“One does not simply remove the head off a SR20DET”
By far this has been the biggest job ever that I’ve single handedly completed on my Nissan Silvia S15. It really tested my “built not bought” mentality and at times made me loathe the damn thing – chances are you might end up hating your car too.
Whether you’re replacing a head gasket, replacing the VCT cam gear, installing ARP head studs, replacing camshafts or doing some bottom end work – prepare yourself. The process itself is not hard by any means, after all it is just unbolting and unscrewing bits and pieces – which can’t be that hard right? Just don’t take it lightly, there are plenty of tricky bits that require the utmost attention to detail and patience as one error can be very costly (as I painfully found out many times).
It wasn’t an easy decision to make and took me a while to gather up the courage to do this myself especially knowing I’d be tinkering around with serious engine bits. After skimming through the FSM though, it seemed super straight forward and I thought why not, I am trak-life and this is how we roll (or not).
On top of it all, I hit a flock of birds with one stone doing this all myself though since removing the head meant I could do many other things along the way too.
New camshafts, new valve stem seals, new valve springs, new rocker arm stoppers (RAS), new head studs and a new head gasket were in order. This was all preparation for more power, much much more of it. And the best part? I knew exactly what was going into my motor and the quality of workmanship.
Tools Required: Everything but in particular a metric & imperial hex socket set, trusty torque wrench, Nissan gasket sealant, 27mm socket/spanner, might as well wheel in the entire tool cabinet
Technical Difficulty: Intermediate
Profanity Level: Medium to SUPER MAX
Time required: 1-2 days if nothing goes wrong and you know your way around things, otherwise definitely a week or so if you’re a noob like me.
*It has got to be said: Everything you do is at your own risk! Make sure you know what you’re doing. trak-life is not responsible for any damages through following our guides especially one as big as this one. This guide just supplements the official FSM so use that as your primary source of truth.
- Relieve fuel pressure by pulling out the 15A fuse in the driver side fuse box, then crank the car just enough to relief the pressure (just as it’s about to start, turn it off).
- If you have a strut brace now’s the time to remove it, 3 x 12mm bolts each side.
- Follow my injector replacement guide here to remove the intake plenum.
- Pop open the fuel cap and then detach these 2 fuel filter lines going into the fuel rail (top fuel filter hose goes into top line). Precious fuel is going to gush out so let it be and plug it up with a bolt when it stops. Also remove the 2 x 10mm bolts which secure that hard line to the intake manifold.
- Remove the 3 fuel rail bolts, remove the fuel rail and be ready to catch the black washer which flushes the rail to the intake.
- Unplug these 2 connectors going from fuel rail into the intake.
- Unclip this connector from the bracket and you should now be able to remove fuel rail completely.
- Now’s a good time to check out the condition of your injectors. My Five-O (JECS) high-flowed 1000cc injectors still perfect condition!
- Remove the 3 x 14mm support bolts and 1 x 12mm sneaky bolt hiding in bottom right towards the firewall.
- Remove this coolant hose that goes to the throttle body (spills coolant onto alternator) and any other ones going into the intake manifold.
- Fun Part I: Removing/loosening the 3 support brackets since the intake manifold won’t budge without loosening these. There is one that is only accessible from the bottom so if you are jacking up your car now make sure you’ve tightened your top strut nuts (sounds like this happened to some one?). The 14mm one below the starter is accessible via a ratchet with extension piece, just loosen it a few mm… make sure you WD40 the crap out of it first though. The other lower 14mm next to the alternator can be accessible via a spanner through the belts, again just loosen this one too. Other bracket shouldn’t give you grief. By loosening these bolts, it will give you enough room to wiggle the intake manifold out from the studs on the side of the head.
- Now you can start unbolting the bolts holding the manifold to the head. For the bottom ones a 12mm spanner works and there is one particular one where a ¼” ratchet is the only way due to limited movement (you’ll know which one this is). There are also 2 hidden nuts bottom left and top right.
- The intake should now be free enough and coolant might be gushing out now but one last thing is the fat coolant hose at the bottom, pop that one out via a screwdriver or 10mm socket. Should be free now! Stuff some rags/newspaper into the open intake side.
- Time to do the exhaust side! We’re half way there!
- Take off both breather tubes to rocker, wiring bracket on rear and heat shield.
- Now is a good time to remove or turn your hot side intercooler pipe to get more access to the 14mm exhaust manifold nuts.
- Remove the dip stick guide (10mm bolts) and banjo 19mm bolt for the turbo coolant line which will allow access to the first exhaust manifold nut.
- WD40 the crap out of the all 14mm exhaust manifold nuts then proceed to remove with either spanner or ratchet with extension.
- Remove spark plug cover via the allen bolts, unplug and remove coilpacks (10mm bolts) and then spark plugs.
- Don’t forget to remove this wiring bracket from the rear left side.
- Loosen the rocker 10mm bolts in this order then remove them all.
- Remember to unclip the CAS wiring running along the front of the from the rocker cover too (push down on the lever on the clip and it’ll open… or just pull the whole clip out by force).
- Take off rocker cover and gasket and store somewhere safe, getting there!
- Time to manually turn the crankshaft, you’ll need that 27mm socket and can get to it from the bottom, you will just need to unclip the bottom part of the fan shroud and move it out of the way to get the ratchet in there (it’s plastic so you can use a bit of force to push up on the bottom clip).
- THIS PART IS SUPER IMPORTANT TO GET CORRECTLY, a.k.a Fun Part II.
Put car into neutral if applicable. We now need to make Piston #1 top dead centre (TDC) by turning the crankshaft manually clockwise, TDC is indicated by the pointer being on the second notch of the crankshaft pulley.
The goal is to have the camshaft dowels at 10 o’clock intake side and 12 o’clock exhaust side AND the cam sprocket notches under the timing mating marks (dark grey links). Because of #VCTlife though you won’t see the intake dowel so you will need to rely on the notch and exhaust side indicators.
Keep rotating the crankshaft clockwise until you get these three lined up. (As I did this incorrectly I’m using this picture from zilvia.net to show you the correct positions). I don’t care how long you’re turning for and much your arms ache but you must get this right! Just be patient or else you’ll end up like me and stuffing it up completely and creating much more work later on (trust me on that one).
Once these three things line up it is crucial that you again check the pointer on top of the crank pulley is the second notch from the left confirming piston #1 is at TDC. If it isn’t then keep going!
*The other method is to simply pop it to TDC and paint the chain link corresponding to the notch on both sides. You can think of it as working with a timing chain that has no markings. Remember the markings are just a reference point to help you put the cams/sprocket back into correct the spot on the timing chain so you don’t screw up the timing.
- Remove the 2 x 10mm nuts on the chain tensioner and pull it out. This gave me grief as the gasket sealant held this in really tight. Use a flathead screwdriver to try and pry it open but I ended up having to give it a tap with a long flathead screwdriver from the inside to get it to budge.
- Unclip CAS connector and remove the 2 x 12mm bolts and gently pull out the CAS.
- Before we forget, remove the 12mm bolt at the rear holding in an earth for the coil plugs. It’s a bitch of a 12mm bolt to get to, only a spanner will do. Once that’s out you can just move that harness out of the way.
- Remove your timing chain guide, some reason I didn’t have one which might explain the occasional random timing rattle.
- Put it into 5th gear (so crank doesn’t move) and remove the cam sprockets from the camshaft. Skip this step if you’re not intending to change cams as you can lightly wiggle them out as one piece.
The 24mm bolts holding the sprocket to the camshaft will be on ridiculously tight, unleash the trusty breaker bar while holding the camshaft still with a spanner/shifter on the hex portion. Don’t let the timing chain bear the load and whatever you do, watch out for that washer on the nut when taking the bolt out! If it falls down the front cover it’s gonna be fun times… (grumble)
- Time to get those camshafts out! Remove the 12mm bolts, brackets and oil tubes. Loosen the bolts in this order as per FSM.Ensure you store the corresponding bolts and brackets together and in the correct order as you will need to put them in the exact same order.
When lifting out the cams try and keep tension on the timing chain. Reason for this is you don’t want it to become loose and have the bottom crankshaft sprocket skip a tooth on the chain (although I don’t think this is actually possible).
I took the EX cam out first and then cable tied the chain the dip stick so there wasn’t much slack.
- No harm taking out the 4 x 12mm coolant neck bolts now to remove it from the head. There is also another 12mm bolt hidden underneath in a bracket that only a small ratchet with extension piece can get to. If you can’t get to it you can always wait till the head comes off in Step 36. (For reference the shorter bolt is the top one)
- Get those outer head bolts now, 4 x 10mm. The rear one is a pain in the arse if you still have the exhaust manifold on but it is doable with a 10mm spanner and a massive 1cm range of movement.
- Now hopefully you have a 10mm hex socket because there’s no way you’re getting the stock head stud bolts out with allen keys.
Loosen in this order:
You will need some massive but steady force here, the “crack” when the nuts gives way gave me the tingles all the way up my arm. Borrow your mate who lifts if need be.
- Decision time!
Option #1: Attempt to take the head off with the manifold and turbo still in place.
Option #2: Remove the exhaust manifold and turbo for a much less painful operation (RECOMMENDED)
With a bit of work I managed to remove the head without removing the manifold and turbo (I saw someone else do it this way). If you want to go down this path just be wary that the installed head gasket will get crumpled and damaged with you wiggling the head around so probably can’t be reused… not that you would.
The strategy here is to angle the head against the exhaust manifold so the studs can slide out (I cheated and removed the first two studs from the head for some extra clearance). Make the missus feel important by getting her assistance in keeping the timing chain taut while the you wriggle the head around and lift it off.
In hindsight though I really shouldn’t have been a lazy ass and just removed it all one go as you have to anyway so the head back can go back on seamlessly.
- Turbo and manifold on or off it still isn’t over! There is still the hidden 12mm bolt under the coolant neck which has got to be removed if not already. Then you might realise the back is still being snagged by on that black wiring bracket… it’s because there is still one more earth cable attached to it which is stupidly hard to get to previously. Pop that out and you should finally be victorious.
- Thrust the head high up in the air with victory. High five your missus. Go for a victory smoke. Update your status on Facebook. Donate to trak-life. Not all at once of course unless you’re Chuck Norris.
- If you’re sending your head off to have some work done (skimming, valve springs and/or valve seal replacements like me) you’ll need to remove your rocker arms, hydraulic lifters and shims which is a very simple affair… hopefully they didn’t pop off when you were wrestling the head off.
NOTE: You will need to reinstall them exactly the way they were so store them in a way that you’ll remember. I bagged them in sandwich bags with their corresponding piston numbers.
- Time to clean up the block! Remove the old head gasket and use a scraper to get any of the old gasket gunk off. Use brake cleaner to remove grease/grime. Be careful not to push the gunk into the water/oil galleys, block them up with tissue/rags or just simply scrape away from their direction. I didn’t use any Scotch Brite on the block surface after reading people’s opinions about it online.
I basically kept going over the block with the scraper and wiping it up over and over again to ensure there weren’t any lumps or grooves. The quality of your build depends on the quality of your work so be proud of what you do! My block didn’t end up being mirror polished and super schmick to look at it but I know it was smooth and uniform across the whole surface. Run your fingers/fingernail over the surface to feel the finish.
- One thing I forgot to do is make sure the block stud bolt threads are nice and clean. Use some compressed air or a cloth on a screwdriver.
- I HIGHLY recommend test fitting the head studs in the block threads just to make sure all is well. Clean the block end of the studs with some WD40 and hand tighten them into the block. This a good precaution so that you know there won’t be issues tightening them down once the head is on… and a good time to fix the threads if one is stuffed (It’ll cost you $200… one of my threads was very unhappy. Greg from Actionthreads made it happy again though) CHECK!!! Don’t be a moron like me and use brake cleaner to clean the cylinder bores and piston because it really dries it all up and encourages rust to be developed rather quickly especially if you’re not doing this all in one go. If you want to know how to break rust on your seized engine let me know… Lube the walls and pistons up with some oil instead.
- Once you’re 100% sure the block is good it’s time for that head gasket. Apply some gasket sealant to the front timing area only prior to putting it on (I used the genuine Nissan stuff).
On a side note I chose not to spray any copper spray or hylomar onto my Tomei MLS gasket which took me ages to decide on after much thought and research… ultimately it’s up to you.
- Pop the head gasket on, should line up easy. Make sure it’s the right way up obviously. (I used a Tomei 1.2mm thick & 87mm bore MLS gasket).
- You can pop on the rear black bracket to the head now as it’s damn near impossible when it’s back on, remember the earth cable that goes onto one of the screws. (I ended up not bothering with it)
- Time to get that head on! Beforehand though I cleaned the bottom side of the head with brake cleaner just to make sure it was spotless. Good idea to wash your hands too to avoid getting grime on there again when handling it.
- Get a helper here to hold up the timing chain (keeping tension on it) and feed it through the front of the head and moving the timing guide chain out of the way accordingly. Try and get it first go, should easily lock in place flush if you’ve lined up it all up correctly.
Remember to zip tie the chain to something again to keep it taught.
- Now that the heads in, it’s the head stud bolts time! Make sure you wear a singlet for extra powers.
Personally I went with ARP head studs part #204-4204 (VW Golf/Jetta) as I was told they are the correct length for the SR20DET. But my recent research tells me ARP’s current offering for the SR20DET are now the correct length (used to be a tad short and not reaching the bottom of the block) and stronger as it is the ARP “2000” version. Anyway I’ve seen many people use my version with no problems.
- Follow the instructions per ARP manual which is basically hand tighten in the bolts without any type of lube on the block end. Then you’ll need a 3/16” allen key (bloody imperial!) to tighten them all the way down to the block as much as you can, they should all be sitting at about the same height.
- Apply the supplied ARP lube to the top stud threads and nuts, don’t worry if you smear some around the head. Pop the washers in while you’re at it, be very careful with the rear ones…
- From what I’ve read, the best way to torque the ARP head studs is in four increments: hand tight, 25 ft/lbs, 55 ft/lbs & 80ft/lbs. And yes you will need to tighten them in this criss cross order every increment:
NOTE: Be careful with the studs closest to the firewall! If you drop the nut there’s a chance it’ll drop into the rear gallery or even worse straight down into the sump which means head off again! Thankfully my magnetic stick saved me…
- With the scariest bolt tightening part over, whack in the 10mm inner top and outer hot side bolts (These are very low torque, FSM says 9.0-11.8nm)
- Time to pop in the hydraulic lifters but prior to that you will need to bleed any air out of them by popping them upright in some fresh oil and watching bubbles. You can speed this up by push down on them with something thin enough (I used an allen key).
Hopefully you bagged them all in order with the respective shim, guide & rocker arm, install when ready!
- Don’t forget to apply new oil to the shim, guides and rocker arms.
CHECK!!! For the exhaust side, the rocker arm guide (one with the notch) is the top one and for the intake side it is the bottom one when looking from rear of engine to front.
- Now it’s cams time! If you’re NOT changing to a different set of cams then skip to item #4 below. Otherwise, continue on!
- One camshaft will have a longer alignment dowel, this goes into the exhaust sprocket. The camshaft with the shorter dowel goes into the VCT gear.
- Lube the threads of the bolt as you screw it into the respective camshaft. Note which camshaft is for intake and exhaust side, there should be a marking like “IN” or “EX”.
- There’s a few ways to do this but I chose to tighten both sprockets to the camshafts off the engine. I popped a towel on the ground and proceeded to use a shifter and ratchet while holding down the cam gently with my foot. The FSM says 90ft/lb torque is about the same as the headstuds! So yes they will need to be on ultra tight. Unleash the power! Obviously take care not to damage anything especially the sprocket teeth.
- Using new oil, lube up the sprocket, camshaft and the guides on the head. Some people use assembly lube but the FSM says engine oil is fine. Be generous!
CHECK!!! Confirm the rockers are still sitting properly on the guides and shims.
- Time to whack the cams on. Check that you are in 5th gear with handbrake up and the crank marking is on the second notch. As a sanity check I put my magnetic pick up tool down spark plug hole #1 to ensure piston 1 was at TDC.
- Release the timing chain from whatever you cable tied it onto and make sure it doesn’t go slack (trusty wifey or whatever is handy here).
Assuming that the timing is still correct and the way you left it previously with everything mating up, install the first camshaft with sprocket attached ensuring the dark grey mating mark on the chain sits exactly on the notch on the sprocket (I did the intake cam first).
Make sure all the links are properly seated on the sprocket teeth. The dowel for intake side should be pointing 10 o’clock they say, but #VCTlife means you won’t see the dowel.
CHECK!!! Ensure the timing chain is properly inside the timing guide grooves in the front cover (mine was actually sitting on top of the edge which is danger but lucky I realised phew)
- For the exhaust cam, position and maneuver the sprocket onto chain again with the notch on the dark grey mating mark. As you can see the dowel on this sprocket it should be about 12 o’clock.
You should have enough slack to do this otherwise you chain may be caught on something or not sitting in the guides as mentioned previously.
- Don’t worry too much if the camshafts are not sitting flush in the guides (grooves) on the head as one of the cam lobes will be already pushing down on the valve spring, it’ll be ok when you pop in the brackets.
- Verify that the timing dark grey chain markings all mate up with the sprocket notches and the exhaust dowel is 12 o’clock while crank pulley is 2nd notch (1st piston TDC). If so we’re all good!
CHECK!!! If you want to be super paranoid, follow the Tomei diagram and count the teeth from the edge to the notch tooth. I did this! It’s 5 on the intake and 9 on the exhaust side when looking straight on parallel with the front cover.
This step is required if you stuffed up your timing in the beginning and didn’t align the markings to the notches, imagine it as installing cams on a chain with no markings.
- Lube and put the camshaft brackets, oil tubes and baffle plate back in order. If you have a RAS it makes it that bit more challenging lining up everything and then bolting it down. FSM suggests to tighten in this order:Don’t use much force tightening the bolts. Make sure you use the correct RAS for intake or exhaust side, the Tomei RAS is specific.
- Time for the CAS. Line up the right dot to the notch before you insert. As you insert the CAS, the gear catches onto the sprocket and it will slightly turn and the left notch will replace the position of the right notch. You may have to rotate the CAS body to line up the notch with the left notch.
- With any luck you will be dead centre in relation to the screw hole meaning everything is factory timing! Bolt those 12mm bolts if all is in order.
If the screw bolts aren’t in the middle, things it’s possible things aren’t lined up properly and I’d go through and check everything again especially the cam dowel locations. If you’re 100% sure everything is fine then continue on (my CAS bolts weren’t in the middle). You will need to check it with a timing light when she’s all started up to double check base timing is spot on 15 degrees (or if you’re using an aftermarket ECU, lock the timing at 15 or 20 and sync the timing with that).
- For the timing chain tensioner, press back on stopper and push the sleeve in enough so you can get the hook on it. Ensure the sleeve is centered too as it can rotate and give you headache fitting it in.
- Pop some gasket sealant on the block and lube up the oil ring.
It’ll only go in about half way and you’ll need to bolt in the 2 x 10mm nuts to completely get it in as the sleeve will release automatically (if it doesn’t you can manually turn the engine slightly and it should release).
- Is it really time to whack on the rocker cover and close the engine? I believe so!
If you have new spark plug and rocker cover gaskets get them out. Always insist on genuine!
- Before that though (sorry… anticlimax), if you installed the Tomei RAS for the first time you will need to grind out this part out of your rocker cover:
- Pop on some gasket sealant on the 3 x half moon areas of head and whack on the gasket.
- The rocker cover should line up easy enough on the gasket and then bolt up the 15 x 10mm bolts to close the engine! Jump for joy!
- I’d recommend whacking in the spark plug and coilpacks loosely just so nothing falls down those holes.
- From here on it’s a much simpler process bolting the stock pieces back up. Take your time and hopefully you don’t end up with spare nuts and bolts!
- When it is time for you to attempt the daunting first crank, don’t forget to install the 15A fuse again. Prime the fuel pump a few times to build pressure in the system.
- With spark plugs out, crank a few times. Securely install the plugs and coilpacks thereafter.
- With the CAS disconnected, crank for 5 seconds 3 times to get the oil flowing in the system.
- Connect the CAS and let her rip! After a few goes the heart should start pumping again, all your hard work has paid off! Remember to check your base timing!
This whole process for me took way too long, about 4 months actually from start to finish! (I guess it didn’t help going on two holidays during it all). So if you’ve been hanging for this guide I do apologise… but then again, good things come to those who wait.
Putting this guide together made me remember all the effort required to see this through to the finish line. Behind the scenes there were endless late nights in the blistering cold and constant stress day in and day out on why things didn’t go to plan. But now in retrospect even with the countless setbacks and frustrations I’m glad I endured through it all – you can’t buy that kind of experience.
So if you’re reading this in preparation for doing this yourself or have already used this guide to successfully pop the head off then I’m hoping that I’ve helped you out!
In closing, I’m happy to report the engine has recently seen the dyno and a trackday at maximum power with no issues at all! Yeeeeeeeeeeeee boi! The power of trak-life DIY!
Update 10/5/2017: Car is still perfect with no issues! Has seen 4 more trackdays being driven to the absolute limit and is all well and good. Be proud of what you build. And if in doubt, check check check and check! Or just comment here or ask a question on our Facebook 🙂