I'm getting seriously frustrated. Sr20 wont fire - Page 2 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

landins13 · 02-26-2008, 07:59 PM

so for those of you who have been helping me out, i know i said i wouldnt have an update for a while, but i figured out whats wrong, i snapped a camshaft in half. i have no idea how, but the engine had no compression because nothing in the head was turning, the intake cam snapped clean right where it attaches to the cam gear. im in the process of taking off the head to check and see if i have any bent valves i probly will, and at this point im thinking about buying a new head so if you see one let me know (dick tracy) i really appreciate it.

Landin

slider2828 · 02-26-2008, 09:14 PM

Did you follow torque procedures in the FSM? Only real way to snap the came, but if you cranked it with the valve open, you can be assured of a bent valve. Better safe to rebuild the head seriously or break it apart and chek all of the valves.

Big Bronze Rim · 02-26-2008, 09:33 PM

Yup, I would say 99.999% of the time a broken cam is due to install error. Sucks to hear. You probably need to pull the head to check for bent valves.

GuardianLlama · 02-26-2008, 09:38 PM

Quote:

Originally Posted by Big Bronze Rim

You probably need to pull the head to check for bent valves.

Sr's are interference motors?

I didn't think that they were.

but I'm still a

jskateborders · 02-26-2008, 09:51 PM

Quote:

Originally Posted by johngriff

Sounds like it has no compression? You would know.

Fuel + Spark + Compression + Air + Timing = Run. Its got to be one of those 5.

.fixed it. . . . . .

landins13 · 02-26-2008, 11:30 PM

heads off, now bent valves, how the hell this happend i have no idea im still trying to work things out.

slider2828 · 02-27-2008, 01:36 AM

You probably didn't torque the cames center outwards like FSM. THe cam snapped, and the valves stayed down or open. You cranked the car and the piston's slapped into the valves hence bent valves. Since you know you have bent valves, you might as well rip the entire engine out as you probably will have nicked the pistons a little or just really clean on the bottom end...

Big Bronze Rim · 02-27-2008, 07:47 AM

Quote:

Originally Posted by GuardianLlama

Sr's are interference motors?

I didn't think that they were.

but I'm still a

It is. And the OP unfortunately has bent valves to prove it. Time to build the head and upgrade cams! You MUST follow the proper torque sequence or broken cams WILL be the result.

landins13 · 02-28-2008, 01:40 PM

i did follow the proper torgue sequence and had them torqued down properly, i was bolting down the trans when my buddy reassembled the head, and he flopped the cams, he had the intake cam on the exhaust side and vise versa. the head is toast, im buying a whole new one.

Gjohnson7 · 02-28-2008, 10:20 PM

So, I assume you and your buddy are going half on a new head???

Well, lesson learned. Next time you make sure you handle the most important part and tripple check your work.

02-26-2008, 09:14 PM	#32
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	Did you follow torque procedures in the FSM? Only real way to snap the came, but if you cranked it with the valve open, you can be assured of a bent valve. Better safe to rebuild the head seriously or break it apart and chek all of the valves. __________________ Turn and Burn!

02-27-2008, 01:36 AM	#37
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	You probably didn't torque the cames center outwards like FSM. THe cam snapped, and the valves stayed down or open. You cranked the car and the piston's slapped into the valves hence bent valves. Since you know you have bent valves, you might as well rip the entire engine out as you probably will have nicked the pistons a little or just really clean on the bottom end... __________________ Turn and Burn!

02-28-2008, 10:20 PM	#40
Gjohnson7 Zilvia Addict Join Date: Mar 2004 Location: Broken Arrow, OK Age: 44 Posts: 980 Trader Rating: (7) Feedback Score: 7 reviews	So, I assume you and your buddy are going half on a new head??? Well, lesson learned. Next time you make sure you handle the most important part and tripple check your work. __________________ LSX Kouki Project, swap completed in Dec 09

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02-26-2008, 07:59 PM	#31
landins13 Zilvia Addict Join Date: Jan 2008 Location: Baltimore Posts: 986 Trader Rating: (3) Feedback Score: 3 reviews	so for those of you who have been helping me out, i know i said i wouldnt have an update for a while, but i figured out whats wrong, i snapped a camshaft in half. i have no idea how, but the engine had no compression because nothing in the head was turning, the intake cam snapped clean right where it attaches to the cam gear. im in the process of taking off the head to check and see if i have any bent valves i probly will, and at this point im thinking about buying a new head so if you see one let me know (dick tracy) i really appreciate it. Landin

02-26-2008, 09:33 PM	#33
Big Bronze Rim Zilvia Member Join Date: Jan 2006 Location: San Antonio, Texas Age: 46 Posts: 173 Trader Rating: (0) Feedback Score: 0 reviews	Yup, I would say 99.999% of the time a broken cam is due to install error. Sucks to hear. You probably need to pull the head to check for bent valves.

02-26-2008, 11:30 PM	#36
landins13 Zilvia Addict Join Date: Jan 2008 Location: Baltimore Posts: 986 Trader Rating: (3) Feedback Score: 3 reviews	heads off, now bent valves, how the hell this happend i have no idea im still trying to work things out.

02-28-2008, 01:40 PM	#39
landins13 Zilvia Addict Join Date: Jan 2008 Location: Baltimore Posts: 986 Trader Rating: (3) Feedback Score: 3 reviews	i did follow the proper torgue sequence and had them torqued down properly, i was bolting down the trans when my buddy reassembled the head, and he flopped the cams, he had the intake cam on the exhaust side and vise versa. the head is toast, im buying a whole new one.