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You'd have to remove the ring from the piston then put it back in the bore to measure. No biggie, just data for my spreadsheet of failed engines.Quote:
Originally Posted by Jimvr4
Not really what I was getting at.Quote:
Originally Posted by RealMcCoy
I'll break down todds engine in a couple weeks for you Chris.
Jason
OK, I obviously made an incorrect assumption... Now I'm curious, what type of data are you gathering on engine failures? What do you intend to do with the data gathered?Quote:
Originally Posted by anyonebutme
I'll make 1 post then I'll quit derailing the thread and make my own when I'm ready, lol. I got the idea from a well known powerstroke diesel tuner who was fed up with no hard data on why some engines fail and some seem to last forever getting beat on. Although his engine failure survey was centered on the tuning and not hard parts, it only took like 10 engines to see a definite pattern, which changed everyone's strategy. Ever since then HP numbers have been climbing and failures have been falling. Used to be 350-400HP was the limit for PMR's before windowed blocks, now more than a couple of trucks are running clear of 500HP at the wheels on the "weak as glass" PMR's.
Back to the data, the old engine in my car seemed to be magical, STL members can attest to that. 25psi of boost on pump gas, 28 counts of knock, beating the living piss out of it, 9K+ RPM overshoots on stock valvetrain, it would not break (all accidentially). It would seem like it broke, but would then run fine and look fine on disassembly. After 122K miles and full teardown #1, mains were to copper (all copper edge to edge IIRC), rods were wearing but ok, and it had blow-by issues. Rods were straight and pistons tops were good. So, why does this engine not break and some engines seem to spit out parts first sign of knock? Theory is one thing, but like the diesel tuning survey showed, reality can surprise you. Not all engine failures, especially on factory engines, can be explained simply by "detonation". There is a definite cause, a chain of event's origin, and it's never "detonation" or "knock". I'm less concerned with origin in my study or this thread, just patterns.
I'm too early in the data to know what exactly I'm shooting for, but a couple high HP race engine builders told me to start gathering data on the actual tolerances our engines have in certain areas. First thing that stood out to me was how loose my ring gap and piston to cylinder fit was compared to "factory spec", and they said it ended up where they would put it if building an engine to take a beating. I also noticed that the factory bore fit was not as consistent as I thought it should be. I could also be off in left field.
Really? I find that surprising. Interested thoughQuote:
Originally Posted by anyonebutme
I'm wondering if my engine has a bigger end gap. Supposedly the engine was rebuilt 20k miles ago but when I took it apart back in Sept everything was completely stock. The bearings had some copper wear so I assumed it didn't have any work done on it. Who knows maybe one of the owners had it re-ringed. I've always wondered how much bigger the stock end gap should be on a stock setup running more boost. Factory calls for .0118 - .0177" 1st and .0177 - .0236" 2nd. On my stroker I did a .015" 1st and .018" 2nd recommended by Ray. It's a completely different piston/piston clearance setup nonetheless.
Made more progress today. Removed the oil pan, oil pickup, oil pump, and rear main seal housing. Open up the oil pump with my impact driver and everythings looks great there:
http://jns.jimnshar.com/40300ab0.jpg
Now that this is getting serious it's time to break out the documentation:
http://jns.jimnshar.com/3fd15200.jpg
http://jns.jimnshar.com/3ff00ab0.jpg
The main bearing cap would not budge after I pulled all the bolts out. Not sure what to do I checked the forums and found a thread on the other site that said to use a rag and a dead blow hammer. So I refitted four of the bolts in a few threads, flipped it over and pounded and it popped loose and hung there by the bolts. There are no spun mains or rod bearings but there is certainly wear on the mains that I can see:
http://jns.jimnshar.com/40100ab0.jpg
I can see the skirts of all the pistons through the bottom end. There are no piston lands broken anywhere. It doesn't look like anything serious happened to the engine but with the girdle off, there is still resistance to rotation. I think I am going to find some rough rod bearings when I get further:
http://jns.jimnshar.com/40500ab0.jpg
The third main bearing has two sets of shims around it, if you look at the picture above you can see them. Is this normal?
Thrust bearings.
I can't tell from the picture but on the main bearings is that oil or copper showing? It looks like oil. If it's not copper the bearings actually look decent.