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Took apart the rest of the short block and cleaned the pistons.
A few observations just from this experience as well as doing several other engine types.
Way too much oil is burned onto these pistons. With perfect bores and no other signs of wear, the indication is that we need massively better oil control. No more oil can go into the intake.
Oil control rings were not controlling oil very well
Second ring is a "napier" ring - it has a sharp lip on the bore side. That, combined with the beveled second ring groove allow this burned, coked oil to gather in the napier groove. Research needed.
Rods look and feel robust - good enough for probaboy 25-40% more power as long as revs are not high and detonation is kept at bay.
Ring gap, as mentioned, is way too small even for a high po N/A car. I don't think anyone is safe to mod with stock gap for long.
Rod bearings show above that there is anomalous wear on the down stroke, as if there is oil film issues or low level detonation pounding the bearings. Will open rod clearance just a tad.
Mains have some fretting and look to be a bit more worn than I had expected at this mileage (100k) - will replace and possibly open up a bit.
Head gasket is put on with some black sealant in areas I am surpised about.
Will probably coat piston skirts and put heavy ceramic coat on top and run stock otherwise with more-gapped rings.
Massively overbuilt like old-Mercedes. Sharp casting edges affected my OCD so I had to smooth it just a bit. Just a bit of 80/20 (20% of the work for 80 % of the improvement)
And finally, if not most concerning, but we are all basically "aware of" is this crank snout issue. Just cookoo crazy.
This is a major WTF moment for me, even though I have seen others talk about it. Why the hell do we have a half and inch and even less of the keyway holding the pulley?
This to me solidifies that if you touch it, you have to pin it. The pinning and the torquing of the bolt are of critical importance and you cannot fudge it.
I'm a little torn here. This is not a track car - I have those. This is a family car I can trust (operative word).
Plan A - Coat pistons (52 dollars a hole - just for safety - iron is still on them) + Rings (Ring gaps to more like .022 instead of .012 (80 bucks a hole) and put the bottom end back together with new bearings
Plab B - Nikasil Block and get some custom pistons. More money. 1500 for nikasil and unknown amount for pistons - maybe 200 a hole or less.
Only reason I hesitate on this is that there ARE some mods - bigger bottom pulley, larger TB, spray meth, etc.
I personally believe with opened ring gaps and coated pistons the headroom on the engine increases by a bit - as long as there is no detonation. E85 resolves most of that.
My thinking is that it had to be set up tighter than that from the factory, there is always some wear, and it worked for 100k, surviving who knows what over the years, Seems like that would be enough gap. If all our engines are set up like that, it does work. You used to hear about cars blowing #8 from leaning out, but it's gotten rare now that people are aware of the problem. Ring gap is one of those tighter the better things...until they touch...
I would trust the engineers on this one, unless you are going to sleeve it, then all bets are off. Or if you use a different ring material.
I guess the true test would have been to tear down a full bolt on motor and see what the results. I do agree that with more power and no real intercooler(Not heat exchanger) upgrade available the heat will be much greater.
On a side note, did you see a lot of oil in the intake system of the motor? With most non enthusiasts doing 10k mile oil changes on these high performance engines maybe that could be causing the coke of the oil? I don't know just throwing out ideas.
There was indeed oil where it probably should not be.
As I’m sure people know, this is for emissions as we have not had open crankcase since 1956. But there are modern ways to keep the oil out of the combustion chamber and its critical as ooo is much easier to burn and therefore causes detonation if present in large enough amounts.
So when you order mains, you get both. Even though many times the engine requires different clearances according to the letters on the crank, and the numbers on the block. This was mentioned by the gentleman on youtube that rebuilt the engine in chapters in great detail.
What I also found is that you order rod bearings, and unless I am missing something, they are all yellow. I will have to determine this clearance. Seems like before anything I have to have the crank polished.
Read the Wisco thing. I've run many Wisco pistons over the years, never had one fail. Two things I picked up. First they are using cast iron blocks as their example. Second, under mistake #2 they say OEM specs can be as little as 1/3 what you need for the new pistons, and you must follow the specs that come with the piston. I'm kind of on the fence now. Oem pistons--oem specs, plus a little for added power? It would be good to know what oem specs are with 0 miles as a starting point. Back when you signed up here there were lots of guys over 500 at the wheels and a few at 600 with stock internals. We know it works. If it was me, I'd try to find someone who really knows this particular engine. Everyone has an opinion based on their experience, Maybe someone at Eurocharged has real world facts for THIS engine with stock pistons.
Please post up everything you learn about the bearings too, I suspect that job is also in my future.
Your call, but if the rings were expanding enough to nearly close the gap, the carbon buildup would be crushed and washed away. how hard do you drive it? Any full throttle on a cold engine events? I thought about using a heat gun to cook one of the old rings and see how much you can tighten it up in a cold bore. Also thought about warming up the block to see where that takes it. I have no idea how to do that though.
Okay. Updates coming faster now. Short block is nearly complete. Heads next. I think I have some pics of the last few stages. Taking apart the interior a bit for some carbon fiber because "I'm THAT guy".
This is an M113k block that fits nicely in the back of a C7 corvette.
03-18-2019, 02:59 PM
