TRD 4AGE cam gears- Indexed (and 1JZ)

[oldcorollas]

so i was bored and decided to index the TRD camgears i have lying around.
they are basically stock camgears which have been drilled out by TRD.. they have a good fit onto the cam.

the change in angle of the cam is listed as positive (advancing), or negative (retarding) from the slot i designated as the zero position.

as you move from holes 1 to 2 to 3 etc, and hold the cam still, the gear teeth move clockwise relative to the cam.
ie, the cam moves anticlockwise relative to the belt (retarding) if you engage the ger and belt as nearest position.

for example, if you change holes from 1 to 2, and line the teeth up to the nearest position, you will retard the cam by 2.5 cam degrees.

to get the cam to advance (+ve numbers on diagram), you need to advance the gam gear one tooth (and then the holes effectively retard from the new position).

holes 6 7 and 8 are effectively retarded a whole tooth. holes 7 and 8 are the same position as holes 2 and 3, just one tooth out.

there are 36 teeth and so the teeth are 10 cam deg apart,
to work out crank degrees, multiply the cam angle change by 2.

a summary, in cam degrees (crank degrees), of the available positions (these are all within 1 deg)
-1 (-2) (hole6)
-2.5 (-5) (hole2/7)
-5 (-10) (hole3/8)
-7 (-14) (hole4)
-9 (-18) (hole5)
-11 (-22) (hole6)
(and by advancing belt one tooth)
-1 (-2) (hole6)
+1 (+2) (hole5)
+3 (+6) (hole4)
+5 (+10) (hole3/8)
+7.5 (+15) (hole2/7)
(and by advancing 2 teeth)
+9 (+18) (hole6)




hope this helps someone

[Ben Wilson]

You must spread some Reputation around before giving it to oldcorollas again.

I'm sure it works, but it makes my brain hurt looking at it here.

I could probably make sense of it on an engine....

[oldcorollas]

I'm sure it works, but it makes my brain hurt looking at it here.

I could probably make sense of it on an engine....

LOL, it does my head in too

engine rotates clockwise when looking at the front of engine.
cams rotate clockwise.
if you move cam clockwise relative to gear, the cam advances
if you move cam anticlockwise relative to gear, the cam retards
and vice-versa.


edit:
now if you take a 4AGE cam gear, and rotate to the angles shown then you can get:
this is in cam degrees (crank degrees) of advance (+ve) or retard (-ve))

-9 (-18)
-7.5 (-15)
-6.5 (-13)
-5 (-10)
-3.5 . (-7)
-2.5 . (-5)
-1 . (-2)
0
+1 . (+2)
+2.5 . (+5)
+3.5 . (+7)
+5 (+10)
+6.5 (+13)
+7.5 (+15)
+9 (+18)

by moving to different holes or moving one tooth. hopefully that is enough adjustment?

only problem is you need an index jig that has 0.5deg steps (or is accurate to 0.5deg)

[roadsailing]

this is a good idea, its basically vernier adjustment using the wheel teeth as one set of "lines"

might give this a go, its the cheapest way of having adjustable cam wheels.

dont suppose you have the spacing of the holes? it could be worked out backwards, but not withut getting a headache

[oldcorollas]

yah, it's an idea that has been used since the dawn of time.. and not just for cars.
it's common to use for OHV cars, cos it's not so easy to take off the timing chain covers to adjust anyway and there is no bling if it's covered up.

the spacing from the centre to the adjusting hole is critical for a good fit and no slop. in these ones, even a film of paint is too thick for it to slide in properly.

hmm.. i can try to measure the angle of the holes.. will do tonight.

although, it's pretty easy to work out for indexing on a jig. each tooth is 10deg apart, so to work out the angle, just move the jig X x 10deg + (half crank angle)

acutally.. not so easy. trying to make up diagram now and getting confused

[oldcorollas]

1JZGTE cam gear has 48 teeth
each tooth is 7.5 degrees
is 1.5 deg adjustment enough?

(assuming it has one stock slot we use for reference)

CAM ADVANCE ANGLE
-7.5 (one tooth)
-6 (292.5-6=286.5) 39teeth-6deg
-4.5 (225-4.5 = 220.5) 30teeth-4.5deg
-3 (150-3 = 147) 20teeth-3deg
-1.5 (75-1.5=73.5) 10teeth-1.5deg
0 (stock
+1.5
+3
+4.5
+6
+7.5 (one tooth)

[oldcorollas]

K and T angles coming (how many teeth?)

[roadsailing]

the indexing head i'm thinking of is accurate to 0.5 degrees (well near enough, just need to go between degree ticks at the worst)

fantastic info, i cant rep you because i have to spread it around, so ill just give you my thanks!

[inertia]

Nice work OC

[Grega]

OC. you've got issues. love your work

[oldcorollas]

if anyone wants to put up the tooth count of say..
K, T, G and J motors as well, we can work them out.

same deal, X(360/teeth) plus or minus the advance amount

[wilbo666]

if anyone wants to put up the tooth count of say..
K, T, G and J motors as well, we can work them out.

same deal, X(360/teeth) plus or minus the advance amount

1JZGTE = 48 Teeth

Cheers
Wilbo

[Mr Revhead]

awesome

when iv had more sleep ill get my head around that...

have you compared the TRD ones to the small port ones? i agree same casting... but i think differemt material? has been a little while since i have had a smallport one in my hand though

[oldcorollas]

i don7t have a small port one, BUT from pictures they do look the same.. pretty much
i'll bring one with me and compare when i get a chance.

they are a bti big for me to stick in the analysis machines at uni without cutting up tho

[Big T]

I think it becomes a little more complex once you add TRD cams to the equation... these are 272, 7.5mm lift cams but im sure all the TRD range would have these additional adjustments. Not sure on how if affects the adjustability as im having trouble working out how just the cam gears work on their own!



And just for reference... stock cams.


Eddie.