Rb25Det Neo Cold Start Knock. Piston Slap?

[NeoMaggots]

Here is a video of the knock from underneath the oil pan. https://www.facebook.com/photo.php?v=10202158035533359&l=7946916124426248770 I shut the car down once the knock was over. After those first few it stops. Going to start tearing into it tomorrow. plans are to go over the timing belt/ tensioners. cut open oil filter see how that looks, and drop the oil pan have a look in there.

[Guilt-Toy]

its a conrod bearing.

[NeoMaggots]

=x Full tear down is necessary you would assume from that mild knock? It only does it on full cold starts. Im going to drop the pan and check the crank for out of round, but only being able to get 2 points checked isnt proper ><

[scotty nm35]

What oil filter are you using? If the anti drainback valve is leaking overnight it can take a few seconds to pump the oil up. Mine was doing a similar thing with a certain brand filter. I changed to K+N and never looked back.

Is it fine at all other times and just does this at startup? No other noises?

[NeoMaggots]

^ This. I am praying this is the problem. Hp-2008 is the K&N filter for the rb25's? Nobody had one in stock still looking.

[Ben C34]

=x Full tear down is necessary you would assume from that mild knock? It only does it on full cold starts. Im going to drop the pan and check the crank for out of round, but only being able to get 2 points checked isnt proper ><

That seems pointless.

[NeoMaggots]

^ yeah I don't know what I was saying well the motor is out of the car now, should be on a stand tomorrow. It was not the oil filter drain back valve, i tested it did not leak a drop Guilt-Toy seems to be correct. I'll know in a day or two. Pictures to come. And picking up a s2 long block tomorrow. Any chances I will be able to get it to work with my NEO ECU/Harness?

[scotty nm35]

You pulled the engine already? I would have cut open the oil filter and dropped the sump to see if there was bearing particles first.

Keep us posted, I think the cas is different between the two engines, and a few other small differences.

[Ben C34]

Yep, cas wiring needs changing and different plug on vct solenoid.

[NeoMaggots]

Yeah the motor was in a 240sx super easy to pull. I was in need of a new timing belt and water pump a few seals and pulleys. No signs of bearing in the oil filter, my last oil sample came back pretty regular but there's no telling until I tear it down. Any tips for When I pull the head to keep any stray coolant from getting down the cyl. Don't want a bunch of glycol getting down there if everything ends up looking healthy and it was just a bad tensioner pulley or oil pump

[StevenCJR31]

Glycol wont hurt the cylinders at all

Water can tho

[Ben C34]

Remove the coolant plug on the block

[NeoMaggots]

Piston slap, #6 has bad signs of Detonation. Now to figure out why only that cyl. is bad. Must have screwed up my wiring or bad injector.

[GTSBoy]

What plenum are you running?

[NeoMaggots]

stock. stock boost, stock injectors, ecu etc. 3" straight pipe exhaust no cat. and a rather large front mount intercooler. all swapped into a Nissan 240sx

[GTSBoy]

I asked because #6 can be leaned out by a bad plenum. Even without that possibility, #6 often suffers before the other cylinders because it runs hottest. I suppose you could/should go looking for things like bad injectors/plugs and possibly even oil squirters for other reasons why it might have pinged itself to death.

[NeoMaggots]

I'm assuming I should go ahead and port out this oil drain? if I do this and put in the restrictors should I still pop out that rear welch plug and install a drain right to the sump. (drift car) I would like to not need to install a drain.

[GTSBoy]

External vents are almost essential. If you don't provide them then ALL the air flow from the bottom of the engine up to the top has to pass up through the drains, against the flow of oil. The extra up velocity makes it hard to get the oil to go down. Add in some extra flow area, velocity goes down, drainage works better.

Edited October 6, 2013 by GTSBoy

[Ben C34]

Notice GTSBoy called it a vent not a drain? Cos it is a vent!

[NeoMaggots]

okay got it thanks.