thinking it was the timing the timing cover has been removed. according to the book it says the oil gear and cam gear marks need to be in line and the timing chain gears should be in line also with the #4 cylinder at TDC. Where should the rotor be pointing? To the #1 or #4 cylinder?
Normally, engine timing is aligned using cylinder #1.
Hate to say it but engines spark even when the timing is incorrectly set, you need a manual for a “crank no” start condition, sounds like you are winging it, on one wing.
Hook up a timing light,turn it over to see if you have any spark. Then you can worry about if it is at the right time.
Books always use #1 cyl for timing.
#1 and #4 come to TDC at the same time…The distributor could be pointing at either one. Engine timing is one thing, no spark is something else.
Since you have opened up the front of the engine, you might as well replace the chain and gear, needed or not…After you button that up, we can investigate the lack of spark…probably the ignition module inside the distributor or the wires connected to it.
I agree with Caddyman. In fact would take it a step further: since you’ve opened the hood, simply replace the entire engine.
What do you mean, “engine turns over but no spark”? Do you mean “starter motor works but big engine doesn’t”? Have you taken out a spark plug and laid it against the block to see if as my country friends would say “you got fahr”?
How does your engine “turn over” without “spark”?
What were the conditions of the failure? Why did you take the engine apart this far? Why did you think it jumped time? Does the engine cranking sound unusual? Does it sound like it has no compression? I really want to know what happened to this truck to make you think it had jumped time.
To answer your questions, when you have the timing set installed, the marks on the crank gear and cam gear should be aligned vertically (perpendicular to the ground), nearest one another if I remember correctly. You should check a repair manual to verify. Haynes should have clear photos to illustrate this. Once this is accomplished, cylinder #1 will be at top dead center of the power stroke. Your distributor needs to be installed with the rotor pointing at the cylinder #1 TOWER ON THE DISTRIBUTOR CAP. On most, if not all, Chevy V6 and V8 engines, this does turn out to be pointing at cylinder #1 on the engine (right front corner). Make sure when you install the distributor that the oil pump drive on the pump and the distributor line up and the distributor goes in all the way. Failure to do so could strip out the helical gears on the distributor shaft and the camshaft. Getting that distributor to drop correctly is sort of an art form and can really trip up a novice, but don’t lose your patience with it and do it wrong or you will never get this engine running. Once the distributor is correctly installed, you can try to start the engine and set the timing. Your truck has electronic advance which needs to be unhooked before you can set your timing. Check your repair manual for the procedure. If it doesn’t start, you need to start diagnosing the problem. For a no spark situation on this vehicle, I would suspect the ignition module. It is located under your distributor cap and is easy to replace. Good luck.
“Turn over with no spark” typically means the engine will crank over, but the ignition system is not functioning. Normally, diagnostics have been taken far enough to eliminate the possibility that the engine is not getting fuel. Any decent technician can interpret a complaint like this and either diagnose the car, or in the Internet realm, point the OP in the correct direction. Please try to limit your responses to those which have value and relevance.
ok. I’ll try to explain…going down the road engine started to lose power and there was a big backfire (kinda like 30-30) and when i shut it off it dieseled. Then I tried to start it and it started so I continued to my destination. I got there no problem. When I left I was almost home and the engine lost power again and again the loud backfire out the exhaust. This time it didn’t start. As far as compression goes, the cylinders are in the 115 to 120 psi range. I checked that. there are no unusual sounds when the engine is being cranked over but there was no spark at the coil or spark plug. A new coil has been installed with no change. I used a manual to check the timing gear replacement. As I said the manual uses #4 cylinder to make sure the oil and cam gears and the timing chain gears are set in the right place and this has been verified several times. But my question is after this procedure is copmplete where should the rotor be pointing to under the distributor cap, #1 or #4? Could it be the distributor is bad of the cam gear driving it? Haven’t pulled the distributor yet, but I’m thinking maybe that’s the next step. Thanx for your input.
From what you describe here it sounds like the timing chain has slipped. That is why it backfired, the compression is low, and you can’t start it now. If you aren’t getting spark then I’m not sure what to say about that except to make sure the ignition is getting power to it.
Since you say that your alignment procedure is setting things up to cylinder #4 TDC then the rotor should be pointing to the wire position for #4 cylinder.
Did you check your timing marks before you removed the chain and gears? Were they off, even a little bit? Low compression readings can be accounted for by the chain being off by a tooth or two, but any more than that and you would be getting much lower than that. 115-120 is a little low, but I’m not sure it is low enough to account for the engine jumping time. It seems more like typical wear on an old engine. Based on the engine in the truck and what you experienced, the central fuel injection unit is definitely suspect. A leak out of that will cause backfiring and failure to start due to a seriously over-rich condition. I would still try putting it back together and trying to start it. If you still don’t have spark, I would try a new ignition module. They are cheap and easy to replace, probably cheaper than the coil you didn’t need. If you didn’t pull the distributor, I would recommend against doing it. There should be no need to do it, and getting it to go back in will be tough if you are ‘new to cars.’
the haynes book is a little confusing seeing all the different variations on the electrical configurations. I.E. the book list my distributor in the HEI class but says that distributor is at the front of the engine and its not in my truck. Anyways there
were 2 tests for checking the coil to the modulator in the distributor. (wire to wire and wire to ground) if either failed it says to replace the coil (not the primary, so yeah that was a waste) wire to ground failed…no continuity. That’s going to mean pulling the distributor but I’m feeling pretty comfortable about that since I have had to do this before.
It seems there are two problems going on here. I am wondering about the ignition system and how you are checking for spark. Are you placing a plug in a plugwire and then putting the plug on a good engine ground point to test for spark?
I have never heard of a chevy engine that uses the #4 cyl to set up the timing, I would check another manual. Manuals have typos, and this looks like the case here.
Turn the engine over by hand one turn. The distributor should rotate 1/2 revolution. With #4 at TDC, the rotor will be pointed at #1 or #4 contact in the cap because #1 is at TDC too!
If the distributor spins, it will generate a spark (should generate a spark) reguardless of the timing…
Did you find your chain VERY loose?? Was the cam gear chewed up and or falling apart? Many are plastic coated and when this coating wears off, the chain can jump time…
first I want to thank everyone for their input. I’ve checked and rechecked timing. It is where it suppose to be. The is no extra play in the chain and the gears all look have no sign of wear. I have been checking the spark by removing the plug and and turning ober the engine. The pick up coil test I had performed indicated that it was bad and it has now been replaced. However, I still have no spark. It would apear the only thing left to do is to change the (darn, I drew a blank there) but its the box (modulator?) the bos that the pick up coil plugs into. It’s been quite a challenge and continues to be. Thanks again to all of you for your help. I’ll be back.
Thank you for your comment, mark9207.
I asked a question: does the engine actually start or is the OP sayin the starter motor works?
I asked another question: has the OP performed a simple test to see if there is “spark”?
I also raised the issue that you raised below: “Why did you take the engine apart this far?”
What is your problem?