The DOHC installation 'unspoken' details thread

[PhyrraM]

.......the biggest question is for headgasket?? ej20g or ej22t?? what do i order at the dealer?:P

The head gasket always needs to match the bore. So order a EJ22T head gasket.

[kimokalihi]

Order both the gasket and the belt at the dealer.

[93forestpearl]

.......the biggest question is for headgasket?? ej20g or ej22t?? what do i order at the dealer?:P

The head gasket always needs to match the bore. So order a EJ22T head gasket.

+1 The 22T OEM gasket is very tough. It handles 25 psi from a 30R without issue.

[SLODRIVE]

Timing belt is 96 legacy DOHC belt I believe.

Get it from the dealer, don't use those cheap aftermarket belts.

I gotta disagree...go get a Gates belt, they are the BEST (most OEM belts are mfg. by Gates) and they cost a lot less than the dealer charges.

[kimokalihi]

Yeah I forgot about gates, I was thinking of the Ebay ones.

[smh0101]

Heres a trip for ya... ALL ej series DOHC (I dont think there are any other ones lol) Timing Belts are the same. You can even use one for an ej257 and it will work just fine.

[asc_up]

You use the head gasket for whatever shortblock you're using, so you need the EJ22T headgasket.

[ciper]

I'm lazy and didn't read the entire thread BUT I want to point out that there is a difference in cam sensor "heights"

I tried to use a 91 EJ22NA cam sensor on EJ25D heads and alhough the car ran I found out the sensor was actually hitting the timing marks! My sensor somehow didnt break though it has some nice scrapes across it. A thin washer between the sensor and the cam journal mounting solved this.


I also want to say YOU HAVE TO COUNT BELT TEETH. There is no other way to correctly install a belt, especially on hybrid engines. Remember you are probably using a different thickness of headgasket than was originally used so the marks will not be accurate. Decking the heads adds another change into the mix.


Even the belt markings may not be right (yes I have seen it). I suggest counting the teeth with the belt in your lap and mark it with a pen or white out ahead of time. This helps alot when using an old belt.

Page 15 of this document http://endwrench.com/images/pdfs/TBeltEWWin05.pdf says

Note: Here’s a great check — there should be exactly 44 teeth between the mark on
the crank sprocket and the one on the passenger’s side cam pulley, and 40.5 teeth
between the crank mark and the driver’s side cam mark.

For the DOHC 2.5na engine check page 18 of http://endwrench.com/images/pdfs/2.5Timing.pdf

By far the most accurate method of determining proper belt alignment is to
count the belt teeth. This diagram illustrates the tooth counts for all five timing
marks. Tooth count Z1 is 54.5 teeth. This measures from the crankshaft pulley
timing mark to the right (upper) intake camshaft sprocket timing mark. Tooth
count Z2 is 51 teeth. This measures from the crankshaft pulley timing mark to
the left (upper) intake camshaft sprocket timing mark. Tooth count Z3 is 28 teeth.
This is the number of teeth between the (upper) intake and (lower) exhaust
camshaft sprocket timing marks. The Z3 tooth count is the same for both the left
and right sides of the engine because the same relationship must be maintained
between the upper and lower cams on both sides of the engine.

To help eliminate confusion realize one tooth count is using valleys on the belt (teeth on the pulley) while the other side uses teeth on the belt (valleys on the pulley). This confused the heck out of me at first.

I'd be willing to bet many of you who used the timing marks on the pulleys or covers are off by one tooth on both drivers side cam pulleys!

[epicfail]

Any idea how many cam-timing degrees between belt teeth?

[kimokalihi]

Wait, now I am confused. I counted the teeth on the belt, not the valleys. Is this correct? I don't understand what you said about one count being valleys and one count being teeth.

[ciper]

According to page 11 of this document http://www.endwrench.com/images/pdfs/TBeltEWWin05.pdf

a one tooth mistake will commonly put timing off by about 15 degrees.

This person had one cam gear off and lost lots of power http://forums.nasioc.com/forums/showpos ... stcount=12

I believe this would make it 14.4 degrees retarded (360 deg / approx 50 teeth per cam sprocket)x2(four stroke engine)= 14.4

[Penguin]

I just replace the spark plugs on my ej22t/20g doch engine,..
it turns out the car was running on 3 cylinders(still could break therear end loose in almost any turn). I talked to my best friend who is now works for the dealership and is factory trained, and he said that every dohc turbo he has done a tune up on has longer threads on the spark plug. I.E. the SOHC plugs are not getting all the way into the cylinder.
I am thinkin about use wrx plugs to be safe

anybody else noticed this?

[cj91legss]

Never even heard of it, i'm getting ready for my DOHC installation so i'm reading this and learning. I'll be using the 20H heads.

So Should all the DOHC guys buy some other plugs or what?

[PhyrraM]

I haven't either. I will be testing it this weekend. I'll bring pics too.

[Penguin]

I remember that atleast one late model ej engine has longer plugs... just don't remember whice one
I will have my buddy double check as well
he just seemed really sure

[cj91legss]

Well i suppose it would make some sense if there was a plug that went deeper into the heads.

[SLODRIVE]

DO NOT use longer plugs in the older DOHC motors! EJ257s and possibly other late-model EJs need them, but using them on 20H/G heads can damage things with a quickness. A quick search online will give you the proper NGK application for any Subaru application, including JDM engines.

[cj91legss]

hmm, I see... I would have thought to use the Correct plug that is recommended for the Head you apply to your block.

[kimokalihi]

Identifix often gets calls from techs stumped on a nostart
with supposedly all the magic ingredients: Spark, fuel,
and compression at 110 psi.The problem is a skipped belt.
A properly timed car will typically crank out 175 psi.Two
teeth off will drop it to around 110 and the engine won’t
start.You might want to think about checking ignition timing
while cranking the engine.

[Grayguy]

So, is there any intake mani that will bolt to these style (I have ej25D heads) heads that has the more arched intake runners so the air intake for the turbo can pass under the intake manifold like the newer turbo cars?

[mike-tracy]

^^ EJ20k intake manifold should fit the bill, and has provisions for mounting the coil pack in the normal place.

[Grayguy]

What cars had those/how hard are they to come by?

[kimokalihi]

97 JDM forester is one. The 93-98 JDM legacy twin turbos had under the manifold intake even though split and fed both turbos.

[Grayguy]

Hmm, maybe I'll have to track on of these down and play with it. I Hate how cluttered the intake area is on 92 stock, and I'd like to switch it up when I put the Dohcs on.

Does anyone know if I need the ej20K IAC too? And are the fuel rails the same?

[JDMath]

i did the swap! and the car really dont run well , do i need to retune ?? revtronix stage 2 chip.... dont know whats the problem...