Double Roller Timing Chain - Advance or Retard?

[Duke Nukem]

I'm getting ready to put a 351W into my bronco. I decided to put in a double roller timing chain and I have the option of installing it with 4 degrees advance or 4 degrees retard. What are the pros and cons of setting up the timing chain with advance or retard, or should I just leave it it the middle?

My goal is to simply have a smooth running, reliable engine with good low end power, nothing wild. The engine is set up to be basically stock but will be mass air fuel injected. It is a 69 block with a fresh rebuild, bored .040 over. It will have standard cast iron, flat-tappet heads. I'll be using a mild lift cam and long tube headers. Any recommendations on this?

 

[broncnaz]

Usually the cam manufacturer will recommend what to set it at usually straight up. If you have a cam that is a little bigger than needed you can advance it to get the powerband slightly lower or retard it to move the power band slightly higher. Generally it only moves the powerband a couple 100 RPM so usually straight up is fine if you have the time and like to play with things you can try it in different positions but its usually a lot more work than its worth. If you were racing it might be worht it but in a street/ trail rig it wont make much of a differance.

 

[NoJoe]

x2 like bronconaz said, no advance no retard just straight up and HALF HARD.;D

 

[Broncobowsher]

As they have said, unless you have the wrong cam in it, put it straight up.

If the cam works better at a different advance/retard, they would have simply ground it into the cam that way when they made the cam.

 

[72Sport]

Not sure about 351 but some 302 racing double roller chain are wider than stock.
Check the width of the crank sprocket with your stock one. I bought one that was about .100" wider than stock for a 302. It causes your pulleys to be out of alignment. Might not be a problem with v-belts but serpentine you might not be very happy.

 

[wildbill]

Not sure about 351 but some 302 racing double roller chain are wider than stock.
Check the width of the crank sprocket with your stock one. I bought one that was about .100" wider than stock for a 302. It causes your pulleys to be out of alignment. Might not be a problem with v-belts but serpentine you might not be very happy.

I had to ask How dose a timming chain change the pullies ??:? ?:? ?:? Bill %) ;D

 

[bax]

I had to ask How dose a timming chain change the pullies ??:? ?:? ?:? Bill %) ;D

Good point I was wondering that too.
As far as advance or retard goes. I am a fan of advancing 2 degrees. Bringing the cam in a tad bit sooner helps with some of our low rpm goofin around. Also unless you take the time to degree the cam in on the install you will never know where you are at. Dont think that straight up is always correct.

Bax

 

[Broncobowsher]

I had to ask How dose a timming chain change the pullies ??:? ?:? ?:? Bill %) ;D

The harmonic balancer bottoms out on the lower sprocket. If the sprocket is thicker then the balancer doesn't go on as far. that is how it could happen. The only thick chain set I know of is if you ask for a 289hi-po set.

Note that there are different crank dampers and the motorsports catalog offers spacers to accomidate which balancer/pulley combo you are running.

If need be, it would be easy for a machine shop to trim the back of a balancer to pull it in closer, but I would look real hard for correct parts before machining anything.