Removing/Installing RB head

[240slidekat]

can someone give me a quick run through on removing and installing an RB25 head. i was going through the manual and its kinda confusing and i also heard that theirs different angles when you torque or something???

[Shocker]

remove the timing belt, take off the cam gears, you can pull the cams if you'd like to keep the valves in the head so you dont bend them on accident...

Then remove the 3 holder bolts, theres 1 up front by the intake, and 2 in the far back they have 10mm heads.

Start at the front side or back of the head doesn't matter, do the last row, then the first, then second to last, then the second to first set... and so forth, go back and forth. Then remove the head...

Install is the reverse procedure of this, you need to make sure you re face the head, and if your using a metal HG I suggest the block to. Look at some of the head gasket threads for more info.

thats just a brief summary and how I do it. If your leaving the cams in make sure your TDC so you can access the head bolts.

[Darius]

DO NOT reinstall the cams with the motor at TDC! Rotate the crank ccw from TDC until all the pistons are about equally recessed in their bores. That way the valves won't get bent when the cam shafts are reinstalled (I don't know of anyone who has personally done this<cough> , but um, I have heard of it happening to someone ). The reason being the cams can only be installed in a certain position or they won't lie straight. Once the cams are in, you can rotate them to the TDC position and then SLOWLY AND CAREFULLY rotate the crank cw to TDC to line up the marks for the timing belt installation. If you feel any resistance, stop and evaluate.

[Coolwhip]

Rub it in time?

As well. If you have ARP head studs currently installed, I suggest removing them before trying to slide that heavy head off of them straight. It's a royal PITA with them installed.

[Shocker]

lol Matt, well if you keep the cam dowels 15 degrees above horizontal like the picture shows it works perfect, you just need to really watch the #6 cylinder and what that lobe is doing... the cams want to twist their own way while being tightened. So I slowly cap them and rotate them with my wrench to the proper position. When its time to put the gears on they are pretty much dead nuts.

FSM tells you to do it that way for a reason....

I do agree. do double triple 1000xxxx times check that ****ing belt. I counted all the teeth like 5 times on each side before I even considered rotating it. Then I turn it over about 20 times ever so slow, just listening and feeling for any resistance. Do make sure your spark plugs arnt in while doing this, and you have tape over the holes of them......(been there done that)...

[gawdzilla]

can someone give me a quick run through on removing and installing an RB25 head. i was going through the manual and its kinda confusing and i also heard that theirs different angles when you torque or something???

the angles when you torque that you're referring to is an alternate way of getting proper torque using a different style tq wrench. most people use the bending tq wrench or the clicking ones now

you shouldn't have a problem putting the cams in when the motor is TDC. just clock the cams like the FSM says

[Darius]

Oh I read the FSM and followed the install procedure except I must have been off on my cam alignment. However, I couldn't have been off by more than 10-15 degrees and I ended up torquing my head down with my valve resting on my #6 piston. This is why I modified my install procedure to take any potential of f__king up the valves out of the equation.

[Shocker]

Yeah your cam angle had to have been off... I install my cams once in my head son my block. You had to have to since your running HKS cams...

When at TDC as you know #1 and #6 are all the way up. So I visually watch my lobes as long as they are on their main circle and not lobe, theres going to be ZERO contact.

If it works for you awesome! I just like using my FSM as a reference for personal relief lol.

[240slidekat]

most of the things you guys said make sense. ok now how bout torqueing the head. i believe the arp are suppose to be torque at 80 ft/lbs. so do i torque it 40 ft/lbs in the sequence mentioned above then 80 ft/lbs?

[Coolwhip]

70ft/lbs if you're using the ARP moly paste

[240slidekat]

i pulled the head out today and its confirmed my #4 valves are stuck open. the block looks fine though.

[Coolwhip]

did you end up picking up that head you were looking at?

[240slidekat]

yea not just need time to put it in.

[tgxlayzie]

realy late but just joined the forum but shocker seems like u missed steps on the removal. 2 take off da head where are these 3 10 mm bolts and bolts that you start from the outside n work your way in. are they under the valve covers. and also i see 3 alan key bolts between the spark plugs do you take those out as well are its not nessesary. and from what i understand if the 1st cylinder is at tdc you dont have 2 take out the cams or is it nessesary to take them out 2 get 2 the head bolts?

[tgxlayzie]

o yia n where can i get a fsm

[Coolwhip]

two around the outside of the cylinder head toward the back of cylinder 6.

1 is also on the exterior toward the front by cylinder 1.

The hex plugs in the head are for the coolant system, no need to remove them.

TDC will leave the notches in the cam shafts exposing the head bolts. No need to remove cams for this effort.

[rbs14kouki]

got my FSM here : http://phase2motorsports.store....html

i did not took the cams out of the head for the instalation !!! i have a rb26dett !!! i think it's the same for the rb25

[Coolwhip]

a picture of a RB30 but it has the same bolt locations as the RB25.

Marked in red...

[StricNyne]

i like how u ninja 'ed that rb30 pic in there

[supersayianjim]

bumppers, why because iam going to do a head job next month. how "important" is it to get the head decked?? iam keeping the bottom end in the car.

and if iam removing the head, do i need to take each bolt off in a 2 part sequence?? or removal, it dosent matter??

[Darius]

If you aren't reinstalling a metal head gasket, then you can leave the bottom end in it and not deck the head. If you want to use an MLS gasket, you'll need to disassemble the block and have that milled flat too.

And no you don't have to remove the head bolts in a 2 part step. Just make sure you loosen from outside into the middle and tighten from the middle out. I'd recommend upgrading to ARP studs and nuts while you have it apart.

[Coolwhip]

I'll ninja my way back in this thread..

If anyone needs ARP head studs and head gasket (or top end gasket kits) let me know you're from Nico and I'll hook it up.

http://www.rawbrokerage.com/arp-202-430 ... rb20-rb25/

http://www.rawbrokerage.com/cometic-pro ... -051-rb25/

[email protected]

[supersayianjim]

If you aren't reinstalling a metal head gasket, then you can leave the bottom end in it and not deck the head. If you want to use an MLS gasket, you'll need to disassemble the block and have that milled flat too.

And no you don't have to remove the head bolts in a 2 part step. Just make sure you loosen from outside into the middle and tighten from the middle out. I'd recommend upgrading to ARP studs and nuts while you have it apart.

so touching(not myself) on this some more..

-ive heard that from a few people that the iron block dosen't need to be decked. so what would happen if i just mill the head and install a mls and some head studs???

-also not sure how the milling process goes exactly, but don't they take material from the bottom of the head?? and if thats so hence why they have different head gasket thicknesses??

-provided i did go with an oem replacement, would a new gasket and studs last up to higher boost than the stock bolts??

[Darius]

so touching(not myself) on this some more..

-ive heard that from a few people that the iron block dosen't need to be decked. so what would happen if i just mill the head and install a mls and some head studs???

-also not sure how the milling process goes exactly, but don't they take material from the bottom of the head?? and if thats so hence why they have different head gasket thicknesses??

-provided i did go with an oem replacement, would a new gasket and studs last up to higher boost than the stock bolts??

I tried not milling the block my first time around with an MLS and it was a bad idea. I pulled it all apart again when the head leaked coolant and ended up milling the block anyways.

Yeah they remove material from the head surface and you can compensate with a thicker gasket. Typically, they don't take enough off to make much difference.

Yes, many people remove the old gasket, clean up both surfaces, put a new OEM gasket in with ARP studs and have pushed decent amounts of power out of it with no trouble.

[240z4u]

I have said this a million times. Stock block motors break ringlands before destroying headgaskets almost every time.

[X-TuN]

Off Topic: What is the socket size for the nut of the ARP head studs for the RB26DETT. I know its 12 point. So far I've tried a 12 point 11mm, 12mm 1/2" but they were all to small. Does anyone know?

[Coolwhip]

IIRC should be a 12point 1/2" if not 13mm.

[X-TuN]

IIRC should be a 12point 1/2" if not 13mm.

Thanks Rick but it's actually a 12 point, 14mm deep socket.

[Linux2501]

To bring up an old post and to ask a serious question and not to be flamed, If say I were to replace the HG on an rb20 without it being blown Would i just need to get it milled or just cleaning the material off and replacing it with an Oem Nissan HG would be okay. Suggestions?