Settling on timing

[projectmidnight74]

SBC 350, mild cam, flat tappet pistons, 3 inch exhaust. Today i took the liberty of installing a timing tab. After that, my ADHD was not satisfied as I feel the truck has a slight miss and I want to get the timing correct. So, i bought a timing light. To my understanding, I set TDC, painted the mark white, then. Started it up. Came up to temp, and tried to check timing aroud 1800 rpm, and I got 50 degrees advanced. Also, i never see the white mark when timing, only this black mark that I guess was there when I never knew it to be. Its in the advanced area when at idle and again when around 50 degrees with vaccum plugged. Am i too far out or am i ok. Please help.

 

[Broken85]

Did you disconnect and plug the vacuum advance port on the carburetor before attempting to set the timing?

 

[fast 99]

Timing is set with vacuum advance disconnected at idle. Probably need to start by verifying correct timing mark by bringing #1 cylinder to top dead. There were several different timing marks and pointer locations used over the span of several decades.

To answer one question, 50 degrees is too much. Has the centrifugal advance been checked?

 

[projectmidnight74]

Did you disconnect and plug the vacuum advance port on the carburetor before attempting to set the timing?

Yes this was done

 

[dsteelejr]

Something isn’t adding up. How did you figure TDC?

 

[legopnuematic]

A small block Chevy can have two or three positions of timing tab/balancers. A stock/original/correct 1974 engine will have the timing tab at the ~2:00 position. A later small block, say 1979, will have the tab at the 12:00 position.

Why this is relevant, is the balancers for each timing tab position are keyed/marked in a different spot to work with that specific tab/balancers combination. So if you have for example a 12:00 balancer with a 2:00 tab, or vice versa, everything will be out of wack. Or due to age the outer portion of the balancer could have spun providing an incorrect reading.

If you verify TDC on #1 and remark the balancer for true TDC, then the mis match doesn’t matter as it has been remarked.

If the engine didn’t have a timing tab, I’d check on the timing cover looking straight down from the water pump to see if it has it there.

Got any pictures? We like pictures.

Later 12:00 tab for reference

You must be registered for see images attach

 

[projectmidnight74]

Timing tab was added after rebuild of a Goodwrench SBC donor. Not the original motor. Verified Tdc ...so I thought....by removing number one spark plug and rotating the motor until I felt pressure coming from that cylinder. Marked the balance with a white pen but I cant see it when attempting to verify timing with the timing light. Only the black mark that I discovered was there. Truck runs fine. But I don't know what any of my numbers are and it's driving me mad.

 

[fast 99]

Just using pressure isn't close enough. Piston needs to be near TDC. I use a long straight screwdriver in the spark plug hole, turn the motor BY HAND until screwdriver doesn't move up/out. This will get the mark in the area of the timing tab. Won't be exact TDC but good enough to check for a pointer mismatch or spun damper ring.

When things don't add up always go back and re-check. What your describing doesn't make sense.

 

[Sad Sack]

Very handy add-ons:

https://www.jegs.com/i/Fluidampr/388/620101/10002/-1

Mr. Gasket 1591 Mr. Gasket Timing Tape | Summit Racing

Free Shipping - Mr. Gasket Timing Tape with qualifying orders of $109. Shop Timing Tape at Summit Racing.

www.summitracing.com

 

[projectmidnight74]

Just using pressure isn't close enough. Piston needs to be near TDC. I use a long straight screwdriver in the spark plug hole, turn the motor BY HAND until screwdriver doesn't move up/out. This will get the mark in the area of the timing tab. Won't be exact TDC but good enough to check for a pointer mismatch or spun damper ring.

When things don't add up always go back and re-check. What your describing doesn't make sense.

How long of a screwdriver we talkin

 

[fast 99]

Just a number 1 straight or phillips about 6" or so. Long or large enough handle it can't fall in the cylinder.

 

[Broken85]

This is a worthy investment for $20. Plenty of miles on mine. Be sure to lock-tite the brass tip on before you use it. This will get you to almost perfect TDC so you know what your timing mark is actually telling you. An upgrade from a screwdriver at least (which I have used plenty of times).

Amazon.com

 

[projectmidnight74]

Ok gents. Removed number one sp. Sound it over this time with a longer screw driver and seems as thought the original white mark was correct. Went over the white with a black marker. Will do the timing light test again shortly.

 

[Ricko1966]

Where is the timing groove on the balancer,in relation to your black and white marks?

 

[projectmidnight74]

Where is the timing groove on the balancer,in relation to your black and white marks?