[glhs#116]

This flipping thing! I tell you. More ups and downs than a roller coaster.

So. I left it. Wrote the previous post. Worked on some other things. Let it get dark and let the roads dry out a bit. I fired up the car after it had been sitting a few hours but it was still warm in its bones. Choke didn't come on. Fired almost right away. Sounded good. No rattle. Did a little converter push. Quiet. Drove out onto the road. No knocking. Amazing. Drove down the road sort of trying it out a bit. Doing some light acceleration. Just about like it was before all this started. Turned to take a longer drive where I could have otherwise turned around. And right about there it decides it wants to do the knocking under load thing. Well, I turned around just as soon as I could. Tested a bit on the way back. Same as last time, I feel like it isn't as bad if you load it when it is spinning faster already. Like before it is fine when you aren't accelerating. But if you do the sort of acceleration that would be normal just pulling away from a light in traffic (not a race) then it sounds like rods are about to fly.

It will do the knock again against the converter (wouldn't earlier today before the drive)

https://youtu.be/QVKUWwueHUQ

I don't get it. The rattle cold particularly makes me think of a piston related thing. Like a stiff wrist pin. But the way it seemed to go away when I kept it warm and kept it running and revved it and such. That also seemed like something that was stiff and just needed to loosen up or flush out some grit or something. But when I went to actually drive and it starts out OK and then within a minute or two starts doing that stuff again. I'm again thinking basically along two lines
* A partially blocked oil passage that supplies oil to a bearing but with not enough pressure
* A cracked flex plate or something weird like that. But then I think it shouldn't care about warmup and such..

I guess tomorrow after church I might as well start pulling.

Sam

[AG]

I've only had two motors with rod knocks before and both occurred all the time regardless of rpm. Have you put a stethoscope to the block while it's running to listen for a knock?

[VCho455]

Have you removed the oil filter and cut it open? That will give you your best insight into the oiling system.

[tooski]

I am having a very similar occurrence. At a steady rpm, 2, 3, 4 K no noise. Light to medium acceleration I get a tapping. WOT I can't hear anything. I once had a 4 cyl engine with a rod knock. This is nothing like that. When I disconnect my vacuum advance the tapping volume is decreased. It sounds almost as if I have just one cylinder that is detonating under light/medium throttle. Perhaps one lifter that gets noisy only under light to medium throttle? At any rate I will be tearing it down to check bearings, rods, broken rings, lifters. etc.

[glhs#116]

I hear all you "cut the oil filter open" people and I need to tell you that this engine just ate a cam. I cleaned bunch or shavings out of the pan. I'm not feeling like I'm going to learn much from this exercise because I already expect to see some metal in there. Although, maybe not since the oil and filter have now been changed, what? Maybe four times in the last hundred miles or so. So I feel like metal in the engine (although now really all of it gone from places I can see) is not new information to me. What I'm more needing to know is where any is that I can't see / haven't found.

Anyway, today should be the day for engine coming out. I think the hoist I got has too short an arm so that might be fun. But we'll see. Just been doing some last minute YouTube googling for noises. My noise does sound a lot like piston slap. But I had a little of that before anyway. Never known it to change and get loud under load. I'm slightly worried about wrist pin. Especially since I don't have another piston and rod assembly to swap out if that was it. But in the samples I've heard wrist pins sound more, I dunno, tinny. Ah well. I'm probably procrastinating against a job I don't want to do..

Sam

[AG]

If the engine ate a cam I would be taking it out and completely dissemble for an autopsy. Then clean the block and everything else and assemble with necessary new components.

[glhs#116]

So, yeah. This stupid hoist is like 2 inches too short to reach the centre of the engine from the side (no hope from the front). So tomorrow morning I'm taking the car down off the jack stands and turning it around and jacking it back up. If I'm having to swing the engine as I lift at least I can miss all the driver's side stuff. Passenger side looks like it has a lot less things to run into. Putting it back should be fun but that's not tomorrow's problem.

Sam

[graygator]

Before you pull the motor, look long and hard at that flex-plate after you unbolt the converter and push it back. And at the crankshaft bolts.

[Schurkey]

Cut the filter open. If you see iron/steel bits 'n' pieces, they may be from the damaged cam/lifters.

You see non-magnetic bearing material--copper, lead, tin, aluminum--that's a whole different failure story.

[steve25]

Once all is unhooked that needs to be got at from under, remove the front tires and sit the rotors on wood.

That will gain you a easy 2 inches of lower nose clearance.

[Scarebird]

Originally Posted by steve25

Once all is unhooked that needs to be got at from under, remove the front tires and sit the rotors on wood...

The rotors are not made for that sort of load and may distort or break.

[steve25]

Really!

Please re-think this I need to ask of you.

Think about the forces and loads a rotor experiences when the front brakes are close to being locked up at high road speeds.

I might have a concern if the rotor was just a hat type, but not like ours with the fins in between both outer and inner sides, not to mention that I have done this many times with no adverse issues.

[78w72]

I know this doesnt help much, but between the mic on your phone & my little computer speakers... I dont really hear any "knocking" noise in any of those vids, especially the recent one holding against the brake in reverse & drive, just sounds like a motor under load, no other "major" noises. But that doesnt mean much since small noises can be lost or masked when recorded on a phone & played back on another phone or small PC speakers.

Resting the car on the rotors probably isnt a good idea, but shouldt harm anything if done once or twice, but the weight of the car focused on 1-2" of the bottom edge of the rotor is a totally different force than calipers clamping on the sides as designed.

Ive pulled a few engines from the side when the nose was too long to get the boom arm of the puller to reach the engine, especially 79-81 cars. Most 2 ton pullers should reach from the side, the pump body will just about touch the fender but the arm should reach enough to pull it, drop the nose of the car as much as it will go & remove tires (without rotors touching) then extend the puller arm to the 1/2 ton range & see if it fits... if not, pull the nose or fender as a last resort. Good luck if you decide/need to pull it!

[Scarebird]

Originally Posted by steve25

Really!

Please re-think this I need to ask of you...

Below is the cross section drawn from memory of the aftermarket replacement rotor for 1969-72 A, 1969 F and 69-74 X bodies. It is of course a one piece unit, holding the seals and bearing along with the dust cap. The area circled is my concern. I have seen significant core shift - as much as a hundred and fifty thou. We used to cut up rotors to make hubs for some low volume apps not worth a run of aluminum hubs and found this core shift - it played hell on our parting tool.

Use the frame or outer end of the LCA.

[glhs#116]

Time for a visual aid.

Yeah, it's touching


Oh, and I'm not sitting it on rotors, don't worry. I jacked it up so
* It's easier for me to support the transmission and unbolt it
* I could take the wheel off and get the hoist right up next to the wing

This is the hoist I bought mail order sight unseen. "1000kg" capacity (which seemed more than enough). Turns out, capacity 250kg at full extension (Project Farm guy voice, "We're going to test that!"). That's about 550lbs. I figure those figures have to allow a certain amount of "grace" which I'm guessing is up to double. So I don't expect it to fold in two. Just complain. Should be fun trying to nurse it back into place.

Sam

[steve25]

I appreciate you making or taking the time to draw up the cutaway of a hub and rotor assy , but the offset is highly exaggerated for one and you have a 360 degree perimeter of that metal thickness between the rotor section and the hub that’s used for support if you sit the rotor on wood, which let me repeat I and others have done this many many times with no bad repercussions.

Sorry about getting off the rails here a little Sam.

[78w72]

Must be the design of different pullers, and thats only a 1 ton puller so it is made smaller than the 2 tons that most will reach to center of engine on the longest arm setting with 1000lb rating. 550lb might be pushing the limits of the puller with a Pontiac V8?

I was a little worried on the 1 ton scale with aluminum heads just because it was so high in the air to clear the tops of the fenders.

[Scarebird]

Originally Posted by steve25

...but the offset is highly exaggerated for one and you have a 360 degree perimeter of that metal thickness between the rotor section...

The thickness is usually about 200 thou of the crappiest iron you can get. Said rotor:

[Scarebird]

I made my own square tube insert that is considerably longer than the stock one, and hung weights on the back of the hoist to counterbalance it.

[Schurkey]

Yup, that's the "dirty little secret" of commonly-available engine hoists.

They're given a reasonable load rating only because the boom is too damn short to be useful. The hydraulics are undersized/undercapacity, the boom is undersized, the entire support structure is too-thin steel. Not only does the manufacturer save on materials, but due to the small size and light weight, they save on shipping costs.

They're essentially high-profit junk sold by disreputable companies in order to deceive the purchaser. They get by with it because most purchasers don't ask about the boom length--they "assume" that an engine hoist is suitable for hoisting engines OUT OF THE VEHICLE, not merely "up off the floor".

Commonly-available engine stands are not any better. The only reason they can achieve their rated weight capacity is because the standoffs for the bolts going into the bellhousing bolt-holes are unreasonably short--you have exceedingly poor access to the flywheel/flexplate area.