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Discussion Starter #1
well first off i am very confused about how adjustable cam gears do thier jobs..i mean i did a search and couldnt find exactly what i wanted to know..my question is how do aftermarket cam gears work..especially if they are installed on a car with variable valve timing or other systems like it..i dont understand how the computer can adjust the cam timing while at the same time they have aftermarket cam gears that are already adjusted....wouldnt the ecu get confused or something because of this??. i dont understand how adjustable cam gears can work with those honda guys that put them on thier cars with vtec and stuff like that....also can someone quickly explain how adjusting the cam timing makes more power..and also can someone tell me if changing the octane alot can change the way the cam settings effect the performance...the reason i ask is becasue around here where i live i can buy either 93 octane or 94 octane from the pump....i was wondering if i will have to stick with one octane if i have a car with adjustable cam gears that are already set...also i was wondeirng the same thing if i have a boost cointroller and an s-afc alredy tuned..does the octane make a difference especially if i am runnig race gas sometimes...

ok i tired to explain as best as i could ..this might so like a newb question but whatever it is...

any info would be great..
thanx in advance
ant
 

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I'll take a poke at it but someone please correct me if I am wrong. Adjustable cam gears change when the valves open and close in relation to combustion and piston position. This change in valve timing can yeild more horsepower because it changes when and how much air/fuel exits or enters the cylinders. Vtec controllers on the other hand don't directly control valve timing but they control when the ECU switches from low-throttle settings to high-throttle settings. Cam gears would still affect both settings throughout the entire RPM range.
 

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Whilst on the topic, I'm waiting for a set of cam gears. Are they a pain in the arse to install??? What about lining / setting them up??
 

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They are not that tough to install. Mine were put in when I knew nothing about Supras but I helped out the guy who did it. It seemed easy the way he installed them, he didn't even take off the timing belt. Just make sure you get the belt on the right teeth in the end. :)
 

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VeilsideTT said:
They are not that tough to install. Mine were put in when I knew nothing about Supras but I helped out the guy who did it. It seemed easy the way he installed them, he didn't even take off the timing belt. Just make sure you get the belt on the right teeth in the end. :)
So how about lining up the cam gears. I'm sure you dont just slap 'em on there?! They are after all, adjustable.
 

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They are adjusted by loosening the inner bolts on the gears. This way you can keep them on the same tooth of the belt but slightly alter when they tell the valves to open and close. It is very simple to adjust them, especially if you keep your spark plug cover off.
 

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Discussion Starter #7
ok

ok this is all good info and it cleared upo how they work together...but one thing i stillk didnt get answered was about the octane and fuel sttings for an s-afc and all that stuff

thanx
ant
 
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We have INTERFERENCE motors, you must not turn the crank once you have the crank aligned for changing the timing belt (same procedure for changing the cam gears). The alignment procedure is to rotate the crank until you have the #1 piston on TDC; check for the cam mark with the cam cover and align the WHITE mark on the crank pulley to 0. Then Rotate the Crank Pulley Counter Clockwise 60 degrees until the YELLOW mark on the crank pulley lines upto 0. The cams should be exactly FOUR teeth away from TDC. Now you can change the Timing belt, Cam gears, Cams, etc. It is very helpful to remove all the T/B covers when doing this. Good Luck.
 

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MKIV4door, I believe you are mistaken, I have always been told the supra engines are not interference. ie if your timing belt brakes it's no big deal, just get a new one and everything *should* be fine. The only time I have heard that it might become an interference engine is if you install some huge cams. You can see here
 

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I have been told the engines are NOT interference.

Also, race gas will affect AFC settings but the new AFCs can store more than one map.
 
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I use to believe the same thing . Sorry though, but you are both wrong, 2jz motors are interference motors, im positive of that.
 

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What makes you positive of it? I've heard time and time again from knowledgable people and VERY RELIABLE sites such as MKIV.com that it is non-interference.
 

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MKIV4Door said:
I use to believe the same thing . Sorry though, but you are both wrong, 2jz motors are interference motors, im positive of that.
Positive eh? Find something to back up what you're saying. The 2jz-gte and 2jz-ge engines, unless modified with camshafts with greatly increased lift or oversized valves) are non-interference engines:

http://www.mkiv.com/faq/faqtt.html#enginegeneral
(last sentence of the first paragraph on "engine general description"

Though it does appear that the 1998+ vvti 2JZ-GE engine is an interference engine. . .

http://www.troublecodes.net/tbelt/toyotatb.shtml
http://www.autoref.com/toyo01.html

Or you could try giving your local toyota mechanic a call. . .they could also set you straight.


It appears that MKIV4door drives a lexus with swapped gte internals. . .who wants to bet that his is a '98+ with VVti?

It's also a wonderful thing that they're non interference or i would have had a head full of bent valves when my timing belt got cut last winter.
 
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Hey ray(1.3 liter) wanna chime in on this one. He is the one who broke it down for me when I argued the same points you guys are arguing.
 
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