Please help me with timing

[SpitzSpitz]

The original settings for my 1968 428CJ according to chiltons should be 6 degrees BTC. The harmonic balancer has a TDC with a - numbers on one side and + numbers on the other. I am assuming that +6 is 6 degrees BTDC, however the car has run on, not bad but just slightly and the car runs very rich. I have tried to adjust to -6 BTDC but the car will not run at all. What am I missing here? Whats up with the - & +. The engine was built by a professional race engine place so I doubt the cam or crank gear is off a tooth. The engine does have all high performance parts, how much does this affect the orginal timing? It has 160 miles on it so far. Would like to take it on an extended run this weekend, but I don't trust it yet. I would appreciate any help.

Thanks very much.

The Spitz

[dalola]

Spitz,

The negative(-) side is your BTDC(or, advance), 0 being TDC, and positive(+) side ATDC(retard), all based on cyl. no. 1. If your spec calls for -6, that would be 6 BTDC. You may want find true TDC at the No. 1 cylinder, and see where everything is for a reference. Then, I would consult the engine builder to see if perhaps he was playing with cam timing or something.

You may also want to check to see that the timing indicator is in the correct location. I'm not real familiar with FE engines, or where the pointer is postioned. Don't overlook an accurate timing light, either. If you have access to the kind that has the electronic advance/retard, you can dial in whatever +/- you want until the 0(TDC) lines up with the timing indicator. These types of lights usually go up to 180 degrees + or -, which can be handy if things are really screwed up.

Regardless, I would question your engine builder about this.

Dave

[HighPlainsDrifter]

I had the same problem with a 455 olds motor a while back, the machine shop that balanced the engine took the harmonic balancer apart and put a new rubber seal in it and didn't put it back in the correct spot, so that screwed up all the timing marks on the balancer. You could try another balancer or find top dead center for # 1 as the piston comes up on the compression stroke and see if the marks are lined up or if you need another balancer.
Perry.

[SpitzSpitz]

Dave thanks very much for the feedback, if -6 is 6 degrees BTDC then I must have problems because the car boggs down and will not run in that position. I am skeptical about the pointer, Isn't there a way to set the timing using a vacuum gage?

Thanks for any replys

The Spitz

[DAVID GAGNARD]

Spitz;


I, too, am not too familar with the timing pointer set up on an FE,but you can not go wrong with the following.

Bring number one to top dead center and make a mark on your harmonic balancer and call it 0.,no matter where it is,that is supposed to be it,then you use a timing tape on the balancer set at 0 with your mark and mark off your desired settings. You should be dead on.

I had a similar problem with my motor (351-W) when I changed balancers. The pointer for my motor bolts onto the front of the water pump and the hole on the pointer are elongated to some degree and you could move the pointer back and forth approx. 4-6 degrees. I set number one on tdc and using a white-out pen made a line on the balancer for a reference point,then adjusted my pointer to read tdc at that point. I actually have to elongate the holes some more for the exact line-up, but now I know it is correct. I also checked the marks on the balancer with a timing tape just to be sure and they were correct.

This is also assuming that your cam is set "straight up" and not retarded or advanced,you may want to check with the engine builder to verify that.

Hope this helps.

David

[SpitzSpitz]

OK Guys, thanks very much, I will try your suggestions and see what happens. Thanks again, have a great Labor Day weekend.

The Spitz

[mr0077]

Spitz, one last thing...to verify the + and - numbers, consider this: Normal rotation of the motor is clockwise when looking at the front of the motor. As the timing mark on the damper rotates toward the zero on the timing tab, it will be (naturally) BTDC as it moves toward the zero, and ATDC after it passes zero...that will tell you what the + and - marks mean for sure. If they're to the left of zero, they're BTDC, etc.
Have a good Labor Day all!

[dave hendon]

you haven't mentioned what type of advance your dist uses,
if it has a vacuum advance,disconnect it to set the 6 deg.
my cobra has a 351w with a mallory dist that has a electronic advance module.in order to set my timing i used a light that can be adjusted so that all you need is tdc marked, i then rev the engine to 3000 and set my timing to 36deg, these are the numbers i found in my cam specs.
dave

[SpitzSpitz]

Ken Smith, you da man. Once I bumped the engine over and verified that the engine did turn clockwise it was a simple task of realizing that +6 is 6 degrees BTDC. I was in fact 12 Degrees off. I reset the timing and reset the carburator and it seems like a different car. No more black smoke or poor idle or run on. I celibrated with a 100 mile drive. Thanks guys you made my Labor Day weekend.

The Spitz

[Jack21]

One more thing Spitz.

If you're working with a stock distributor, and a stock advance, the 6 degree lead is a good starting point. Fords always were a little light on this, and frequently 8 or 10 degrees worked better.

Having gone to the trouble to build one of these, I can't imagine you're using a stock distributor without at least a curve kit, or an MSD billet. What you're looking for is total lead, static, plus mechanical. Typically this is around 34 degrees total (with vacuum disconnected), and should be all in by 2200 - 2400 RPM.

Once you know where "0", or TDC is, rev the engine, watch the pointer with a timing light, and see where it stops. Adjust it until it stops at 34. Then let the engine idle. Where the pointer is now will be your initial lead. You may be surprised that this is more like 12 - 14 degrees.

Now hook your vacuum line back up and go cruising.

[Tim Votaw]

This discussion was helpful. I have somewhat the same problem with a Romac balancer not lining up with the timing pointer @ TDC #1.

Question 1: The OEM timing pointer I have has a round peephole, a half-round notch, and a straight edge, from bottom to top. I installed it on the passenger side of my front cover (351W-based motor). That is right, right?

Ques. 2: When I roll the motor around to TDC #1 on compression and get the air pressure against my finger, I then insert a straw into the spark plug hole and carefully rotate the motor until the piston is full up. I assume that is true TDC, although the cam I have is fairly radical and may affect this a bit.

When I check the balancer, the BTDC marks are almost over on the driver side at about 1:00. The timing pointer is about 11:00, so I'm off several degrees of rotation. Is TDC for timing purposes when the piston is all the way up, or when the compression is still occuring (pressure against the finger)?

Looks like timing tape may be my solution. Thanks for any help.

Tim

[DAVID GAGNARD]

Tim;


The way I do it is just before I bolt the heads on I add most if not all the front dress and harmonic balancer. Then with my home made tool with a dial indicator I get # 1 to Top Dead Center and set my timing pointer to TDC on the harmonic balancer..... I have had to use different pointers a time or two as I was using parts form different engines. You may find this especailly on Chevy's as they had many different pointer configuratiosn over the years. Ford did also,but I find not as many. Once you have # 1 on TDC and you set the timing pointer to TDC on your harmonic balancer you are sure everything is o-k and can proceed to finish the engine with no worrys about the timing being off when you try to start it the first time.

Also, this is a good check on your timing chain to make sure you are not off a little. If things do not line up or you are not sure it is easier to find the problem now than when the engine is complete and in the car.

A lot of timing chain sets come with three different keyways,straight up,plus 2 or 4 degrees, and minus 2 or 4 degrees. It is not hard to set it plus or minus when putting things together,especially if there are a bunch a guys there to "help".

David

[Tim Votaw]

Good approach, David. I think I'll go back to the basics and work forward. Thanks.

Tim