bearings again!

[holeset]

well the first of the friday night drags started off really good,the skyline was running consistent mid to high 11s on the quater at about 195km/hr running real strong with clutch slip and a bit of wheelspin at the top of 4th,then disaster!
OH YES the all familiar KNOCK KNOCK,the worst so far,definitley not surge now ,im thinking the tune to 14psi may not be all that safe under 4th gear load,well this is the third bottom end we have wrecked,this one was ground under size with more clearance and with a 14litre sump we thought it would last at least 3 months,anyhow we will carry on maybe run a nice 5-8psi seen as it did the same times on 8psi boost and go from there,ill pull the bottom end down this weekend and have a close look at some metal spray i got done as well - suspect cause? well still love the way these motors rev so will give it another shot on a fresh botton end.
i all else fails maybe go for some E85 fuel and tune?

[tmorgan4]

Front or rear sump?

[Nealoc187]

what's the car dyno at?

[holeset]

front sump with modified pickup and baffles,as for power not actually sure, dyno kept shutting down on full power runs but on the fuel mapping and tune to bout 5000rpm it saw about 350kw@wheels

[elwesso]

Im curious to wonder why you keep throwing bearings because havent other people boasted similar HP or more with no issues on the bottom end?

[holeset]

your guess is as good as mine,but it looks like oil starvation again,one of the bigends has failed completely,it has fallen right out,plus all the bigends have a lot of wear and the mains dont look much better,might start looking at feeding the bottom end directly from the oil pump,also ill check for any blockage or restriction in the oil cooler side of things,either way ill try and get another motor in a couple of weeks,im thinking also maybe these bottom ends dont react that well with more than 10psi, our little FJ20 runs 30 plus psi all day long on a non braced 2 bolt cap bottom end.

[elwesso]

DO you have an oil pressure gauge? If so, where do you check pressure at, at the stock pressure switch?? If nothing else it would be good data to have for others.

[Krazykouki]

post pictures of the bearings the way they came out...that would help diagnose the failure.

[b20vtechb]

man i hope i don't end up with these issues on my build. i spec'd out my bearing clearances a bit looser then the nissan spec on both my main and rod bearings.

it might be your getting detonation and beating up the rod bearings and that is causeing the failures. post some pictures of the spark plugs form the cylinders with the worst big end wear.

[Krazykouki]

man i hope i don't end up with these issues on my build. i spec'd out my bearing clearances a bit looser then the nissan spec on both my main and rod bearings.

it might be your getting detonation and beating up the rod bearings and that is causeing the failures. post some pictures of the spark plugs form the cylinders with the worst big end wear.

lol...the OEM specs are there for a reason. You already know the engine has oiling issues and then you hope you don't have issue's...do it right the first time and you won't have to worry about it.

[kingkilburn]

Obviously you (krazykouki) have no idea what you're talking about. Maybe you should read up on the specifics of the VH's oiling/bearing issues.

[b20vtechb]

man i hope i don't end up with these issues on my build. i spec'd out my bearing clearances a bit looser then the nissan spec on both my main and rod bearings.

it might be your getting detonation and beating up the rod bearings and that is causeing the failures. post some pictures of the spark plugs form the cylinders with the worst big end wear.

lol...the OEM specs are there for a reason. You already know the engine has oiling issues and then you hope you don't have issue's...do it right the first time and you won't have to worry about it.

the stock clearances are crazy tight, and even more so when the motor is going to be turbo, you obviously haven't built many engines with a power goal considerably higher then the stock output.

[Mettler]

IIRC, Oil cooler, fittings and lines should be no smaller than -12 at any point. Also, don't have long lines.

[holeset]

wel well i think i actually discovered the cause of bearing failure

Please dont laugh but you all might as well because we are.

The dam oil feed to the turbo is in the wrong place acting like a massive oil bypass!

I dont know what we were thinking when routed this line on but all i can put it down to is late nights and rushing to get it going.

The oil pressure gauge wouldnt haved warned us because this is also in a position to read excellent oil pressure before the turbo oil feed,funny thing is its taken 3 motors to realise this.

So in a month or so with a bit of overtime at work should have another botton end coming
fingers crossed we dont wreck this one ,the old engine crane is getting a right old hiding.
May also look into feeding the main bearings directly and a stock car dude told me to increase the size of all the oil cooler lines and back the oil pressure off?
Not sure on the oil pressure thing.

[klh6686]

Has anyone looked into oil restrictors similar to what is used in the rb engines which are known to have the same issue of sending too much oil up top?

Example: http://www.hytechengines.co.nz/product_ ... ucts_id=34

Also glad you found your problem and thank you for sharing with us, hope the next engine lasts a lot longer!

[Bart]

You got me thinking, so what is the correct way to oil the turbos? I actually got a remote oil filter, i cant remember off the top of my head but i think i have used a T on the return line from the filter to oil the turbos. So the return line goes to the turbos and to the engine block.

wel well i think i actually discovered the cause of bearing failure

Please dont laugh but you all might as well because we are.

The dam oil feed to the turbo is in the wrong place acting like a massive oil bypass!

I dont know what we were thinking when routed this line on but all i can put it down to is late nights and rushing to get it going.

The oil pressure gauge wouldnt haved warned us because this is also in a position to read excellent oil pressure before the turbo oil feed,funny thing is its taken 3 motors to realise this.

So in a month or so with a bit of overtime at work should have another botton end coming
fingers crossed we dont wreck this one ,the old engine crane is getting a right old hiding.
May also look into feeding the main bearings directly and a stock car dude told me to increase the size of all the oil cooler lines and back the oil pressure off?
Not sure on the oil pressure thing.

[lyon23]

Hey Holeset any updates on your swap. I didn't want to thread jack the other guys post.

[holeset]

just doing main bearings and big ends on a mint motor i picked up a couple of months ago and and about ready to stick motor back in,fingers crossed on bottom end, not going to run as much boost,stick to an easy 8psi this time and go give it a good hammering at the track.

[klh6686]

awesome news, I'm sure she'll take the abuse a lot better this time. Keep us updated!

[DRFTBLD]

So where did you tap the turbo feed lines from?

[holeset]

going to run an oil feed somewhere off the oil gallery near the head,once i found one ill post a pic

[silv8]

I have run my oil feed from the cap screw bung near the original oil filter plate. Is this going to be ok? Where did you run yours from to get the bypass. Mine is sweet now on e85 11psi of boost and 547.9bhp tuned fat for skids.

[holeset]

hard to see but this is where i did have the line screwed in(you can see where the braided hose runs,this is also a huge feed,about 9.5mm inside dia,i was told to run no smaller than 8mm for the Cat C15 turbo i was running,this is also a likely reason i was suffering damaged bearings from the pressure drop at the oil feed,i may run a restrictor this time as well.