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Discussion Starter #1
Gents,

I have a slight problem that is becoming more of a concern as I begin to think about it.

I recently had my NA-T supra tuned in August in a very hot environment. I was told by my tuner that cold starts in the winter will be harsh. I did not know what to expect.

Since then the only changes I had made were cam gears and timing belt. I recently changed from Fidanza cam gears to older HKS cam gears. And I also changed from a stock timing belt to a Greddy fine tune belt with a billet timing belt tensioner.

After that point the car has sounded like shit. The car also had an exhaust leak at this point, but the difference from idling before to after the new changes is drastic. I was wondering if the rough start/idle is due to the changes or could the timing be off? I also did notice that the belt has some wiggle room on the cam gears, you can actually slide the belt slightly from front to back on the cam gears.

Since this all has happened the car has sat and waited for a new plan of action. I am thinking of just going back to the fidanza cam gears with stock timing belt and see what happens. I am just worried that my timing is currently off.

Mind you all work was done by a professional mechanic, but I just need some clarification for my own peace of mind.
 

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Over Medicated
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Have you checked the timing with a light to see where it's at? That would be the first thing I would do. Also turn the #1 piston to TDC and make sure all the cam timing marks line up with the backplate.
 

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Discussion Starter #3
Currently the car is sitting at my mechanics house, I will ask him to check this evening or I will look this week if I can get over there
 

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Discussion Starter #4
I did notice that the HKS cam gears are VERY WORN, the grooves for where the TB sits are basically worn out completely.
 

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Discussion Starter #5
Just spoke with my mechanic, he will be checking the timing tonight.

Also, any inputs on the worn down cam gear being the problem?

This is my diagnosis:

Initially with the stock timing belt and fidanza cam gears my timing belt was SUPER TIGHT and this was when the car was tuned.

Since then, the old HKS 3 bolt cam gears and Greddy timing belt were installed. After they were installed the timing belt was SUPER LOOSE. The belt could easily slide front and back on the cam gears like it should, but in this case it seemed too much. At one point the actual timing belt hung maybe 1mm or less over the cam gears.

I think the car isn't happy with the timing belt changes, plus the exhaust leak. Any inputs or suggestions are greatly appreciated. Thanks.

Cliff
 

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EchoDeDupra
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The old HKS cam gears are known to wear out and ruin belts and throw timing off.
 

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Function over form
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if you're still using the stock distributor be sure you have phased the rotor inside of it as well when you're setting the timing with the #1 piston at TDC. this happened to me a while back and i just had to rephase my rotor. the AEM also doesn't get a great cam signal from the distributor like it would with coil packs and a 7M CPS apparently. look in to getting coil packs. i'm about to do my conversion and will post results.
 
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