Timing issue

[CARR33]

Just finished installing a 355 in my project. I timed it at 10 degrees btdc and it ran terrible. Timed it the old fashioned way, advancing until it pinged under a load and then backed it off a little. It ran fine but when i checked it with a light it was at 18 degrees btdc. It has a cloyes chain set. If i used the wrong keyway that would account for 4 degrees. It has a comp cams 268 xe cam, performer rpm heads and intake, dui dist, a 600 cfm carb, hedders, and 10.25 to 1 comp. Should i pull it apart to check the position of the bottom gear or leave it alone? It also has a fluidamper balancer that is new.

[CARR33]

Now i really feel stupid. After talking to the folks at cloyes they told me advancing or retarding the cam by using the different keyways on the crank gear changes the rpm range where the power band is, it has nothing to do with the timing marks on the harmonic balancer. I was thinking if i used the 4 degree advance keyway it would affect the timing by four degrees at the balancer. Back to square one.

[Lee H]

18 is not outrageous but keep in mind these trucks are heavy and you will be detonating even though you can't here it. Most guy's with builds like yours end up running about 12-16 and 30-34 at 2500 RPMs. With vacuum that would be about 50 all in at 2500 RPM. What is your timing with the vacuum applied?

[CARR33]

I'll get back to you with more specifics another day. My truck is in my son in laws garage now, about a 45 minute drive away. It's heated and the outside temp is in the upper 20's.

[smn69]

You might also want to verify TDC using a piston stop in the #1 cyl.

[allengator]

I would try it around 12-14 and see how she runs...
If you dont HEAR any ping at 18, I would think 12-14 would be pretty safe...

[LONGHAIR]

Originally Posted by CARR33

It also has a fluidamper balancer that is new.

Originally Posted by smn69

You might also want to verify TDC using a piston stop in the #1 cyl.

With an aftermarket balancer, that would be the first thing to check.

This may sound stupid, but what does DUI say to run it at? I have never used one of their distributors, but the website makes it look like that are calibrated individually...per provided specs. Is this the case? Did you spec this unit for this engine?

[superchevy]

Here's some things you might try:

How to Set the Timing for Optimum Performance:
When you think about it, setting the timing at idle speed makes no sense at all: You don't operate your car at idle, and timing changes as the rpm changes. Fact is, the timing spec at idle speed is provided as a simple
way for most people to set the timing, and is not a good procedure for optimum performance.
Small block Chevys (and most other GM performance V8 engines) perform best when the total timing (full centrifugal advance plus the initial timing setting with vacuum advance disconnected) is all in by 2,500 - 2,800 rpm and is set to 36-38 degrees. If you have an adjustable timing light, this is very easy to check.
If you don't, you need to scribe a 36-degree mark on your harmonic balancer. Here's how:
Measure the circumference of your harmonic balancer using a sewing tape measure (or other flexible tape measure). Get it as accurate as you can. Take this measurement and divide by 10. The number you get is
the distance to 36 degrees. Measure this distance CLOCKWISE from your existing harmonic balancer timing mark and place a clear mark on the balancer.
Remove your distributor cap and rotor. Remove the 2 centrifugal advance springs. Install the rotor and the cap (without the springs). Disconnect the vacuum advance.
Start the engine. It may kick back a little due to the advance coming in immediately without the springs. If you're using an adjustable timing light, set the light to 36 degrees advanced. Now rev the engine just a little while observing the timing marks with the light. It shouldn't take much rpm to peg out the advance without the springs installed. With an adjustable light set at 36 degrees, align the stock timing marks with 0 when the timing is pegged out.
With the non-adjustable light, align your new 36-degree mark with 0. Rev the engine a little to make sure the timing will not advance any further. Shut it down.
Pop the cap and rotor and re-install the springs. Put everything back together, but leave the vacuum disconnected. Start it up. For future reference, make a note of the timing setting at idle. This is your new
curb idle timing spec. Now give the engine a few quick rev's past 3,000 rpm and verify that the full timing (36 degrees) is coming in. If it's not, you need to change to a softer set of springs until you get full 36-
degree advance before 3000 rpm. (NOTE: A stock set of springs will usually not allow full centrifugal advance to come in before redline rpm. If you have stock springs installed, don't rev the engine beyond its limits to try to force full advance in.)
Shut it down and hook up the vacuum. Now do a road test.
The 36-degree 2500 rpm advance curve is optimum for performance, but may require premium fuel. Lug the car around, and punch the throttle at low rpm while listening for detonation (.engine knock.). If you're
getting any audible knock, you MUST retard the timing. Retard the timing in 2-degree increments until engine knock stops. Engine knock will seriously damage engine components if not corrected.
If you get no knock, you may see slightly improved performance at 38 degrees total timing. This is particularly true if you're running at high altitude.
If you have no engine knock under acceleration, but the car "chugs" or jerks at cruising speed (light throttle application), you are getting too much vacuum advance on top of the mechanical advance. You may need to change out the vacuum advance diaphragm with an adjustable unit available from aftermarket sources. Adjust these units so that you get the most vacuum advance possible without any "chugging" or jerking at cruise speed.
Your timing is now set for best possible performance. Make note of the new setting, and use this for your future tune-up work.

[swamp rat]

Subscribed!

[vasquezmrysvll]

got it

[Jacfourteen]

All good advice, just wanted to add that I have a similar setup to you and I run premium fuel and have my initial timing set at 16* btdc and have no pinging and it runs good. I have yet to run through the full procedure outlined above, but I'm gonna do it soon.