Boost retard or locked out timing?
 

I have MSD6BTM boxes with the built in retard. The dyno sheets that came with the motors when I purchased the boat say the motors are at 28 degrees total with 1071 super chargers and 7 psi boost. Is the 28 Degrees of timing at max boost once the box pulls out the timing, If so how much timming is being pulled out? I am being told by freinds that I should unhook the boost line to the boxes and run the timing locked at 28 degrees. There reasoning behind this is that if the retard malfunctions I will hurt the motor. Any advise would be appreciated.

The ones I used years ago were a separete component and adjustable with a dial. Evidently these must be some how referenced or done internally???

Maybe PM Griff.

I don't know specifically how the retard works in those boxes.. I like to keep stuff simple. I would just run them locked at 28*. Its not that much timing and shouldn't create problems on start up.

Years back I ran the MSD Boost Retard boxes. Mine were adjustable and would pull back 1-3 degrees per pound of boost.

I was wary of them (as with the entire unreliable MSD) also, disabled the boost retard function and set at 28 total.

Kurt

with 7 psi you should be fine @ 28, 26 may be better, have to be carfull with grade of fuel, just do a plug check and make sure it is not lean..or bad things will happen..

I would not go less than 28. Retarding the ignition causes high exhaust valve temps possibly leading to tuliped or broken valves.

I use to run my BBC in a 22 daytona at 32 locked out. Started up fine and ran fine. 14-71 and 10 psi on pump gas. Owned the boat for 4 years. Never had a problem. It was a lighter boat though.

Thanks for the replies!
The guy that built the engines says if I lock out the timming that I will lose power down low and in the midrange because I am taking the timing curve out,is this true? He says there is still a timming curve in the distributor and that it helps with performance and that the retard just doesnt let it go above 28* at full boost?

I highly doubt you would lose power down low unless he set it up with a lot of timing down low. More timing in the lower rpms adds power. Also it helps it idle smoother. You would need to set the distributor up with no advance curve aka locked and then set the timing at 28*

If your engine builder says locking the advance will hurt the low to mid range..find another engine builder..have that timing in down low will help !!!