1987 Firebird 2.8L V-6 automatic.

Ok, first, we replaced the timing chain and notice 2 lines on the balancer. What is the 2nd one for? The thicker one is the one to set the timing, right?

Ok we are using the thicker mark. Before we had the car set at 14 degrees. It seemed ok, but for the heck of it we bumped it up. At 16 it managed to knock 0.5 sec off the 1/4 mile time. We were afraid to run much more then this, but decided to play with it at the dyno last night. Well we got it set at 19-20 right now and it gave the car 3 hp from the 16 degree run. Still the car has no ping and is running on 87 octane. Ideas?

We are assuming the balancer has slipped big time. Is there a way to check timing w/o using the timing light, via the computer? Cause I have no idea where my timing really is.

Is there a way to fix the old balancer. If not where do I go for a new one? Dealer? Parts store? Any clue on cost for a new one?

 

I just checked autozones website, they have one for the 91 3.1l, but it is not cheap at all, try 90 bux .

 

Cool I did not know they had a website for looking up prices and what not thanks! Is it Autozone.com?

Are the 2 compatible 3.1 and 2.8? Honestly, I was figuring $150.00. Hence wondering if it could be fixed. If Autozone carries one that I guess we could buy a new one and compare it to see just how out of wack mine is. If we find out where it should be in comparison. The dealer, I 'm sure, would not let you order it and then take it back!

 

Napa has it, part # BK6005213, for $43.95. Ordering one right now!

 

First, make sure there's two lines, and not three... my '86 2.8 has three. I thought the multiple lines died in '86, and '87 just had a single line. The three multiple lines were for a special timing gun that had some kind of magnetic probe, when it saw a missing notch, the gun knew where the engine was. ('Fact your balancer scale might have a tube sticking out of it, about an inch long.)

I posted how to check for balancer slippage a while ago, but to save you the search, here it is (from post https://www.thirdgen.org/techbb2/sho...hreadid=118747 , where I was helping out Erick/Xenodrgn, RIP...

And here's a little "warning" that nj88v6 gave for people that would follow my procedure:

In fact, that message might be helpful to you, too: https://www.thirdgen.org/techbb2/sho...hreadid=125150

I wouldn't try fixing the old balancer, but for now, you can at least set it correctly. If you find out that when the #1 cylinder (front passenger side cylinder of course) is at TDC on the compression stroke, the balancer mark doesn't line up with 0 degrees on the timing tab, then just mark the "correct" location of 0 degrees on the balancer with a scribe, or white out.

Remember too that we're not checking timing by doing this... I remember someone got confused by that. We're just checking for a correct balancer, which would point to 0 degrees on the timing tab when #1 is at TDC of compression stroke (not exhaust stroke).

 

Oh and LT1, if you can get an actual GM part #, put it in at http://www.gmpartsdirect.com , they're usually much cheaper than a dealer. Only catch is that you have to know the part #. If you don't know, and the dealer can't-- or Won't!-- get it for you (like some people found out with the TSB on the 82-88 rear disc brake recall package, dealer didn't want to give them the part #), you can email the guys at that website. They NEED the car's VIN, though, I was told by JoelO175 that you just can't say "I have an '86 2.8 engine code S." They want the car's entire VIN. Kinda lame, especially if you say "I have an automatic." But if you know the GM part # already, you don't have to tell them a VIN, just order the part.

 

yes, redraif, it is autozone.com, or orileyauto.com, and I think advanced has site, and prob napa too.

I never thought of just moving piston and seeing if my mark is on 0, while engine is tdc What a stupid me Another trick to try on my s10 to see whats wrong.

 

This may just be a quirk of the 2.8, but I have noticed that you barely have to move the distributor to get a big change in timing.
Also, now that I think about it the mark did line up when I brought #1 to TDC...so maybe the problem is somewhere else? Any ideas????

 

The balancer mark lined up with 0 degrees on the timing scale? Hm. Is your distributor 180 degrees out, maybe? Did you try putting #1 to TDC compression stroke, and pulling the cap off, to see if the rotor was pointing between #1 and #2?

(For those that think i'm nuts, the rotor would point between #1 and #2 because: With #1 at TDC, to have ignition timing at 10 degrees advance, the spark fires 10 degrees BEFORE the TDC of #1. So by the time the piston reaches TDC, the spark's already fired, and the rotor's ready to "ignite" cylinder #2.)

 

I don't think it could be 180 out, Tom...its not running as well as it shoudl, but I would think it would be running far worse. I'll check it tonight though. I'm starting to suspect the distributor end play may be the problem; too much endplay can cause "spark scatter" , and make it nearly impossible to get an accurate timing reading. I'm going to pull it out soon and see if I can shim it some (Moroso and others sell shim packs for about $4).