lo all,

i'm coming up to my 105k timing belt change on my 02 TJI 3.5 4sp Auto w/romano vsi lpg, and in considering going down the track of cam advance while im in there.

im will be sticking with the oem cams (#6 i think) for now, and i have so far fitted a k&n panel filter, phenolic gaskets to the manifold/tb, wildcat extractors, and a lukey rear muffler (AL- part#)

my questions are:

* is the best advancement still considered as +0.63mm (+2deg) on the rear and +0.95mm (+5deg) on the front?
* will my idle degrade/change?
* will the exhaust drone increase at any particular rev range?
* has anyone got any sound/video of a 6g74 that has been advanced?

cheers Ash

:bump::bump::bump:

so im guessing that nobody has done this mod or knows anything about cam timing?

i advanced mine a tooth each cam, got flamed saying it was too much etc, etc, probably is but who cares. Car has more usable torque down low, i can get up most hills in 5th gear at 1500 revs at 60k. I have lost up high at about 6,200 it wont rev as hard. I put number 6 cams in my 3 litre.

How many deg would that be? Sounds quite good to me, the 3L donk is bit lazy below 2500-3000.
Ash, why would you have different timing between rear and front cams?


i advanced mine a tooth each cam, got flamed saying it was too much etc, etc, probably is but who cares. Car has more usable torque down low, i can get up most hills in 5th gear at 1500 revs at 60k. I have lost up high at about 6,200 it wont rev as hard. I put number 6 cams in my 3 litre.

i advanced mine a tooth each cam, got flamed saying it was too much etc, etc, probably is but who cares. Car has more usable torque down low, i can get up most hills in 5th gear at 1500 revs at 60k. I have lost up high at about 6,200 it wont rev as hard. I put number 6 cams in my 3 litre.

1 tooth is ~7.5 degrees and im not one to comment on if thats too far advanced or not.
how about idle quality? and exhaust drone?

How many deg would that be? Sounds quite good to me, the 3L donk is bit lazy below 2500-3000.
Ash, why would you have different timing between rear and front cams?

about the different advances you'd have to ask someone with more knowledge on the engine... this is just what ive read on the searches ive done

I have heard that 1 tooth is 15 degrees. But i would need someone to confirm that for me.

I am very interested in advancing my cams, is one tooth 7.5~? because that sound pretty much perfect to me?

I am very interested in advancing my cams, is one tooth 7.5~?


I don't know how many degrees one tooth equals - but all you need to do is count how many teeth on the cam sprockets - then divide 360 (full circle) by the number of teeth.....

so, say that there are 36 teeth on the sprockets
- then one tooth is "full circle of 360/number of teeth" = 360/36 = 10 degrees.

It's hot as heck at my parent's farm today, and I should be doing an oil-change or swapping rear springs on KJ - instead I am crashed on bed under ceiling fan. I'm not gonna be counting sprocket-teeth today (or anytime soon).
But someone may like to count the teeth.

I have heard that 1 tooth is 15 degrees. But i would need someone to confirm that for me.

actually your right 1 tooth on the cam is 7.5deg but relative to the crank its 15deg
im gonna go with the being tired excuse.... :ninja:

Yeah, 1 tooth is a bit too far, you will get the same amount of torque from advancing the cams less, but you will still have good up high torque (the exct distance to move them is in a thread that i made, not so long ago). At 6200, your car will be making SFA power at all, even when standard, You may as well be in the next gear at a more appropriate spot on the torque curve. My mate has a tj 2 vrx, and he was originally going over the line of a 1/4 mile stip in 3rd, When he started changing to 4th, he gained about 4mph.
I have had my cams advanced for about a year or so, best mod i have ever done.

Yeah, 1 tooth is a bit too far, you will get the same amount of torque from advancing the cams less, but you will still have good up high torque (the exct distance to move them is in a thread that i made, not so long ago). At 6200, your car will be making SFA power at all, even when standard, You may as well be in the next gear at a more appropriate spot on the torque curve. My mate has a tj 2 vrx, and he was originally going over the line of a 1/4 mile stip in 3rd, When he started changing to 4th, he gained about 4mph.
I have had my cams advanced for about a year or so, best mod i have ever done.

and how did your idle/exhaust note change? got any vids or sound recs?

Why dont you guys get a set of adj cam gears? Your only looking at about $250 for a set, anywhere from like 1-12 degrees of advancement or retardation

yeah thats what i am planning on doing... but i want to know if im gonna end up regretting it (read wife not happy) and just wanna know what i am to expect

You can just Make your own gears by filing them out. Unless you are planning on putting your car on a dyno, changing the advance and re-dynoing reapeatedly, it is probably not worth your while to pay that much for adjustable gears.

The Car (3.0L) sounded much the same, Idle developed a small lump, but i started running mobil 95 and that went away after a ecu reset, Exhaust note got somewhat deeper on idle, ad it has a really nice throb (almost subaru like), and developed a slight rasp (i have a straight thru, with only a rear 's' bend redback exhaust) but i couldnt care about that because i only drive it at 1500 - 2000 rpm, which is too low to here the rasp.
Fuel consump went down by 1.5 - 2L/100 kms around town (i consistantly get about 10L/100 kms driving fairly eratically), because i am now revving significantly less to get equal power. but it now uses s***loads when i drive it hard, also throws out a bit more black smoke when i give it a bootfull.

I went from just beating my friends verada (5sp auto, 3.5L) to absolutly eating it, (especially off the line) which is a good ffort for a 500cc smaller motor (mine is manual though)
, I get a fair bit more wheel spin off the line, and have to be more concious of axel tramp.

If you have a standard exhaust, you will get a really deep induction rumble as well.
Thats about it, best free mod ever....

sweet as.... so in short... coupled with the other mods and a flowed TB the car is gonna be awesome!

i was considering doing the key way mod but if i later on decide to change my cam profile then it would have been time wasted

yeah...thing is...you can make minute adjustments with cam gears either way. by filing them out...well that's just dodgey, you've obviously stuffed around with timing WAYY too much making it better down low and horrible up high. I still prefer it if people did it the proper way, although it does cost money, do it once, do it right

;1194290']Why dont you guys get a set of adj cam gears? Your only looking at about $250 for a set, anywhere from like 1-12 degrees of advancement or retardation

where do you get a gear set at that price? and whats the part #?

where do you get a gear set at that price? and whats the part #?

ebay.com is your friend :D same cam gears as few mitsu cars in the US eg. eclipse...

Blue = Part #961639
Silver = Part #961634
Red = Part #961636

I got mine from the same seller as Tuffy has listed so i won't bother anymore...

Ebay US.
Part number looking it up now
Eclipse 3L 00-05 model 161881
http://www.fidanza.com/cam-gears.aspx

http://cgi.ebay.com/ebaymotors/Fidanza-Cam-Gears-Eclipse-Galant-Diamante-Endeavor-SOHC_W0QQcmdZViewItemQQhashZitem4832a468a1QQitemZ3 10087280801QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories
There ya go

i undr srand what you mean tufftr but alittle bit out will make sfa difference. yeah, advancing cams 6 or 7 degrees makes the top end alittle less torquey but by no means does it make i horrible.

i undr srand what you mean tufftr but alittle bit out will make sfa difference. yeah, advancing cams 6 or 7 degrees makes the top end alittle less torquey but by no means does it make i horrible.

Shouldnt of said horrible. I just dont like the guesswork with a file, you really have no idea how much your advancing it by. screw it up and your up for another set of cam gears. I understand not everyone has $250 for a modification but at least with the cam gears, something goes wrong, set them back to 0, easily done! anyway carry on

yea we are only talking about .6mm and .9 mm. just use these as a guide when filing. max of .6 for the front etc (.55 - .65mm is close enough) because remember, even adjustable sprokets arent 100% spot on. and also, as long as you only file to avance them, you can always set them back to zero anyway. i just think for normal duty engine, the precision of a pair of macrometers and a chainsaw file is more than accurate enough. of course in the hands of someone that knows what they are doing and fully understands what they are actually changing inside the motor. if a person were to do it without fully unerstanding the ins and outs of how magna ohc cams work, then itotally agree that they should buy some adj sprokets and get there mechanic to do it. beacause if you know what you are doing there is no guess work.

;1194357']Ebay US.
http://cgi.ebay.com/ebaymotors/Fidanza-Cam-Gears-Eclipse-Galant-Diamante-Endeavor-SOHC_W0QQcmdZViewItemQQhashZitem4832a468a1QQitemZ3 10087280801QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories
There ya go

That seller quoted me US$40 for postage for 1 set - which is not unusual for that size or value shipment as the US Postal Service savagely hiked rates for such items not that long ago - so with the AUD down to ~0.90USD the total cost will come in around AU$275. I've ordered a set...

Andy.

Good work mate. Mightaswell while the $$ is high anyway.

Ok question. Why advance the front and rear cams different degrees? Wouldn't this unballance the engine?

No it wont unbalance the motor, You need to advance the cams differently for a couple of reasons. In a nutshell, it makes it better for more driving situations, ie high and low revs.

If the power band on a magna cam lasts for around 2000 *just an example* and one comes in at 3000, and one comes in at 4000, you will have power at 4000, Heaps of power from 4000-5000, then less power at 6000 because both cams are out of their usable range.

Ahh alright that does make sense now. Thanks

Ok I've thought about the cam timing a little more again. And having the timing offset makes sense in the fact that it will widen out the power band, but I still seem to get stuck on the fact that each bank will be firing at different times, so wouldn't the power be pulsing and this would set up a resonance in the engine. Also if the different banks are working more independantly would th power be applying a pulsing force rather than a steady force.

Ok thinking more now the cam has no effect on spark timing. But I still don't like the idea of them working on seperates times. I honestly don't know overly much about cars, but work with aircraft, and ANY kid of resonance we find we go to all ends to eliminate it. This seems like it would almost induce one. Resonances are bad...

ok, you're right, cam has absoltley nothing to do with when the spark fires on these motors....
The bang from the petrol and air will always happen at the same time, as it is controlled by your ecu, and done by the spark plugs...... regaurdless of your cam timing (unless you get pre ignition, we wont go into that though)

Now, The idea of advancing the timing is to allow for the exhast fumes to get out sooner, therefore, piston is not recompressing the old exhaust fumes on the exhaust stroke (after the bang from the air and fuel by the piston). However, because we are opening the exhaust valves sooner, we are in turn closing the intake valves (this can be stopped on double over head cam cars, or with a custom cam grind) So at high revs, there is not enough air being let in, although the exhaust is being let out perfectly.

You just have to remember, the cam is only to do with air getting in and out of the engine, nothing else.

Now, all those people who advance there cams 1 tooth each, you are actually closing your intake valves really soon, so even though at low end you have torque, up high you have nothing. This may be ok if your in a manual (or 5 speed tippy), but in an auto, it will alway try to put you in higher revs when you give it some gas, because this is where it has most power from factory (the computer will still think the car is standard, so it will want to rev higher). SO in autos, i would be inclined to leave them, or just advance them y 4 degrees or so, because unless you are able to select the gear ( 5 speed tippys) it will always want to rev until 6000, when your powered died at 5000, so it is just slowly and painfully reving its ring off to get into the next gear. (imho)

just placed an order with ultrarev.com for a set of gears.... they're on sale @$10 off a set and google checkout also has $10 off so delivered to the door it is $213USD/$230AUD

so after many months i finally got the time to fit a new timing belt kit and fidanza gears.... not too soon either as the rear bank had jumped back 1 tooth :eek2:

just to clarify tho, on the fidanza gears if it is set at +1 and +2.5 then the cam is set to +2 and +5 degrees and therefore the center of the lobes are at 109 and 106 deg atdc. and ive got it right or i need to reset them.

i must admit the engine feels alot more drivable as is (but doesnt hurt to get it right)

so after many months i finally got the time to fit a new timing belt kit and fidanza gears.... not too soon either as the rear bank had jumped back 1 tooth :eek2:

just to clarify tho, on the fidanza gears if it is set at +1 and +2.5 then the cam is set to +2 and +5 degrees and therefore the center of the lobes are at 109 and 106 deg atdc. and ive got it right or i need to reset them.

i must admit the engine feels alot more drivable as is (but doesnt hurt to get it right)

if the 1 degree is 1/360th of the rotation of the sproket, then yes, you have to double it. Id say this will be the case.