My first DOHC SR20DET Cylinder Head Build (Shimming Issue) - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

zero2toy · 04-30-2012, 03:07 PM

Hello All,

I am new to the SR20/Nissan world and this is my first endeavor into 4 cylinder/turbo charged motors. I am currently building the cylinder head. Here's my story, what I've done, and my questions. I will try to give as much detail as possible, please don't respond with, take it to mazworx or a machine shop, I'm trying to do this myself, learn a little, and advance my own mechanical skill set with my new toy.

Story:
I bought a forged bottom end with slightly built head (BC 264 with valves, springs, and retainers) that had a spit rocker. I found that a valve bent and the valve guide was cracked and exhaust cam lobe was chipped. I went ahead and bought another cylinder head, had it decked. I swapped out all the upgraded parts from the first cylinder head and installed a new BC ex cam and valve, I was following a thread I found on Tomie solid cam to do the install. I lapped the valves to be sure I had a nice seal as I want to boost.... alot(20psi)

What I've Done:
I bought a Overhead Cam Feeler gauge and was trying to check my clearances between the base circle of cam and the rocker arm, based on a thread I found for building a 9000 rpm tomie solid lifter head. I cannot get even the smallest feeler gauge in between the base circle and rocker arm of any intake or exhaust rocker arm. I now have a FSM and it states to use a special tool to insert in the Hydraulic Lifter housing that mounts to a dial indicator to measure the height of one valve with guide on top of it, and then measure other valve with no shim to find the correct height of the shim for other valve, therefore leveling the rocker arm.

Question 1:
Since I lightly/moderately lapped my valves, is that possibly why I cannot get my feeler gauge between base circle of cam lobe and rocker arm? I am sure I have installed the same guides and shims that went with valves from the original cylinder head, if that even matters.

Question 2:
Will this FSM/dial indicator procedure be the way to go for me? It seems that the procedure would only really work if I had stock valves and had not lapped them, changing their installed height by IDK some thousands of an inch..... Since I cannot currently get a feeler gauge in there, wouldn't leveling out the shim to the guide be pointless..... since im already touching rocker to base circle. FYI when I roll the motor over it seems to make compression on all 4 cylinders so it doesn't seem like i have any valve sticking open but I could be wrong.....

Question 3:
Do I have to buy the Tomie valve guide and shim kit to get a small enough guide that will allow enough room to get the feeler gauge between the cam and rocker and allow me to get a measurement?

Question 4: I've seen it mentioned several times that FSM states there should be .14-.17mm of clearance between the rocker arm and cam lobe base circle. I have yet to see this in the FSM... but that's the measure I have been going with. Can anyone confirm this? It would seem logical that you wouldn't want any space there or your rocker arms would chatter all crazy. Is this measurement just there so that the hydraulic lifter can adjust and take up the slack? I've read in other threads that even honda motors have clearances between rocker arm and cam but it just doesn't seem logical to me, but what do I know.

Just FYIs, I bleed and soaked the lifters. I kept all the guides and shims with their original valves from the original head.

I'm just wondering if I should go ahead and level the guide and shims and let it eat, or do I buy the Tomie solid lifter guide/shim kit to get a proper measurement and then order all new shims and guides from them to level everything and have the correct clearance from rocker arm to base circle?

Thanks in advance to all readers and helpful contributors.

t

green_pea · 05-01-2012, 07:31 PM

my question to you is are you using HLA's or solid lifters???

zero2toy · 05-02-2012, 05:57 AM

Quote:

Originally Posted by green_pea

my question to you is are you using HLA's or solid lifters???

I am using the stock HLAs

c-los13 · 05-02-2012, 06:53 AM

Well explained! Thumbs up!

zero2toy · 05-02-2012, 08:38 AM

[QUOTE=c-los13;4667596]Well explained! Thumbs up![/QUOTE

Thank you. I'm guessing everyone else just takes it to a pro and has this done for them. I will probably just measure the clearances on the other head i have on my backup motor. If they measure correctly ill just pull the head off that motor and try again to swap parts and measure clearances, without lapping valves.

green_pea · 05-02-2012, 05:22 PM

ok so if you are using HLA, you shouldnt have to use feeler gauges as the miniscule amount of high gained up top after the lapping was done will not matter because the HLA will take up the slack. If you can get your hands on an old HLA and disassemble it, you can make a tool to measure the shim height like the FSM states. hope this helps you

heres one i made earlier

zero2toy · 05-03-2012, 07:25 AM

Thanks a bunch. I am going to make this tool and hope the HLAs can do the job of adjusting to my valve heights. Found a write up explaining the same thing you did. http://www.socal-drift.com/forum/sho...Valve-Shimming

Thanks again.

zero2toy · 05-03-2012, 07:35 AM

I am still not 100% confident this will work, as I have read the HLAs do not bleed themselves. If my current valve height is too high and my valves are staying open, it would seem the HLAs would not bleed down to allow full closing of valves. But on the other side of that coin, they wouldn't be Hydraulic Lifters if they didn't adjust/bleed somewhat.... But I am going to level these rockers and see what happens. If it fails then I buy the Tomie shim and guide kit and get er done that way, the expensive way. (less something catastrophic happens, fingers crossed)

green_pea · 05-03-2012, 05:54 PM

Quote:

Originally Posted by zero2toy

I am still not 100% confident this will work, as I have read the HLAs do not bleed themselves. If my current valve height is too high and my valves are staying open, it would seem the HLAs would not bleed down to allow full closing of valves. But on the other side of that coin, they wouldn't be Hydraulic Lifters if they didn't adjust/bleed somewhat.... But I am going to level these rockers and see what happens. If it fails then I buy the Tomie shim and guide kit and get er done that way, the expensive way. (less something catastrophic happens, fingers crossed)

thats right, the HLA's are not self bleeding. I hear what your saying but you have to remember that the valve spring would have greater pressure than the HLA at holding the valve closed.

zero2toy · 05-05-2012, 06:23 PM

Thanks that gives me more confidence. Ima go get the parts to make the measurement tooland get this measured out tomorrow.

04-30-2012, 03:07 PM	#1
zero2toy Join Date: Jun 2011 Location: Tampa Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	My first DOHC SR20DET Cylinder Head Build (Shimming Issue) Hello All, I am new to the SR20/Nissan world and this is my first endeavor into 4 cylinder/turbo charged motors. I am currently building the cylinder head. Here's my story, what I've done, and my questions. I will try to give as much detail as possible, please don't respond with, take it to mazworx or a machine shop, I'm trying to do this myself, learn a little, and advance my own mechanical skill set with my new toy. Story: I bought a forged bottom end with slightly built head (BC 264 with valves, springs, and retainers) that had a spit rocker. I found that a valve bent and the valve guide was cracked and exhaust cam lobe was chipped. I went ahead and bought another cylinder head, had it decked. I swapped out all the upgraded parts from the first cylinder head and installed a new BC ex cam and valve, I was following a thread I found on Tomie solid cam to do the install. I lapped the valves to be sure I had a nice seal as I want to boost.... alot(20psi) What I've Done: I bought a Overhead Cam Feeler gauge and was trying to check my clearances between the base circle of cam and the rocker arm, based on a thread I found for building a 9000 rpm tomie solid lifter head. I cannot get even the smallest feeler gauge in between the base circle and rocker arm of any intake or exhaust rocker arm. I now have a FSM and it states to use a special tool to insert in the Hydraulic Lifter housing that mounts to a dial indicator to measure the height of one valve with guide on top of it, and then measure other valve with no shim to find the correct height of the shim for other valve, therefore leveling the rocker arm. Question 1: Since I lightly/moderately lapped my valves, is that possibly why I cannot get my feeler gauge between base circle of cam lobe and rocker arm? I am sure I have installed the same guides and shims that went with valves from the original cylinder head, if that even matters. Question 2: Will this FSM/dial indicator procedure be the way to go for me? It seems that the procedure would only really work if I had stock valves and had not lapped them, changing their installed height by IDK some thousands of an inch..... Since I cannot currently get a feeler gauge in there, wouldn't leveling out the shim to the guide be pointless..... since im already touching rocker to base circle. FYI when I roll the motor over it seems to make compression on all 4 cylinders so it doesn't seem like i have any valve sticking open but I could be wrong..... Question 3: Do I have to buy the Tomie valve guide and shim kit to get a small enough guide that will allow enough room to get the feeler gauge between the cam and rocker and allow me to get a measurement? Question 4: I've seen it mentioned several times that FSM states there should be .14-.17mm of clearance between the rocker arm and cam lobe base circle. I have yet to see this in the FSM... but that's the measure I have been going with. Can anyone confirm this? It would seem logical that you wouldn't want any space there or your rocker arms would chatter all crazy. Is this measurement just there so that the hydraulic lifter can adjust and take up the slack? I've read in other threads that even honda motors have clearances between rocker arm and cam but it just doesn't seem logical to me, but what do I know. Just FYIs, I bleed and soaked the lifters. I kept all the guides and shims with their original valves from the original head. I'm just wondering if I should go ahead and level the guide and shims and let it eat, or do I buy the Tomie solid lifter guide/shim kit to get a proper measurement and then order all new shims and guides from them to level everything and have the correct clearance from rocker arm to base circle? Thanks in advance to all readers and helpful contributors. t Last edited by zero2toy; 04-30-2012 at 03:47 PM..

05-01-2012, 07:31 PM	#2
green_pea Join Date: May 2012 Location: Sydney, Australia Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	my question to you is are you using HLA's or solid lifters??? __________________ nationaldriftographic.blogspot.com/

05-02-2012, 05:22 PM	#6
green_pea Join Date: May 2012 Location: Sydney, Australia Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	ok so if you are using HLA, you shouldnt have to use feeler gauges as the miniscule amount of high gained up top after the lapping was done will not matter because the HLA will take up the slack. If you can get your hands on an old HLA and disassemble it, you can make a tool to measure the shim height like the FSM states. hope this helps you heres one i made earlier __________________ nationaldriftographic.blogspot.com/

05-02-2012, 06:53 AM	#4
c-los13 Zilvia Junkie Join Date: Feb 2010 Location: Edinburg, Texas Age: 35 Posts: 446 Trader Rating: (0) Feedback Score: 0 reviews	Well explained! Thumbs up!

05-02-2012, 08:38 AM	#5
zero2toy Join Date: Jun 2011 Location: Tampa Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	[QUOTE=c-los13;4667596]Well explained! Thumbs up![/QUOTE Thank you. I'm guessing everyone else just takes it to a pro and has this done for them. I will probably just measure the clearances on the other head i have on my backup motor. If they measure correctly ill just pull the head off that motor and try again to swap parts and measure clearances, without lapping valves.

05-03-2012, 07:25 AM	#7
zero2toy Join Date: Jun 2011 Location: Tampa Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	Thanks a bunch. I am going to make this tool and hope the HLAs can do the job of adjusting to my valve heights. Found a write up explaining the same thing you did. http://www.socal-drift.com/forum/sho...Valve-Shimming Thanks again.

05-03-2012, 07:35 AM	#8
zero2toy Join Date: Jun 2011 Location: Tampa Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	I am still not 100% confident this will work, as I have read the HLAs do not bleed themselves. If my current valve height is too high and my valves are staying open, it would seem the HLAs would not bleed down to allow full closing of valves. But on the other side of that coin, they wouldn't be Hydraulic Lifters if they didn't adjust/bleed somewhat.... But I am going to level these rockers and see what happens. If it fails then I buy the Tomie shim and guide kit and get er done that way, the expensive way. (less something catastrophic happens, fingers crossed)

05-05-2012, 06:23 PM	#10
zero2toy Join Date: Jun 2011 Location: Tampa Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	Thanks that gives me more confidence. Ima go get the parts to make the measurement tooland get this measured out tomorrow.