total timing too high?

[fryedaddy]

i switched from cj heads to bbm,before it liked 41-42 degree of total timing with my msd pro billet dist.i knew the bbms required less timing.my engine still seems to like 39-40.does that sound ok or too much.need some opinions.

[blykins]

How do you know it likes it? 

[fryedaddy]

from test driving,,hell i dont know,what is normal,i dont have any fancy dynos or expensive gadgets.just the seat of my pants.i have a 25 degree bushing now with 14 int and 39 total.does that sound reasonable,if not any sugestions

[TJ]

I have another question to add... Is it a matter of too much total time or total time is too early?  In other words, perhaps a slower rate of advance is needed? 

I ask not so much to help fryedaddy but rather I'm  hoping for any advice to help my understanding.  The dizzy on my pickup is set up to hit its max advance around 2700 crank rpms.  The dyno showed no more peak power was made above 32 total time.  I've been running 12 initial but seems like other BBM head owners are liking 18-20 initial.  I'd wondering about bumping up my initial but slowing the rate of advance so that I don't hit total time of 32 until a little higher rpm. 

My dizzy already has the heavy springs installed so I can't slow the advance rate anymore.  If I set initial to 18 then I'll be at 32 total time by around 2000 crank rpms.  Seems early to me.

[fryedaddy]

I have another question to add... Is it a matter of too much total time or total time is too early?  In other words, perhaps a slower rate of advance is needed? 

I ask not so much to help fryedaddy but rather I'm  hoping for any advice to help my understanding.  The dizzy on my pickup is set up to hit its max advance around 2700 crank rpms.  The dyno showed no more peak power was made above 32 total time.  I've been running 12 initial but seems like other BBM head owners are liking 18-20 initial.  I'd wondering about bumping up my initial but slowing the rate of advance so that I don't hit total time of 32 until a little higher rpm. 

My dizzy already has the heavy springs installed so I can't slow the advance rate anymore.  If I set initial to 18 then I'll be at 32 total time by around 2000 crank rpms.  Seems early to me.

Ii have 1 lite spring and 1 med spring all in by 25-2700.do you have a 390 or 428,the 390s dont need as much timing as the 428.my engine is running fine,i just want to be safe with my timing settings.i have a spring-bushing kit,i can change them out if i knew which ones would work best for me

[fryedaddy]

.im just your average joe who happens to love and run fe engines for over 40 years with no special tools or skills

[fryedaddy]

want do some of you 428 guys normally set your timing on with bbm heads,initial and total please.

[fryedaddy]

how about a reply or two,i have my dist out today,it would be a good time for a bushing-spring change if i need to.right now it has 25 bushing and 1 lite spring and i med spring

[fryedaddy]

i have my distributor right here on the table laid out with my bushings and springs msd8495 wondering which ones to put in

[plovett]

I've never run or even seen BBM heads, but if they have an efficient chamber that doesn't need a lot of total advance, you want a very fast advance curve.  So if you only need 34 degrees total advance, I'd use the one of the quickest bushing/spring combinations with the MSD distributor.  I think the black bushing has 18 degrees of advance.  I'd use that.  Set your initial timing based on your total.  So you if you need 34 total, set the the initial at 16.  Depending on your combination you can choose springs to bring in the total when you want it.  I'm guessing you want it pretty quick, say in the 2500-3000 rpm range.

JMO,

paulie

[blykins]

Black bushing, set total at 32 degrees and try it. 

I run two light blue springs.   Should be all in by 2500-2600.

[fryedaddy]

i just put the blue one in its 21 degree adv.on a 428 are you sure 32 total is enough.i can take it back out and put the 18 in but i would have to set int timing on 14,is that ok.if im guessing right its not as much the bore and stroke as it is the heads when figuring timing.i going back out to the garage and taking the dist back out.i will put the black bushing in,lite blue springs.it will be 14 int 32 total,if i have to add a couple int,it will still just be 34 total.where is the save zone31-38?i just dont want to mess up a new engine by having the timing off bad

[blykins]

32-34 degrees total is where you need to be. 

I'd use the black bushing....

You don't have to pull the distributor out, you can hot swap the guts with the distributor in the engine. 

[fryedaddy]

just got back in the house after running my engine for a bit.im going the right direction.with the 21 bushing in 14 int and 35 total and the lite springs in,it sounded way crisper when revving.im going to drive it and see how it does before i try the 18 black bushing.BRENT i replied before i read you post.i will put the black one in and make sure its not over 34 when i try it

[blykins]

Give it a shot and try it.  Remember, if the seat of the pants doesn't change (or dyno, or ET) with the total timing pulled back, then it's a win/win situation. 

In a lot of engines that I dyno with BBM heads, the power doesn't change from 32-36 degrees total, but you're always better off with some more toleration to pump gas. 

A quick curve won't show up on the dyno, but it will in the car...