ugh... rod knock? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

SR240DET · 12-14-2004, 04:27 PM

yeah.. i did that stupid duel exhaust cam thing.... yeah.. didnt match for shit.. anyways.. during the process the the sprocked fell outta place when i was about to mark it on the chain... so i matched everything up by taking the front timming cover and everything.... and it all lined up..( im putting everything back to stock..) now that i have everything back to stock... when it turns over.. it knocks....... its a fast pase knock... i know its hard to identify sounds on line... but how can i tell what this knock is? ( rod knock?)

also... how can i tell i have bent valves?

RBS14 · 12-14-2004, 04:40 PM

It's too late now, but always put a wrench on the crank pulley and turn it a full 720 degrees by hand before you try to start it. If you did it wrong you'll feel it stop or extra resistance or something when a valve touches the piston. You might try this now and see if anything hits.

SR240DET · 12-14-2004, 04:49 PM

damn i wish i woulda known that.. when i turned the crank pully by hand... it wasnt very smooth... i turn it.. and it would turn..... then it would get hard all of a sudden.. and i would have to force it fairly hard... then it would turn alot smoother... then get hard...

hmm... bent valves?

Sil Beer S13 · 12-14-2004, 05:15 PM

So you dont have an SR?

RBS14 · 12-14-2004, 05:21 PM

that could be valves hitting pistons and if it is, starting it definately bent them. That's not the only thing that could cause it to be hard to turn in certain spots, but it's definately one of them. It's been a while, but if I remember correctly, at TDC, the lobe on intake cam on cylinder #1 is just about to push down the valve, and exhaust lobe has just closed. The flattest part of the lobes will be almost flat on the shims. I'm not 100% sure on this, but I'm close. The cams are not 180 degrees opposite eachother or anything like that.

SR240DET · 12-14-2004, 06:07 PM

what kinda piston damage can i expect? thanks for the help btw

SR240DET · 12-14-2004, 06:11 PM

Quote:

Originally Posted by RBS14

that could be valves hitting pistons and if it is, starting it definately bent them. That's not the only thing that could cause it to be hard to turn in certain spots, but it's definately one of them. It's been a while, but if I remember correctly, at TDC, the lobe on intake cam on cylinder #1 is just about to push down the valve, and exhaust lobe has just closed. The flattest part of the lobes will be almost flat on the shims. I'm not 100% sure on this, but I'm close. The cams are not 180 degrees opposite eachother or anything like that.

what kinda piston damage can i expect? thanks for the help btw

RBS14 · 12-14-2004, 07:30 PM

IF you threw your valves into your pistons, the engine is toast. Bent valves and jacked up pistons. Dents, bent etc. IF that's the case, keep on the lookout for someone doing an SR swap.

12-14-2004, 04:40 PM	#2
RBS14 Nissanaholic! Join Date: Feb 2003 Location: Santa Cruz/San Diego Posts: 2,271 Trader Rating: (0) Feedback Score: 0 reviews	It's too late now, but always put a wrench on the crank pulley and turn it a full 720 degrees by hand before you try to start it. If you did it wrong you'll feel it stop or extra resistance or something when a valve touches the piston. You might try this now and see if anything hits. __________________

12-14-2004, 05:21 PM	#5
RBS14 Nissanaholic! Join Date: Feb 2003 Location: Santa Cruz/San Diego Posts: 2,271 Trader Rating: (0) Feedback Score: 0 reviews	that could be valves hitting pistons and if it is, starting it definately bent them. That's not the only thing that could cause it to be hard to turn in certain spots, but it's definately one of them. It's been a while, but if I remember correctly, at TDC, the lobe on intake cam on cylinder #1 is just about to push down the valve, and exhaust lobe has just closed. The flattest part of the lobes will be almost flat on the shims. I'm not 100% sure on this, but I'm close. The cams are not 180 degrees opposite eachother or anything like that. __________________

12-14-2004, 07:30 PM	#8
RBS14 Nissanaholic! Join Date: Feb 2003 Location: Santa Cruz/San Diego Posts: 2,271 Trader Rating: (0) Feedback Score: 0 reviews	IF you threw your valves into your pistons, the engine is toast. Bent valves and jacked up pistons. Dents, bent etc. IF that's the case, keep on the lookout for someone doing an SR swap. __________________

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12-14-2004, 04:27 PM	#1
SR240DET Zilvia FREAK! Join Date: Mar 2002 Location: orida Posts: 1,490 Trader Rating: (0) Feedback Score: 0 reviews	ugh... rod knock? yeah.. i did that stupid duel exhaust cam thing.... yeah.. didnt match for shit.. anyways.. during the process the the sprocked fell outta place when i was about to mark it on the chain... so i matched everything up by taking the front timming cover and everything.... and it all lined up..( im putting everything back to stock..) now that i have everything back to stock... when it turns over.. it knocks....... its a fast pase knock... i know its hard to identify sounds on line... but how can i tell what this knock is? ( rod knock?) also... how can i tell i have bent valves?

12-14-2004, 04:49 PM	#3
SR240DET Zilvia FREAK! Join Date: Mar 2002 Location: orida Posts: 1,490 Trader Rating: (0) Feedback Score: 0 reviews	damn i wish i woulda known that.. when i turned the crank pully by hand... it wasnt very smooth... i turn it.. and it would turn..... then it would get hard all of a sudden.. and i would have to force it fairly hard... then it would turn alot smoother... then get hard... hmm... bent valves?

12-14-2004, 05:15 PM	#4
Sil Beer S13 Zilvia FREAK! Join Date: Jul 2003 Location: Chino!...NOT CHINO HILLS! Age: 43 Posts: 1,117 Trader Rating: (0) Feedback Score: 0 reviews	So you dont have an SR?

12-14-2004, 06:07 PM	#6
SR240DET Zilvia FREAK! Join Date: Mar 2002 Location: orida Posts: 1,490 Trader Rating: (0) Feedback Score: 0 reviews	what kinda piston damage can i expect? thanks for the help btw