Timing way off, but runs great?

So....... my sbc 350 has a weird timing issue. Its reading 35 degrees initial, and 60 degrees total. Yes, I used a piston stop and made sure TDC is correct on the dampener, and yes I am hooked onto wire #1, and yes I disconnected and plugged the vacuum advance. I even bought a new timing light thinking my old Craftsman was defective, but both give me the same reading. The engine seems to run great; it isn't hard to start and doesn't ping. Apparently its giving me 25 degrees of mechanical advance by 3000 RPM, which seems about right. I'm just curious why the initial and total is shifted so far up the range? Can it actually be running good with 35 initial degrees?!

I would just leave it alone, but its bugging me to know what's going on.

 

Slack in timing chain causing incorrect cam timing. More ignition timing helps make up for it.

 

out ring slipped on the damper?

 

Are you sure the balancer hasn't slipped?

 

there are two types of balancers one is clocked off ten degrees (or something) and you need the right timing chain cover for balancer. Checking timing chain slop isnt tough tho.

 

I should add that this is a fresh engine with a new chain not too long ago. The dampener outer ring hasn't slipped either (also brand new). I triple-checked it this morning.

Thanks.

 

Use a piston stop to confirm pointer and damper marks agree for TDC. Thats the first step otherwise you are pissing into the wind/chasing your tail .

 

Thanks John, and no offense, but are people not reading my original post?

 

Matt, are you sure you have the right timing cover / tab for the balancer? I believe the offset tabs do read more advance when they're mixed.

 

Matt : Guilty as charged ! Did not read it corectly/fully. Got to be a issue with the tab /balancer relationship . I can't see how it would even start without massive kickback with that much initial advance.

 

If the piston stop method indicated TDC on the tab as you stated it did, then there's only one thing that comes to mind.
If it ain't broke don't fix it.

If its "running great" why would you question "if it is actually running great"
Must be something that got you wondering about the timing.

 

Well I wanted to get into tuning the carb a little bit, maybe try leaning it out a touch for better mileage. But everyone always says to make sure your timing is set correctly before messing with the carb, so I figured it would be good to know where it was actually set. When I first got it running I just timed it by ear to the point where it runs good, but now I want to see if there's more power/efficiency to be had.

Thanks all. For now I'm just leaving it alone.

 

I think you have a worn timing chain and has jumped one tooth,or it was,nt timed correct.I had one that jumped one tooth rode ok till it jumped another and wouldn,t start.New timing chain it ran so much better.

 

He has said it was a fresh engine with new chain and gears.

 

I don't know what to tell you, but I cannot believe that a small block Chevy would even turn over with out the starter kicking back with 35 degrees of initial timing. In fact it is so far advanced that at idle I'd be surprised that it would even keep running. Something just isn't adding up. Hope you find what it is and post it here.

 

It don't matter what the chain is like, where the timing chain is, tooth off, stretched or on the floor,
Tab indicates TDC and that's been verified by piston stop test.

Timing light says spark is at 35 initial and 60 total off the crank. The timing chaim is out of the equation, degreed cam is out of it, a Tooth off, 180* off none of that matters. It's running great, starts easy, not pinging, not overheating, plenty of pep.

There are no symptoms of overly advanced ignition timing, late cam timing, there is only a measurement on the light and a mark on the balancer. If the light is known good and the mark is verified. Id double check that again.

What's the static compression ratio of your recent build, and what's the results of the compression test.

 

Sounds like late cam timing to me.If the chain and sprockets are new is it possible that the cam locating pin hole or the keyway in the lower sprocket are machined incorrectly?

 

Haha, no shit. Went right past ME...

 

Could you post a pic of the piston stop that you are using.
There has to be an answer to this, and I believe that it might be something with the stop.
As stated before, the timing #'s your are getting make no mechanical sense.
Have you put a vacuum gauge on it?
Good luck with it.

 

That was my thought too.

It does seem strange that it starts well with that much initial advance.

 

as fedman said i would put a vacum gauge on it

 

As we know, a piston stop test requires two stops Durring the test, two marks, and the measurement between them is TDC. This could be off a negligible amount due measuring accuracy and markings.

 

The thing is, if theory doesn't agree with the facts, theory is wrong!
Fact-It will not run or start well with that much advance. Therefore, the timing light is lying to you!
I'd pull a valve cover and turn it over to split overlap on #1 cylinder. Betcha the pointer is nowhere near 0!

 

Here's a pic of the piston stop. I just gutted an old plug and threaded a 3/8" bolt into it with the head cut off. By the way I'm running Vortec heads.



I will put a vac gauge on it again but from what I remember it pulls around 16". The cam is a Comp 268H, specs here: http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=15&sb=2

 

i did some dyno testing of motors with vortec heads and they didn't like a lot of timing 2 degrees + or - from the best hp and the hp there was a a big drop and that was 32 for one a 34 for the other i would recheck everything something isn't right

 

Not to pick on you just asking, when you used the stop did you rotate the engine clockwise, then counter clockwise and split the difference. And it will run with that much advance, at least a 301 will. If you have to much advance you will notice a surge (rpm changing) at a steady speed. Roger

 

Matt, The piston stop looks to be spot on.
When you bump the piston with it how many degrees away from zero are you, the higher the number of degrees you are away from TDC the greater the possibility of an error.
Oh, and when you are checking TDC you do have all the plugs out so you can have a nice soft feel for the engine as you roll it through?

It sounds like you have a nice running engine, you just need a piece of the tune-up puzzle to be happy. Heck that is a lot better than having a crappy running engine and looking for the problem!

 

No worries, I don't feel picked on. I did mark where it hit on both sides. The difference was exactly where the original TDC mark already is. Thanks for asking.

EDIT: Fedman, the two marks were about 40-50 degrees apart.

 

Matt, I might have missed this earlier in the post.
Did you buy a dial back timing light, and what ignition system are you running,
I know that some ignition systems and dial back lights have issues working together. Maybe it is something as simple as that.
Someone might chime in who knows what units are not compatible with each other. We just have to be smarter than the problem!

 

Got an HEI distributor on it. No MSD box or anything that would be causing problems. (I've read about that issue with dial-backs.) Bought an Actron CP7529 light today, cause I was almost positive my old Craftsman dial-back was messed up. Guess not