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View Full Version : How do you time a rb20 HELP PLEASE


lrb99
06-02-2011, 09:10 PM
I just got this and I'm thinking timing so any pics/info will help me a ton the guy said he put a new cam angle sensor and I don't know what he did it had some electrical issues I got this worked out and now this thanks

96Turbo
06-02-2011, 09:13 PM
google search for an rb20 fsm (factory service manual)

it will walk you through it, step by step


on my rb25, you're supposed to warm it up, then unplug the tps (throttle position switch), and set the idle to 750 RPM.

Using a timing light look at the crank pulley, the far left mark is 0* BTDC and each mark to the right is 5*. On the RB25 spec is 15* BTDC at idle. Loosen the 3 10mm bolts on the CAS (front timing belt cover on the end of the exhaust cam) and turn it till you get 15*

Sileighty_85
06-02-2011, 09:14 PM
Mechanical or Electrical timing?

Electrical :the CAS only goes in one way.

lrb99
06-02-2011, 09:58 PM
It just won't start it cranks good I just don't know anything about RBs I've only had KAs so its new to me I don't really know how to check spark on individual coil pack plugs and I don't know if the guy I bought the car from even put a CAS into it or not so how do I check if that's good or not ? Would that make it not start?

curbhuggerrps13
06-02-2011, 10:06 PM
remember a small thing back back back way in the days called a distributor? well its like one of those but with alien future technology added.

Sileighty_85
06-02-2011, 10:12 PM
whats the Part Number on the CAS?

lrb99
06-03-2011, 03:49 PM
CAS # is there are two different numbers so the one closest to the motor is T2T49171 4y24A . The one closest to the radaitor is 2373102U11

Sileighty_85
06-03-2011, 05:12 PM
I dont think thats the right CAS for your engine

http://i73.photobucket.com/albums/i235/Neil_85/FAST/CASSearch.jpg

dsastr_clan
06-03-2011, 05:14 PM
damn ^^this guy is good???

lrb99
06-03-2011, 06:15 PM
I know it has a Mitsubishi emblem WTF is that I thought that seemed weird and yes your the kinda help I needed thank you

lrb99
06-04-2011, 02:52 PM
I need help. I need to know if I need to retime my car after I put a new CAS in ? Any one have anything on this kinda stuff?

Sileighty_85
06-04-2011, 02:57 PM
Like I said it only goes in one way should be around this area, you will still need a timing light to get it set correctly (this should be the top left one looking at it)
http://i73.photobucket.com/albums/i235/Neil_85/Miyukis%20Silvia/DSCN5312.jpg

but if that is the wrong CAS then the engine will not run

lrb99
06-04-2011, 03:20 PM
My numbers were wrong? There are bigger and smaller ones what numbers am I looking for?

Sileighty_85
06-04-2011, 03:52 PM
Give me the ECU # and I can pin point it better

lrb99
06-04-2011, 04:15 PM
Ecu# is 23710 04u02. The mec# is r132. 1112

Sileighty_85
06-04-2011, 04:26 PM
well FAST gives that part number that your CAS has but doesnt show up under the Parts Manager

But this CAS P/N 23731-08U00- shows as being used on your RB

and FYI your RB is a 90-91 if you didnt know.

Id check over your harness and connections before locating another CAS

singlecamslam
06-04-2011, 04:35 PM
On my rb25 the cas top bolt is to the right, and the car runs fine, but i know its supposed to be right in the center. My idle wont go below 1000 RPM, so how can i time it...? i have a timing light and not sure where to hook it up, and wont it be useless if i cant get the right idle?

Also, should i just manually time it by adjusting the cas, and making sure that is directly centered the best i can? SORRY FOR THREAD JACK

lrb99
06-04-2011, 04:45 PM
Your cool I need to know pretty much the same thing. As it sits now it won't start but cranks good sounds like it should startbut won't I'm lost on this like I said I've only had KAs. How do I check spark?

lrb99
06-04-2011, 04:48 PM
CAS # is there are two different numbers so the one closest to the motor is T2T49171 4y24A . The one closest to the radaitor is 2373102U11

Mine is wrong then

lrb99
06-06-2011, 04:37 PM
I did go through the harness everything looks good but when I bought the car he told me he had to replace the CAS and I wonder if he got the wrong one ? And never figured it out I don't know I'm an ok mechanic but I don't know much about this motor when I put the new CAS in do I have to time it ? Or is it plug and play and adjust the CAS ?

singlecamslam
06-06-2011, 09:45 PM
Here's what mine looks like at the moment. I know being rotated this way it leans the engine out. My car runs perfect and is fast so i dont want to be messing with it, but do you guys thing aligning it right in the middle would be a good thing? Just by eyballing it/ measuring both sides.
http://i200.photobucket.com/albums/aa37/oldskool916/012.jpg

lrb99
06-06-2011, 10:24 PM
Any info on timing???

Pandapants
06-07-2011, 04:21 PM
Mechanically, make sure the markings on the cam pulleys line up with the markings on the back of the timing cover, and the marking on the crank gear lines up with the marking on the oil pump. This is top dead center. Locate the lines on the timing belt (new I hope), make sure the belt is facing forward, and align the markings on the belt with their respective markings on the cams/crank gears. If done correctly, you should have 46 cogs (NOT TEETH!!!), not counting the alignment marks themselves, between the crank pulley mark and the exhaust pulley mark (48 cogs if you count the cam marking, 49 if you count the crank and cam marking. You should also have 37 cogs between each cam marking, 38 if you count the intake cam marking, 39 if you count both cam markings.

Electrically, the cam angle sensor has a marking on the backside of the sensor; it's a little dot, and a marking on the drive spindle. You just match those markings up and insert the sensor into the cam, and bolt up the 3 bolts. Double check your work with a timing gun. Hope that makes sense.

singlecamslam
06-07-2011, 04:59 PM
Heres what that guy is talking about in pictures. Follow this and i'm sure you'll figure it out.

How to Guide_Changing the Timing Belt on a RB25DET (http://www.scribd.com/doc/16408415/How-to-GuideChanging-the-Timing-Belt-on-a-RB25DET)

Than in order to use a timing gun i would make a wire going from the no. 1 coilpack to the spark plug so you can use a timing gun.

lrb99
06-07-2011, 05:43 PM
Yeah I was following it kinda thank you

Zacho
06-07-2011, 06:41 PM
If you are unsure if your CAS is functioning take out the fuel pump fuse, remove cas, ignition ON and spin it with your fingers. Listen for injector clicks.

Sileighty_85
06-07-2011, 06:43 PM
does the fuel rail have little black plastic spacer where the mounting bolts go?

lrb99
06-07-2011, 09:54 PM
KAs are like that I'm not sure would have to look

lrb99
06-09-2011, 05:18 AM
I get my new CAS today or tomorrow I'll let you guys know what happens thanks

lrb99
06-09-2011, 04:39 PM
The CAS I got has different numbers to the numbers are. 23731. 02U10. I'm lost on this maybe my ignitor went bad? I have no clue