Timing Curve

General Gauges, Wiring, Ignition..

Moderator: John_Heard

Message
Author
User avatar
stroker1
Posts: 333
Joined: Tue Apr 03, 2007 1:14 pm
Location: Dunn, NC

Re: Timing Curve

#31 Post by stroker1 » Tue Aug 12, 2008 11:12 pm

hugger73hatch wrote:It's a 6al. However, I never had any problem before until I locked the distributor out. That is the only thing I changed. My buddy has one of those high dollar snap on lights, all digital. Maybe I should try that?
Not trying to beat a dead horse but like I said, if it was not locked out before then you probably would not have noticed it moving from the advance in the distributor. As it speed up the advance might try to hide some of the cam walk. Now it is locked out and you can see any loose play from the cam walking front to back or the distributor shaft itself walking up and down inside the distributor housing.

Also, going back to your statement that it was not like this until you locked it out.......IF it is not walking then are you sure you didn't loose a shim from the distributor shaft when you removed the gear to lock it out???
'87 S10 stock suspension, Caltracs, 9" rearend, 1.82 Glide, 383 SBC,
Brodix Track1 Heads, 14:1 compression, 180 shot plate,
2" tube Hussler Headers, 1.38 60ft., 6.20 ET 1/8th, 109 MPH,
Still Tuning, more to come.

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#32 Post by hugger73hatch » Tue Aug 12, 2008 11:28 pm

stroker1 wrote:
hugger73hatch wrote:It's a 6al. However, I never had any problem before until I locked the distributor out. That is the only thing I changed. My buddy has one of those high dollar snap on lights, all digital. Maybe I should try that?
Not trying to beat a dead horse but like I said, if it was not locked out before then you probably would not have noticed it moving from the advance in the distributor. As it speed up the advance might try to hide some of the cam walk. Now it is locked out and you can see any loose play from the cam walking front to back or the distributor shaft itself walking up and down inside the distributor housing.

Also, going back to your statement that it was not like this until you locked it out.......IF it is not walking then are you sure you didn't loose a shim from the distributor shaft when you removed the gear to lock it out???
No, I am not 100% sure about that. I remember 1 shim fell off and I put it back, but I am not sure if that was the only one. Something else I will have to check.

One of these days I am going to get this crap figured out I reckon.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#33 Post by hugger73hatch » Wed Aug 13, 2008 11:02 am

I am going to pull the distributor tonight and check the shims. I am starting to think now that it is the cam walking though. I am going to stick a screwdriver in it to se if the cam will move back and forth.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
ytnova
Posts: 735
Joined: Fri Oct 28, 2005 9:21 am
Location: orlando, florida/ under a hood
Contact:

Re: Timing Curve

#34 Post by ytnova » Wed Aug 13, 2008 3:09 pm

Are you using the same timing light at the track that you used at home/shop? They do differ from one to the other, I always make sure I use the same one. You might also check the gap from the distributor to intake, put it in with no gasket and just make sure it is not bottoming out on the oil pump.
I am not really sure what the question is, but I am pretty sure the answer is Big Block.

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#35 Post by hugger73hatch » Wed Aug 13, 2008 4:52 pm

ytnova wrote:Are you using the same timing light at the track that you used at home/shop? They do differ from one to the other, I always make sure I use the same one. You might also check the gap from the distributor to intake, put it in with no gasket and just make sure it is not bottoming out on the oil pump.
Same light. I will check the gap from distributor to intake as well. Hopefully have something for everyone later on tonight.

Thank everyone for being so patient with me. I am a self taught mechanic, so I am not as up on everything as most here. This is also my hobby, I reckon it's a good thing I don't make my living doing this, or I would be up the creek :-)
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#36 Post by hugger73hatch » Wed Aug 13, 2008 11:02 pm

Ok. I pulled the distributor tonight. Has a little bit of play in the shaft, maybe .010 up and down, which I don't think is enough to matter too much. Double checked everything again. Gear looked fine. The only thing I noticed was I was missing the washer for the locknut, so I installed a new one. I also checked the distance from the oil pump shaft to the intake and from the collar of the distributor to the tip of the shaft and all of that is within clearance. I reinstalled the distributor and fired it up. The timing was creeping up a bit, but not as much as before. At idle before it was going as high as 46* and then when I brought the rpms up it would drop to 34*. Now it is idling about 37* and drops to 34* and stays there even at high rpm.

I also tried putting a pry bar between the water pump and timing cover and noticed no difference. Anyway I set the timing at 34* at about 3000 rpm and so far it will not drop below that and only goes as high as about 37* at idle. I think someone told me that even though it is locked it may move 2-3* from idle to wot.

I still want to try a different light to see if maybe something is wrong with mine.

Does anybody know for sure about it dropping 2-3* if that is acceptable? I am just curious?

One other thing I noticed during all this was that occasionally it will skip a beat. At first I thought it may be in the timing light, but after listening to it a couple of times I realized it did have a little bit of a mis, and you could see it in the light. When I had the distributor apart I noticed the magnetic pickup had some rust on it, I guess from condensation and such. Does anyone know if this may cause the occasional skip, and if so is there a way to clean it?
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
stroker1
Posts: 333
Joined: Tue Apr 03, 2007 1:14 pm
Location: Dunn, NC

Re: Timing Curve

#37 Post by stroker1 » Thu Aug 14, 2008 7:59 am

I think a 2-3* variation is pretty common for a distributor with a magnetic pickup built in. Mine has about 3* worth of wiggle to it from idle to 4500 rpms. I time mine to where it falls back to at 4500 rpms. Because at WOT I want it to be right. I don't really care if it's a few degrees high at idle. I'm thinking pretty serious about going to a crank trigger to tighten down on my timing for n2o.

I would be concerned about the occasional skip. In my distributor the reluctor wheel was rusted up pretty bad a couple times. I cleaned it up with some fine emery cloth. Made a big difference. I tried spraying it with WD40 once in awhile, it has helped but not completely stopped it. :smt005
'87 S10 stock suspension, Caltracs, 9" rearend, 1.82 Glide, 383 SBC,
Brodix Track1 Heads, 14:1 compression, 180 shot plate,
2" tube Hussler Headers, 1.38 60ft., 6.20 ET 1/8th, 109 MPH,
Still Tuning, more to come.

User avatar
ytnova
Posts: 735
Joined: Fri Oct 28, 2005 9:21 am
Location: orlando, florida/ under a hood
Contact:

Re: Timing Curve

#38 Post by ytnova » Thu Aug 14, 2008 9:46 am

Curiosity, has the engine been lined honed more than once? I have seen new chains that are loose, and the problem is now the crank is closer to the cam. They don't really advertise them, but most timing chain companys sell shorter timing chain sets in .005 increments. Is there any chance the cain to cam bolts are loose?
I am not really sure what the question is, but I am pretty sure the answer is Big Block.

User avatar
stroker1
Posts: 333
Joined: Tue Apr 03, 2007 1:14 pm
Location: Dunn, NC

Re: Timing Curve

#39 Post by stroker1 » Thu Aug 14, 2008 10:14 am

Question: When you checked it with the pry bar behind the water pump did you dent the cover a little? Sounds like for some reason the cam has stopped walking. You didn't change anything except pull out the distributor and put it back in, right? It just don't make sense that you pulled out the distributor and put it back in and the timing is more steady. :scratch:
'87 S10 stock suspension, Caltracs, 9" rearend, 1.82 Glide, 383 SBC,
Brodix Track1 Heads, 14:1 compression, 180 shot plate,
2" tube Hussler Headers, 1.38 60ft., 6.20 ET 1/8th, 109 MPH,
Still Tuning, more to come.

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#40 Post by hugger73hatch » Thu Aug 14, 2008 9:54 pm

stroker1 wrote:I think a 2-3* variation is pretty common for a distributor with a magnetic pickup built in. Mine has about 3* worth of wiggle to it from idle to 4500 rpms. I time mine to where it falls back to at 4500 rpms. Because at WOT I want it to be right. I don't really care if it's a few degrees high at idle. I'm thinking pretty serious about going to a crank trigger to tighten down on my timing for n2o.

I would be concerned about the occasional skip. In my distributor the reluctor wheel was rusted up pretty bad a couple times. I cleaned it up with some fine emery cloth. Made a big difference. I tried spraying it with WD40 once in awhile, it has helped but not completely stopped it. :smt005

I am going to do that. I couldn't believe how rusted up it was.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#41 Post by hugger73hatch » Thu Aug 14, 2008 10:07 pm

ytnova wrote:Curiosity, has the engine been lined honed more than once? I have seen new chains that are loose, and the problem is now the crank is closer to the cam. They don't really advertise them, but most timing chain companys sell shorter timing chain sets in .005 increments. Is there any chance the cain to cam bolts are loose?
Brand spanking new Dart block. Just purchased at the end of last summer. Maybe has 20 runs on it. So the answer is no. I don't think the cam bolts are loose, I am pretty anal about making sure that type of stuff is right (OCD- I will check it 3 times to make sure). I am going to try to run tomorrow night as it seems like it has gotten better. I will end up going through it this winter to check the timing chain and end play and all that stuff.
stroker1 wrote:Question: When you checked it with the pry bar behind the water pump did you dent the cover a little? Sounds like for some reason the cam has stopped walking. You didn't change anything except pull out the distributor and put it back in, right? It just don't make sense that you pulled out the distributor and put it back in and the timing is more steady. :scratch:
I didn't press that hard on the cover, so I don't really think that I put a dent in the cover, but at this point anything is possible. I did have the bushings backwards on the gear, the bronze bushing was not on the bronze gear, so I changed it. I also noticed the washer was not behind the lock nut holding the distributor locked out. I am not sure if any of this helped or not. I also used a spare battery to hook the timing light to, which is what MSD recommends. I also put a flat washer on the distributor hold down bolt as well as the lock washer, hoping it would help hold the distributor a bit tighter. One last thing I did was put the cover that holds the wires on the distributor cap. Believe it or not, I think that helped the most, not sure why, but it seemed like it did.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#42 Post by hugger73hatch » Sat Aug 23, 2008 8:32 pm

Ok, just an update. Still having the problem. Took it over to my buddies shop today, who is a full time mechanic. Tried his timing light, same thing. We both seem to now think it is an internal issure with the cam walking and the timing chain possibly being worn, so I am going to pull the motor out, hopefully next weekend, and see what I find. Shouldn't take me that long, I have about got it mastered to about 2 hours working by myself, since I have pulled the engines that I have ran about 10 times in the past 3 years. Anyway I will keep everyone posted as to what I find. Thanks for all the input so far.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#43 Post by hugger73hatch » Sat Sep 06, 2008 9:07 pm

Pulled the motor down and found the cam was walking. The end play was .020. I am going with a bullet cam this time as well as a hex a just timing chain set. Thanks for everyones help. Some new numbers will be coming soon.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#44 Post by hugger73hatch » Sun Sep 28, 2008 5:42 pm

Ok, got it running last night. Timing is not moving now. Just a little video I took on the digital camera. Not as good as a video recorder, but at least you get the idea. Now I just have to work on getting the tune right. The carb seems a little bit off.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

User avatar
hugger73hatch
Posts: 360
Joined: Sun Oct 21, 2007 10:42 pm

Re: Timing Curve

#45 Post by hugger73hatch » Fri Oct 10, 2008 9:22 pm

Well got to the 1/8 mile track tonight. Car ran it's new best. 7.02 @ 98.125 with a 1.48 short time and not very good track prep. I was hoping to get it into the 6s, but I guess that will have to come later. I need to get a new set of push rods as they are a little bit too long, maybe that will help too. Maybe I'll just throw a shot of nos on it and that will definitely get it there. :mrgreen:

I can't complain for a cheap Herbert roller cam. Maybe this winter I will bite the bullet and go ahead and get me a Bullet Cam.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

http://www.esquireservices.net

Post Reply

Who is online

Users browsing this forum: No registered users and 13 guests