[firstnova2]

Engine is a 355 with 177 weiand blower. Street strip car running 7.6 / 1/8 th mile. Trying to get a little more out of it so got a spring kit for the distributor. The springs that are in it are the heavy silver ones. Timing right now is set at 17 initial and 32 total , all in by 3000 rmp. I want to bring in timing sooner to see if I pick up any thing. I put the two light silver springs in and now timing is at 17 initial but jumps to 38 total without changing anything else. Looking at the msd instructions do I need to change the bushing too in order to limit total timing ? If so which bushing do I start with?

 

[Gr8apmech]

What do the plugs look like?

Do the plugs tell you the engine needs more timing or less?

Read the plugs then go from there to see what timing you need to change. You may need to add timing or reduce initial timing.

Just a suggestion.

 

[J-Rod]

yea you'll want to change the bushing to limit the total amount of mechanical advance

red bushing (smallest) - 28*
silver -25*
blue- 21*
black (thicker) - 18*

SO for example if your goal is 32* total,
initial would be:
red - 4*
silver - 7*
blue - 11*
black - 14*

some places offer a 10* bushing also

**the above example is assuming the vacuum advanced is locked out

 

[firstnova2]

yea you'll want to change the bushing to limit the total amount of mechanical advance

red bushing (smallest) - 28*
silver -25*
blue- 21*
black (thicker) - 18*

SO for example if your goal is 32* total,
initial would be:
red - 4*
silver - 7*
blue - 11*
black - 14*

some places offer a 10* bushing also

**the above example is assuming the vacuum advanced is locked out

Thanks. Thats what I thought by reading msd directions but just wanted to verfy it.

 

[steed]

Mh, strange, that the timing goes up to 38 without changing the bushing. Have you already check the timing with the heavy springs and higher rpm?
I would try one heavy and one light spring first. If the springs are too light, the idle rpm may rise up without any throttle (self experienced ).

Don't go over 36 degrees as maximum.

greets
carl

 

[novaracer1]

Mh, strange, that the timing goes up to 38 without changing the bushing. Have you already check the timing with the heavy springs and higher rpm?
I would try one heavy and one light spring first. If the springs are too light, the idle rpm may rise up without any throttle (self experienced ).

Don't go over 36 degrees as maximum.

greets
carl

I was thinking the same. if all you changed is the springs to a lighter set, then it would bring the total in quicker. That's all that would change.

 

[J-Rod]

i ran into the same issue when i installed a new msd distributor in mine. The factory calibration (chart A) comes with two heavy springs, i mean HEAVY, and the red bushing. The springs are actually so heavy, that the mech. adv. doesnt reach its full curve untill about 5500 rpm.

Take a look at the charts:

so when he installed the light springs it will now allow the full advance cure in by about 2500rpm and picked up those few extra degrees.

 

[bowtie0069]

Joe, I know your little blower doesn't make a ton of boost, but beware of detonation--listen carefully when you make your timing changes. Pull a couple plugs after a pass and see how they look--you don't want to be picking up parts off the track!

 

[firstnova2]

Mike. Whats weird is last time I set / checked my timing I was at 17 initial and 32 total all in by 3200. I changed the springs to the light blue from the heavy silver the other day. I didnt put a light on it until I did the spring swap. With the blue sprngs it was at 38 total. It didnt make sense so I put the heavy ones back in and checked it again. Was still at 38 total. Somewhere along the line my timing has changed. I put the blue ones back and Im pulling a few degrees back out. Everything I read says not to go more than around 32 total. But I guess I have been running 38 for a while and didnt know.Last Thursday at the track I lost about 2/10 on my time and trying to fugure out why. I think bringing in thetimin g faster might help if I dont increase total. Also trying a new carb I had built that is boost referenced