Cronicus

well i kinda wanted to pull a few more horses and being i had a snap on timing light with advance whele out in the shed i though id give it a shot.
took out the old schol schilstons that came with the car and read up, like it suggested to leave the vacume advance lines on enshure of no cracks or breaks etc etc. warmed to normal temp and enshured nothing was turned on "but the engine" and that it was idling at a flat 800 like the underhood sticker says.
the under sticker says it should* be at 7 degrees BTDC when i put the light up to it its reading me 5.
now this is of course as long as im understanding this correctly and understanding the way the timing scale works which i have illistrated below to make shure im not gona blow her up.

now being if the pic below is correct and the longer side of the scale repersents the btdc area of timing then i got 1 problem solved"again just to cover my ***.

my next question.
i am all for pushing the motor and bringing out hp sooooo.
naturaly you advance the timing to do that but if your in the btdc range does that mean i just bring it closer to 0, or do i send it even further retarted to like 10, also if its supposta be at 7 and reads 5 currently has sum 1 already done this for me, or just scrued around with it?

should i whomp it completly outa the btdc range......to a tdc value ....but i only have about a quater inch of scale to read on on the other side of the timing scale in what i belive is the tdc range....

i didnt know what to think so i called my girls dad and explaned to him, hes a mech. of 30 years and is no stranger to achiveing hp or pushing engines.
he suggested sum1 may have played with the timing to pass emissions possibly and suggested i set it to 7 plus 2 more bring it to 9 degrees retarted or btdc.
now being that this is the oldest car ive ever owned "so i need to ask" wont further retarding the car make it loose power?
what should i do?
for note my elevation is 5314 feet above sea apromaxiatly and this is the 2.8l

Cronicus

so i just set it to 9 btdc imediatly the engine became louder but the idle has not changed if 50rpm's tops tach stil reads about 800 possible 850 from what i can interept it is not pinging or diseiling, and seems to have smoothed out.
i am gona take it around the block and see what happens.

and i have another ?
can i further set the timing advanced or retarted" again assuming what i just did is gona help perforamce" can i run a higher octanne say 91 instead of 86 and set the timing even more mmm different from now to achieve more power?
thanks

Cronicus

it apears to have more *****.
then again gauging things by a feel of the pants difference is never the best way to go.
again if yall could answer a few of my other questions id so so aperciate it.
-dave

NismoPick

It's a common practice to turn down the timing on older (distributor) cars to get it to pass emissions. You can just turn it right back up afterwards. The stock timing is 7-9 degrees BTDC... but you can turn it up further. I believe SHADY is running 15 degrees BTDC.

Cronicus

im stil overwhelmed by the fact that retarding the timing wil bring more power but ya.
if im at 5 and a half thousand feet , what should i dial in?
i know using higher octane is really only needed if u have due compresion but ho w can this factor in, if it can?

theramz

That engine was designed to run on higher octane gas. Just because you can't hear a ping doesn't mean it isn't detonating at high rpm. At that altitude you are starving it for air so a cold air intake will make a noticable diff. You can advance to the 9 btdc no problem but run the 92+ gas always. Your drawing and mech are correct except the advance should be on the btdc side. The engine rotates clockwise looking at the front so advance is on the right of the scale. Make sure you are getting more anvance when you increase the rpm to be sure your vacuum is working. Take baby steps on power tuning.

Cronicus

wow i didnt know it needs 92+
i can only get ahold of 91 out here. of course there is octane booster but....
i later found out earlier today i had the btdc and atc sides mixed up but ya.
there is a cai on here and stock the low flow air intake was taking in cold air, i just added 3'' smooth pipes and a hi flow cone "amsoil filter"
so if i start runing 91 or better whats the safest advancement beyond 9 btdc i should go, and stil be able to utalize it?
thanks a million.
and when i rev up the motor its a lil hard to keep track of the timing mark but it is jumping so the vac advance is working. ill proly replace it later anyway just to be shure.

theramz

91 is okay but I wouldn't bother putting a booster in it unless I was planning to go to the track. You can start with 9 degrees and drive it for a little while. Pull the plugs and ask your mech to "read" them for you to check for detonation. More advance gives you more power on the top end to a point. If you want the best out of it you will need a engine management system like MegaSquirtnSpark to program the whole rpm range. The old girl is 30 now so don't expect a whole lot. There is a reason she has lasted this long, she's a quick little sports car not a race car.

Cronicus

ya shes a lil moster and i have reason to belive shes been re-built.
the block was coated in a blue paint a good while back, underneath is a darker more resiliant black-brown. that is unles nissan painted them blue.....?
again i thank all of you for your advice.


btw ive been hearing alot about the megasquirt systems these days, how hard is it to hook one up and bolt on this garette t3 "besides fabracation to fit" i got sitting in my closet.
or would i be better of just droping in the turbo motor?

NismoPick

That's been asked literally 1.2 million times. It takes more than "slapping on a turbo" to make it work. Feel free to search about turbo conversions...

Cronicus

i have been

BoulderZ

Minor note: The higher your altitude, the lower your octane requirements. Generally, the gas stations adjust their supply and signage to make the change. For example, the standard 3-octane pump in Colorado is going to have as low as 85 for "regular" and as high as 91 for premium. It's very hard to find higher than that at stations here. On the other hand, at lower altitudes, 91 is typically mid grade. The dumb part is that we still pay the "premium" price at altitude, though we're basically buying mid-grade product.
One thing to check out while you're messing with timing: At idle, you're advanced to either the stock 7 degrees BTDC to make sure you ace emissions, or more advanced to where you like how it's running. But, use your light to check that your vac advance is working correctly at higher rpms. The mechanisms inside the distribs are pretty old and many of them do not work well at all, needing cleaning and/or replacement.
have fun,
Dave

Cronicus

thanks for the reply, i wil definetly inspect the mechanical advance parts!
for the most part when i rev up i do see the timing **** as the rpm's raise i loose track of it at about 2500+ but anyway ya.
the powerband feels about right for what i need a street general pourpse with a tad hi end preference. feels like most of the torque is being released about 3300 -4900 highest i have been thinking about bumping it up a degree or two possibly begging for more of the powerband up to 5400 and again i know im probably beating a dead horse but man she stil runs like a monster.

btw i hit 125 today racing a beamer down the freeway, although his brand new bmw put up with the z no prob the kid got scared at about a buck fifteen. i really need sum z rated tires lol.
cheers and thanks -