Timing Marks

[Zero Balance]

Engine is 350 cid chevy. The manual calls for 8deg before TDC however when I put on the timing light my marks are way over to say the eleven o'clock position and even 10deg. will stall out. The motor was installed prior to purchase. The old motor was a 307 I believe. I know there are several sized balancers that can be on this engine and I am beginning to suspect mine is the wrong size. What are the steps to discern the correct balancer and if necessary go with timing tape? It runs ok timing it by ear but I want it right.
Any thoughts?

 

[mkast]

Re: Timing Marks

The first thing I want to know is are you on the #1 cylinder?
Move #1 to TDC (top dead center) on the compression stroke.
Look at the damper to verify the timing marks.
After you do this, get back to the board.

 

[Zero Balance]

Re: Timing Marks

Yes, #1 cyl. 0 deg TDC the timing mark shows about eleven oclock.

Take into consideration 0 deg is based on piston and valve position and rotor pointing to #1pos. as well.

 

[mkast]

Re: Timing Marks

Long story short, I put a Crane cam in my 454.
Timing off #1, the timing marks were way off, moving the dist to bring the mark to 8 degrees made the engine backfire and stall.
Found out, because of the cam, I have to time the engine off the number seven cylinder.
Start clipping the timing light on different cylinders to see if the marks align.

By the way, I tried the timing tape, too expensive to keep blowing off, even using 3M Super Adhesive.

 

[Zero Balance]

Re: Timing Marks

Thanks, I'll call the previous owner for a little info and give that a try. Timed right she runs like a scalded cat but it's been a method of chance getting her there. Thats why I considered the timing tape.

 

[Maclin]

Re: Timing Marks

What distributor and ignition system do you have? Makes a lot of difference in the procedure used to set the static timing, some of them require you to set some jumpers to get to base timing mode.

Why don't you post back with the year, make and model of everything......

 

[Zero Balance]

Re: Timing Marks

Just your basic dinosaur...Mallory unilite dist. on an older model 350. I'ts really a no brainer. I never considered the cam. I'll have to give that a gander before I can give any more info.

Thanks again

 

[bruceb58]

Re: Timing Marks

Long story short, I put a Crane cam in my 454.
Timing off #1, the timing marks were way off, moving the dist to bring the mark to 8 degrees made the engine backfire and stall.
Found out, because of the cam, I have to time the engine off the number seven cylinder.
Start clipping the timing light on different cylinders to see if the marks align.

By the way, I tried the timing tape, too expensive to keep blowing off, even using 3M Super Adhesive.

Something is just not right.

Also, why not use an advance timing light. No need for tape.

 

[Fishermark]

Re: Timing Marks

Found out, because of the cam, I have to time the engine off the number seven cylinder.

 

[Fishermark]

Re: Timing Marks

I know there are several sized balancers that can be on this engine and I am beginning to suspect mine is the wrong size.

Actually, they moved the timing tab and the mark on the balancer if memory serves me correctly, You might have a mis-matched balancer - timing tab.

 

[bomar76]

Re: Timing Marks

You are either:
1. On the wrong wire.
or (more likely)
2. The hub on the harmonic balancer has slipped, and you need a new one.

 

[bruceb58]

Re: Timing Marks

You are either:
1. On the wrong wire.
or (more likely)
2. The hub on the harmonic balancer has slipped, and you need a new one.

I think #2 as well.

I think that may me Mkast's problem as well. A different cam would never mean adjusting timing off of a different cylinder. That is just illogical.

 

[bomar76]

Re: Timing Marks

Yeah, I forgot to add the the "time off #7 'cause I have a different cam" is just ridiculous.....

Slipped balancers aren't really all that uncommon.

 

[Malibud]

Re: Timing Marks

I think i have the same problem in my old GM truck. Would this cause a miss at idle? Can I run it like this ?

 

[mkast]

Re: Timing Marks

Yeah, I forgot to add the the "time off #7 'cause I have a different cam" is just ridiculous.....

Slipped balancers aren't really all that uncommon.

New damper, just for fun aligned it to the old one, both were the same.
I put this question out five years ago when it happened.
Rebuilt engine.
Static timed the distributor to #1 cylinder. Stock Thunderbolt, (1987)
Tried to start engine, backfire.
Turned distributor, engine running great.
Took the boat out ALL season, ran great.
That winter, I wanted to get to the bottom of this.
Pulled engine, removed timing chain cover. Noticed that the locating pin on the cam was at 9 o'clock instead of three o'clock, with the engine at TDC on number one cylinder. Keep in mind, the engine ran great all season long.
Got on the phone with Crane.
After about three hours, they called me back.
Told me to install cam as per the engine manual (Mercruiser, Chevy etc.) Then rotate engine 180 degrees, install chain.
To shorten the story, I reassembled the engine the same way it came apart, it ran great all season. Reinstalled the engine, went to #1 with a timing light, mark on damper was under the water pump not near the timing tab. Clipped on to number seven cylinder plug wire, timing mark is at 8 degrees on the timing tab. Engine runs great.

 

[Maclin]

Re: Timing Marks

Mkast, that put the distributor 180 degress off. You could re-clock the distributor to get it back in synch. Or just time it the way you do, but the next guy might go crosseyed figuring it out.

 

[mkast]

Re: Timing Marks

Mkast, that put the distributor 180 degress off. You could re-clock the distributor to get it back in synch. Or just time it the way you do, but the next guy might go crosseyed figuring it out.

The distributor was put in after the engine was buttoned up.
I can understand how you can question what happened, how do you think I felt about it.
What do you think I said to Crane when they told me to install the cam the way they did.
I've degreed the cam in, perfect cam timing.
Keep in mind, engine runs perfect.

 

[Maclin]

Re: Timing Marks

I am not questioning anything Crane told you, they know what the cam needed. But what I mean is, the way they had you reset the cam put the dizzy 180 off when compared to "normal" keying and clocking points. The dizzy does not care, and it will not affect performance at all until you are in a coma and you brother in-law wants to check the timing!

 

[Maclin]

Re: Timing Marks

Oops, I was wrong on the 180 off, I had the firing order wrong from memory for the BB Chevy. If it was 180 off the #6 wire would work. It is 270 or 90 off depending on how you want to look at it. Sorry for the confusion I added in....:redface:

 

[bruceb58]

Re: Timing Marks

The clocking of the distributor still will not matter. As long as all the wires are in the correct firing order, all will work out.