Bearings! Spun. Fun.

a_kelley

a_kelley

mechanical fixer
Joined
Jan 26, 2010
Location
Rutherfordton
Did a head job on an accord 2.3. deck was warped .003 in 5 inches. Smoothed it out, it was fine for 3-4 weeks. VTEC system failed first (no wonder, supposed to have 57 psi @ 4k) fail safed to no rev past 4k after about twenty miles after reset. Fast forward fifteen miles. Oil light flickering at idle. Five more miles, rod knock. Tore bottom end down, spun 4/5 mains. What's the most probable cause? Warped block resulting in out of align crank bearings? That's the most logical explanation I've heard. Others were mickeyed oil, excessive clearance to begin with, and bad luck(that is the worst explanation which doesn't satisfy my curiosity) no coolant contaminated the oil at any point, but radiator was completely stopped up with stop leak. What say ye?
 
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Yes that is copper showing on the four to the right on the far edges. Far left is only one that did not spin. Thinking it'd be better to put a short block in than trying to polish crank and throwing bearings and oil pump in. Also, no sludge was present in the pan or the head originally. My buddies Honda civic 1.7 did the same exact thing, did the head and bottom end fell apart in relatively short time. Under 2k miles after head job. This was the first block I've ever seen the deck warp on. Maybe due to aluminum block and way way over heated/cooked. Neither were ever low on oil nor did they use oil after the head jobs. I'm scratching my head as to why... Out of true crank bearing axis in the block seems to make the most sense, considering it happened to not just one but two Honda's done by two different mechs.
 
Did you check the bottom end at all during the rebuild? I'm wondering if the bearing damage happened during the original overheating, and was just a matter of time before full failure. Oil breakdown from high temps, and loss of bearing clearance from expansion can kill things pretty fast, and any block distortion during overheating. Without inspecting the bearings during the rebuild, damage could have already been done and you wouldn't have known. I'm not saying you did anything wrong, just that you don't have any information about how bad the bearings already were, which makes it hard to determine cause.

What's the oil pump rotor look like? Did you check the new head gasket against the old one to make sure there were no differences in block-to-head passages?
 
Gasket was right, I did not check the bottom end when I did the head. Haven't pulled the oil pump to inspect it, but is it usually worthwhile to throw bearings in it and roll or always better to pull it and send it to the machine shop?
 
a_kelley said:
Gasket was right, I did not check the bottom end when I did the head. Haven't pulled the oil pump to inspect it, but is it usually worthwhile to throw bearings in it and roll or always better to pull it and send it to the machine shop?
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Not usually necessary to check bearings for a Honda head gasket replacement, that's why this is an odd failure. Often surface the head, very infrequently the block, and good-to-go after the gasket replacement.

I'm not saying you did anything wrong or that you should have done anything different, I'm just questioning whether crank alignment problems from a warped block is the likely conclusion.

In my experience (I'm an ex-Honda guy from my younger days) it takes a pretty diligent effort to warp a Honda block without a much worse problem from the head. If the radiator was that messed up with stop leak, that's a pretty good sign that there might be some significant long-term overheating damage or detonation that can wipe the bearings out over time. I'm guessing there was a coolant leak and significant overheat and some time in the engine's life. Maybe some oil starvation problems in the past too if the maintenance was sketchy enough to have stop leak in it.

I'm just thinking that the deck warp and stop leak are just signals for enough cumulative overheating damage that the bearings didn't stand much chance of long term survival, and whatever overheating/gasket failure event that was bad enough (to make it cross your path in the first place) was the nail in the coffin for the bearings. Likely the worn bearings were helping things along..

Does this car look like it was beat on at high RPM at all? The 2.3 is somewhat known for spinning bearings at high RPM. Probably not related at all, given all the other questionable things about the engine's condition and history.
 
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Oh, so short block is probably the way to go. Crank and block are probably pretty well trashed at this point. I'd take a long look at the head too if you're going to be replacing stuff.
 
Talked with a few of my friends/associates that are mechanics, some with as much as 40 years experience, from street bikes to HD truck motors, all agree lack of sludge and the fact that the deck was warped that collective knowledge says that this block is for certain out of alignment on the crank bearing surfaces. Throw in the mix am unknowledgeable owner likely dumping cold water into a motor that is potentially at 300+ degrees between the stopped radiator and head gasket coolant leak and you have instant total warpage. That explains the one bearing being relatively unscathed and the others down to steel at the same locations. Yes rpm was a factor in it dying quickly, but the root cause was there before running the crap out of it looking to reproduce the vvt issue. Exactly the same thing happened to my buddies for exactly the same reason. Got it hot enough to distort the crank bore in the block. Since most mains call for 1-2 thou, half a thou distortion is enough to cause it to grenade. I'm happy to know the cause of the failure, it's crucial to me in that I want to know the why, not just how to fix it. Anyone can change a motor.. well almost anyone. Takes someone who knows to tell you Why the failure occurred. Again, not very common occurrence, but once is common enough, even if its one in one hundred.
 
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