My first DOHC SR20DET Cylinder Head Build (Shimming Issue)
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Yea, but can you turn?
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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 that 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
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 that 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
__________________
So why don't you just throw more money at it?
So why don't you just throw more money at it?
Last edited by mewantkouki; May 1, 2012 at 06:22 AM.
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A good how to do it story.
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Tampa Racing to the Top!
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Tampa Racing.com covers the Tampa car scene and supports many fund raisers, worthy causes and events that enrich our community. We hope you enjoy them all.
What do I do? ---- on-site *Aftermarket* spring/suspension installations --- on-site impact wrenching---street lowering with your own stock springs...........True Bi-xenon HID projector headlight conversions........ Much more at Bob's Garage!
https://www.tamparacing.com/forums/b...ontact-us.html
https://www.tamparacing.com/forums/b...e-senor-honda/
Here is the listings of ALL New Mexico Car Events Including Route 66 Anniversary
https://www.tamparacing.com/forums/t...ar-events.html
Top Car Club Meetings? Click a city
Got a video? Email it to Bobfixesitup@yahoo.com
________________________________________________
Keystone Motor Club (Founded 2012)... Free car show Every 3rd Saturday, newsletter is
https://www.tamparacing.com/forums/e...-car-club.html
Keystone picture gallery is here:
https://carstoshow.com/eventdetails.aspx?eventid=93202
Veterans and Friends on First Saturday...Some pictures....
https://carstoshow.com/registerevent...eventid=102331
Port Richey Rod Run at Coast Buick GMC
https://carstoshow.com/registerevent.aspx?eventid=99114
50's Diner US19.... A Florida Attraction.
1730 US-19, Holiday Fl 34691 click: https://www.tamparacing.com/forums/t...acing.html CHRA sanctioned cruise-in.
Cruise-In; Free; Every Saturday 5-8PM plus 10% off the whole menu to cruisers
50's Diner pictures are here: https://carstoshow.com/eventdetails.aspx?eventid=93194
All Cars Every 2nd Saturday Free Breakfast: Since 2015 and more. click: https://www.tamparacing.com/forums/e...ast-tampa.html
Tampa Racing.com covers the Tampa car scene and supports many fund raisers, worthy causes and events that enrich our community. We hope you enjoy them all.
What do I do? ---- on-site *Aftermarket* spring/suspension installations --- on-site impact wrenching---street lowering with your own stock springs...........True Bi-xenon HID projector headlight conversions........ Much more at Bob's Garage!
https://www.tamparacing.com/forums/b...ontact-us.html
https://www.tamparacing.com/forums/b...e-senor-honda/
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