Head Gasket Installation - SR20DET

[s14unimog]

Since it seems there is limited, and sometimes contradicting, information regarding a head gasket installation; I felt I would share my pictures and experiences in hopes of constructing a helpful/resourceful thread.

Since head gasket removal was covered quite well by an individual on NICOclub, I will just provide the link to that thread.

DIY: SR20DET Head Removal by Mrzabala: SR20DET Forum (rear-drive): Nissan Forums / Infiniti Forums - NICOclub (http://forums.nicoclub.com/zerothread/254179)

Depending on what your needs are for your particular project, your repairs or upgrades, may differ from mine. As some of you may know, and for the ones who don't http://zilvia.net/f/engine-tech/277711-check-your-screws.html , my engine recently ate a throttle body screw and so needed some repairs. I had the head decked, cleaned, JWT valve guides installed, new seals, compression zones checked, head assembled, and a missing cam cap replaced/fitted.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29001.jpg

Before you get started, its a good idea to go ahead and bleed your hydraulic lifters; its very easy and only takes a minute. The lifter removes just by pulling on the exposed end and is located under the outside leg of the rocker arm.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29002.jpg

Submerge the lifter in a container of new oil and depress the check valve located inside, at the base, the lifter. the FSM lists the use of a "suitable tool" so I used an appropriate sized allen wrench. with the check valve depressed go ahead and compress the top of the lifter until you feel it bottom out; you can release the check valve at this point. You should see air bubbles if its needed and once you're done, the lifter shouldn't compress anymore. Repeat if necessary.

Next you want to go a head and clean the block surface as well as you can. I used a window scrapper with a new razor to remove the majority and then a dremal with a some what nonabrasive wheel, you don't want to create low spots. Use good judgment and just clean it. After its clean go ahead and apply a continuous bead of gray liquid gasket to the front timing cover area. Remember that a little goes a long way, so don't get carried away with a 0.250" bead.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29004.jpg

Install head gasket. This step is somewhat debated, I choose to use Copper Spray for added tack on the two surfaces but I know that you don't necessary have too. As it was explained to me, it can't hurt but could help and I have no experience to argue otherwise.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29003.jpg
http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29005.jpg

Next apply another continuous bead on top of the gasket around the front timing cover area. My understanding for this is only to prevent weeping from the front cover.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29006.jpg

After you drop the head on, its now time to install the head studs. I am using ARP hardware so here is the information to know. If you are reusing head studs, its important to verify that they have not stretched. The area of stretch is usually in the threaded area of the stud its self, so look for differences in diameter. The O.A. length should be 6.600" +/- 0.010". Replace them if it exceeds this tolerance.

To install them, you use a standard (not metric) allen wrench and thread them all the way down into the block. You need only to snug them down, no torque spec's req'd. DO NOT USE bolt smoothing compound on block threads!

Install all 12pt nuts and washers with bolt smoothing compound. From my research, it seems there are two versions of head studs. Apparently, ARP has redone the kit for the SR20DET and now requires 105ft/lbs. I have an older kit which requires 80ft/lbs; this will be the 3rd time I've reused these. Refer to the FSM for exact torque sequence, or just remember: tighten from the inside out and loosen from the outside in. Tighten them in stages and let your last torque set be your biggest jump. I did...

25ft/lbs - 55ft/lbs - 80ft/lbs

Don't forget to reinstall the 4 remaining, 10mm socket, screws shown removed in the thread listed above.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29008.jpg

The next step is to reinstall your mechanical timing assembly, set your timing chain tensioner and reinstall your CAS @ 15deg BTDC. The FSM calls for you to separate the cam sprockets from their corresponding shafts but its not necessary to install them. Make sure you have the dots at the silver links and the crank still at the second mark from the left.

http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29009.jpg
http://img.photobucket.com/albums/v721/s14unimog/RepairstoheadOct29010.jpg

After all of this is done, and after rotating the assembly nothing binds, reinstall your intake manifold and associate components and the same for the exhaust side. I hope this was helpful...

Please add your experiences or comments. I'll let you know if something doesn't work out right...

[Tearlessj]

OK, now I have always heard that you HAVE to get your head and blocked decked to use a metal headgasket. Anyone know this for sure?

Good write up for sure though. +1!

[s14unimog]

I would say for sure on the head, especially since it usually warps long before the block does. Mine was merely surfaced, it was within FSM tolerances. You can always do the straight edge and shim pack test to be sure.

[240sxfamily]

OK, now I have always heard that you HAVE to get your head and blocked decked to use a metal headgasket. Anyone know this for sure?

Good write up for sure though. +1!

yeah same. people have been telling me that but im using the copper spray for an extra seal.

[let5l1de]

I would say for sure on the head, especially since it usually warps long before the block does. Mine was merely surfaced, it was within FSM tolerances. You can always do the straight edge and shim pack test to be sure.

Nice writeup!

The head generally seals to the block just fine (I do recommend resurface/deck) providing everything is very clean and stright. ARP hardware is highly recommended when using a MLS Type HeadGasket. Stock old SR head bolts will stretch... PERIOD. The problem with improper MLS HG installations are typically found at the front cover mating surfaces. Watch for leaks...

~mario


edit:
yeah same. people have been telling me that but im using the copper spray for an extra seal.

Why not...

Old Time Engine Builders used to spray a light coat of paint onto the headgasket to help promote sealing of water/oil passages.

~m

[s14unimog]

^ yeah that is a concern of mine, I have another SR powered car I picked up from a guy and its weeping from the front cover...what a bitch. This is my first head gasket install so I hope everything works out.

[Pure_JDM]

ditto^... mine's weeping there as well, so a new looks in the near future for me.

[240sxfamily]

^ yeah that is a concern of mine, I have another SR powered car I picked up from a guy and its weeping from the front cover...what a bitch. This is my first head gasket install so I hope everything works out.

So then the spray does seal it more properly? My head is decked and stuff but the block isn't.

[s14unimog]

The Copper spray is ONLY a tack spray for the head gasket its self. The Grey Silicone is for the front seal and prevents the oil weeping

I have talked to a number of different professional engine builders and the consensus is to USE copper spray.

[let5l1de]

So then the spray does seal it more properly? My head is decked and stuff but the block isn't.

The copper spray will help seal the inconsistencies or very slight imperfections that a metal gasket will not.

MLS type HG's are exceptional for hi boost apps but are unforgiving. Use a high performance Fel-Pro HG when you can, epically for beginners...

~m

[let5l1de]

The Copper spray is ONLY a tack spray for the head gasket its self. The Grey Silicone is for the front seal and prevents the oil weeping

I have talked to a number of different professional engine builders and the consensus is to USE copper spray.

The tack spray is to seal as well... I am an engine builder.

~m

[s14unimog]

^ Right, only to help the head gasket seal not prevent oil weeping from the front cover. I am using the Cosworth MLS b/c I run low boost @ 15psi and high boost @ 25psi . I dyno'd 394rwhp @ ~17psi, it ran great until the screw was eaten; that was about 300 miles after tunning.

[240sxfamily]

so shall i use RTV on the front cover piece? so it will seal that as well?

[let5l1de]

^ Right, only to help the head gasket seal not prevent oil weeping from the front cover.

Did you use any sealant on the headgasket between the timing chain cover & head? If so, what did you use.

~m

EDIT:

looked at the pics... It's grey sealant with no copper spray.

This is good for most novice builders since it does seal larger imperfections much better. I may or may not use the grey sealant (always use coppers spay) between the front cover & head depending on machine work performed and type of build. If you slap a MLS HG on without kissing the block and cover, you will almost certainly need a thicker grey sealant because of imperfections at the cover to block mating surface

~m

[s14unimog]

yeah, see the pictures? there is only one timing chain cover, we're talking SR20 here (noticing your avatar)

[let5l1de]

Sry for my lost train of thought... Cover and head... One more reason why less leaks should be prominent for SR front cover/head....

The area I'm concerned with on either KA or SR is the squareness of the top of the timing cover and block.

[VNG704]

Just some FYI:

I used VW ARP head studs sold by frsport.com. The reason they gave me was, it's slightly longer and will make up for thicker head gaskets. It fits and holding fine on my SR. Tip, when lubing the head studs, don't get any on the ends that go into the block. If you do, the lube will not compress and you'll get inaccurate torques. Meaning keep the lube on the threads.

[s14unimog]

^ good point! I only used it on the top. Bolt smoothing compound should ONLY be used on threads that are NOT blind projection.

[let5l1de]

Just some FYI:

I used VW ARP head studs sold by frsport.com. The reason they gave me was, it's slightly longer and will make up for thicker head gaskets. It fits and holding fine on my SR. Tip, when lubing the head studs, don't get any on the ends that go into the block. If you do, the lube will not compress and you'll get inaccurate torques. Meaning keep the lube on the threads.


VW as in 1.8L, available in a few different diameters as well.

~m

[HYPNOTIK]

Someone mentioned a Fel Pro HG and I've been considering using one as well. Does anyone have any first hand experience with a fel pro on a SR? Good, bad?

[ericb382]

I called apexi (since I was using an apexi HG) before I installed mine and asked if they recomend copper spray/RTV. They said no to both.

The way I look at it, the only time you need RTV around the front cover is if you haven't had the block and front cover decked together. If both your block and head have been resurfaced, no need for copper spray. If you've taken a straight edge to them (not freshly machined) and they are good, copper spray.

I also heard contradicting stories as to whether or not it was necessary to retorque head studs after heat cycling a metal HG. I called ARP for this (as I was using their studs,) they said yes. After your first heat cycle go through, break each headstud loose, and retorque. One at a time.

I'm sure some people will disagree with me on my outlook on copper spray and whether it's worth re-torquing, but I like to get my recomendations directly from the manufacturers. Yes, I know, many people get away without retorquing, but it takes maybe an hour. Why not have the added security.

[let5l1de]

I called apexi (since I was using an apexi HG) before I installed mine and asked if they recomend copper spray/RTV. They said no to both.

Many MLS HG Manufactures actually recommend no spray or rtv due to possibly hindering the ability to seal properly. Another example is Cometic. Cometic Gasket Inc. also recommends a dry install due to the fact that a .001" thick viton rubber seal is bonded to the outer metal layers.


The way I look at it, the only time you need RTV around the front cover is if you haven't had the block and front cover decked together. If both your block and head have been resurfaced, no need for copper spray. If you've taken a straight edge to them (not freshly machined) and they are good, copper spray.

I generally support this theory. So many people just buy the MLS type HeadGaskets and install without reading or ignoring the proper procedures for installation.

I also heard contradicting stories as to whether or not it was necessary to retorque head studs after heat cycling a metal HG. I called ARP for this (as I was using their studs,) they said yes. After your first heat cycle go through, break each headstud loose, and retorque. One at a time.

I also generally agree with re-torquing the bolts or studs after the initial full heat cycle. Again, people disregard instructions or they are too lazy to perform this re-torque procedure.This can be an engine saving step that doesn't take very long to perform.


I'm sure some people will disagree with me on my outlook on copper spray and whether it's worth re-torquing, but I like to get my recomendations directly from the manufacturers. Yes, I know, many people get away without retorquing, but it takes maybe an hour. Why not have the added security.

Factory recommendations is where I start as well, but all too often we run into situations the factory respectfully have never fully addressed. Seek advice from quality engine builders familiar with your build combined with MFG recommendations and your best judgment.

~m

[s14unimog]

I think there are a few different ways to complete a head gasket installation and I think they change based on what kind of gasket you use. I was also advised from one of my information sources to re-torque them. He also recommended I paint the 12pt nut and stud so that I can see how many rotations I actually pick up; its not necessary to paint them, but it shows you the difference.

As for the discrepancy between copper spray and liquid gasket on the timing cover area. I think the copper spray is optional, but as it was explained to me, "it can't hurt but it could help" so I choose to go that route. As for the liquid gasket, I don't think its optional. The FSM clearly indicated that it IS necessary for the installation and we all know, this would have considered perfect parts being installed; enough reason for me.

[ericb382]

But the FSM is assuming you are using a stock HG. Once you switch to a metal HG, you should use the specs designated by the mfg of the HG.

[s14unimog]

Correct, but consider the differences of the two head gaskets and the specific location in question. Would you honestly put that back together without liquid gasket? Especially when considering the sealing issues associated with a MLS type head gasket when compared to an OEM one.

[ericb382]

If the block and front cover were decked together like they are supposed to be, yes. I didn't have any problems with mine leaking....

[s14unimog]

If the block and front cover were decked together like they are supposed to be, yes.

I can't agree with you. The FSM lists for you to use it and it would have considered a perfect decking surface between the two surfaces. I'm glad yours isn't leaking though.

[rc1honda]

OK, now I have always heard that you HAVE to get your head and blocked decked to use a metal headgasket. Anyone know this for sure?

Good write up for sure though. +1!

I had my head decked but not my block. Used the copper spray with a apex-i 1.1mm. My leakdown test says i have about 6% leakdown in all cyclinders which is bacially what a brand new engine will read.

So no you don;t have to get the block decked. Just deck the head and use the spray and it should be fine.

[let5l1de]

So no you don;t have to get the block decked. Just deck the head and use the spray and it should be fine.

Please keep in mind that all engine tolerance/clearance are not all the same form one engine to another. IMO every engine that is receiving the MLS HG upgrade should be check for squareness with a straightedge on both head and block.

Some get away with slapping a MLS HG on, others pay the price with a leaking front cover. They typically seal the cylinders without an issue.

~m

[ericb382]

I can't agree with you. The FSM lists for you to use it and it would have considered a perfect decking surface between the two surfaces. I'm glad yours isn't leaking though.

The FSM gives procedures for a stock HG. We are talking about aftermarket HG's. I hope you wouldn't use the FSM's torque specs when torquing down ARP head studs.... Same concept.

Like I mentioned earlier, I called Apexi (the manufacturer of my HG) and asked them what they recomend for THEIR HG. They said not to use anything. I didn't and it worked perfect. Like I also mentioned earlier, there are some instances where I would deviate from their recomendations to match a specific application, but in a perfect world (head, block and front cover machined) you don't need it.

[s14unimog]

The FSM gives procedures for a stock HG. We are talking about aftermarket HG's. I hope you wouldn't use the FSM's torque specs when torquing down ARP head studs.... Same concept.

Like I mentioned earlier, I called Apexi (the manufacturer of my HG) and asked them what they recomend for THEIR HG. They said not to use anything. I didn't and it worked perfect. Like I also mentioned earlier, there are some instances where I would deviate from their recomendations to match a specific application, but in a perfect world (head, block and front cover machined) you don't need it.

I am very aware of the differences between this installation and that of a standard OEM head gasket. With that said, I would think a MLS headgasket could use the additional "support" to seal that area. I spoke with Cosworth USA about my application and they recommended the use of liquid gasket on the front cover. I am not the kind of individual to do motor work without extensive research.

I appreciate your input and can end this debate with a few more words.

For all who read this write up:
If you feel you don't need liquid gasket and are confident that it will not leak, then don't use it. If you feel that you might need it, use it.

[ericb382]

So cosworth probably doesn't put the "additive" on their HG's that Apexi does. I was told by apexi that they put an additive on their HG so you don't need RTV. This is a perfect example of why you should contact the mfg our your particular parts for their recomendations, because every brand does things a little different.

[s14unimog]

^ good point! That's an interesting bit of information about Apexi; I never knew that.

[s14unimog]

just a bit of closure. I've put about 30 miles on the car since I've done the head gasket and all seems to be well. I will do a leak down soon and post those results.

[ericb382]

just a bit of closure. I've put about 30 miles on the car since I've done the head gasket and all seems to be well. I will do a leak down soon and post those results.

And a bit more closure for the topic.... I leakdown tested mine after my HG install with 0% leakage (shitty harbor freight tester tended to stick on 0 then shoot all the way to 100 when there was a problem.) I drove it untill my fuel pump went out during HPDE and melted my CP piston. Yes, the HG held better than the piston. Don't take this as a bash on CP at all, I love them, it was just lean as shit, no piston will hold that.... but the HG did.

[s14unimog]

That is no bueno, I had a "less than intelligent" roommate that had the turbonetics single kit on his 350Z with some random reflash (bought the kit used and not complete). Long story short, he had no wideband and has gone through 3 motors (from lack of understanding the problem) and in one of those, destroyed a set of CP pistons before any head gasket issues. Without confident and correct monitoring of your A/F's you are almost guaranteed to burn your pistons down.

"The correct air/fuel ratio balance of an engine is most critical for piston longevity, durability and proper engine operation. The combination of too much fuel or too little air will have the same result – thermal growth or piston crown erosion."

Engine Builder Magazine - Heavy Duty Technology: Piston Failure Analysis
By Dennis Nail

I've been draggin ass about doing a leak down test, but I've run the motor fairly hard with no issues.

[91240sxhatch]

i have a few quick questions. i am about to do put my motor back together. i am reusing my apexi head gasket and arp studs. i am probably going to use the copper spray on the gasket and liquid gasket on the cover area as mentioned.

note: there was nothing wrong with the hg or head before. i am replacing the bottom end/shortblock.

my question is when you put the liquid gasket on do you let it dry at all before dropping the head on? it seems to me that the weight of the head would push it all out. and at what point of the liquid setting/drying do you start the torque sequence?

and one more thing. arp recommends their moly lube to install the studs. but its just an assembly lube so can i use my redline assembly lube in lieu of the arp brand?

i was able to seal a cometic hg on my last sr20 but it was brand new. any advice helps. thanks in advance.

[Turb]

Should I our rtv on my valve cover gasket?

[cotbu]

Rtv should only be needed on the half moons. You can use it as a bandaid, but why? Buy a new gasket!

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