Help please - Cam timing experts

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73Grapes

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Hi guys, I bought a 73 dart 340 last summer and never could get it to run right. Motor was "rebuilt" at some point by an engine shop. My buddies and I tore into it this past weekend as one of them suspected that the cam timing was possibly off a tooth. When we pulled the cover it was obvious there was a problem.

The car ran, started fine, idled a bit shaky but idled. It was gutless, and ticked when you got into it. Also the previous owner added a line on the balancer for timing, which was about 30 degrees off from the factory notch.

Any thoughts? Usually it's dot to dot correct?

Thanks in advance,
Robin
 
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Should be dot to dot if #6 is on DTC compression stroke, #1 will also be TDC but not on compression stroke.
 
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Actually... Chryslers ( or should I say the Dodge Brothers ) sprocket dots are top and top on compression stroke. The 2 dots closest together will be the exhaust stroke ( We've went over this a zillion times ). In the end the only difference is in how where when you drop the intermediate shaft and dist' in. If the dots are set dot to dot closest together, 1 crank rotation gets top top. I wont argue that closest together dot to dot isn't the easiest sight. So... build it that way then turn it 1 round if you need to set the rotor at #1.
And as far as it did run but not good... I saw the same in a Ford V6. 3 teeth gone off the crank gear and the chain had jumped about as far off as yours. The owner dialed the dist' far enough to make it run then drove it to the dealership. Top speed was about 25 mph LOL
 
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#6 is compression stroke, not #1, had to edit lol.
 
Seems to me the keyway should be a about 2 O clock and not straight up, so your motor isn't a TDC.
Are you sure that you are using the correct mark as the dot on the crank gear?

See, this is the normal position on the keyway using dot to dot at TDC.

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gtsdude said:
Yes it should be, IF he is on TDC
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Exactly, but it isn't at TDC and his timing mark on the crank sprocket should be about three teeth to the left, which should bring the dots inline when it is at TDC.
 
TDC and dot to dot mark on the lower sprocket should be right here where I put the red dot.

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TrailBeast said:
Exactly, but it isn't at TDC and his timing mark on the crank sprocket should be about three teeth to the left, which should bring the dots inline when it is at TDC.
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I guess I didn't see where the op posted it was at TDC? But yes you got a good pic of what it should look like.
 
Thanks everyone for the replies, I am going to verify whether this lower gear has another dot I couldn't see.
I'm more familiar with SBF's way of cam timing, so thanks for the quick education on how these Mopars work.
 
You need to degree the cam BEFORE you take it apart and see where it's at.


I've assembled many engines where the costs didn't line up.


You have to verify where the cam is at first.
 
yellow rose said:
You need to degree the cam BEFORE you take it apart and see where it's at.


I've assembled many engines where the costs didn't line up.


You have to verify where the cam is at first.
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But were they 3 teeth off? :D
That motor is definitely not at TDC in the pic he posted, but looks like the marks would line up if it was.

Not arguing your point, just noting what I see.
 
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Alright, so we checked with the crank at TDC, both compression stroke for #6 (dot to dot - 6 o'clock and 12 o'clock. And on compression stroke for #1 (dots at 12 o'clock and 12 o'clock). Can't see a problem inside. Next we're going to try to degree the cam and replace the timing gearset as a precaution incase it was off from the factory. ?

Anyone have any thoughts on this? We replaced the entire ignition system with an MSD mechanical advance distributor, msd 6a box, new plugs, wires, changed from eddy 650 carb to a known working Holley 600. The engine still has to run off the yellow painted mark on the balancer as timing point. I believe it takes tons of advance off the scale (stock mark) to run well enough to drive. I'm really frustrated here on what to do next.

Bottom end has good compression. 150psi all around, one has 160 and one has 135. Don't think that's the issue.

72 block /
.020 over Keith black 10.5:1 Pistons
U heads with 2.02 intake valves, which look to have been hogged out both sides. Comp cam xe-262, A904, with 8 1/4 rear open.

Any additional help is greatly appreciated.

Thanks
 
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Did you check your damper to see it was lined up with TDC mark (or zero mark on cover) when number #1 is at TDC compression?
 
X2 check your timing mark at TDC #1 on compression stroke. If it's not lined up, may have an earlier balancer or balancer outside portion has slipped. 69 and earlier had timing marks on other side of the cover with a matching balancer.
 
TrailBeast said:
But were they 3 teeth off? :D
That motor is definitely not at TDC in the pic he posted, but looks like the marks would line up if it was.

Not arguing your point, just noting what I see.
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Had several that were off that far. In fact, one entire summer was wasted fixing stuff because we were not decreeing cams going out the door. And they were using reground cams.


I think to save a core, the regrinders will let the indexing be off to make a grind fit. Just my guess, but I've seen it so many times it's not funny.

As long as the cam is timed correctly you can forget the dots aren't even there. A quality gear drive has no dots. Dots are for the factory to slap an engine together. Anything other than an OEM should be able to degree a cam and should be doing it every time.
 
I think something's off. I'd expect more cylinder pressure with compression above 10:1 and that cam. Degree it as YR says. Don't look at the dots and think it's fine. Degree it and know. Timing marks and tuning aside - mechanically something is not right.
 
What camshaft and initial timing on engine prior to teardown?
 
First find TDC at #1 plug with a dial indicator.
Second check TDC timing mark on damper
Third degree cam with dial indicator and degree wheel.

It does not matter where it is now. Any bent valves or "marks" on the tops of pistons where a valve head may have "touched" it?
 
If it takes 50 degrees initial to run, it sounds like the polarity in or to the distributor is reversed. Try switching the two wires going to the distributor.
 
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