Teardown feedback please...

I've taken engines apart before, but quite honestly never took the time to "study" the parts to understand what they were telling me about engine operation. This is a small block 360 motor, weekend driver, about 7 seasons, a few 1/4 mile races in-between, but otherwise a normal 7k mile street time.

Well, I have taken quite the opposite approach this time around and would appreciate feedback on what these pics are telling you. As best as I can tell there are really only two problems here:

1) some main cap walk on #1 and #3, which shows in the cap<=>block spotting (there is probably a real professional term for this) and the tell-tale wear on the bearings

2) weird cylinder wall wear on #4, not sure if this may actually be a crack?
About 3 years ago I ran into head exhaust cross-over porosity which caused coolant to leak through to the cylinder, but it never locked - steam only as best as I could tell - and when I pulled everything apart the walls looked clean, and when the machine shop pressure tested the head to find the leak it was a tiny amount of air bubbles coming through, tiny enough that it took them a while to figure out where this was coming from

Beyond that I am a little surprised by the 2nd piston ring wear pattern, I expected it to look like the top one with even wear.

Here are the pics:

1) cylinder wear




2) connecting rod bearings




3) main bearings






4) piston ring


5) main cap walk


[img]http://darcio.no-ip.org/mopar/teardown/cap_walk_2.jpg[/img]
[img]http://darcio.no-ip.org/mopar/teardown/cap_walk_4.jpg[/img]

All feedback greatly appreciated, maybe this all looks "as expected", I am hoping those of you with way more experience than I can share your know-how.

Thanks!

I see a helicoil there with all the metal transfer, Hmmmm, just an observation

csk,

Indeed, helicoil was installed by the machine shop (very competent one), the mains were then align-honed and on tear-down I tested the turning torque to see if anything got loose.

Problem here is that would mean having to overcome the existing break-away torque first...so this is an approx. at best. Anyways, things were up to spec. However, as you pointed out I'm thinking that combined with other harmonics (maybe detonation?) this may have had some effect on things?

I always heard that when installed correctly a helicoil is actually stronger than the original thread, is that true or just an old tale?

I can't see any off the pictures,. but second rings wear from the bottom up, they are tapered.They act as a oil wiper /scrapper. If they are worn the whole way across the face they are way gone in my opinion.

I can see the 2 pics of the mains. looks pretty normal to me.

You need full time oil to the rods. You should be using full groove mains.

The smile in the bore in that location could be piston rock and the ring pack digging into the cylinder wall.

What you see on the main caps is the cap and the block flexing. Pretty normal when you start pushing a stock block. If you are using bolts you can install studs, but it won’t stop a flexible block and cap from moving around.

The cylinder looks like a crack to me. In your second picture you can see a jagged line that continues around the bore. A mag test will let you know for sure. You might try a scotchbrite pad to see if you can 'erase' that line, or use a 90 degree pick to feel for a crack.

Finally figured out how to look at the images.....I've seen spots like that in a cylinder that sat with water in there making the eyebrow look then ran and rips all rust off leaving a rough grey mark like that.

the mains were then align-honed

Im wondering why you have such a shine vs cross hatch marks from the align hone?

Was that heli coiled main the only one showing signs of capwalk?

I wouldn't know how to even begin answering the shine vs cross-hatch marks question. This motor was at the machine shop about 15 yrs ago, heck, maybe even 20 actually...about a year afterwards I put it all together (so def a DIY assembly job).

Regardin the heli coil, yes, there is a single fix, that being on #1 main and is the part that showed the cap-walk.

I'm not going to be doing anything with this block for a while (maybe just nothing more than a spare), so let me try that scotchbrite pad approach.

Umm...the pics come up fine when I view the post from here. I'm actually hosting them on my own web server at home, but it's over a 1Gig fibre connection so neither speed nor availability should be a problem.

Having said that, what did you have to do to finally see them? If it's something on my end I'm happy to fix it.

Regarding the rust hypothesis. If the cylinder exhaust cross-over exposy was starting to let go it may explain this little "puddle" accumulating between the piston and the compression rings and just eating away at the cylinder wall. I do recall having a surprising amount of steam coming out of the exhaust during the season's start-up. Of course I was worried about the epoxy having let go so I checked the coolant level and there was no issue there. I kept my eye on this throughout the season and never had to add coolant as it remained at the same level. Still, the volumes we might be talking about here could be so tiny that it would be impossible to tell just by looking at the overlfow bottle level.

No problem on your end. I'ts just me I couldn't just click on the little icons. I had to right click than open in new page. I'm not to tech savvy. I still haven't even owned a cell phone yet.

Look at the location of the mark, if the piston was stopped and there was a little water in there, is it in the right spot? the outside of the bore. I've seen those many of times when people bring me engines that have been sitting (sometimes outside, in the rain,snow ect.) and they get them running again. A sharp bottom line with a horizon area above it. I've also seen those on peoples race engine that sit a while, they are randomly placed where the cylinder rusted from sitting. No sharp bottom line on those though.

what I appear to see on cylinder wall is a water/fuel stain, on main caps I see metal transfer most likely from detonation
gary

Are the journals all standard or undersized?

As for that bore mark, that’s typical of water setting in the bore. In fact, in your situation it looks like you have two of those marks.

Transman,


Yes, both the connecting rods and the mains are 0.010" under.

Regarding the cylinder wall mark, I'm thinking whatever coolant may have leaked through would have then settled around both the 1st and 2nd rings...probably even down to the oil ring as well?

That makes sense since the mark is on the outer block side that would have allowed the coolant to pool there.

I have also seen main bearing inspection reveal similar random shiney areas also, once. Inspection was after about 10 dyno pulls, before it went into the car. What does this mean? I’d like to think it’s normal, but something tells me it shouldn’t look like that.

Can you post the backside of the bearings laid out like you have ?
Also, how about some close ups of crank journals, clean and dry with good lighting?