Crank won't turn when installinf rockers. HELP!

TCL · 07-28-2019, 06:06 PM

I need help with my cam install. After I install my rockers and go to turn the crank, it will turn a little then stuck. I removed the rockers leaving the rods in and it turns freely. So install 3 of the rockers only to test it, when I turn it turns but when it gets where it presses the spring the crank gets hard but it turns. Once it the springs come up then it turns freely again. I have no idea what could it be, please help, thanks.

Juiced1 · 07-28-2019, 06:51 PM

Is it just building compression and getting difficult? Try taking the plugs out.

SpazmXylam · 07-28-2019, 06:55 PM

either we assume timing is correct and you are turning against compression.

-or-
the pistons are contacting the valves unable to make it to top dead center by the open valve.
first option is normal and good. second is a bummer and expensive if forced. If it still binds up completely assembled with spark plugs removed then you will want to recheck timing or pushrod locations (if they are different lengths for intake/exhaust).

s346k · 07-28-2019, 09:12 PM

pushrods too long?

Chevyfan4life · 07-28-2019, 10:36 PM

Quote:

Originally Posted by Juiced1

Is it just building compression and getting difficult? Try taking the plugs out.

X2

s346k · 07-29-2019, 04:32 AM

Quote:

Originally Posted by s346k

pushrods too long?

eh nvm i just read the entire post. the phenomena you’re experiencing is the compression stroke.

TCL · 07-30-2019, 11:42 AM

Quote:

Originally Posted by Juiced1

Is it just building compression and getting difficult? Try taking the plugs out.

Yes I did, thats the first thing I did. Didn't work.

JCunningham · 07-30-2019, 10:10 PM

what cam specs? did you use a torque wrench and torque the rockers to 22ftlbs when each cylinder was at top dead center? The cam has to be on the base of the cam lobe befor you can torque the rocker down. what push rod length?

L78toLT1 · 07-31-2019, 08:17 PM

Your valves are hitting the pistons, no doubt about it. Did you mill the heads or deck the block?

wwiiavfan · 07-31-2019, 08:23 PM

I would suggest you stop and take it to a reputable builder. From your descriptions it sounds like your valves and pistons are trying to occupy the same space, not good.
There’s a good chance you’ve already bent some valves, so I foresee an expensive lesson learned, but I hope for your sake I’m wrong!

Good luck!

wwiiavfan · 07-31-2019, 08:26 PM

Quote:

Originally Posted by L78toLT1

Your valves are hitting the pistons, no doubt about it. Did you mill the heads or deck the block?

Not an expert but I’m guessing you can still have piston valve contact on un-milled heads & block if the cam timing is out of whack.

ssmofo · 07-31-2019, 09:41 PM

What JC Cunningham said,

HDRDTD · 07-31-2019, 10:18 PM

One 'possibility' is that the new rocker arms are a different ratio, increasing the distance the valves travel enough to contact the pistons?

s346k · 08-01-2019, 12:43 AM

Quote:

Originally Posted by TCL

the crank gets hard but it turns.

explain this. is the motor turning over completely?

07-28-2019, 06:06 PM	#1
TCL Drives: 2017 Camaro SS/ Nightfall gray Join Date: Sep 2016 Location: Saint Augustine,Florida Posts: 33	Crank won't turn when installinf rockers. HELP! I need help with my cam install. After I install my rockers and go to turn the crank, it will turn a little then stuck. I removed the rockers leaving the rods in and it turns freely. So install 3 of the rockers only to test it, when I turn it turns but when it gets where it presses the spring the crank gets hard but it turns. Once it the springs come up then it turns freely again. I have no idea what could it be, please help, thanks.

07-30-2019, 10:10 PM	#8
JCunningham Drives: 2017 2SS M6 Join Date: Jun 2013 Location: WNY Posts: 7,070	what cam specs? did you use a torque wrench and torque the rockers to 22ftlbs when each cylinder was at top dead center? The cam has to be on the base of the cam lobe befor you can torque the rocker down. what push rod length? __________________ real ZL1 wheels and brakes, 285/305 Michelin Pilot Super Sports, Pray ported Intake manifold, Soler Throttle Body, Rotofab intake, EFI Tuning Flex fuel kit, full American Racing Headers Exhaust, 1 7/8" w/ cats H pipe and mufflers. Full 1LE suspension, with BMR adjustable sway bars and links, GM aluminum cradle bushings, Hurst shifter with lighter reverse spring, TWM shifter knob, Tick level 1 transmission. I should have bought a ZL1

07-31-2019, 08:17 PM	#9
L78toLT1 Drives: Hyper Blue 2016 2SS 6M Join Date: Sep 2017 Location: North Ga Posts: 1,787	Your valves are hitting the pistons, no doubt about it. Did you mill the heads or deck the block? __________________ Baby Blue 2016 Hyper Blue 2SS/6m/MRC/NPP/Silver Rally stripes/ZL1 wheels & brakes/GForce DS and axles/ZLE Cradle Bushings/FE4 ARB front & rear/SEMA Grill/Rotofab dry/95mm TB/Magnuson 2300/Full LT4 fuel system/JMS boost-a-pump/E85 Sensor/Ported CID heads from LME/Cammotion PD cam/Thompson Motorsports forged shortblock/catted Kooks 1 7/8 headers /JRE remote tuned

07-28-2019, 06:51 PM	#2
Juiced1 Account Suspended Drives: 2012 2SS CAMARO 45th Join Date: Apr 2011 Location: St. Charles, IL Posts: 18,663	Is it just building compression and getting difficult? Try taking the plugs out.

07-28-2019, 06:55 PM	#3
SpazmXylam Because Racecar! Drives: 17 SS 1LE Join Date: May 2018 Location: St.Paul Posts: 56 View My Garage	either we assume timing is correct and you are turning against compression. -or- the pistons are contacting the valves unable to make it to top dead center by the open valve. first option is normal and good. second is a bummer and expensive if forced. If it still binds up completely assembled with spark plugs removed then you will want to recheck timing or pushrod locations (if they are different lengths for intake/exhaust).

07-28-2019, 09:12 PM	#4
s346k Drives: like an old lady Join Date: Jun 2012 Location: indiana Posts: 2,395	pushrods too long?

07-31-2019, 08:23 PM	#10
wwiiavfan Drives: 2017 1SS Hyper Blue Join Date: Apr 2017 Location: Wisconsin Posts: 478	I would suggest you stop and take it to a reputable builder. From your descriptions it sounds like your valves and pistons are trying to occupy the same space, not good. There’s a good chance you’ve already bent some valves, so I foresee an expensive lesson learned, but I hope for your sake I’m wrong! Good luck!

07-31-2019, 09:41 PM	#12
ssmofo Drives: Chevy Camaro Join Date: Jul 2019 Location: Dallas Posts: 420	What JC Cunningham said,

07-31-2019, 10:18 PM	#13
HDRDTD Drives: 2013 Triple Black ZL1 Vert M6 ECF Join Date: Mar 2011 Location: Trenton, Michigan Posts: 7,047	One 'possibility' is that the new rocker arms are a different ratio, increasing the distance the valves travel enough to contact the pistons?

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