Alright, well here is the story. Screamer27 and I just got done rebuilding the engine in my '86 IROC (305 TPI). When I bought the car the head gasket was blown and three pistons were cracked at 4000 miles on the engine. So we pulled it, replaced pistons, rings, ported the heads, and since we had it out, we put in a SUM-k1102 cam and lifter kit. We got it all assembled and dropped in the car. When we first started it we had the distributor about 60* BTDC. So we pulled the distributor moved it a notch and got the timing at about 15*. To keep it running the idle adjustment screw had to be all the way out just to keep it running. I noticed when I was moving it around that it would run quite well at about 35-40* BTDC according to our light. Anything lower and it would just try and die. After about 5-10 minutes of running at the supposed 15* BTDC timing the manifolds started to glow, we immeditly shut it down when we saw that. If the manifolds are glowing like that then I know the timing has to be way off (extreamly retarded correct?) for it to be burning in the manifolds like that. It seems as if either the timing light is way off, the outer edge of the harmonic balancer managed to slip, or maybe the timing marks bolted on to the side of the timing chain cover is off. We check the marks on the timing chain cover and they seem to be located where the other two engines in the garage are (one 305 out of another '86 IROC and a 350 from some mid '70's truck). The only difference in the timing marks is that my engine has the marks bolted in with the timing chain cover bolts (aftermarket timing chain cover) and the other engines have them as a part of the cover. So I don't know what would cause this to be so far off, any ideas would be greatly appreaciated.

Oh and yes we did disconnect the wire above the heater box (found out the hard way when the timing was jumping around the first time we shined the light on it =) ).

 

Also it seems that the IAC is sticking or something. We have the throttle stop screw all the way out, and it won't come close to catching the pedal. The car will rev, but likes to hang around where it reved too. any other suggestions?

 

I'd tend to agree. Find TDC of the compression stroke on the #1 piston by removing the spark plug and manually turning the crank (starter or wrench). Put your finger over the hole (not in the chamber) and feel for the compressed air coming out to know when you're on the right stroke. When you get it to the top compare it to the balancer.

 

Yup, sounds like your balancer's timing mark and your timing tab aren't a set.

 

Would you have any idea on how to go about setting them if they are off?

We are going to try pulling the balancer off another 305 TPI today, and try holding it up to the one on this engine to see if the marks line up. Provided I can see the alignment marks on the crank from the front of the balancer, if not then I guess I will have to attempt to pull the balancer while the engine is in the car.

I will go do that here in a few hours and report back.

 

Have fun man. If we have to, is it possible to switch timing covers with the engine in the car? I really don't want t but if we have to switch from the other tpi 305 block, we will.

 

Easiest thing to do would be to find #1 TDC accurately, by sticking something like a pencil in the spark plug hole; and then marking the balancer with white paint or something to correspond to whatever timing tab you have.

Pulling the balancer with the motor in the car is not a problem. If you do it from below, you don't have to take off anything else except the belts. The timing cover is a different matter. I'd avoid disturbing that if possible since it's much more invasive.

 

Ok, that sounds like a great idea. We will give it a try when i get off work.

 

As to your IAC and hanging idle and what not, it may be that your Thorttle Body need some lube, it sounds like it hanging up and not coming back all the way. My IROC was doing that before I sold it, but I never got deep into investigating it. In the other thread, sorry about the FAQ rebuke, I missed that you had got the wire in this thread. My buddy was doing the same thing the other day, and couldn't get the timing right. Had to set him straight. His TA runs good now!

 

Thanks for you help so far guys.
I just pulled off the main pully and looked at the balancer. It seems that the timing mark is shifted a little over two inches back (retarding our timing readings) from the keyway on the crank. The other balancer from the other 305 TPI has the mark just about lined up with the keyway. So it looks like either I should get a new balancer if there not too bad in price or try and make my own mark.

 

Well we were able to make a new mark and set the timing pretty good. Now the only problem is with the IAC sticking, that and if its idling below about 1200 RPM in park/neutral it will die when its dropped into gear with out tapping the throttle right as it goes in. Then it will idle fine in gear at about 700-750 RPM (anything lower and it will die). I am hoping that is just a problem with the IAC and it will go away once we can get that fixed. Does anyone have any ideas if it could be something else or not, causing the rpm to drop so long then come back up right when its put in gear?