I work on stationary industrial engines. I see a lot of 4.3L and 5.7L engines with various problems.
For the past month there has been an engine that has plagued us. The timing kept jumping all over the place. We replaced every component on the ignition system except the distributor. Even had the distributor out (and obviously didn't look at it hard enough) and didn't notice that the shaft was broken in two pieces.

It could be possible this is your problem.....However this particular engine we could get running. Yours will not run. *shrugs* just a suggestion.

I'll definitely check the overall integrity of the distributor when I pull it out Sunday. It was intact when I put it in just prior to attempting to start the engine, but who knows? Thanks for the input!

[This message has been edited by FieroJoe (edited 10-16-2004).]

Update from the weekend:

Retimed the engine and installed the distributor properly with a new pick-up coil and working ignition module (BTW, the pickup coil was within 10 ohms resistance of the old one...830 and 820 ohms across the terminals, I was hoping that it would be broken!). I used a leakdown gauge to verify that as I was turning the crank to line up the timing mark, it was on its compression stroke. With my foot on the floor while cranking, I could hear each cylinder firing...my friend witnessed flames shooting out of the intake and hot vapor coming out the exhaust...so it's at least doin something. All 6 candles are trying to light in succession.

However, I noticed something interesting...

At a different point on the damper's revolution cylinder #1 holds compression much better than at what I am calling #1 TDC. For those who have looked at a 87 V6 damper, you will note that there are three different marks present. What I have set the timing by and timed the engine with in the past was the largest one; that is the mark that I am currently using. But, as I was applying air pressure to the cylinder while turning the engine, as one of the other marks began to line up with the stationary timing marks (the ones on the front cover that is), the cylinder was hold pressure much better than when the largest (current) timing mark was lined up. I found this very odd...it's as if I was given the wrong timing set. Wrong, as in the mark that you line the gears up with on the cam gear was indexed differently in relationship to the hole in the gear that the cam's pin goes through.

I have pictures to prove that the cam to crank timing is correct, but what I didn't do was check the new timing set that the engine shop gave me against the old one that came out of the running engine when I tore it down to be rebuilt. Like I just said, the engine shop provided me with this [Clevite] timing set and I didn't really have any reason not to trust that it was the correct one. As I see it, it could have been index incorrectly just enough to where the Helm manual's valve adjustment procedure would still work, but the engine would be impossible to time since the valves could be partially open when the cylinder wants to fire, and hence my firing through the intake and the exhaust simultaneously.

The next thing before inspecting the timing set is to try a new computer. FieroMaster88 is being kind enough to let me borrow his old one so that I may try it.

Something interesting to think about regarding the timing sets though...

I looked up and compared numbers from Autozone's website regarding 2.8L timing sets. S-10's, Fiero's, and F Bodies have the same timing set, where as the W, J bodies have a different number. Just something to chew on...

Edit: Goofed on the timing set compatibility

[This message has been edited by FieroJoe (edited 10-20-2004).]

Lets see those pics. Your supplier may have given you the incorrect cam and or crank gears.

Crap! I may have to call the guy and see if he knows what part number he gave me, since the picture that I had in my head that showed the cam/crank timing is now nowhere to be found. I bet you could have looked right at it and told me if the mark is index correctly to the cam pin eh?

quote Originally posted by FieroJoe: Crap! I may have to call the guy and see if he knows what part number he gave me, since the picture that I had in my head that showed the cam/crank timing is now nowhere to be found. I bet you could have looked right at it and told me if the mark is index correctly to the cam pin eh?

I would have taken a pic of my own to compare with as I have a 2.8 somewhat disassembeled to rebuild. The timing cover is off of it.

quote Originally posted by FieroJoe: However, I noticed something interesting... At a different point on the damper's revolution cylinder #1 holds compression much better than at what I am calling #1 TDC.

Sounds like it might be useful to find TDC on your own. This is easier with the engine out of the car, but can be done installed.

Remove all the plugs so the engine is easy to turn by hand. Bring the engine to what you think is #1 firing. Stick something down the #1 spark plug hole to see if the piston is at TDC. Turn the engine slightly each way to see if the piston goes down. If it does then you're at TDC.

Once you do this, then you can check cam timing. Pull the rear rocker cover. Bring engine to #1 firing. Make sure both valves are closed. Rotate engine through 720 degrees and watch the valves move. You be able to tell if the cam is way out of time. You probably won't be able to tell if it's one tooth off, but if that was the case the engine would still run.

Doug

Indiana_resto_guy: If the timing cover is still off of your engine, please take that pic anyways and send it my way. That way, if it comes to having to take the timing cover off with my engine, I will have something to compare it with. I'd really appreciate it.

Doug Chase: I know for sure that #1 is at TDC when the large, painted timing mark is at 0 degrees on the timing mark. I do happen to have a picture of that. It's the valves that just makes me wonder. After I adjusted the valves and before I put the valve covers on, I turned the engine around by hand quite a few times to make sure that everything was kosher as far as my valve adjustment. I adjusted the valves, in their correct order, until was zero lash in the pushrod, and 1.5 turns tighter after that zero lash. Once they were all adjusted and I turned the engine over a few revolutions, the pushrods were still able to spin (as if they had been seated better after turning or something) but there was no slop between the rocker arm and the pushrod. On each rocker stud there was also about the same amount of thread exposed...so it makes me believe that I have them all adjusted to the same, or close to, amount of compression (compression along the rocker, pushrod, and lifter...not engine compression here).

quote Originally posted by FieroJoe: ....... I adjusted the valves, in their correct order, until was zero lash in the pushrod, and 1.5 turns tighter after that zero lash. ......

This may be your problem!!! The correct adjustment for this engine is 3/4 of a turn, not 1.5. The Haynes book is wrong. More than likely, your valves aren't closing completely, which can cause all sorts of wierd problems....like popping through the intake and such.
It would be well worth the effort to remove the valve covers and readjust the valves.

------------------
Rod Schneider, Woodstock, Ga.
"You can't have too many toys!"
1988 Fiero GT
1966 Porsche 911

quote Originally posted by Rodrv6: This may be your problem!!! The correct adjustment for this engine is 3/4 of a turn, not 1.5. The Haynes book is wrong. More than likely, your valves aren't closing completely, which can cause all sorts of wierd problems....like popping through the intake and such. It would be well worth the effort to remove the valve covers and readjust the valves.

All the maintainance books I have (GM manuals) also say 1 1/2 turns as well but I usually go only 1 turn or until the lifter plunger (tappet) is about half way into the lifter bore. The tappet is the key for me.

quote Originally posted by FieroJoe: Indiana_resto_guy: If the timing cover is still off of your engine, please take that pic anyways and send it my way. That way, if it comes to having to take the timing cover off with my engine, I will have something to compare it with. I'd really appreciate it.

I will e-mail it to you later today if your e-mail is current and correct (in JPEG).

quote Originally posted by Indiana_resto_guy: I will e-mail it to you later today if your e-mail is current and correct (in JPEG).

as long as your cranking the crap outa that engine a compression check would let you know if somethings wrong...

quote Originally posted by cptsnoopy: as long as your cranking the crap outa that engine a compression check would let you know if somethings wrong...

Look further backwards in the topic to reveal compression issues. #1 can get 90 psi currently, and the adapter for the small spark plug threads that I have does not work well with Fiero heads...the heads have a counterbore in them large enough to get a standard spark plug socket into, but not large enough for me to put a socket on the compression checker adapter and tighten it properly. I can only get it as tight as I can safely twist the hose, therefore I may be able to get more than 90 psi if there is blowby through these spark plug threads. 90 psi should be enough to fire, which the engine is doing under conditions outlined in the previous posts.

Indiana_resto_guy: Any picture format will work and the email address you sent those Helm scans to is my current one. Thanks!

[This message has been edited by FieroJoe (edited 10-22-2004).]

As a joke, take the distributor cap off, look at the wires to your ignition module. It's very easy to smash one putting the cap on. I replaced an ignition module without noticing that one wire was crushed flat and grounding to the distributor body. It's one of those things you won't see unless you are looking for it.

quote Originally posted by Azriel: As a joke, take the distributor cap off, look at the wires to your ignition module. It's very easy to smash one putting the cap on. I replaced an ignition module without noticing that one wire was crushed flat and grounding to the distributor body. It's one of those things you won't see unless you are looking for it.

Thanks for the idea, but I think I'm good as far as that is concerned. The wires are tucked in nicely.

quote Originally posted by FieroJoe: Doug Chase: I know for sure that #1 is at TDC when the large, painted timing mark is at 0 degrees on the timing mark. I do happen to have a picture of that.

Good. We can rule that out.

quote It's the valves that just makes me wonder. After I adjusted the valves and before I put the valve covers on, I turned the engine around by hand quite a few times to make sure that everything was kosher as far as my valve adjustment.

When I suggested you turn the motor over by hand and watch the valves, I wasn't talking about valve adustment. I was talking about watching the valve timing.

If you start at #1 firing TDC and turn the engine, then just before 180 degrees you should start to see the exhaust valve open. Just before 360 degrees you'll see the exhaust valve closing and the intake valve opening. Just after 360 degrees the exhaust valve should be fully closed and the intake significantly open. At 540 degrees the intake valve should be almost closed and it should stay closed all the way up to 720 degrees (back where you started).

This will tell you if you've got the cam timing set correctly without needing to pull the front cover.

Doug

Any update? Does it run yet?

quote Originally posted by Doug Chase: Any update? Does it run yet?

I received this from Joe today:

quote [B] Hey Keith, I just got back to school where my computer is, and I was going to email you back and let you know that I got the car running! The valves were adjusted too much...I put 1/4 turn on the nut after zero lash this time. Runs great now! Just gotta fix a squeaky belt issue, and it's pretty much all good to go. I really appreciate the effort you've put forth to help me figure this out. I hope that I will be able to return the favor sometime. Thanks again, Joe

So he's up and running!
I just hope he has proper oiling up top.

[This message has been edited by Indiana_resto_guy (edited 11-01-2004).]

Doug, you were completely correct. I readjusted the valves to only a 1/4 turn after zero lash and it started right up! Too bad I had to buy a new lower intake gasket, and it was only available as a whole kit...so that one gasket was $25

Sorry about the delay as far as updating this topic, but it was a busy enough weekend on top of getting the car running, and I just got out of class right now. Going to go back to the rent's house and drive it back here to school tomorrow, so I can drive it around down here and get some more miles on it before it gets too cold!

Thank you all for your help!

quote Originally posted by FieroJoe: Look further backwards in the topic to reveal compression issues.

just to be sure, i had done that. I noticed that you checked one cylinder and admit that it was a guess at best.

glad to see you got it going!

[This message has been edited by cptsnoopy (edited 11-01-2004).]

quote Originally posted by Rodrv6: This may be your problem!!! The correct adjustment for this engine is 3/4 of a turn, not 1.5. The Haynes book is wrong. More than likely, your valves aren't closing completely, which can cause all sorts of wierd problems....like popping through the intake and such. It would be well worth the effort to remove the valve covers and readjust the valves.

Gee, do I get a prize for guessing the problem?

------------------
Rod Schneider, Woodstock, Ga.
"You can't have too many toys!"
1988 Fiero GT
1966 Porsche 911

You get the super duper mega awesome award! Of course, this award is of the highest honor in the engine weirdness diagnosing community!

quote Originally posted by fuzz: I too believe the problem is in the timing. The only other thing I would check is that the valves aren't set a little too tight. So when the oil pressure starts building up you are holding the valves open just a little. Good luck, we have all been there where it should start and some little thing is keeping it from happening.

Glad you got it going. Sometimes you have to check the obvious.

quote Originally posted by FieroJoe: Doug, you were completely correct. I readjusted the valves to only a 1/4 turn after zero lash and it started right up!

To be completely clear, the credit for this idea goes to somebody else, not me.

I'm glad you got it running!

Doug

quote Originally posted by gunnie: Glad you got it going. Sometimes you have to check the obvious.

If you read my whole first post, you'll see that I did check the obvious. To me, having followed the directions in a factory service manual for reassembly did not lend itself to check into things not as obvious as tearing apart the whole top end of the engine to check the valves.

Sorry, I never meant to salt the wound. It's just hard to help someone over the computer. Glad it's running