RB26 cam swap into an RB20

[Sil240]

What lifters would I use? RB26 or aftermarket?

I'll check up on prices, and see if the wallet agrees.

NOPE, they are the same as VG30.NOT RB26 as i put before. If you can get the ones that were with your cams.So they have the same wear pattern.Or you can get the Tomei ones i think they're like 350-500 can't remember.Just remember to RE-Break in the cams.Assembly Lube

NEVER GO IN DRY!!!!!!! lol :-)
Modified by Sil240 at 8:21 PM 1/23/2007

[DriftingisLame]

Yeah I lubed the piss out of them, dont worry..

I'll look in to the tomei ones, or keep an eye out for 26's

[Sil240]

Cool coolSo you got her running??What was the problem?I think i missed it.

How's the idle? (like stock i'm guessing)Did the sound change at all? (Intake or Exhaust)

[Shahee1]

For what its worth... My 200,000 km+ rb20 made it from eugene, OR, to phoenix, AZ (24 hour drive?). Never got hot, never had to stop to fix anything... Developed a miss about an hour before I arrived, but I think I know where a loose connection is.

RB FTW

When I was looking into this swap it was 2 or 3 yrs ago and he was on his first cam swap ... I dropped it after searching for months on several forums ... decided to go aftermarket.

[DriftingisLame]

Cool coolSo you got her running??What was the problem?I think i missed it.

How's the idle? (like stock i'm guessing)Did the sound change at all? (Intake or Exhaust)

Yeah its been running for a while.. Since I created this thread lol! The idle's sucked since the day I bought it. Its always been a little low and unsteady, its the same as it used to be but with a kick *** sounding lump to it... but it wants to die a lot. I know the cams are contributing, but the idle should be better than it is regardless.

Idle sounds different, way cooler.. Through the power band its not much louder, might have more of a growl though.

[klh6686]

You need to take a look at this, specefically the cam lobe center angles. As you can see, a 26 and 20 do not have the same cam lobe center angles. I'm by no means a camshaft expert but i believe this is going to affect the timing slightly and i believe your car w/ 26 cams on 20 stock timing is actually going to have some valve overlap at idle! this is why your idle is ****ty. You need some adjustable cam gears and you need to adjust the cams until you get a good idle and good power.

Also, rb26 lifters will not go in a 20 head, or a 25 for that matter!!! stop spreading wrong information!!! if you want solid lifter you need to A) Buy a rb25 and swap 100% full gtr valvetrain into it (from valve seats, valves, valve guides, spings, retainers, lifters, EVERYTHING!) B) buy a neo 25 C) buy a 26 D) Buy aftermarket solid lifters for 20.

BTW: I researched some old posts from sydneykid and he recomends starting at 2 deg adv on intake and 4 deg retard on exhaust.



Disclaimer: all this is IMHO
Modified by klh6686 at 2:43 PM 1/23/2007

[Sil240]

Yup he's right Its the VG30 lifters that fit not the Rb26.Don't think those come solid stock, at least the US versions.

Take a look here.http://www.tomei-p.co.jp/_2003...b2520

[DriftingisLame]

You need to take a look at this, specefically the cam lobe center angles. As you can see, a 26 and 20 do not have the same cam lobe center angles. I'm by no means a camshaft expert but i believe this is going to affect the timing slightly and i believe your car w/ 26 cams on 20 stock timing is actually going to have some valve overlap at idle! this is why your idle is ****ty. You need some adjustable cam gears and you need to adjust the cams until you get a good idle and good power.

Also, rb26 lifters will not go in a 20 head, or a 25 for that matter!!! stop spreading wrong information!!! if you want solid lifter you need to A) Buy a rb25 and swap 100% full gtr valvetrain into it (from valve seats, valves, valve guides, spings, retainers, lifters, EVERYTHING!) B) buy a neo 25 C) buy a 26 D) Buy aftermarket solid lifters for 20.

BTW: I researched some old posts from sydneykid and he recomends starting at 2 deg adv on intake and 4 deg retard on exhaust.



Disclaimer: all this is IMHO

Modified by klh6686 at 2:43 PM 1/23/2007

I spread no wrong information..

This helps immensely! Where did you find that graph?! I saw SK's post suggesting adjustable cam gears and a setting to start with... I am a newb at this still so I would not know what to do after the +2IN -4EX.. I dont know how you're supposed to tune that properly. Since I dont fully know what I'm doing with the adjustable cam gears, I'll keep reading and buy some when I'm ready. I wouldnt buy cam gears and take SK's word for it, and just adjust them to the settings he suggests.

I'm also going to keep reading into the solid lifter conversion, and decide if its worth it or absolutely necessary.

Thanks for the information-Max

[klh6686]

I didn't mean you specifically in spreading wrong information, mainly the people that say to just get rb26 lifters, but like i said they WILL NOT work in any other rb head unless you swap ALL items in the head to gtr parts. Also, I would recommend that you purchase some cam gears or make your stock one adjustable or figure out something. SydneyKid is probably one of the most knowledgeable english speaking persons that you will ever come across in regards to dealing with any RB series motors. Anyways, you need to do something to straighten up that idle because at that duration your idle shouldn't sound much different than stock.

[DriftingisLame]

Yeah you're right. I will be checkin around on ebay for some adjustable cam gears.

Do you think the different cam angles of the rb26 cams would cause only bad idle? Or would my top end be effected negatively as well? I havent noticed much of a top end gain, which is what I was expecting.. Maybe cam gears are a must, to be able to make use of the larger rb26 cams.

How will I know how to properly adjust my cam gears though? That is something I know nothing about.

[klh6686]

yea, like i said, I'm no cam expert either. The key to adjusting your cam gears would be understanding the difference in the lobe center angles and how that affects valve overlap. the way your car is now suggests it has too much valve overlap at idle thus struggling to keep an idle. This will affect your top end as well but not as drastically as your idle.

Let's look at the lobe center angles: (assuming r32)

rb20detIn: 115Ex: 120rb26detIn: 113Ex: 125

Now this is assuming your rb26 cam is a standard r32, do you know that it is for sure?

Now like i said, I am in no means a cam expert but you can tell that you need to adjust your current intake cam 2 degs to make it similar to the rb20 and the exhaust 5 degs to make it similar. I do not know for sure which way they need to be adjusted but going by what sydneykid said there ya go.

[DriftingisLame]

Okay great, thats very helpfull!

I was actually told these were r33 rb26 camshafts.

[klh6686]

Ok well standard r33 has same spec as r32 so no change there. One thing you should probably check out to confirm valve overlap at idle is your compression. I don't know how well this would work for you, but once you get the adj cam, adjust them to the specifications and then recheck the compression. Ex: currently compression should be low because of valve overlap maybe 100 psi. adjust cam gears, if compression goes up to 170 or so you should be better than you were. Best way to adjust them is on a dyno though.

[DriftingisLame]

Cool, I'll try that.

I will probably be dyno testing the car after the cam gear installation.. The thing is, seems like it would take a lot of trial and error, and dyno time is expensive.

Thanks again for the help.. I really appreciate it!

-Max

[Sil240]

GTR Shop 30-06-2005 06:20 PM --------------------------------------------------------------------------------You can fit solid into hyd and visa versa.My question being.. why? solid cams have a less agressive ramp rate due to not have to compensate for hyd lifter squash.If anything, keep the hyd cams and convert to solid lifter.

You should install the cams & cam gears set at 0. Then adjust them on the dyno.That is the only way you'll know if your making progress.

[DriftingisLame]

How do I know if the tune is correct? Making more power from the adjustments on the dyno doesnt necessarily mean I'm adjusting them in the proper direction..

Kinda like rotating the boost controller knob in the + direction, yes it will make more power.. haha.

I just want to make sure the cam timing is safe.. And I dont know what the crap I'm doing lol.

[Cpt_Impossible]

This is why wideband and knock sensor are your friend.

[DriftingisLame]

Feel free to go into detail.. I am but a newb

[Sil240]

Hey,did you every find the procedure to set the cams??

I think that might be my problem.I have the FSM at my parents house but I wanted to go over it before this weekend.

You should set the cam gears on the DYNO.Yeah having a Wideband and a Knock sensor are good, so you have keep safe Air/Fuel ratio's and make sure your not pinging.

But pretty much you adjust it slightly then take a pull, then keep on going till you get max power & reliability.

[DriftingisLame]

Right now I'd rather it just idle and have as much power as before than maximum power lol! Dont want to push my luck.

Right now I'm basically convinced that if I spend another $200 on adjustable cam gears, I'd solve my idle problems and actually utilize the higher lift and duration for a real power gain.

Then I'm still using hydraulic lifters... +$400 for tomei... Suddenly the stock cams are starting to look very tempting.

I just moved 1200 miles from home.. $600 isnt in my budget right now. I'm either forced to wait untill my tax returns get here or throw the stockers back in.

[Sil240]

The FSM says you are supposed to install the cams with the knock pins rotated 15 degrees from horizontal (CW on the intake cam and CCW on the exhaust cam). Darius-

Did you degree your cams properly?Because I know I just slapped mine in.That's where I messed up.

Man well y don't you yank those cams out for right now. Put them in a safe place till you have $$.Moving is kinda more important that cams.

[DriftingisLame]

I'm not sure what you mean, but yeah.. I just slapped em in. Seems like there was only one way to put them in though.. I took pictures of the cam lobes in relation to the cam caps and lined up the new cams like the old ones... When I bolted on the cam gears, my marks were already lined up. I thought I did it right anyway, Lol.

Thats probably what I'll be doing, get my low end torque back, and be able to idle like normal in phoenix traffic. Holy crap that would be awesome.

[Sil240]

lnstallation. Align the crank pulley timing indicator and the timing belt cover timing indicator (0 deg) so No. 1 cyl is at compression T.D.C. position. (This operation is not necessary when the cylinder head is removed as single unit).

Turn the camshaft so No. 1 cyl is at compression T.D.C. position (Operation is easier if th camshaft is turned 60 deg before or after No. 1 cyl T.D.C point when the cylinder head is installed as single unit).

Verify the position of No. 1 cyl is at compression T.D.C by knock pin in front end of camshaft.

To install camshaft, temporarily tighten NO. 1 cam bracket and check that camshaft thrust section is positioned securely.

Tighten camshaft bolt 540 deg (1.5 turns) in the order shown in the figure one the previos page.Cam bracket tightening torque (kg-m): 0.92 - 1.2

Caution:1 Coat the cam journals and end of the camshaft with engine oil before installlation.2 Do not rotate camshaft. ( The valve and pistons may interfere)

[DriftingisLame]

I didnt move piston 1 to TDC, but I marked the **** out of everything... Literally the cam gears went back on exactly the same as they came off, and the timing belt marks lined up.. It was stated earlier that the cam lobe center is a few degrees different on the 26 cams, so the adjustable cam gears are necessary.

I'll put in my stock cams this weekend. I've had this plan for a while to build a spare block with my tax returns. Maybe I'll do all of this at the same time, and put the 26 cams on the shelf for now..