I am having trouble with the farm truck. 1978 Dodge Power Wagon. 318. Took the timing cover off because we suspected that it jumped a tooth on the chain. Well, it didn,t but the chain is stretched BAD. So, I am changing it. I got a Mopar Perf (Melling) double roller timing chain. However, this is where I am confused. Correct me if I am wrong:
You are supposed to put the engine on TDC and then line the sprocket marks up when installing the chain. Crank mark at 12:00, cam mark at 6:00. When the crank is at TDC, the keyway on the crank is at 2:00. When I removed the old timing chain and sprockets, you can plainly see the dimple is at 12:00 on the crank sprocket and the keyway is at 2:00. On the new sprocket, you have three options for timing. 0 degrees, 4 degrees advanced or 4 degrees retarded. I obviously want to use the 0 degree keyway on the crank. The problem is that there is only one dimple (timing mark) on the crank sprocket that is right above the 0 degree keyway. Where I am confused is that this is going to require me to turn the crank way back to line the timing marks up on the two sprockets. IT will no longer be on TDC.

Any ideas? Miss stamped sprockets? Am I missing something?
Thanks,
Jamie

The engine was in time when you took the old set off, I'd just put the new set on without turning anything. You could make your own mark at 12:00 on the crank gear with a center punch or something for future reference if you'd like.

You should find the straight up dot towards outer teeth area of the new gear, a couple of teeth away from keyway. And do not use the dot that is by the keyway. The keyway will be at 1;30 clock position when #1 is at tdc.

Maybe I am missing the mark then. I will check it again.
THANKS!
Jamie

#1 at TDC compression stroke. Install sprockets cam at 6 o'clock, crank at 12 o'clock. I usually lube up the chain as well so it's not dry on start up. Hope this helps.

Above image is showing #6 firing.

I would install the sprockets "on the marks" and then when you reinstall the timing cover and balancer, CHECK TDC.

Use a positive stop:



Put in no1, making sure the engine is NOT on TDC, and there is room for the tool to go in.

Gently wrench the engine around until it stops "on the stop" and make a temporary mark on the wheel right under TDC on the tab

Do the same CCW

True TDC will now be halfway between these two temporary marks, and if the original mark was correct, that is where it will be

You may just be seeing the difference caused by chain stretch

As someone else said, when the marks are "dot to dot" the engine is ACTUALLY on "no6 ready to fire", not no1. If you do not rotate the engine you want the rotor pointing to 6, not 1.

You probably did not pull the dist, so it should be OK except a minor movement to retime (for chain stretch)

Is this thread still open and being read? So should I point my rotor to #6?? I set my marks the same as in the picture above.

My local parts store does not have a positive stop...

Is this thread still open and being read? So should I point my rotor to #6?? I set my marks the same as in the picture above. 12 o clock and 6 o clock, never found out this info until now.

Quote:

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#1 at TDC compression stroke. Install sprockets cam at 6 o'clock, crank at 12 o'clock.

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WRONG !!

This should read #6 at TDC compression stroke.....

It starts and idles fine, so leave it that way or change the dist wire for #1 to #6?

Revs ok, idles with some slight hissing and small pops, has some blowback out of the EGR hose.

Runs awhile then heats up and pings, just put new thermostat in it and have the heater core out.

I did reset the timing some and it heats up sooner than it did, about 1 mile vs. 8miles.

Pings, loses power and heats up. Plugs are very soot filled each time.

Also cannot see my mark with the timing light, solid line across dampener painted white.

But yes when the dots are aligned as in the picture above that is actually firing cylinder #6 , #1 cylinder is at TDC , but on a different part of the stroke cycle.



Yep and thats what make people go hmmmmm.

So #6 wire to the #1 tower? Hmmmmmmmmmmm.....

Since I do not want to tear the timing cover and front end off again, I will just point the dist to #6 because I know for the the gears were cam 6 0'clock and crank 12 o'clock when I bolted it all back together. All this time this little piece of info was missing.

i thought small blocks line up pointing towards each other. big blocks both point up.

Nope both small block and big line up dot to dot and are firing on number 6 when doing so.

If the engine is running at this point no need to do anything. You got lucky.

Other than the heating up issue, loss of power and pinging of valves after a while its fine, I read on another board of a similar issue, they tought it was running too too lean, person swapped out a carb and it fixed it, at this point, I do not want to go chasing my tail, so may play with needle adjustments, rebuilt the carb three times to make sure, put in another step up piston assembly with needles from another carb that may have had good settings, so not sure where to go. I know one thing if I have to pull the timing cover off again (for the third time) I will put in a rougher cam. Current carb is a Carter BDD 2 barrel.