a valve on the mian line, then route it overboard. Use the vavle to regulate the flow that goes overboard to balance the cooling through the engine - pretty cool (no pun intended) trick that is supposed to allow the cylinders to all make the same power.
The puke tank is the one the blue hose routes to. The hoses don't match because this was a "cheap" fix. To the left of the distributor vacuum can you can see the water line.
http://www.***boat.com/forums/attachment.php?attachmentid=37619&stc=1&d=1187739991
Another view, this time of the left side. The second valve cover hole is one I had to make to route the hose. You can also see the red valve that acts as the variable coolant discharge restrictor.
http://www.***boat.com/forums/attachment.php?attachmentid=37620&stc=1&d=1187739991
Hope this helps!

[hkunz]

I just realized I had pics of all three of my boats in the last post...

[Liberator TJ1984]

Here's a link to a friends 455 build up...he dogs it and has a 250shot of NOS on it :D
http://www.***boat.com/forums/showthread.php?t=67287&highlight=455+build

[BoatPI]

Consult Joe Mondello, Mr. Olds.

[OCMerrill]

I ran a 455 (461) in my Flat v-drive boat 20 years ago.
What I remember besides the oiling issue was valves, spring pressure, and push rods.
Valves would mushroom fairly easy when spring pressure was added so aftermarket valves are necessary over 5k in rpm. Also to spin up more rpm bigger push rods are needed. To fit 3/8 dia push rods the heads need to be drilled. In certain castings its real easy to break into water. I don't remember the casting numbers but I ruined a few.
We spun to 6800 rpm all the time. Never held it there for very long. I think we blew the motor 1/2 dozen times until we got all this stuff sorted out. Then is was pretty tough.
We tapped the back of the valve covers and welded bung fittings to the Dooley pan to help the oil drain.