Cam bearing surface slightly rough?

[Torchred96]

After taking out the cams on the driver's side (left the sprockets on) I noticed about 4 of the lifters on the intake cam seem to have bled down and are soft. Recall I'm working on a ticking lifter noise.. This after sitting for about a month in my garage. None of the exhaust lifters exhibit this softness..or sponginess..

I ordered the complete set of lifters for that bank (16) and am awaiting their arrival. And since I have time on my hands, my mind was thinking...perhaps overthinking as I tend to do....but,Im thinking that perhaps an oiling issue to the intake cam may have caused the lifters to collapse? Then, I went to look at the head and noticed that the bearing surface where the oil galley that feeds the cam appears to be rougher than the rest. How rough is too rough and should I try to polish it somehow?

Also..How can I check to see if oil is indeed flowing through this galley?

[Hib Halverson]

Originally Posted by Torchred96

After taking out the cams on the driver's side (left the sprockets on) I noticed about 4 of the lifters on the intake cam seem to have bled down and are soft. Recall I'm working on a ticking lifter noise.. This after sitting for about a month in my garage. None of the exhaust lifters exhibit this softness..or sponginess..

I ordered the complete set of lifters for that bank (16) and am awaiting their arrival. And since I have time on my hands, my mind was thinking...perhaps overthinking as I tend to do....but,Im thinking that perhaps an oiling issue to the intake cam may have caused the lifters to collapse? Then, I went to look at the head and noticed that the bearing surface where the oil galley that feeds the cam appears to be rougher than the rest. How rough is too rough and should I try to polish it somehow?

Also..How can I check to see if oil is indeed flowing through this galley?

I tend to think you don't need to worry about that.
Why?
Well...let's consider what would happen if there was no oil flow in that oil passage. There's be no oll to the cam bearing and the camshaft would have long ago seized up. Clearly, you don't have any camshafts which are seized so oil must be flowing to the cam bearing surfaces.

As pointed our earlier, the majority of the cam bearing wear occurs in the cam cover because load wants to push the cams outwards. If that cam bearing surface on the head seems more rough it may be because it's not worn.

Lastly, I would consider carefully using any abrasive to change that surface.

[Torchred96]

Thanks Dynomite and Hib. Well, hope these pics don't change your mind. Keep in mind the car has been sitting so the oil u see is not the circulating oil, it's just old oil i dribbled on it keep moisture/rust at bay. Btw the 2 pics are of the same bearing surface.

[Paul Workman]

I just happen to have a head sitting next to me (doesn't everybody?) and I see something on some of the bearing surfaces that looks like light scoring, similar to yours, but perhaps a little lighter.

There is some similar scoring on the cam cover bearing surfaces - perhaps slightly deeper (but still pretty superficial).

the head came off at approx 45000 miles to be ported. Up to then, it ran fine w/o any oil issues. Both heads had some of the same type of superficial scoring on some of the bearing surfaces, but deemed insignificant by me (and later by Pete).

For unrelated reasons, one head was damaged and I replaced it with a head off of a 92(?) LT5 that Marc was parting out. My motor now has 55k on it and there has been no problems with either head before or since.

All this to say you're probably OK. But, timing the cams is something best done with the motor out of the car anyway. So, sending the head off to one of the gurus for inspection and expert opinion and measuring is a consideration. (Can't really tell from the pictures...)

BTW...What kind of oil are you using?? I hope it isn't API rated "SN" or the like.

P.

[Torchred96]

Thanks Paul, Hib and Dynomite.. It's not going back together anytime soon I don't think. I still want to look at a couple of the bearings in the bottom end. I wasn't comfortabe with the noise it was making with a stethescope on the plenum..sounded like metal to metal rubbing somewhere...along with the ticking. I've never heard that before on my lt motors. I've haven't put that many miles on the car since I've had it in a year..maybe 3k if that. I changed the oil shortly after buying the car, again after the porting process and added only one quart since, all mobil 1 10/30 synthetic. Of course that was before reading recommendations.

The Cam surface on cam cover opposite this oil bearing doesn't look bad at all. Scuffed but not gouged. The cam itself is shiny and does not appear to have any aluminum transferred to it, nor is it scored like the head. All the other bearing surfaces look fine, in head and cam cover.

One thing that still gets me is that several of the intake lifters can be depressed with finger pressure approx 1/8" or so. ON the exhaust side, none of them are soft at all. Just wondering if that may be an oiling issure which is really why I started this whole thread.

[A26B]

Sam, if you are adament about checking the mains, you will have to pull the engine. Remember the LT5 has a lower crankcase "girdle" that houses all of the main caps together. All the main caps come off at one time.

Rod bearings, not a problem.

[A26B]

The rod bearings would have to be worn pretty bad to "feel." You should be able to get to a couple of rod caps with the crank in any position, but with the top end apart (cam covers off) I would not recommend turning the crank. You could get a sampling of rod bearings that way.

I would expect to see normal wear on the rod bearings with 140,000 miles. You could probably drive it another 60,000+ miles, but the problem is, once you start, where do you stop, short of a major overhaul? That's always a difficult decision on an engine with that many miles.

To answer you specific question "should I change them as a matter of course just because it has 140k miles?" $40.00 for a new set of rod bearings? You betcha I would put new in. Are there other factors to consider? Yes, time & labor as well as condition inspection of the rest of the engine.

Your question: "Do rod bearings necessarily indicate similar condition of main bearings?"

Maybe, but not necessarily. The LT5 has a tendancy for the #4 main bearing to fail first. After noticing this in several engines, I mentioned it to Brain White, who was an engineering intern with Lotus in England on the "new" LT5 project during development and then an Engineer on the LT5 project with Mercury Marine at Stillwater. Brian said that the problem was initially with the #5 bearing, due to the load imposed by the heavy dual mass flywheel. The #5 bearing width was increased and appeared to solve the problem. Considering the propensity of #4 bearing failure, he believes the #4 bearing should have also been resized.

What does all this mean? To me it means you may be able to get a sampling of bearing wear by looking at a couple of rod bearings, BUT it is not necessarily indicative of main bearing condition, #4 in particular.

The LT5 can be expensive to overhaul, but is still preferrable to buying "another" used engine of questionable condition. Horsepower by increased displacement can be had with little additional cost with new sleeves, pistons & rings for the same or less cost as stock replacements. The stock rods are heavy but hell for stout. The crank is most likely in great condition. Your heads may need new lifters, guides, seals and a valve job but very likely rebuildable.

About new or used lifters on new or used cams. Here's my take on that;

New cam, New lifters only

Used cam, reinstall used lifter (if servicable) on the same lobe only
or
Used cam, new lifter OK

No easy answer or shortcuts, just a decision by you on how much time & money you want to invest.

[Hib Halverson]

Is there more than one cam bearing surface in the heads that looks like that?

What did the cam journal that was running on that bearing look like?

By chance, had you been doing periodic oil analysis? If so, can you post the last print out from the lab?

[Pete]

How many miles on the motor?
Has it been apart before?
Is it all factory assembly?
How do the cams look like?

From the looks of it they look like normal wear but without having it in front of me to feel how deep the grooves are can't really say for sure/100%.

Use some Scotch bright on one cam bearing surface and see if it polishes smooth then it's ok,you will not hurt anything.

It is very hard to find one ticking lifter if you know which bank it is i would change all the lifters on that bank.

Had this same issue with a friends low mileage Z (20k) we just changed all the lifters and no more ticking.

Melling JB-2236

Pete

[Torchred96]

Is there more than one cam bearing surface in the heads that looks like that?

What did the cam journal that was running on that bearing look like?

By chance, had you been doing periodic oil analysis? If so, can you post the last print out from the lab?
__________________
Hib Halverson
Technical Writer
95 VIN140

Hib. No That's the only one that concerns me. The cam journal looks fine. No metal appears to have transferred to it from the head, and it is not scored..You can tell where it was riding, but it's only discolored as far as I can tell.
No oil analysis. Honestly I wouldn't even know where to get that done. Only changed the oil 2x so far in the circa 3k miles i've owed it.

Thanks for your responses.