powerproman

First time tearing down and rebuilding a classic 455! Unfortunately, the friend I'm assisting had someone overhaul the motor without really knowing what they were doing. The first thing I noticed when I pulled off the intake manifold was that the lifters were not even close to being centered on the camshaft. This caused some of the lifters to be damaged as well as ruining the camshaft. What I'd like to know is what (if any) spacers or bushiings might be installed with the camshaft? I know the button on the eccentric is supossed to hold it from moving towards the front of the engine. Is there anything but the timing chain that holds it from "floating" to the flywheel end of the engine? Just trying to figure out how the camshaft could have been misaligned. After tearing everything down, I was able to manually line everything up. I believe the cam is the correct cam but I'm not sure about how it aligns or secures in the correct position. Any help would be appreciated!

MDchanic

The lifters are not supposed to be centered on the cam lobes. They never are on any engine post-1930s or so.
The off-centered-ness makes the lifters rotate.

The cam is naturally pulled and held toward the back of the engine by the resistance of the oil pump and distributor drive gear.

- Eric

Octania

Many things can lead to ruined lifters and cam, but placement of the cam is low on the list. Poor break-in or poor oil are more likely.

Got photos?

Make sure you get the proper "holey" plug in the aft end of the driver side oil passage, to lube the distributor drive gear well.

powerproman

MDchanic,

Thanks for the reply! Originally from Maine myself. (Fort Kent) I can relate to the lifters being somewhat off centered but these were only riding on about half of the cam lobe. It caused some chipping on the lifters and destroyed several lobes on the cam. I will say that I believe that there were some lubrication issues possibly going on as well. I recall pulling the valve covers and noticing that there was very little oil on the roller rockers or in the head in general. I realize that this could be a MAJOR issue with this newly rebuilt engine and I will figure this issue out as well. I'm still perplexed by how off center the lifters were. I also will mention that the gear on the crankshaft was installed backwards with the timing marks on the backside instead of the front side. This could account for some of the off centered issue as well couldn't it? Any more advice would be appreciated. I can build small block Chevy's all day long but have never messed with a Olds 455.

MDchanic

About half of the cam lobe covering about half of the lifter sounds about right to me.
I wish I had some pictures.

A reversed cam sprocket could conceivably cause misalignment, but I've never compared both sides to see whether they were symmetric.

You mention roller rockers. This wasn't a roller cam, was it? They need different treatment.

- Eric

powerproman

Octania,

Can you expand a little more on the proper "holey" plug you referred to? I'm going to go out and look at the block on the engine stand after you clarify this...thanks!

Pat

MDchanic

The pipe-thread plug in the back of the right (if I recall) bank oil gallery is supposed to have a roughly 0.030-0.040" hole (I forget the exact dimension) in the middle, to squirt the distributor and oil pump drives.

If they're dry, that could cause problems.

- Eric

powerproman

MDchanic,

The gear doesn't appear to be symmetrical. It appers to be thicker on one side than the other. Not sure if that matters or not as far as alignment goes. Is there anything that installs with the camshaft? (spacers, bushing etc?) Just want to eliminate the possibility that the original installer didn't miss something....

powerproman

I will check on the plug....great information guys! Thanks for sharing...

MDchanic

Nope. Shaft, then gear, then washer, then bolt.

Far as I know, the back of the gear is the thrust bearing that keeps the shaft lined up front-to-back as the oil pump drive pulls it backward.

You should get a copy of the relevant Chassis Service Manual so you can see the exploded views.
Available for free on WildAboutCars.com.

- Eric

64Rocket

Yes, get a shop manual and study it. It will be way more informational than us telling on the internet. We can help but a book with pic's make it so much better.

Gene

455man

Pics tell a lot. Also make sure you use a high zinc oil or zinc additive on a flat tappet cam during breakin. Lots of people continue with the zinc additive after breakin due to zinc levels going down over the past decades. There is a proper breakin procedure for new cams also. Did you prime the oil pump before starting it?

Macadoo

Just getting ready to pull my heads and cam this weekend. It's a stock (so far) '71 350 but maybe this will help. This is looking down the center of the lifter valley. I haven't touched the cam yet so should be accurate.

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MDchanic

Not much to see, but the little I do see looks good to me.

- Eric

slam1918

if the engine was rebuilt with a roller cam/lifter set up there is definetly a bushing that goes on the cam & crank gear. Dick Miller's site sells it along with a new cam button. You can check the cam run out by popping the freeze out plug and putting a dial indicater on the back of the camshaft. New roller cams do not need to be "broken in" the same way the traditional solid or hyd camshaft break in requires.

BTW, I'm a summer time Mainer.....Pemaquid

Macadoo

Not much. But it does show some offset. Thought this might help the OP.

MDchanic

Oh yeah. You're not the OP.

I was posting from my phone - no avatar pictures.

- Eric

Macadoo

You youngins' and your phones