timing wheels/cogs??

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slidewayzagain
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timing wheels/cogs??

Post by slidewayzagain »

93 s13 ka24de
is there a difference between the intake cog and the exhaust cog in the clocking of the keyway slots?
Mine have approximately .25" difference.
Method of discovery is using the upper timing chain to align the cogs tooth for tooth and one cog is different in the keyway (the slot that goes on the nipple on the cams).
I have jwt gears that I am trying to install a 248 ex cam intake side and a 264 bc intake to use on the ex side and have been having a nightmare.
I then took the jwt gears lined up tooth for too :!: th using the chain wrapped around the gears and noticed that 1 stock gear all lines up good with both jwt gears keyway and all, but 1 stock gear does not.
I will try to get a pic posted in the next few moments for viewing.
may your rods stay oiled and your nuts tight
slidewayzagain
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pics of off set

Post by slidewayzagain »

Image
Image
[/img]
the top is the offset being shown with stock gears
only 1 gear is offset this way is this normal or not? all 3 other gears line up perfect.
may your rods stay oiled and your nuts tight
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Walperstyle
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Post by Walperstyle »

With JWT cam gears each hole Isn't 2.5 degrees... you have to line up the hole, and the number on the gear to get the 2.5 increments. Its hard to explain via text. I have a video on youtube that might help.

Basically, you have to lock one cam while you work on the other, rotate the cam to fit the hole, while you also line up the number. Number to number, letter to letter at TDC. Then you will have the proper adjustment.

ps, why do you have the chain on the single cog? I'm confused at what you are trying to do with it installed all like that. The timing chain goes over the top to the 2nd cog. It will line up, when it does, then you have the results near where you want.
Image
slidewayzagain
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Post by slidewayzagain »

in the top pic you can see the keyway slot is misaligned on one of my stock gears.
all three others match up correclty, I was trying to figure out if I had a bad lwt gear or a weird stock gear.
Also whhen degreeing a 248 cam for intake what the normal alignment for jwt gears, stok is either 3 or 4 teeth ccw for the gear.
the bc 264 intake aligns perfect on the exhaust side, but that 248 has been a pain to get to match any number/letter combo.
the dowel on the 248 is between 7 and 8 oclock when using the 3/4 teeth method.
may your rods stay oiled and your nuts tight
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nismoautoxr
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Post by nismoautoxr »

When you sent me the text last night ...I thought you were having trouble with stock gears and cams . Unfortunately Im afraid I cant offer any input on your quandry there . I have had no experience with JWT gears or installing an exhaust cam in
the intake side but I do know a little about split overlap and opening and closing times so read read read on that and if you dont have a degree wheel and a good dial indicator by all mean buy one and learn the ropes of using it .

Back when I was doing circle track racing and toying with differant cam timing configurations....I used to remove the dowel pins from teh cams all together ....degree everything the way I needed it and then repin everything ...that way you dont have to worry about this that and the other working or not working or making sacrifices just because that is as close as you could mechanically get it in its current configuration which is almost always a fair amount of lost potential power and driveability. Just a suggestion for you and that requires no expensive gears
Ricky Ragan,
95 SE ,LS1 N/A and T56, 230/232 @.050 cam, MS3 with MS3X,GC coilovers,17x8.5 Enkei RPF1 on 255 40 17 RS3 Hankooks, 377HP/351TQ , megasquirt3 fully sequential
slidewayzagain
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Post by slidewayzagain »

ok after more studying I found out that
the keyways should be the same.
the idler sprocket is one tooth off every so many turns.
in this thread this is where I rmove the upper chain and reinstall at
Kfred wrote:Image

If the motor is at TDC in this picture, and the dot on the idler lines up with the red dot I put in the picture, then the timing is right. Let me know if the dot on the idler lines up with the red dot, i can't tell from the pictures. The best way to check is going to be to slowly rotate the engine CCW a hair, then you should be able to tell which link the idler dot will mesh with.
viewtopic.php?t=47855&postdays=0&postor ... l&start=20
talking about the 6 oclock position on the idler being correct not the 5 oclock at tdc
I install the 248 cam 4 teeth ccw the 264 bc cam at stck spot .
you swap the in and ex over whith bc cams
now if only I can get the jwt gears to align on the 248 ex cam im using onthe in side
gonna give jwt a email/chat and see if they can advise me a start point using their gears
may your rods stay oiled and your nuts tight
slidewayzagain
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Post by slidewayzagain »

[quote="supakat"]The cams are correct. If you were to swap cams, it would hit the piston most likely. Remember with these, you swap the exhaust for intake. So the orange goes to intake and green exhaust. The intake cam actually has two dowel pins. Also to clarify, I matched these up against stock 248 and 240 cams. When I say 6, I mean unmarked links. I would like to add if I touch the chain in between the cams where the top guide is, it will advance the cam as well. I am pretty sure the tensioner should hold the cam back from advancing.
Image[/quote
in this thread it shows the 5 0clock position for the idler marks
which of theses is correct for tdc
may your rods stay oiled and your nuts tight
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sdaigle240
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Post by sdaigle240 »

i think you have to count links not look at dots. the dots work for first time assembly but liek stated they dont always line back up after rotating the motor. if you put the first piston at TDC and your cams are pointing the right way with the correct amount of links between i think you are good regardless of how the ideler is lined up. most likely u know this and im missing the problem all together.

http://www.nicoclub.com/FSM/240sx/1995/EM.pdf check out pg-17-19 for factory chain diagrams
airman wrote:I'm all about spreadsheets. Bitches love spreadsheets.
schmauster920 wrote:I shall cast my own pistons in the sands of time, then forge them in the depths of hell.. as funds allow
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slidewayzagain
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Post by slidewayzagain »

thats about the answer I got from jwt guy.
But this is a new assembly still on stand.
as long as I am at tdc cams lobe pointing out I can use either position on the idler 5oclock or 6 oclock .
so I will install the bc cam straight up and the 248 4 teeth ccw mark these as 1 an 1 for the jwt then adjust from there
I will be setting for a 0 or negative overlap and as close to this as possible with inatake opening 1 degree atdc
Intake Duration 215* @ .050" (248 Advertised)
Max Lift: .367" (9.32mm
Exhaust duration: 218 at .050" (264 advertised
Exhaust lift: .375" (9.53mm)
so its off to the garage I go
if any1 has degreed the 248 248 with jwt gears like supakat done (which I am copying)
chime in
may your rods stay oiled and your nuts tight
slidewayzagain
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Post by slidewayzagain »

so this is the final results if I done it even halfway corect...
Lsa113
Your cam has an Overlap of -12.00 degrees
Intake Duration of 214.00 degrees.
The Exhaust Duration is 214.00 degrees.
The Inlet Cam has an Installed Centerline of 98.00 degrees ATDC.
The exhaust cam has an Installed Centerline of 128.00 degrees BTDC
intake open 9 btdc
intake close 25 abdc
exhaust opens 55 bbdc
exhaust closes 21 btdc
this is using a 248 s13 exhaust cam for intake and a bc 264 for exhaust and
http://www.wallaceracing.com/camcalc.php
for the calc
my setup
1993 ka24de 89.5 bore 8.5:1 compression supertech
248 s13 exhaust cam for intake and a bc 264 for exhaust
holset hy35w 9cm housing on a cast iron revhard type mani
stock head shimmed .009"-.011" intake annd exhaust
godspeed intake mani
ms2 with ls2 cop and sequntial injectio 850cc/min
isis 255 fuel pump
may your rods stay oiled and your nuts tight
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