Technical Small Block Chevy 12 and two timing tab issues

Hey all,

New small block Chevy crate engine, 350 long-block. I placed a little bit of a cam in the engine (slightly bigger than a thumper, numbers-wise/can't remember now since I put the engine together last winter). The engine also sports a 60s style re-pop of the finned shorty water pump with a Milodon style aluminum timing cover beneath that. The dist is an electronic ignition, small-body, with an external coil on the firewall (Chinese special from Slea-bay that had created some fun conversations on this very site!).

Problem. When I put the engine back together (cam, new lifters new rockers, yada, yada) it didn't come with a balancer, so I bought a 6.75 for 60 bucks. There were two keyway slots, so after I meshed the gear drive, I lined the balancer groove and timing tab (attached in the traditional location, 2 o'clock ) and all lines up perfectly.

Anyways, When I fire the car (runs okay with ear timing but wanna dial it in), the timing light is reading up at 12 noon on the block. Now, I would place a 12 o'clock timing tab on the engine, but they are not avail aftermarket that I can find and most importantly, I just can't see the damn light there since I have the short water pump pressed against the timing cover.

I read around online and it seems Chevy made several balancers and several tabs. No vibrations and the engine fires and runs pretty damn well with just ear timing. Several people online suggest that there is a measurement of 2.5 inches back from the original balancer groove that will get me to the 2 o'clock location. Others suggest making a piston stop, finding TDC, and then painting a new line or drill bit dimple with a dab of white paint. Still, some suggest buying timing tape.

I am hoping that there are some SBC gurus out there who can verify.
Again, when I pull the plug one 1, I find TDC, the balancer slit at the 2 o'clock location (all as it should be). Yet, start it up and throw a light on it and the light flash/balancer slot can be seen way up at 12 noon?

Question 1: some have said 2.5, some 2 and 11/16? Is there a standard measurement back from original damper slot?
Question 2: Why is the engine lining up at TDC teh way it should at 2, but the light is still firing at noon?

Does anyone know that specific measurement? Is it b/s that there is a set measurement?
Is there a way to get the light back to 2 o'clock (different plug wire, etc)?

Help! I really wanna get the timing dialed in on this thing. Engine gets up and goes, but I think there is a little more I can milk from her. Tired of getting out of the car on the street and advancing and retarding in hopes of finding that perfect sweet spot.

Disclaimer: all and any thoughts, comments, insults, and comedy will be appreciated b4 we even begin.

The Pork
31 Dodge Pickup, 5-speed Tremec manual, locked spool, 9 inch Ford rear end, 488 gears.

 

You need to establish TDC and mark the balancer and tab correctly. There are several thread on methods to determine TDC.

 

At TDC the damper keyway should be at 1:30, that is, 45 degrees past "straight up", when turning the crank clockwise.

With a 6.75" damper, that's 6.75 x 3.14 / 8 = 2.65 inches, along the damper, to the right of "up".

I don't know where your timing mark will be under these conditions, though.

 

Mr. pork -

NOT...a "balancer"
IS...a "damper"

There is a difference..!

Mike

 

I had the exact same problem with the crate 350 from the Chevy dealer. Never did find the correct solution so set it by ear and have been running it almost 20 years now

 

Fritz,
That's just it. If you pull plug one and then rotate the engine till the piston comes up to the TDC on cy1, the timing mark is dead on. Yet, when I through a light on it, it is flashing at 12 noon? How can it be a TDC on the traditional at 2 Oclock tab mechanically yet the light is firing at 12 o'clock?

 

I hear you Manolcars. I have it pretty damn close to where it is running well enough to take anywhere and she gets up and goes well when I want her to, but I would like to get this sorted out.

Semantics, all know what I meant.

 

I think they are synonymous:

www.onallcylinders.com
A harmonic balancer (sometimes crankshaft damper, torsional damper, or vibration damper) is the same thing as a harmonic damper except that the balancerincludes a counterweight to externally balance the rotating assembly.

 

Thanks for the reply Squirell. That's the third number I have gotten online. I have also seen 2.5, and 2 & 11/16. My fear is that if I go with a random number, measure, file in, and it is off, I will be locking into an indeterminate location and then really be off. There is an equation with Pi or some sh$t, but math was never my thing and I was hoping for a simple answer, but I don't think there is one.

The real confusing thing for me is the fact that the damn thing lines up correctly mechanically, just not when you fire it. I know it sounds stupid, but I may try and go around the horn with the timing light clipped to different cylinders and see if one just happens to fall on the damn mark. I guess my next choice from one would be to cyl 6?

 

Its not firing at TDC, the ignition timing is set somewhere else.

 

uh...that's the 3.14 part of the equation I posted above

 

Do it right. Find zero and put your own mark on the balancer/damper. If you don't find zero, you are still just guessing. Both of my 327s were off 1/4 inch, probably 4 degrees. And that was with all matching original parts.

.bjb

 

never dreamed a SBC could be so complicated.............

 

You're right! Sorry. I am gonna paint a line at 2.64 from the original line and see if it falls on the tab. Thanks, Squirrel!

 

Thanks Jokester.

 

The distance I specified is for where the keyway is in the damper, NOT the timing mark, which is probably off a bit from there.

 

Agreed

Sorry, 2.65

 

I have the same problem with mine. What is going on here?

Sent from my SM-T350 using The H.A.M.B. mobile app

 

https://www.jalopyjournal.com/forum/threads/sbc-crank-key-way.1079007/


Sent from my iPhone using The H.A.M.B. mobile app

 

Mr. pork -
NOT semantics...

Different parts completely !
One "balances", one "dampens" harmonics...DIFFERENT jobs, different parts..!

Mike

 

Dial your adjustable timing light back to 0
Actually I have made that mistake...

If it's right static then it's either your timing is way off or the light is.

 

Well...........I been calling it a dampner sooooooo what do I know?! Anyhow..........
Why the hesitation in making up a piston stop out of an old spark plug?!!! (Its real EZ, I even made one!!)
You DO know how a piston stop works right?, when finding true TDC?!
Once you KNOW where TDC is then you can put a timing tape on the ..........'wheel thang, what ever its called'.
Put the tape so you CAN read it EZ and make a little pointer of some sort. (I made one out of a piece of Alum. and attached it to the front cover. ) The key is....put it where you CAN see it EZ. Where ever you put the TDC indicated on the tape is your new TDC!
Hope you understand......kinda tough me not being there to show you.
6sally6

 

Where is your rotor when your TDC marks are lined up?

 

Vacuum advance still hooked up when you're checking the timing??? Sorry, had to ask.

 

You know, when the long block came in the crate, it came with a sealed bag that had two timing tags and the tiny plug to block off either left or right dipstick hole. Somehow, while cleaning up the garage throughout the winter, I threw that damn plastic bag in the garbage on accident; but thinking of it now, I bet the correct tab was in that damn bag! I would email and see if I can get an extended tab, but as I mentioned, I can no longer get a light down at 12 o'clock for timing with the shorty pump and alum timing cover.

 

No. At first, I thought that as well and plugged it. At least I have 15 on the vacuum gauge, from each carb (checked while there and adjusting air idle mixture screw on both sides of both 4 barrels.

 

Mark, that's the damn thing, dist dropped in with rotor tip pointing to the left bank to number one intake and exhaust valve and the timing marks are dead one TDC; yet, start her up and she is not at 2 but at 12?

Since I have been digging on this, I have found it is a common enough problem. I am glad that I am not nuts. If you look around the web, there are more than 6 different tabs and timing cover differences and balancer set ups.

 

Blowby, I have a really cool expensive Snap-on light that a neighbor gave me. It is has a dial and it is at zero. I thought the same thing initially, so I bought a cheapo Amazon Prime light for 25 bucks and it reads the same, so old Snap-on light is/was good (of course).

But this brings up another idea I found. Another dude on-line said that you can dial back 22 degrees (again, he wasn't sure of teh specific mark ) and get your zero. That is an option as well, but again, if I don't know teh true amount, I am punching in at the wrong s[pot and making things even more confusing

Hey Squirell, how many degrees from 0 back would I be on an adjustable timing light wheel light to get to zero?

 

Hey Squirrel, I am gonna pick your brain a little more with the math, how many degrees back from 0 on a programmable timing light would I be? One guy online said 22, but he wasn't sure.