question about timing

Katana200sx · May 29th, 2002, 09:07 AM

about 2 months ago i advanced the timing on my ga16 and i am just wondering if i did it correctly. i set it to 15 degrees, but my question is if i used the correct pulley mark. i set my timing using the left mark (looking at the pulley from the passenger side fender). did i use the correct mark?...or was i suppose to set it according to the middle pulley mark. the service manual said something about the left mark being -5, the middle being 0, and the right being +5. i didnt understand what that meant so i just set it to the left one. did i set it right or do i need to do it again?

James · May 29th, 2002, 09:38 AM

the pulley you should have been looking at is the crank pulley. if you did it right you would have seen like 5 or 6 marks (can't remember) but the left most one would have shown -5 deg, that is what it refers to...

barnoun · May 29th, 2002, 11:17 AM

Looking from the front of the engine(the top one is closest to the firewall):

-5º
0º
5º
10º
15º
20º

AznVirus · May 29th, 2002, 05:08 PM

mark the timing marks with chalk so you can see it clearer.

Katana200sx · May 29th, 2002, 06:53 PM

ok another question....i took the timing gun and turned the knob to 15 degrees and turned my distributor until the left mark lined up...what does this mean my timing is set at?

sentra94xe · May 29th, 2002, 06:55 PM

Quote:

Originally posted by Katana200sx
i set it to 15 degrees,... <snip>

Just curious as to why you attempted to set the timing at 15 instead of 12? OEM specs show the GA-motor to be BTDC @ 10 degrees, and many folks I know of (been with multiple Sentra lists for 4 years now) put the timing at 12. As I am sure you are aware, anything above 12 degrees on a GA-motor could possibly result in detonation. For the no-brainer part of this post, it is highly recommended to run premium fuel when timing is advance. I've had mine set at 12 degrees for over 3 years out here in AZ, and ran premium ONLY since... never a problem.

*For the record, OEM timing for an SR-motor is 12 degrees BTDC. It has been proven that this engine can have it's timing advanced to 15 degrees.

barnoun · May 29th, 2002, 07:03 PM

Don't go by the knob on the timing gun as that just confuses things. Set the knob to 0º and adjust the timing normally(and oh yeah, make sure to disconnect the TPS too).

sentra94xe: Advancing the timing to 15º gives the most power(dyno proven on sentra.net).

sentra94xe · May 29th, 2002, 07:11 PM

Quote:

Originally posted by barnoun
sentra94xe: Advancing the timing to 15º gives the most power(dyno proven on sentra.net).

After re-checking Kojima's very informative page, you are correct. It appears that 15 degrees IS acceptable to run. Upon reading the clip though, it does state and I quote --- "You can safely run up to 15 degrees on premium gas on the GA16DEs. This has been proven by recent dyno testing on a stock car to give up to 5 more hp at the wheels in the midrange and 2-3 at top end. Remember if you have your timing turned up this high you MUST use 92 octane fuel." --- Unfortunately for us in Arizona, Cali, and other states, 91 octane is our best alternative. Yes, it is just 1 octane point of difference, but I'd rather not mess with it and risk detonating a motor with 112,000 miles on it, and that has been happily set at 12 degrees for this long.

Thanks for the info Barnoun! I learn sumptin' new everyday...

sentra94xe · May 29th, 2002, 07:12 PM

Barnoun, I see that you are from CA.... do you have 92 octane up in San Fran, or are you using 91 like us poor slobs in the desert???

Katana200sx · May 29th, 2002, 07:47 PM

ok guys thanks....i will chalk my pulley (some reason i only see 3 marks) and recheck my timing. btw i always use 93 octane...have for about 5 or 6 months. i think the sr20 guys advance their timing to 17 if i remember correctly

barnoun · May 29th, 2002, 07:51 PM

I'm using 91 too. I've had the timing advanced for about a year now and no worries. Guess the 1 octane point doesn't really make a difference. Actually though, seems like it's just a precaution as I remember one of the guys said he has 15º timing and he's been running with 89 octane with no problems either.

sentra94xe · May 29th, 2002, 07:52 PM

DOH!!! Man, am I having a horrible day with posting! LOL

Yes Katana, you are correct. OEM timing for SR-motors is set at 15 degrees BTDC, and can be advanced from there. My roomate has had his 95 G20 (w/ many mods) timing set at 19 degrees for a long time, with no problems. Many others set it at 17...

I was visiting some friends in Orlando over this past Christmas holiday, and saw that they too have the lucky 93 octane fuel. Some of us out west are not as lucky... send us the good stuff!

sentra94xe · May 29th, 2002, 07:57 PM

Precautiuos yes, but for good reason, as you can imagine. Glad to hear you have been running 15 degrees and 91 octane successfully! Nice to see more data on these engines....

*Somewhat off-topic: Hey Barnoun, have you or do you plan to dyno your car anytime soon? Would be interesting to see what the 15 degree timing is doing over say, the 12. I had a SOTP difference when I first bumped the timing. It was set at 6 degrees from the factory! Needless to say, it freed up a few ponies.

barnoun · May 29th, 2002, 08:24 PM

I don't plan on dynoing anytime soon(no need right now I suppose). Anyways, you can't really compare since my car isn't stock(pulley/exhaust/modified airbox) and has an automatic. You should advance to 15º and see if you feel a difference(I think you will).

sentra94xe · May 29th, 2002, 08:41 PM

Not right now, with it becoming the hottest part of the season here in Tucson (was 103 today, looking towards 106 tomorrow) I don't want to risk messin' with the car. I may try it in the fall...