RB26 cams in an RB20...i did it...kinda

[love_boost]

maybe like skym pointed out you need to do the switch over to solid lifters, it makes a bit more sense.

not speaking from experience or knowledge but you may have to get it properly tuned?

[FunnyGas]

ok. so i got it home sunday. it wouldnt idle on its own. no power before 3000rpm. After 4500rpm it woke up.
so monday night I re did the timing belt. i set the cam gears to 0, and lined up all the timing marks. once i got the timing belt on and set tension i rotated it a bunch of times, and each time it got back to TDC the cam marks were dead on the money. so i started adjusting the cams. got it running the same as sunday night. left it at that.
tried again last night.
was talking to dan (Danno) at the same time. we figured out that the gears are marked wrong. advance and retard are mixed up. when i advance the cam i turn it clockwise as the engine turns clockwise. when i do this the notches go up on the Retard side. knowing this I set it at the reccomended +2 IN -4 EXH. the compression was up to about 80-90 psi compared to the 60-70 from before, and i could hear it when i was cranking, you could hear compression strokes again..
so i hooked everything back up. start up the car. and there is a clunking noise. shut off the car right away. pulled the CAS. checked the gears, nothing slipped. cranked it w/o the CAS. sounds fine. plug in the CAS, it clunks. the clunk is fairly loud. so i crank it over with out fuel (pulled the pump fuse). sound is gone. now no matter what i set the gears at. i get no clunking noise when there is no fuel (CAS off), and when there is fuel.. a clunk.
im soo stumped now... i mean beyond the fact that the cams are giving me greif. now the noise.
any suggestions?

[mcfly]

I would be trying to put the stock cams back in and hoping nothing is broken.

[FunnyGas]

thats the plan tonight.

[J-Ran]

boooooooooooo!

[Dragon Humper]

You guys should try and measure the base circle diameter of the rb20 cams, it seems that could be the largest problem.

That's a good idea. If they are diff. and it's not by much then the hydro followers should be able to make up the diff.

FunnyG, check your PM's.


Jon.

[eklips3]

soo ... what happened in the end ? im still undecided weather or not i should throw in my gtr cams into my rb20 or stick with the stock cams

[FunnyGas]

ok. base circle diameter is off between the 2 cams. rb26 cams are bigger. if you install the 26 cams you have to bleed the lifters, install them, install the cams. fire up the car and hope they pump back up. the issue everyone has is the valves never fully close. this is solved by bleeding the lifters. **DO NOTE** bleeding the lifters is not reccomended by nissan etc. as it shortens the life of the lifters.
when you fire up the car with colapsed lifters.. it will sound REALLY bad. you will have to run the car a few minutes to pump them back up. but it will go away.
its reccomended to use adjustable cam gears as the cam timing is out a few degrees.
i might try it again over the winter.

[ARC240]

No harm done dude, you went out on a limb and tried it out, so kudos to you for that. I bet it was a good learning experience and you've posted some good info for everyone that might be looking to do the same. Let us know how you make out on the second attempt!

[FunnyGas]

well. i got REALLY good at changing timing belts. haha. really its not a hard swap. there was just no info. the ones that did it successfully didnt post exactly how they did it. and the ones who hit the same snag we all do, didnt know why.

[DRIFT4LIFE]

cams

are rb 20,25,26 cams interchangeable?

[love_boost]

from what i know yes.

if you were to swap to solid lifters would it take this problem away?

[linedriver]

from what i know yes.

if you were to swap to solid lifters would it take this problem away?

if your going that far, your beter off buying a set of RB20 poncams or something. aftermarket head parts arent cheap, so if you spend money on lifters to use GTR cams, you might as well get a set of real RB20 cams rather then using what could work.

[love_boost]

have you got it figured out funny gas?
im going to give it a go, i have a spare head if things go wrong. might take a few weeks to get everything done but ill give it a try.

will solid lifters from a GTR slide right in? or will i have to get the valve springs ect?

[FunnyGas]

from what i understood. you need adj cam gears to account for the difference in timing. check the tomei link i posted and make your calculations there. and you will need to bleed the hydraulic lifters. this will allow them to adjust to the larger base circle diameter of the gtr cams. (this is the step most skip that causes the problems, not doing this will have the lifters set for the smaller rb20 cam base circle diameter and the valves wont make a proper seal).
let me know how it goes. i wanna give this another try in the new year.