Whats a good octane for a L69 H.O. sittin for 10 years? I finally got on it today (for the first time EVER in a straight gear , I'm 15). Well once it got up on to about 3800 or so, spark knock had come into play. Would it be because Octane 87 isnt good enough for it? Or is it because its been sitting 10 years, and could possibly be my spark plugs (yes, I am not super great with car diagnostics, or anything .....yet.

 

i would use premium or 93 grade.....you have 9.5:1 compression so i think it would help anyway

 

Hmmm, I'm gonna need a good job even though I buy gas from my dad. He won't gimme much help, to better "prepare" for the future. But so far I got 2 regular fillups

 

Most engines are designed to operate on 87 octane. Just becaue it has that high of compression doesnt mean you nee do trun 92. I have known and herd of a few guys who run 93 in a 13:1 motor. You just need the right heads, and cam and you will be fine. Try 89 and if it goes away, go back to 87. Sometimes, if ya buy it from a bad place, it may have some bad stuff in it.

 

I buy from my dad, and am 120% sure it is not the gasoline. (Exxon)

 

I don't know if it was just my car or what but ever since my first fill-up on my first 3rd gen all I have used is 93. This is premium in New Jersey or in my L69 I use Sunoco 94 but anyway, I put some 87 in my first TA and I'll tell you what, it could barely pull out onto the street much less go fast. From then on it was premium for me and that helped like you wouldn't believe so I'd say go with the premium and get a job if need be.

 

87 Octane was fine in my '83 L69... and I drove it HARD. No knock at all.... kinda sounds like I got lucky though, lol.

 

Could it be the: fuel filter, plugs (which gotta go anyway, good *** there 10 years old ), plug wires, or something to do with distrib? NOTHING is wrong with the gas I use, it is very clean gas. It ain't like its loud its kinda quiet. BTW before I forget would a check engine like come on if the car sits for a second idling?

 

It makes power, just that spark knock will cause it to blow up if I keep doing it, and trust me, it burns NOT to. I want to get a job, but I'm in a jam right now. My grandpas colon busted, so he can't help my dad much, he's just now STARTING to get out and help for about 4-5 hours tops. My dad is byhimself other than me and my grandpa from 6am to 6 pm. Then someone comes in (late everyday 6:15-6:20) and works till 12. Saturday, my dad does the 6-5'er. Sunday my dad works late (3-10.) Mind you he hasn't had a SINGLE day off in over a year. So I'm gonna help him till I can move on.

 

Sorry for the third post, but I dont wanna look retarded, I mean't burns not to floor it, and go fast

 

I would run something like sea foam through it. It is a cleaner that you just hook up to a vacuum port and it cleans out the motor. If a motor is all carboned up inside it is going to get hot spots and hence spark knock easier.

Also check your timing if you havent because if it is set way off it could cause that also. The one thing that comes to mind is that with the engine light on it could be something like your egr which if stuck could cause spark knock.

So in order what I would do is check and see what code the engine light is setting. You can jumper the two terminals on the top right of your aldl and the engine light will flash the codes. Let us know what that says and we can tell you if there is something you need to do. Then check your timing. If that is correct and the the engine code isnt something that would cause this I would get some of the sea foam cleaner and clean out the engine. I honestly think that you wont have to run anything higher than midgrade on the car and probably not even that if every thing is set and working right. So my suggestion is just to go through and find the problem instead of trying to get around it by running a more expensive gas.

Ben

 

Sorry for asking, but what exactly do I use to check my engine codes, and do I do it when the engine light is on right?? It only does it if it sits for a minute, and after it goes off after its been movin about a minute. *** I feel like an idiot asking what to use to check my engine codes.

 

Grrr, I forgot something again but what is my factory timing settings?? Right now the car is just gonna get my bolt ons listed below after my speedo and e-brake, and the u-joint in my driveshaft gets fixed Dang U-joint, somethigns rattling bout where my driveshaft is.

 

There is a connector on the bottom of your dash on the drivers side of the car. If you jumper the 2 top right spots with a paper clip or something with the car turned off and then turn the key on without starting it the engine light will flash. The first code should be 12 which just indicates that the computer is functioning. It will flash short pause flash flash pause flash short pause flash flash......

After it goes through 12 it then will be the ones you need to pay attention 2. It flashes each one 3 times. It doesnt have to be having the probelm at the time, you just do it parked becase it should have the code stored. You can either look them up in a book or ask on here and someone can tell you what it means.

 

Ok, thanks, Ill post a new thread when I get it done, (going to get some help)

 

Good luck with it!!!

I burn reg unleaded in mine.....no probs.

 

I'm glad to see you helping out your family in a tough spot. Stick with it. You are developing a lot of character that doesn't come to a person in any other way

The guy to talk to on this board is RB83L69. Not to dis anyone who has already answered, but he runs an L69 and has for years. He'll be able to tell you how to tune it within an inch of its life

It should be able to run on 87 octane, no sweat. It is an ignition issue, almost certainly coupled with carbon buildup on top of the pistons or in the combustion chamber. New plugs, wires, cap and rotor are in order.

 

MAke sure you have the timing set correctly, and the egr valve is good. @ main causes of a lil spark knock.

 

Do the tuneup, run a can of GM Top Engine Cleaner thru the carb to remove carbon build up & she should run on 87 octane. Running too high an octane for your engine only wastes horsepower & money.

 

I'll have to agree with 496. My LG4 (same compression, knock sensor, etc., as L69, but I was using an aftermarket chip) would ping with 6 degrees base timing on regular, required mid-grade to stop it. When I pulled the intake to fix a coolant leak, I discovered the EGR passages were plugged tight. After getting them open, 6 degrees on regular was no problem again.

With polished chambers and a little more cam now, I'm running 10 degrees base and still using regular with absolutely no pinging.

 

I agree... talk to RB83L69... he has the same engine that you have ('83 L69) although a little modded I think.

He is a mechanical wizard though... ask him anything and he can help you.