Help! Blown Motor??

[Phre0nBurn]

Hey guys...
Ok, I have a 91 240 with a SR20DET Redtop swap in it...

Only upgrades are the bolt ons (Intercooler, pipes, intake, exh., DP, etc)

I was running this motor at 12 PSI when racing, 8 for the regular boring driving stuff...

Well, one night I was on my way out of town, so I went to the gas station a few miles away to fill up... On the way there, It felt weird, Kinda sluggish, just weird... But that was about it...
Well, Just as im about to pull off the exit, I started hearing a knock...
I get to the gas station and pop the hood... Check the oil, glance around, etc, have a friend start the car while im listening under the hood, and bam, there it is... the knock... I think, crap, Rod Knock, because thats EXACTLY what it sounds like...

So, I throw her on a trailer and bring her 400 miles back home... Now im here, and I start her up again, and I notice somehing.. the 'Rod Knock' im hearing sounds like its coming from the head...
I took off the valve cover to see if I saw anything wrong with the cams, or the timing chain or gears, or anything else in there, but as far as i can see and tell, i dont see anything that looks out of place...

Im just not sure what it could be... Any ideas would be really appreciated...
I have an option to get a new used swap for $1000, but if this could be cheaper, then that would rock... haha
Thanks guys...

[Silvia007]

How's the oil pan? Dented at all? If it's a loud knock and raises with rpm, probably a spun bearing. I did notice with a external wastegate, not sure if the wastegate have anything to do with it but, with exhaust leaking at the manifold where it connects to the head causes loud knocking noises also. Good luck!

[fliprayzin240sx]

Got rocker arm stoppers? Pop the Cams and check the valves and rocker arms.

[Wheaton]

sounds like bearing, happened with my ka (oil starvation)

[SRprelude]

i blew my sr 3 months ago, thought it was rod knock or valve train related form the sounds of it. Turned out the oil pump died and the bearing attached to it broke up. It didnt matter though, since the engine was full of metal shavings and the oil starvation damage..........had to rebuild it. Runs awesome now!!

[blu808]

There are oil squarters above the camshafts. What i want you to do is remove the oil cap, and start the motor, i want you to look down inside the oil cap hole and see if that intake cam that is within view is having oil dripped on it by the squarter.


Also i want you to look at the oil pan and tell me if there is any dents in it.

[Phre0nBurn]

OK!!!

UPDATE!!!

I got the car started.... put it all back together...
Now, Aside from the fact that it would hardly run, and the knock is LOUD AS HELL NOW...
I opened the oil cap to look inside @ the squirters, and i couldnt really tell...
But, I did notice...

It was like there was a leaf blower in there... There was TONS of air squeezing out of the oil cap hole....
Is that normal??
Like, It was BLOWING out...

Thats all I really know right now, and its dark out...

[blu808]

Thats blow by. Not looking good for you my friend.

[Phre0nBurn]

Isnt blowby when it goes down into the crankcase??
not up through the valve cover...?
Could I have like shattered a valve? Or cracked my head or something??
Ahh, Im lost... and this sucks...

[McRussellPants]

No dude, that motor is toast.


If its getting worse over time like that its a spun bearing, the blowby at idle means your rings aren't too hot either.

Rebuild it or get a new one. The longer you run it the more money you'll spend on a rebuild.

[Nizzan4u2nv]

There are some cases where you can hear slight rod knock and just replace the bearings. Youve already spun the bearing and the crank isnt right anymore. Sounds like your rings are toast also. Is your exhaust pouring smoke now?

[Phre0nBurn]

Daaaamn.. Hehe
This sucks...

No, I didnt see any thick smoke, but the motor only ran for about 20 seconds before it died...

What would cause that?? Think 14 Psi is too much boost on stock internals??

I spund a rod bearing on my old 300Z too, haha...

Hmm... Wonder how much it would cost to rebuild...
Id prolly be better off spending $1000 on a new shortblock...(new=used)