[glhs#116]

Originally Posted by tom s

I think the 455 HO used the 60 lb pump,the 455 SDs used the 80 lb and also used the larger dist gear.Tom

This is what is slightly confusing. Melling list the 54F for HO and RA, the 54DS for others. As far as I can tell the 54F is 80psi, the 54DS 60psi. From what I see in my Pontiac shop manual the regular Pontiacs got 50psi pumps and the 455HO got a 60psi pump. I went with the 54F because when you plug in 455HO it's what Summit list as correct. But I'm thinking the 54DS would be fine and easier on the cam and distributor. Correct?

Sam

[steve25]

here's what the deal looks like to me!

Your Cams Dizzy drive gear for some reason was going away.

That put a good amount of fine grit in the motor , took out some Bearings and held the pump check ball open some.

Short but sad!

[glhs#116]

So, at a minimum I need the main and rod bearings. If I'm going to deal with the distributor gear thing I need a new cam and lifters, correct? The cam gear is part of the cam, correct? Is there any point getting other than another 068 (like the Melling repro sold by our sponsor)? I recall in previous discussions that there wasn't much to be gained with a different cam unless heads were going to be changed or compression increased. Correct? I mean I'm buying a cam, if there's a better choice than the 068 I'm all ears.

For example, this is the same money as stock replacement:
LUN-10510702

Sam

[glhs#116]

Number 3 main is copper also. This one pretty much fell out of the cap. Not sure if that is significant. It hadn't spun.

[glhs#116]

Number 4 main looks a lot better.

[glhs#116]

Rear main looks like it has a nick that probably dates back to installation time (I didn't touch it taking it out and it is perpendicular to crank travel) but otherwise looks pretty good.




Sam

[1968GTO421]

Sam, Personally I think the Lunati 10510702 cam would work very well in your 455, more so than the 068 would. It has a 112 LSA so it would give good low/mid range power and idle well. Just my 2 cents. Best of luck with your Pontiac. I hate you're in a place with so few competent resources and providers.....may this rebuild go smoother than any of us think.

[STEELCITYFIREBIRD]

You need to get a real good look at the cam and lifters for excessive/accelerated wear on a single or few lobes. It appears fine metal went through this engine.

It likely is embedded in the piston shirts (cylinder scuffing), and it usually makes the wrist pins pretty tight in their bores.
Is there Any anti seize looking, but dark/feeling goop hiding in the pan or near the head bolts, under the valve covers?

You should check the line bore with a straight edge and feeler gauges, caps installed and torqued, and ID of the mains. Tooling to check ID accurately is expensive.
My best advice is order an assembled long block, put the original engine in mothballed storage.

What does the back side of the loose fitting insert look like? Does another insert fit tight, that fits tight elsewhere?

[glhs#116]

Originally Posted by STEELCITYFIREBIRD

You need to get a real good look at the cam and lifters for excessive/accelerated wear on a single or few lobes. It appears fine metal went through this engine.

It likely is embedded in the piston shirts (cylinder scuffing), and it usually makes the wrist pins pretty tight in their bores.
Is there Any anti seize looking, but dark/feeling goop hiding in the pan or near the head bolts, under the valve covers?

You should check the line bore with a straight edge and feeler gauges, caps installed and torqued, and ID of the mains. Tooling to check ID accurately is expensive.
My best advice is order an assembled long block, put the original engine in mothballed storage.

What does the back side of the loose fitting insert look like? Does another insert fit tight, that fits tight elsewhere?

To my untrained eye the lifters and cam lobes don't look at all bad. But I'm ready to be corrected. I definitely see scuffing in the cylinder bores but I don't know how much is normal for a car that's been driven a lot of street miles for many years (as this has).

[lust4speed]

Would be great to see to top main bearing shells. If they look in good shape, then it might be more of a detonation problem. The bearing falling out of the cap is usually another sign of detonation. Signs of detonation show up on the bottom main bearings and the top rod bearings. Pull a couple rod caps off and tap the rods down a bit - if the bottom cap looks good and the top rod half has copper showing it pretty well confirms detonation was going on. If you don't see that pattern, then we can go back to wear and alignment.

[STEELCITYFIREBIRD]

Look at each lobe one at a time, the edge of the lobe would be rounded, the lifter face where it meets the cam dished.
Decent image.
http://www.grumpysperformance.com/worn1.jpg

You may not have this problem, or may have caught it in it's very early stage.

[lust4speed]

And even before we get into catastrophic wear showing the lobe crown looking like a mushroom, the flat tappet lobes are initially ground with a taper from one side to the other and when this initial taper goes away the slope goes flat. Once the taper is gone, the lifter no longer spins and the deterioration accelerates. Even in a photo, if the wear shows all the way across the lobe, the cam is gone. A good flat tappet cam lobe will have a shadow where the lifter base doesn't touch.

[charlie66]

You can look on the back of the bearings and it will tell you if its standard or oversized bearings.. ...

[glhs#116]

Originally Posted by charlie66

You can look on the back of the bearings and it will tell you if its standard or oversized bearings.. ...

They are standard. Crank was replaced five or six years ago when the stock one snapped in two.

[steve25]

Bearings that have lost there crush and just fall out , or hardly clip in are a sure as Dung sign of detonation!

Combine this with grit from failing parts and you end up with a motor that looks unfortunately like yours Sam!

As posted you need to check how the piston pins feel and see how beat up there skirts may be from grit, I would guess there is no one in your neck of the woods who can properly polish a cast Crank no less cut one?

Cast Cranks need to be polished in a certain rotational direction if you do not want new bearings to get chewed up by what looks like a surface that is perfect.

[Formulas]

Snapped prior crankshaft current bearing damage (copper showing) bearings losing fit in block all points to detionation and for a very long time which is also hard on the block .. time to evaluate build stats and tune. .. by the way its hard to tell from pics but its my guess your camshaft isnt original pontiac it appears to be ground from a fat lobe blank judging from the space between lobes see attached pic of 2 examples

[glhs#116]

Originally Posted by Formulas

Snapped prior crankshaft current bearing damage (copper showing) bearings losing fit in block all points to detionation and for a very long time which is also hard on the block .. time to evaluate build stats and tune. .. by the way its hard to tell from pics but its my guess your camshaft isnt original pontiac it appears to be ground from a fat lobe blank judging from the space between lobes see attached pic of 2 examples

That's very interesting. I agree. It looks like that HC-03 cam. Who uses those blanks?

I'm not that worried about the tune. What I think is likely is that I have run it lean a few times. I will see what the plugs and pistons say later.

The biggest contributor to the death of the last crank is probably the old flexplate. The crank split on number 4 main. The flexplate (many years ago) used to have an annoying habit of loosening up the torque converter bolts. It would sound like rod knock and then I would find them loose and when I tightened them up the noise went away. Happened a number of times over a year or more. When the crank finally split and the engine came out they found my flexplate. I'll see if I can find the picture. It had split all the way around the centre. It was basically two pieces. I'm sure that "two piece" flexplate clanging about contributed heavily to the early death of the original crank.



Just to be clear, this is six years ago. My current flexplate (which replaced it) still looks great.

Sam

[Formulas]

Fat lobe blanks? I have no rhyme or reason on who uses them or how to make sure your next cam either is fat or skinny, My HO. Racing HC-03 Lunati 30706 and Comp 296AH-8 Are fat blanks... Hand full of others I have are skinny..

Your current engine, the main bearings if when you pull the crank out and the bearings just kind of pop out of the saddle you still have a problem that points to detonation, I'm not convinced your old flex plate took out your old crankshaft I however would believe a harsh vibration as in detonation took out both of them the converter and healthy flex plate absorbed enough of the vibration to keep the crank alive but when the flex plate was unable to absorb any torsional vibrations due to advanced cracking then the crank failed ...

Hope you get it sorted out and have fun soon

[tom s]

Just a FYI from the front page.I noticed my 366 RA V engine on the highway the oil pressure gauge would have a slight vibration,like 55-60 lb,this at 2100ish RPMs.Also noticed on hard breaking the pressure would drop.Just thought it might have been the pump bye passing at speed and none baffled oil pan(could not remember).Pulled the engine to put my 455 in the bird to run on the road track.Got around to putting the engine on the stand and rolled it over.Well I hear this big clunk in the oil pan(no good).Pulled the pan and found the pick up in the baffled part of the pan.OK so I think the worst,pulled #2 main and it was perfect,(dodged the bullet).Having the pickup tack welded to the pump.Going back together this week.So the moral is the pump pickup hole is low enough in the pan so if the pickup falls off and not stupid high RPMs the engine can live.FWIW,Tom

[chiphead]

Did you guys notice how the wear on the mains is off-center? Both #2 and #3 are off center worn down to the copper. The caps are shifted on the block just a smidge. Likely .0005" or so. Really looks to me like it needs a line hone and the crank checked for straightness.

If it was lack of oil, all the mains would be burned and the inserts would be welded to the journal. I had serious detonation in my 400 and the mains didn't look this bad. #1 looks passable and #4 and #5 don't look half bad.

This is either cap misalignment or a slightly bent crank. This engine ran for awhile with the mains like that. It would hurt oil pressure, but not the cause of the total loss of oil pressure.

Crude checking for a bent crank is easy. Install #1 and #5 block inserts with oil. Sit crank in block. Zero dial indicator on #3 journal and rotate crank. More than .001" runout is possibly bent or serious journal Out Of Round.

If you can't get a line hone done, you can re-assemble #2 and #3 with looser main clearances to make up for the slight cap misalignment. .001" per inch of journal should do just fine.