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Username Post: vortec timing        (Topic#238244)
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-20-10 11:06 PM - Post#1883743    

So I got my motor all together and in the truck and I almost have it running. I did mark the distributor on dissasembly but to no surprise after a full rebuild it isn't working. refresher, this is a 98 350 vortec.

So after trying my marks at TDC and not working I did the following, which also lines up close to my marks. I set #1 cyl to tdc compression stroke. I pull the distributor and line up the drilled hole on the cam gear to the painted line on the housing. I drop the distributor in and it comes close to the #8 mark so I line it up. still wont start. Doesn't really even pop at all. if I advance the timing it starts to pop. if I advance a tooth it pops more but anymore teeth and it seems like it almost wants to start but timing is way off. I tried going 3 gears in either direction with similar results. I even tried 180 degrees incase I had the wrong stroke and it REALLY starts to back fire out the intake.

So do I have to have a scan tool to get this thing to start? I would have thought I could get it close enough that it would start and then you would have to fine tune with the scan tool?

Any thoughts? I have two sources to barrow an appropriate scan tool I would just be more likely to use them if I could drive the truck there.
98 Silverado k1500 4x4 350


 
Low priced Genuine GM Auto Parts
JeremyB 
Senior Member
Posts: 703
JeremyB
Reg: 10-31-01
03-21-10 03:56 AM - Post#1883759    
    In response to 355Cheyenne

Is the fuel pressure good? A scan tool wont do any good until its running unless you want to check the IAT and CTS to see if they are way off and keeping the engine from starting. Have you tried starting it by dumping a little gas down the throttle body?

 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-21-10 08:23 AM - Post#1883857    
    In response to JeremyB

fuel isn't likely my problem as not only do I smell gas after cranking a while. (to a point I am worrying about my cat) but also I am fouling my plugs out. if anything maybe half my problem is the gas in this truck is about 17 months old... I will connect the fuel pressure gauge though just to be sure. I hear the pump prime and before the rebuild everything ran perfect, I just lost oil pressure. Which is good news because I get 35psi while cranking.

I do have a scan tool that gives me freeze frame data if there is an SES, but I am not getting an SES. maybe my timing is right and I messed something else up.
98 Silverado k1500 4x4 350


 
ltlvt 
Senior Member
Posts: 1636

Age: 62
Loc: Wichita Falls Texas USA
Reg: 09-17-00
03-21-10 09:01 AM - Post#1883892    
    In response to 355Cheyenne

I would check things like timing tab ,correct harmonic balancer crank position sensor etc. If i remember Tom you are putting a late model engine in a early model truck. Terry
Runs like a Scalded Dog!!


 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-21-10 09:08 AM - Post#1883898    
    In response to ltlvt

nope this is a stock 98 chevy 350 vortec. I am just rebuilding it to stock spec. because of low oil pressure. I have a couple friends that are GM techs, but they live a couple hours away. I have been talking to them and they say my method is correct and should get it started. so I am going to go the extra mile and pull the spark plugs so it is easier for me to turn over and check for compression on #1 and start over. If that doesn't work then I am going to start t/s this not as a timing problem and check everything. I am just surprised that I didn't get an SES yet.
98 Silverado k1500 4x4 350


 
ltlvt 
Senior Member
Posts: 1636

Age: 62
Loc: Wichita Falls Texas USA
Reg: 09-17-00
03-21-10 09:10 AM - Post#1883900    
    In response to 355Cheyenne

Sorry Tom I thot it was a transplant.
Runs like a Scalded Dog!!


 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-21-10 09:16 AM - Post#1883909    
    In response to ltlvt

Wish it was. I am a lot better with TBI than I am with this sequential junk. I was considering taking the motor out of my mud truck but after seeing how ugly the transplant would be I decided against it.
98 Silverado k1500 4x4 350


Edited by 355Cheyenne on 03-21-10 09:17 AM. Reason for edit: No reason given.

 
ltlvt 
Senior Member
Posts: 1636

Age: 62
Loc: Wichita Falls Texas USA
Reg: 09-17-00
03-21-10 10:14 AM - Post#1883938    
    In response to 355Cheyenne

The vortecs are really a pain to work on. My brother has a 96 that has #6 misfire. He has replaced the spider assy ,the distributor and the fuel pump and still has the problem. I've got a Big block in my 96 3500Hd tow truck and i really wish it was a TBI.
Runs like a Scalded Dog!!


 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-21-10 11:23 AM - Post#1883971    
    In response to ltlvt

Well thanks anyway guys, I got it and it was dist. timing. Not sure what I messed up but I connected a compression tester to #1 and cranked it till I got compression at tdc so I 100% knew I was on the money and then I stabbed the distributor in with the marks lined up. cranked and fired.

I suspect I had the timing correct but that I had fouled spark plugs. when I first cranked it yesterday I was 100% sure I was 180 degrees off and I think that fouled the plugs so that when I did set the timing right it would start. I pulled all the plug and dried them. it sounds VERY healthy and got 40 psi at cold idle. WOOT now I just have to put the grill back on. not today unfortunately as I have to get to my kids skating show. doesn't matter anyway, I went into the DMV to update the tabs and I have 09 on it now and they expired april so if I buy tabs it iwll be 10 until april so I would have to buy tabs twice.. so I am going to wait a month and go in to just get the 11s.
98 Silverado k1500 4x4 350


 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-22-10 07:06 AM - Post#1884528    
    In response to 355Cheyenne

I am going to add this to the FAQ sticky so I am going to compile in here the proper way, not only for my future reference, but any other poor soul that has to deal with this.

Vortec Timing, 96 to 98. This is very common and after dealing with it a couple times on my own I felt I should add to this FAQ. Listed below is good for a v6 or v8, (just line your mark up to the 6, not the 8.) There are two processes to follow, I will list the more favorable A and alternate B:

A:
First if you are doing a smaller job like intake gaskets etc, you want to mark the distributor. Mark the distributor housing to the intake with a grease pencil. Also mark where the rotor is pointing to on the base of the housing. I suggest doing this at TDC #1 compression stroke so that if you accidentally bump the motor over you can put it back. on tear down to find TDC turn the engine over manually until you line up the line on the balancer to the timing mark on the timing cover. Check the distributor and it should be pointing to a #8 in the housing of the distributor. you will note a 6 and an 8. The 6 is where it would have pointed if this was a 6 cylinder. If pointing to that little 8 then you are at TDC #1 compression, if it is pointing in the opposite direction you are at the top of the exhaust/intake stroke #1, not compression and you need to turn the crank a full 360 additional degrees.

on reassembly just make sure you are TDC compression and slide the distributor back in. If it doesn't sit flat on the intake try wiggling the rotor back and forth a bit to get the distributor gear to seat in the oil shaft. If this doesn't work you may need a long flat head screw driver to turn the shaft and properly align it.

B:
If that doesn't work, or you forgot to make your mark or you did a full rebuild with new timing gears and need to get it set this is what you do. Find TDC #1 compression stroke. How do you find it? I found if you are alone the best is with a compression tester. you can turn it until you see it build pressure. I recommend you do this with all the spark plugs out, makes it a lot easier to turn over. If you have 3 hands or more available, you could have some turn the motor over while another puts a finger on the #1 spark plug hole and feel for pressure, once you feel pressure line the timing marks up. Being at TDC you can now move on. Get your distributor. Look on the lower part of the housing and you should see a white vertical line painted on it. Turn the distributor gear until the drilled hole lines up with the white line. look at the rotor and it should now point about at that #8. Stab the Distributor in with the wire harness connector facing towards the fire wall(more towards driver side). Once seated see if you can line of the rotor to the #8. If you can and can lock it down and put the cap on then you are good, if not you may need to re stab on a new tooth but the end result is you want the rotor pointing the the #8 on the housing. (now I am not talking about #8 cylinder, but in the distributor there is a 6 and 8, tiny but it is there.)

That should fire it up, if not then you messed something up and start over. You may need to pull your spark plugs and dry them (air compressor helps here) as I struggled with fouled plugs leading me to think I was wrong on the timing but wasn't.

Lastly once done with A or B, you should get a scan tool that will display the cam retard and you need to turn the distributor to set this to zero.
98 Silverado k1500 4x4 350


 
ltlvt 
Senior Member
Posts: 1636

Age: 62
Loc: Wichita Falls Texas USA
Reg: 09-17-00
03-22-10 08:38 AM - Post#1884594    
    In response to 355Cheyenne

Tom is the cam retard the same as the timing on the scanner. Because with my big block running it says -25.
Runs like a Scalded Dog!!


 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-22-10 11:41 AM - Post#1884700    
    In response to ltlvt

I am thinking that the reading you are seeing isn't cam retard but actual distributor timing that the ecu is trying to attain.

Below is the text from GM Service manual for 1997 Chevrolet C Pickup 5.0L, 5.7L, and 7.4L
Accordind to this you don't set the timing but the timing offset.
You need a "Scan Tool" that plugs into the truck and can read the data from the trucks computer.
Besides from that, it looks like a normal timing procedure.

Setting Timing
Camshaft Retard Offset Test
The ignition timing cannot be adjusted. The distributor may need adjusting to prevent crossfire. To insure proper alignment of the distributor, perform the following:

With the ignition OFF, install a scan tool to the DLC.
Start the engine and bring to normal operating temperature.

Important
Cam Retard Offset reading will not be accurate below 1000 RPM

Increase engine speed to 1000 RPM.
Monitor the Cam Retard Offset.
If the Cam Retard indicates a value of 0° ± 2°, the distributor is properly adjusted.
If the Cam Retard does not indicate 0° ± 2°, the distributor must be adjusted.
Adjusting Camshaft Retard Offset

With the engine OFF, slightly loosen the distributor hold down bolt.
Important: Cam Retard Offset reading will not be accurate below 1000 RPM

Start the engine and raise engine speed to 1000 RPM.
Using a scan tool monitor Cam Retard Offset.
Rotate the distributor as follows:
To compensate for a negative reading, rotate the distributor in the counterclockwise direction.
To compensate for a positive reading, rotate the distributor in the clockwise direction.
Repeat step 4 until 0° ±2° is obtained.
Turn the ignition OFF.
Tighten the distributor hold-down bolt to 3N•m(25 lb. ft.).
Start the engine, raise engine speed to 1000 RPM and recheck Camshaft Retard Offset.
98 Silverado k1500 4x4 350


 
fritz1990 
Senior Member
Posts: 6401
fritz1990
Age: 52
Loc: Kansas
Reg: 02-16-03
03-22-10 11:47 AM - Post#1884704    
    In response to 355Cheyenne

Thanks for the post as I have a 96 that I bought this winter for a song and will have to take engine out.

Regards, Jeff
1998 K1500 6.5 Coal burner
1965 C10 with 498 BBC AFR Heads
1964 C10 Ran 348W for 6 years, now SBC.

Corvettes owned: '74 '77 '78 L82 Silver Anniversary, 2002 LS1

Don't have a nervous come together!

http://picasaweb.google.com/fritz199090


 
JeremyB 
Senior Member
Posts: 703
JeremyB
Reg: 10-31-01
03-22-10 03:49 PM - Post#1884838    
    In response to fritz1990

If you read the Gm service manual, it says that marking the distributor is not sufficient if the intake is pulled, you must get the engine to TDC of cyl #1 and align the indent in the distributor gear with the white line on the distributor housing before inserting the distributor. Marking the distributor should be fine if the crankshaft isn't moved and mark the distributor twice, when its in the motor and after its out since it turns when you pull it.

To find TDC on the compression stroke of #1, pull all plugs except for #1(drivers side, closest to radiator) and turn over by hand until it really is impossible to turn, some timing covers still have a mark on them to help you get it to TDC(no degree markers though)

355Cheyenne

I would be a little concerned about the 40psi fuel pressure at idle, my truck has always been 53-57 psi at idle. I wouldn't think there would be much of a problem as long as a quick blip of the throttle brought it up to 60-66 psi

 
355Cheyenne 
Senior Member
Posts: 3765
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
03-22-10 03:53 PM - Post#1884842    
    In response to JeremyB

  • JeremyB Said:

I would be a little concerned about the 40psi fuel pressure at idle, my truck has always been 53-57 psi at idle. I wouldn't think there would be much of a problem as long as a quick blip of the throttle brought it up to 60-66 psi



40 psi oil pressure @ idle (not fuel) I had zero psi at idle when I parked it so I would have something to rebuild. (it progressively lost pressure over a week of driving from 20 @ idle to 0 and about 11pounds cruizing)

I checked the fuel pressure at some point and I forgot now what it was. all I recall was that it was in spec. but either way it is running like a champ!
98 Silverado k1500 4x4 350


 
wkrpinnick 
Forum Newbie
Posts: 9

Reg: 08-01-10
08-01-10 06:38 PM - Post#1954098    
    In response to 355Cheyenne

i will give your instructions a try thanks much!

 
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