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Didn't know where to put this exactly.
On the way home, made a flat shift going on the highway, bang bang poff and suddenly some wierd knock started. Ran for 25 minutes until I came home, isolated the gearbox in lower speeds during driving and under the hood it sounds like this.
2000 nb1 1,8 turbo 2560, running 7-13psi tapered
https://youtu.be/YqtMSaRysxQ
Any guesses?
My only guess is I'm going to need to find a new engine.
Sad to see as the engine only has 57k miles.
Saw no difference in turbo spool or afrs, no less oil pressure (I have a real one)
I suppose the noise and damage will just escalate further.
How long did yours last?
Need to check the exhaust gasket tomorrow because it looks like it blew on cylinder 2. TBH this was a flat shift with spark cut, guess this is karma because it just passed "MOT" with turbo and everything still mounted.
Thanks curly for the quick response!
Will tear it out tomorrow, will get back.
Compression test done atleast.
#1 140psi
#2 160
#3 180
#4 140
Wth, tested when bought. Had 185-190 on all except #4 with 175-180psi
Just my boosting that done its job? Why so uneven?
The mystery continues....
Since I ran it at 4k rpm in atleast 25-30min and then drove it to my job for another 20min back and forth, call it 3,5k rom times 50min equals 175k revolutions of a (maybe) broken bearing. Why is it not getting worse? Not louder, no loss in oil pressure. 10w-40 when hot at idle (1000~rpm) is at 26psi.
Oh how fun, I'm truly stoked about what I'm about to find.
/
Nuff said?
Directly converted from compression test
#1#4 most bendy boy, #2 less and #3 looks fair.
Yes, my pistonis have had a convo with the counterweights
Yes, the bottom of the rods have met the bottom of the cylinder bores.
Wwjd? No clue but will put in some fordged rods and send it. Splash out on new bearings and hg. Maybe even timing belt, maybe. Figure 180psi compression is quite fair, new rings won't turn my cylinders any more round anyway.
I'd at least hone and re-ring that thing. I'm all for the budget bottom end build otherwise. My rods-only rebuild is going strong, DDing and track days included.
I went rods only as well and IMO fresh rings and a DIY hone are necessary. Patsmx5 did a couple rods only engines and had serious oil burning on the one he didn't do fresh rings and a hone on.
It's just the automatic compression ratio adjustment kicking in. Mazda was way ahead of their time.
But yeah, everything I have read says you want new rings and a dingle berry hone at minimum if you take the pistons out. Gonna be starting this adventure myself soon.
On both of my BP-4W (NB1) engines I replaced the piston rings because of high oil consumption.
From your pictures it looks like the oil control rings have lost their tension.
Do yourself a favor and replace the rings
Oh lawrd have meercy!!!
Well, waiting for reply from bofi racing if they get them chinesium rods back in stock anytime soon. Else I'm going with fab9 manlys and wiseco rings.
ACL bearings or King's? Read a nice comparison that said King's bearings were on the spot in tolerances and the ACL were not. Well how would I even know, with my feeler gauge and vernier caliper?
My friends ask why I'm not sad the engine is broken and down for parts. I said, I was going to do this anyway but now my car made me.
You could also consider standard con rod bearings from King or ACL. It is best to check them with plastigauge. Last time I used the cheap standard King bearings and they all fell nicely in the middle of the spec.
Your main bearings might still be in good shape, use plastigauge to check them.
For piston rings, I think you can find TP, NPR or Hastings, all off them should be fine.
Last time I used the eBay store Asvela from Lithuania, which should be able to deliver quickly to Sweden too.
What tune did you have on the car? Were you datalogging at the time? I'm just curious what your timing and afrs looked like when the event happened. 7psi tapering to 13 I wouldn't think would be enough to bend the rods. I'm running 12 on my 97 right now. Makes me alittle nervous no that maybe my engine won't last much longer. Got 146k on the odometer now.
What tune did you have on the car? Were you datalogging at the time? I'm just curious what your timing and afrs looked like when the event happened. 7psi tapering to 13 I wouldn't think would be enough to bend the rods. I'm running 12 on my 97 right now. Makes me alittle nervous no that maybe my engine won't last much longer. Got 146k on the odometer now.
Well tbh no need to worry. It's my sloppy tuning of the ebc that caused this. Been pounding on these rods for a while.
When I tuned the ebc I got a slow reaction during full throttle + shifting + full throttle. I just cured the boost cut with higher tolerances and set it to 235kpa. Yes it's bad hitting 19psi while aiming for 13-14.
Well tbh no need to worry. It's my sloppy tuning of the ebc that caused this. Been pounding on these rods for a while.
When I tuned the ebc I got a slow reaction during full throttle + shifting + full throttle. I just cured the boost cut with higher tolerances and set it to 235kpa. Yes it's bad hitting 19psi while aiming for 13-14.
With great boost comes great bendy boys.
Okay I hear you. I am worried about that myself. I am trying to tune EBC right now and I have my target set at 170kpa and I keep hitting overboost at 195kpa for some reason. I eventually want to build a forged engine as well, so I will be following your build. Keep us posted with pictures and how everything is going!
Loom at my thread here^^
I had an IDENTICAL sound after flat shifting my nb2. I saw your video and I laughed out loud because the exact same thing happened to me a few months ago. Turns out I had a bent rod contacting the bore. Running really well now on stock pistons and some china rods.
Loom at my thread here^^
I had an IDENTICAL sound after flat shifting my nb2. I saw your video and I laughed out loud because the exact same thing happened to me a few months ago. Turns out I had a bent rod contacting the bore, I am confident that is your issue. Running really well now on stock pistons and some china rods.
Yep, look at #6
Same same, here here.
Made an order from fab9 but seems like they cut staff and the rods are sold out almost everywhere.
Used a honing tool (3 arm) and de-glazed the bores. Had some few minor scratches in some cylinders, nothing major.
My boss is a old tractor mechanic and he looked at my first attempt to hone and just scuffed silently.
Ran for 30~seconds a bit slower then recommended and got a OK crosshatch with matte finish. Also got OEM pistons without damage but same compression, the ones in mine got slightly messed up in the castings on the underside because of shorter rod = smackdaddy on the counterweights.
Also got simple cast piston rings, no fancy chrome moly rings because of text above.
Thanks for the update, this is for some common knowledge. Came across a few threads where this was the first guess, having the same symptoms.
05-03-2020, 04:57 PM
Where do we post failures? Engine knock!
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