Last night around 11pm, a block or two away from my house, I decided to get the ball rolling on my forged rods only rebuild; I bent number 4's rod all out of shape. I noticed it a block away from my house, turned the music down because i felt something in the shifter, and pulled into my driveway at the same time i recognized the very no bueno sound of a connecting rod with scoliosis. Of course I shut it off, and ripped the motor out.
The motor is out and torn apart.
What I am looking for is more experienced folk who have seen the "norm" wear and tear of an engine ( this one was a 250k mile motor untouched) and abnormal wear and tear of an engine, so that I can gauge what I can do/get away with/ and neglect in rebuilding this.
I will attach videos showing off multiple aspects.


2002 vvt stock block car, 10 psi tapered to 14 at redline. Hit spark cut redline when it happen im pretty sure. tiny sr20 turbo.

None of the bores have scratches or pitting that I can feel. Crosshatching is visible, and some kind of staining in the middle of the stroke, along with some very faint vertical marks I can see when the light hits right. I cannot feel them but they are visible.
None of the bearings rod or main, are worn through to the copper. The backs of the rod bearings look horrible, im not sure if this is a normal occurrence but they're not great looking. AFAIK no bearings spun, they were all in their proper places when it was torn apart.
crank rod journals look good from what I can tell, some wear you would attribute to 250,000 miles. Main journals look more worn, and the bearings were more worn, none worn through to copper ( if they even have copper internals?) , none spun, and I cant feel any roughness or edges on them after cleaning them. The video I attached, they were cleaned well yet.
Lots of shavings in my oil and oil pan. I have copper colored goop which looks like that copper coating spray color. Im not sure where the shavings came from. This is also a subject I want to hear from you guys about. Could the shavings be from the wrist pin area of the connecting rod and piston? maybe the backs of the rod bearings? I have yet to find a smoking gun on their origin.

Piston skirts have some wear, nothing I would assume is abnormal. This car has had worn rings for a while now, warm compression numbers being 140-150 and jumping to 200+ with oil in the cyls. It has burned oil for a long time.

1. Can I ball hone smooth, ring, rod, bearing, and clean the oil pump out, then send it - with new gaskets associated.
2. I can get a 1999-2000 bottom end, but would I need the vvt oil pump to use the vvt head?
3. What looks like it needs work that I couldnt do myself? ie: machining equipment.
4. New main bolts? I'm not getting studs because I'd like to avoid having it line bored. what options and where can I get main bolts.

Im aware i'll get the recommendation to just bore it out, have the machine shop fabricate a huge bill of whatever else they need to do, and "be done with it" This isnt an option on the list. Id much quicker source a good bottom end and throw the forged rods I already have in, but would have to reseal a second block, and still do bearings and rings along with ball honing it.

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EVERY ONE OF THOSE ROD BEARINGS SPUN...

Thats where your copper came from...

The fact that they were still lined up is a million to one, but you cant say "none of them spun" when its obvious the back sides are all destroyed on the bearings and the rods look like complete death.

 

im not arguing they looked horrible, i just didnt feel any play when i checked each rod cap and the ends of the bearings were still flush on the rod when i unbolted. Very odd but i suppose it had to come from somewhere

 

I find most high mileage rod bearings look like that. If x4 shells were lined up on the caps and rods, I highly doubt they spun. That's just a small amount of oil that never gets circulated stuck between the bearing and cap for 250k miles.

Nothing in your videos tells me to run away, although I'd be hesitant to ball hone and re-ring it. You can typically get away with doing that once or twice on a BP. Smoke and oil consumption will go up with every ball hone, power will go down. Not a lot, but some. I typically choose much nicer starting points to do that to though.

The sound you heard was piston skirts touching the ends of the crank balance weights. Check the crank for damage. #4 is directly above the sump, so it would have all fallen into the pan there, that may be what you're seeing.

I personally would be having the crank polished and inspected, block, oil pan baffle, and oil pan hot tanked, bored for 83.5 pistons, and replace all bearings, oil pump, small hoses, stock oil/water heat exchanger, and pickup tube. Have all plugs removed from the block and clean out all passages with compressed air and brake clean before assembly/painting. Basic refresh on the head is all you need, have guides and valves inspected, upgrade to some Volvo springs, again removing all galley plugs before cleaning.

You can reuse your head and main bolts. I didn't have my block line bored for ARP studs, your results may vary.

 

Maybe its just a reflection, but looked like the back sides of those bearing shells were worn to copper plus the wear on the rod and cap...

 

OP took a very ADHD feeling video, right as the camera focused on anything he would pan away or tip it over, so difficult to say. Either one of us could be right. I even clicked on the youtube link and went to 4k, full screen. I'm still meh on them. Rods and bearings are being replaced, my biggest concern would be the crank journals. I fight tooth and nail to just polish a crank and use STD bearings, but they can also be ground.

 

smoke and oil consumption going up - is this just the nature of the beast doing at home honing and reringing? Given it burned oil from worn rings, could this be a case where that is not the end result? Ie: is it impossible to remedy or at least make better my oil burning and compression with a hone and rering given they were bad to begin with?

checking piston skirts like you said showed me a very smokey gun. They were ground down and the crank has some damage. Definitely not as in balance as it was before id assume. I went to town on one of the backside of the rod bearings with some brake clean, and that nasty looking wear was wiping off. Experience like yours being a free resource on this forum is a baffling concept to late stage capitalists.

you caught me, i never take my meds unless i want to have a **** day. Anyway i retook the video as best i could. You will have to excuse the shakes. “I fight tooth and nail…” Im not interpreting this phrase very well, are you saying youre an advocate of that being done?

I cannot remember if this was mentioned, but if I can get this straightened out, i was planning on picking up a 2560r and I suppose going for a healthy 300hp on ethanol. Assuming forged rods, is a boundary pump, main studs, or head studs + anything else a must do? I get this is a huge generalization to say something must or mustnt be done for a certain level, just wondering if there is anything as applicable for that level. I cant raise it up that high until I have a bigger turbo and injectors anyway.

acl bearings
chromoly rings
any other valve stem seals comparable to oem or is that non negotiable?

appreciate any insight. Im still waiting on a buy once cry once comment anyone!

 

Damn, that's a bummer but good on you for getting the engine pulled so quickly. IMO pictures beat video here simply because you can zoom easier and linger on things longer.

Just curious, how do the tops of the pistons look? I remember when I pulled mine out they looked a bit like the surface of the moon, but that's probably from me learning to tune on them.

I also went to ARP main studs and asked the machine shop to measure them and line hone if necessary. They shop said they measured out fine and a line hone wasn't needed.

Even with ethanol I think you're going to struggle to get to 300 on a 2560. I'd think 270 or so is a bit more realistic. I'm struggling to get much past 300 on E85 with my 2860, but that's another story. I think you're on the right path. An upgraded oil pump or oil pump gears is usually one of the recommendations alongside an upgraded damper. I think it's a bit harder to get a good idea of what's really necessary because everyone on here seems to go down the "buy once cry once" path as you've seen. On that note, use case is probably worth mentioning as well. Is this strictly a street car, or something that's going to see track time regularly?

 

No track time, pizza delivery car, may try my hand at autocross once or twice. It makes my job very fun getting to throw around a boosted miata all day. Though I do have a a lead foot. Ill go out and take a look and pictures here soon, but to be fair, this motor hasnt seen gasoline since it was naturally aspirated. So I never REALLy worried about knock. I have what I would guess is ringwash? im not sure thats the correct term but i do recall the edges being clean as a whistle. were you happy with your 2860's spool over the 2560? Id like to only buy one turbo, and I dont imagine id hate 270, but i know myself, and would chase that 300 till the end of time if I didnt get it. Im spoiled to this tiny turbo's spool speeds.

what are opinions on cleaning parts with diesel? I was thinking of filling a 5 gallon bucket with some solvents or diesel to clean parts like the pistons and their ring grooves and other misc items. bad idea or not?
Damper might be a bit higher on my list because of the small wobble my balancer had, I had a crank saver and had to tear it off, when I replaced it with another stock key and gear (used to get it running next day) I had the wobble again, small but noticeable.
My logic for the line boring is that im measuring clearances anyway, if the studs make the clearances smaller, I could just get different bearings no?

Loctite on main bolts and rod bolts or just assembly lube and torque.

 

Not to try to take you down the horsepower rabbit hole, but my logic was that I could make 270-300 by taking a 2560 to its absolute limit or by running a 2860 in it's maximum efficiency range. The gen 2 2860 with EBC spools pretty well, although the consensus for the Pulsar clones that a lot of us have started running recently is that they boost creep like crazy. Elevation and such are going to play a part, but a Pulsar 2860 can be had for about $700 shipped. If you're more worried about the budget, a used 2560 is probably going to run closer to $300-500 and is still a great option.

No idea on cleaning parts with diesel, but when I rebuilt my engine it was super nasty. I ended up grabbing a Crock-Pot from marketplace for $5 and filling that bitch up with Simple Green. It didn't fit all the bigger bits, but for smaller brackets and bolts it was pretty dang effective. If you like the smell of simple green it will also act as an air freshener. Just be careful because some stuff will flash rust pretty fast after soaking.

Not sure on the main stud aspect, but I didn't like the tolerances I saw with plasti-gauge when rebuilding and ended up getting new bearings to suit. I think I ended up with the HX bearings that are actually oversized from stock.

All the studs are just torqued with the supplied grease from ARP. I think I did red loctite for the bolts that deleted the oil squirters, but honestly at the temps that the engine runs at I doubt there's any of that left. Check out the videos from Napp Motorsports and Greg Peters on YouTube. The Napp one is long but will cover most of the questions you'll have. Greg's video is a bit less detailed but shorter and more enjoyable to watch.

Screw it, here are links. These videos were probably the most useful for me when I built my engine coupled with a lot of posts on here.

 

the crock pot idea is genius, ill have some time to make a decision on the turbo, that was essentially my thought process too - maxxing out a 2560

i need to look into the oil squirter removal pros and cons, I know nothing about why they get removed or kept.

i have been seeing a few of your guys’ posts regarding boost creep issues and how yall like them, and a few saying they dont mind it because of the built motors. Regardless seems like a good option.

I actually had rewatched stefan’s video less than a week ago because I had wanted to start brushing up on the process and small things that id need to buy for the rebuild when it was planned later. I love those videos, theyre about as good a spoon feed as you could ever ask for.

 

Leave the oil squirters. There is a reason that all production turbo engines have them.

Be thorough cleaning the block, head and crank. The block should be bored and honed by a machine shop. Having a crank ground does not weaken it. Cranks bend at the connector adjacent to the rod journal, not the journal itself.

The rod bent from being over revved.

 

My original plan was to leave my oil squirters in, but the Flyin Miata pistons interfered with them so I ended up deleting them.

Also, on that note, keep an eye out for parts in some of the buy/sell groups on facebook. I snagged pistons, head/main studs, an oil pump, a head gasket and bearings for like $800 and it was all BNIB. I also basically gave away some bearings since I hadn't like the measurements I saw with them and couldn't return them.

 

Think ill leave them, one less thing to fiddle with.
I check this forum multiple times a day generally, my eyes are peeled. Im not one to pass up a good deal. my 200$ pristine junkyard hardtop and multiple junkyard torsens are my testaments

 

Yeah, as everyone else has said, the real fix for that is gonna be an overbore and a fresh hone. Its not heinously bad, and a dingleball hone would probably run ok, but its just tiiiired. As Curly said, oil consumption would go up, and compression would go down trying to get away without boring it. If you take a bore gauge to those cylinders I'm sure they're ovaled in the middle. I also concur with Curly that none of those bearings appear to have spun, and it does not appear to have suffered an oiling related failure. Just the mileage taking its toll.

That rod probably pretzeled itself from too much boost and/or timing in a certain cell; just 1 unlucky combustion cycle where cylinder pressure overwhelmed it and won. I think Curly's "tooth and nail" comment was about trying to have machine shops just polish a crank and not actually grind it undersize. Some crank guys will insist on an undersize grind straight off, whereas some will attempt to polish things and keep them in spec. As mentioned, I'd absolutely keep oil squirters if at all possible, especially if you plan to turn up the wick. The piston cooling and cylinder oiling is well worth any oil pressure tradeoffs you might experience.

 

I am going to check out a bp4 block from an nb1 today. Around 100k miles iirc, definitely should be less tired as a starting point. if i can avoid boring a block out thatd be great. I took the cover off of my vvt oil pump and found no metal, but some scoring on the flat planes of the gears and the surface the gears rotate on, is this cause for a replacement or rebuild? Could I use a bp4 pump and shim it somehow? Im open to advice, giving some machine shops a visit today to figure out lead times as well.
Thinking of taking all of the internals of that bp4 block and using the pistons crank ect. Along with the metal shaving contaminated things being replaced - oil cooler and pan and such. Less of a headache. Just grabbing that block would be a plus.

 

Very hard to make a call on an oil pump without seeing pictures, but again with 250k its gonna be tired and likely ready to be replaced, especially knowing that metal went through it. I would not recommend using a non-VVT pump, they are higher volume to cope with the oil the cam phaser requires and still maintain adequate pressure to the rest of the motor.

The BP4W block would be 1 avenue, I'm not certain if they come drilled for all the VVT oil lines or if you'd need to make modifications to retain VVT. I guess I'm struggling to understand your aversion to boring your current block and going to the first oversized piston? Machine work is not that expensive overall, especially compared to what BP motors go for anymore. As someone mentioned you can probably find a lightly used set of pistons if you look around, and then between rods and forged pistons your power ceiling will be greatly increased. With an eye towards turning up the wick and shooting for ~300hp, you're gonna want to probably pull pistons out of any bottom end and open up the ring gaps a little anyway.

If it were me, I'd be trying to decide between just boring and rebuilding the current engine, or looking for a good running VVT motor to drop in without needing to open it at all, and save the rods-only build for another time when you can do it all. (yes, this might be the buy-once-cry-once post you were waiting for lol)

 

i suppose youre right with the bps being expensive these days. My aversion is somewhat due to knowing most shops are out a few weeks at least here. I also have some idea that if I have a shop do anything, Ill end up with a bill larger than life for things that I hadnt needed.

This is probably just a vendetta against taking my car to any shop, which I have never done for any of my 5 miatas or cars in my life, something Im somewhat proud of - alignments, rebuilds, fab work, wrapping, painting, if I havent done it i learn and get the tools to do it forever. This is definitely not a possibility with the machining aspect l know, but I just need to know there are good shops out there who arent out to get you and get over my fear. Rant aside i am going to get a quote and check out their lead times. I have a few promising shops here.

one of which helped a friend put his valve keepers on for free on a walk in because he couldnt find a tool to do it. They seemed great.
Do I go right on ahead with a bore to 84mm? Hot tank deck and have the head refreshed? This seems like the way.

 

side note what injectors are people running for e85 and built motors?

Ive heard of disco potatos being good for high power and slightly worse spool, definitely old tech but they still hold up fine? Might have found a good deal on one if so.

 

~300 at the crank on ethanol at 45psi/3bar is gonna want around 680cc to stay at/below 90% duty. I've been running ID1050x's on my built K24 and they are fantastic. Great idle, lots of solid data available for flow rates and dead times, etc, they are a result of a collab with Bosch Motorsport. Highly recommend. They used to make some ID725s, but I think but the spray characteristics on the 1050s were so good that they dropped those and the 1050s are now the smallest ones in their lineup. They will also leave you some headroom if you ever wanna go ham and shoot for 400 someday.