So, in my infinite wisdom, I decided to tinker with my timing, distributor, and air/fuel mixture. I took a perfectly running engine, and threw a wrench in it. Why? I found it odd that the timing mark on the lower pulley was not where it was supposed to be.
I started by retarding the distributor, and found it. When I got it to the 5 mark, the DeVille was running rough. This made me think that maybe it was off a tooth, and I proceeded to test my theory. I pulled the spark plug from cylinder 1, and got to tdc. Sure enough, the rotor was not pointing to cylinder 1. When I attempted to start her back up I was unsuccessful. I advanced the distributor and backfired through the carburetor. Retarded, and began adjusting the air. No luck. She ran worse.
Then I went to the carburetor adjustment section of my shop manual, and set it to baseline to start fresh. Unfortunately, by this point my vacuum system was open for the AC resurrection, and I couldn’t get anything to work. Eventually I got her started, but she is not happy.
Anyone able to guide me through some steps to get this sorted out? The AC is back together, and vacuum system is sealed back up.
Sam where was the rotor pointing before you moved it? Are you sure that the number one cylinder was at the top of the compression stroke and not the top of the exhaust stroke?
I had my thumb over the opening to feel when I was on the compression stroke, and the pointer was slightly forward.
The shop manual says that timing should be 5 degrees. A lot of people have found that 8 - 10 works best
Right, but mine was way right. Past 12 o’clock.
Backfire through the carb is an indication that the distributor is out by 180 degrees.
You never know what's been done to these things over the years. So I'm assuming idle was correct and vacuum advance was disconnected and the line plugged off? Both weights in the distributor were on and not broken?
Initially, yes. When the mark was not on the 5 degree mark. Once I screwed ul the air/fuel no. Had the vacuum system open at the Comfort Control panel.
The first part is to verify that the engine is in fact on TDC. Best advise is to check according to the manual. Your harmonic balancer is supposed to be fitted in the correct position. If not then you have bigger issues at hand. So assume that the balancer is in correct position, remove all plugs (to take stress off the starter and make it easier to find the exact spot), turn the engine with some helpers assistance. When the harmonic balancer is on 0 is described in the manual you have TDC.
Second part; lift the distributor and turn it with the rotor slightly anti clock wise of number 1 cylinder. Drop down the distributor and it will turn 1/16 or so clock wise into position. Now you take a piece of string and hold it over the rotor and hopefully number 1 cylinder. If the rotor is pointing to No 1. Great! If not recheck the position of balancer and then lift the distributor and drop it in a new position until you verify that the rotor is pointing to No 1.
1st I would do a simple test to makes sure the timing chain has not jumped or slipped. Rotate the engine so that the timing mark is exactly at 0-TDC. Remove #1 spark plug and look inside with a light. The piston should be at the very top ridge of the cylinder. to make double sure you can have someone using gloves and manually turn the engine slightly one way then the other while you watch the piston through spark plug hole. Either way it should start to come down. If it continues up the timing chain is off. Regardless, you can usually just tell it is at the very to as you cannot really get a screwdriver in there as it is at the top.
From there you can basically throw a distributor into the engine anyway you like as long as the spark plug wires start at the right point and go in the right correct order. The illustration of where #1 in the shop manual is a reference for where it makes most since to have #1 wire and orientation of distributor in order to adjust points through window. If you just think about it when on compression/ignition stroke when you are simply firing starting at #1, then fire in the order 1-8-7-2-6-5-4-3.
So, assuming timing chain is correct, plop the distributor in to the front cover, get engine timing mark to TDC on compression stroke, look at distributor orientation on the cap, and attach spark plug wire going to #1 cylinder to where rotor is pointing to on distributor cap when seated on distributor. Now, continue installing wired in the order 1-8-7-2-6-5-4-3. Since the engine is designed to run with some advance (5 degrees when dialed in), slightly turn the distributor counter-clockwise, lock down, crank engine and adjust timing with timing light. It is that simple.
People, get into studying that illustration with distributor orientation and worrying about whether they get it installed exactly like the shop manual illustration and miss the point you are just trying to get fire to #1 cylinder just before TDC on compression stroke, and then fire the remaining cylinders in the order stated. I 've had people stand me down saying You Can't Get The Engine to Run Unless The Distributor Goes In A Certain Way ---> Wrong! LOL
Just one other hint on timing. You can usually remove the spark plug and feel the compression if someone else can crank the engine over for you. The other and for me easier way (especially if you haven't cemented your valve covers down with Super Duper , requires a chisel to remove, Gasket Cement) is to remove the LH valve cover, crank engine over and watch valves to #1 cylinder. If on the compression stroke the #1 Cylinder intake valve had just opened and closed before TDC. If on the compression stroke it stays closed. Some times you just have to use common sense.
I will veify the current set up coincides with your direction. The only thing I have not payed any attention to is that the mark is on 0 when I feel I am TDC. I followed the book to ensure I am on the compression stroke, meaning pulling #1 spark plug, placing my thumb over the opening, and having my helper turn her over.
I am going to come back to this for guidance tuning the Carter carburetor if I determine the timing chain hasn’t slipped, and I can get the distributor sorted out. You have a part number for AC Delco points for the DeVille? I picked up an Eglin that had the condenser built in, and it didn’t help my issue. Had to reinstall the worn out one to get her to start.
Here is what I did to check for timing chain slippage:
1) Pulled #1 spark plug
2) Placed thumb over hole and had someone turn her over until I felt compression.
3) Inserted a rod into the cylinder chamber for a sight gage.
4) Rocked back and forth from 0 TDC mark.
What I saw was the piston was at its peak at 0 TDC. It was approximately 1/4” - 1/2” before I noticed the piston began to drop. I rocked back to zero and movement stopped at 0. I do not think I have any slippage at the timing chain. The attached pictures show the rotor position at TDC, and where it points to #1 terminal with cap on. Sorry about the poor quality.
To me, everything should be lined up. The wet plugs I spoke about twll me fuel is entering the cylinders,
That won't test for timing chain slippage, you need to know where the valves are in relation to the crank. For that, you'd need a dial gauge on the valves with an index wheel on the crank. If your engine ran perfectly before, you needn't worry about the timing chain having skipped.
I just tried to turn her over. Nothing.
Thank you for confirming my assumption that it was unlikely to have slipped since it was running fine before.