Timing Problems "PLEASE HELP"
Thread Starter
Racer
Joined: Mar 2006
Posts: 313
Likes: 0
From: Fairfield PA
Timing Problems "PLEASE HELP"
I am trying to set the timing in my newly built 383 and having serious headaches.
Info:
When I built the motor I installed an adjustable timing pointer and set the pointer to the TDC mark on the ATI Harmonic balancer after I got the #1 piston TDC using a TDC tool.
When I set my timing gun to 12 degrees and rotate the distributor to get the 12 degrees lined up with the TDC the motor will completely stall or run like crap. Now if I set my 12 degrees on the 20 degree mark on the homonic balancer the motor runs like a raped ape.
I am completely confused, because I just can't see me having the TDC on the pointer 20 degrees off.
Can the cam be degree wrong? I had a builder install the crank and cam and he said that he degreed the cam.
PLEASE some one help me before I start liking the end of a shotgun!
Jake
Info:
When I built the motor I installed an adjustable timing pointer and set the pointer to the TDC mark on the ATI Harmonic balancer after I got the #1 piston TDC using a TDC tool.
When I set my timing gun to 12 degrees and rotate the distributor to get the 12 degrees lined up with the TDC the motor will completely stall or run like crap. Now if I set my 12 degrees on the 20 degree mark on the homonic balancer the motor runs like a raped ape.
I am completely confused, because I just can't see me having the TDC on the pointer 20 degrees off.
Can the cam be degree wrong? I had a builder install the crank and cam and he said that he degreed the cam.
PLEASE some one help me before I start liking the end of a shotgun!
Jake
Le Mans Master
Joined: Mar 2004
Posts: 7,454
Likes: 1,480
From: Little Rock AR
I think you are doing this wrong.
If you have a dial back timing light you should set it for 36 degrees. Then you and rev the engine up untill the timing stops advancing at maybe 3500 or 4000 RPMs or when ever it stops increasing (vacuum advance disabled). Line up the pointer on the tab with the zero on the balancer using the light and lock down the distributor. Reconnect the vacuum advance and thats it.
-Mark.
If you have a dial back timing light you should set it for 36 degrees. Then you and rev the engine up untill the timing stops advancing at maybe 3500 or 4000 RPMs or when ever it stops increasing (vacuum advance disabled). Line up the pointer on the tab with the zero on the balancer using the light and lock down the distributor. Reconnect the vacuum advance and thats it.
-Mark.
Drifting
Joined: Nov 2004
Posts: 1,280
Likes: 927
From: Indiana
2024 C3 of the Year Finalist- Unmodified
I was having similar problems and my son noticed that the **** was loose on the dial back after we used a regular timing light to compare the two on initial timing. We thought the dial back was on zero but it wasn't, which caused timing issues.
Ol Blue.
Ol Blue.
Pro
Joined: Jun 2004
Posts: 543
Likes: 2
From: Miami FL
St. Jude Donor '11, '14
If your are using an adjustable (dial back) timing light, then your target is the zero mark on the damper. As an example to set base timing to 18 degrees, dial in 18 on the timing light, and then find zero on the damper at the pointer with the light.
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
i think i may have screwed up setting my timing this summer, but im not exactly sure.
ive got a dial back (actron cp7529) i set it to 36* and took it upto 3k rpms
which it stopped on the 0* mark and didnt go any higher.
would that be right, or did i screw it up?
only reason i even question it is because initial timing is something like 2-3* and according to the timing light, it was already at 36* max.
ive got a dial back (actron cp7529) i set it to 36* and took it upto 3k rpms
which it stopped on the 0* mark and didnt go any higher.
would that be right, or did i screw it up?
only reason i even question it is because initial timing is something like 2-3* and according to the timing light, it was already at 36* max.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
If you had the vacuum advance line removed from the dist. can and the line plugged, then you did it properly. 34-36 degrees at around 3000 rpm is in the right ballpark. With a dial-back light set to 36 degrees and the engine revved to 3000 rpm, the timing mark should be at 0 degrees on the damper scale.
Thread Starter
Racer
Joined: Mar 2006
Posts: 313
Likes: 0
From: Fairfield PA
Guys I did exaxtly what your refering too. I set my dail on the light to 36 and had someone rev the engine to 3000 and turned my dist. to get the pointer on the 0 mark. And it runs like crap. Vacuum is pluged durimg timing and the light worked fiine last time I timed my buddies truck. I don't think that there is anything wrong with the dist., it is not even a year old Crane electronic dist. that worked flawless last time I used it.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
Thread Starter
Racer
Joined: Mar 2006
Posts: 313
Likes: 0
From: Fairfield PA
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
That IS the correct method. If you've done what you described, you've done it correctly. The only thing to recheck is whether the 0 deg. TDC mark on the damper/timing scale correlates with the #1 piston really being at TDC. That could be where the fault is.....you'd better verify the mark's accuracy with the mechanical position of the engine.
Racer
Joined: Mar 2006
Posts: 276
Likes: 1
From: Pistoia PT (ITALY)
Yes...... it is the correct way!
Vacuum canister disconnetted and carb-port plugged!
Did you see some 24-26° of mechanical advance revving the engine?
(from 12° to 36°)
May the first thing to do is to verify the correct position of your 0° timing mark!
Vacuum canister disconnetted and carb-port plugged!
Did you see some 24-26° of mechanical advance revving the engine?
(from 12° to 36°)
May the first thing to do is to verify the correct position of your 0° timing mark!
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
why not reverify TDC again? shouldn't take long and it would definitely give you some much needed facts to help figure this out
Thread Starter
Racer
Joined: Mar 2006
Posts: 313
Likes: 0
From: Fairfield PA
Thanks Guys!!
Melting Slicks
Joined: Jun 2002
Posts: 2,842
Likes: 99
From: Orrtanna Pa.
I made a home brew label with Avery stock that has timing marks to 36 degrees that I use to set mine up with. (To cheap to buy a degreed balancer.) I stick the label on the balancer using the stock zero degree mark as a reference,and go from there. I also have an adjustable pointer as you mention,but no dial back timing light,just a cheap Autozone light.
The point I'm trying to make is the measuring tools are not state of the art high tech,but the reference points have to be confirmed,or all else will not make any sense.With this setup,I'm confident my timing is dead on.
Let me know if you need any help,I'm right up the road from you.
The point I'm trying to make is the measuring tools are not state of the art high tech,but the reference points have to be confirmed,or all else will not make any sense.With this setup,I'm confident my timing is dead on.
Let me know if you need any help,I'm right up the road from you.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
How did you go about finding TDC.
Your problem is most likely just where you set the adjustable pointer.
Thread Starter
Racer
Joined: Mar 2006
Posts: 313
Likes: 0
From: Fairfield PA
Again Thanks Guys!
This forum is great for ideas and problem solving.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
Ooo! That has happened before, too. Especially, on a recent C3 purchase. PO shifts the wires so the vacuum can is conveniently located and the new owner hooks onto the wire that is 'normally' #1 [as it appears on the distributor cap]. Yep. That's a "hair-puller". 