PQs Camaro [COTW 9/20/10]

[Mr Twisty]

Did the rollers lock up?

[Bell040]

Originally Posted by PQ

At this point I might better (Alabama grammar lol) check the crank too.

I cant see how the crank would be affected. It looks like you had 2 roller lifters fail. Why they failed will be the real question.

Do the rollers still spin?

What springs were you using?

Are those LS7 rollers?

[f5journal]

This sort of damage will take out the cam bearings and cause low oil pressure. I risked not replacing all bearings one time by flushing the engine real well. That DID NOT WORK. The mains went next. So, there is probably collateral damage scoring on both the main and rod journals

[PQ]

Originally Posted by Mr Twisty

Did the rollers lock up?

Nope. They spin free and easy.

Originally Posted by Bell040

I cant see how the crank would be affected. It looks like you had 2 roller lifters fail. Why they failed will be the real question.

Do the rollers still spin?

What springs were you using?

Are those LS7 rollers?

Rollers still spin free and easy.
Dual springs and can't remember the exact ones.
LS7 lifters.

Originally Posted by strych9

Makes sense. There's your cast iron shavings. Anybody care to chime in as to why the rollers locked up in the first place, i.e. "root cause"?

Originally Posted by SM0KE

That aint no count (Tennessee grammar lol)

Originally Posted by JusticePete

You had to tear down until you found the problem. Keep us posted.

You mean 'Have' to? Or you think it can just build it back from here?

Originally Posted by Redemption

Yup! I hurd dat

If it were mine, I'd pull it and have the block tanked and all new bearings, At least. I'm sure the crank is fine. Quick cylinder hone, forged pistons w/ rings and call it good. Be good for 100k low boost miles.

I wiped a cam in my truck engine, low oil volume, not pressure, killed it. Same look, just I had to bang the lifters DOWN, since they were mushroomed so bad. (Flat tappet, not roller). Had to do a full rebuild.

I'd like to save the money and frustration if possible. But I will do what needs to be done.

Originally Posted by f5journal

Well, my hunch was correct on post 4903. Sorry to see this. I have been through this stuff with cams and lifters so many times that I gave up on internal hot rodding.

Without going back through your build, was a cam change part of the conversion. There are also some threads out there about cam failures too...along with some suspect thoughts on oils and synthetic oils on the market today

Good luck on the rebuild

Darryl

Yes, this cam was part of the conversion.

Originally Posted by f5journal

This sort of damage will take out the cam bearings and cause low oil pressure. I risked not replacing all bearings one time by flushing the engine real well. That DID NOT WORK. The mains went next. So, there is probably collateral damage scoring on both the main and rod journals

Fair enough.

But what is causing my oil pressure drop now?

[Mr Twisty]

Originally Posted by PQ

Nope. They spin free and easy.


But what is causing my oil pressure drop now?

The contaminated oil probably fed into your cam bearings.

I'd sure check the crank mains and rods too.

[PQ]

Originally Posted by Mr Twisty

The contaminated oil probably fed into your cam bearings.

I'd sure check the crank mains and rods too.

If a bearing (crank, cam or rod) ended up looking like that lobe I could certainly see it losing oil pressure.

[f5journal]

Wiping off a cam lobe always leads to cam bearing failure and low oil pressure. At least this is my experience.

In both of my experience cases, an engine would not quite rev up right. Felt good, but would only turn say 4800-5000 rpm. In both cases, low oil pressure was next due to cam bearings, and root cause was a lobe that was functioning, but not opening the valves fully.

These were both Gen 1 350 and 383 small blocks with solid lifters at the time...so maybe not fully comparable, but I think so.

[Jekyll-N-Hyde]

Originally Posted by PQ

Attachment 534446

Attachment 534447

Attachment 534448

Attachment 534449

Yikes


We have simular parts now LOOKS TO FAMILIAR brings back memories.


That Cam and those lifters will make a hell of a conversation piece for the Garage.


POS ls7 lifters it seems they love taking abuse.

imo if you have not tore that motor all the way down I would no telling how the crank looks not to mention cylinder walls and etc.


What brand oil and what weight oil are you running ?

[PQ]

Originally Posted by f5journal

Wiping off a cam lobe always leads to cam bearing failure and low oil pressure. At least this is my experience.

In both of my experience cases, an engine would not quite rev up right. Felt good, but would only turn say 4800-5000 rpm. In both cases, low oil pressure was next due to cam bearings, and root cause was a lobe that was functioning, but not opening the valves fully.

These were both Gen 1 350 and 383 small blocks with solid lifters at the time...so maybe not fully comparable, but I think so.

Wouldn't that put LESS stress on a cam bearing?

Originally Posted by Jekyll-N-Hyde

Yikes


We have simular parts now LOOKS TO FAMILIAR brings back memories.


That Cam and those lifters will make a hell of a conversation piece for the Garage.


POS ls7 lifters it seems they love taking abuse.

imo if you have not tore that motor all the way down I would no telling how the crank looks not to mention cylinder walls and etc.


What brand oil and what weight oil are you running ?

Mobile 1 5/30

[Scott@Bjorn3D]

Originally Posted by PQ

Wouldn't that put LESS stress on a cam bearing?

Mobile 1 5/30

Yuck Mobil 1 crap.

[strych9]

Originally Posted by PQ

Wouldn't that put LESS stress on a cam bearing?

Mobile 1 5/30

PQ, think of a garden hose. When you place your thumb over the end of it, you increase the water pressure in the hose by restricting the output. Your cam and crank bearings have the same effect on oil pressure. Hogging out the bearings leaves more clearance, and less restriction (pulling your thumb away from the hose). That's why bearing clearances have such tight tolerances.

[PQ]

Originally Posted by strych9

PQ, think of a garden hose. When you place your thumb over the end of it, you increase the water pressure in the hose by restricting the output. Your cam and crank bearings have the same effect on oil pressure. Hogging out the bearings leaves more clearance, and less restriction (pulling your thumb away from the hose). That's why bearing clearances have such tight tolerances.

So if oil is escaping the lifter then it's not getting enough to the bearing because it get's to the bearing after the lifter?

[strych9]

Originally Posted by PQ

So if oil is escaping the lifter then it's not getting enough to the bearing because it get's to the bearing after the lifter?

No. What's happened is likely one of a couple of things: the cam wasn't hardened properly and destroyed the lobes do to them being "soft", or the roller got a piece of metal caught under it and started galling. I really don't see that though, since you have two bad lobes.

The ground metal circulated through your bearings and opened up the clearances. It's like running sandpaper through your engine. The bearings are really soft, so it takes no time at all for cast iron to destroy them.

[PQ]

Originally Posted by strych9

No. What's happened is likely one of a couple of things: the cam wasn't hardened properly and destroyed the lobes do to them being "soft", or the roller got a piece of metal caught under it and started galling. I really don't see that though, since you have two bad lobes.

The ground metal circulated through your bearings and opened up the clearances. It's like running sandpaper through your engine. The bearings are really soft, so it takes no time at all for cast iron to destroy them.

Got it. I will look tonight.

But considering my severe sleep deprivation I need to sleep after bowling.

Forgot to mention my Trooper buddy came by to 'Help' with beer last night.